Very nice writeup by magnaflow.

http://www.magnaflow.com/05news/magazine/05sportc.asp

Great article. Thanks for sharing it. Give me good direction when after I install my header sometime down the road. Will file this one. Thanks :clap:

Your welcome i just hope this answers alot of questions about the myth of "needed backpressure" .

thanks for posting that.

A couple of things it mentioned that I think are worth repeating here for those that won't read the entire article.

A 1.5L engine should be a 2" pipe unless forced induction is used. anything larger will rob power.

The Cat's in today's imports flow so well that replacing them usually won't see any gains and gutting them will most def. see losses.

If you put on a "big ___ tip" you will get pulled over and end up on beaterz.com.

Finally, when using a proper straight threw pipe, length doesn't rob power. So, use as long as possible to keep the noise down.

that link is filled with so much miss information. 18 PSI of back pressue would blow your muffler off. Too funny and you need some backpressure in any non-WOT type of driving where all street cars spend 99.9999% of the time. You get a 5-10 HP at max from a Scion due to a better exhaust with current cams NA, and more of course forced induced. Don't believe me just unbolt your exhaust after the factory header and let me know how "drivable" your ride is with .5 PSI less backpressure....

Why aftermarket exhaust systems are good!

Produced by, and sponsored by- An aftermarket exhaust manufacturer!

that link is filled with so much miss information. 18 PSI of back pressue would blow your muffler off. Too funny and you need some backpressure in any non-WOT type of driving where all street cars spend 99.9999% of the time. You get a 5-10 HP at max from a Scion due to a better exhaust with current cams NA, and more of course forced induced. Don't believe me just unbolt your exhaust after the factory header and let me know how "drivable" your ride is with .5 PSI less backpressure....

18psi will not blow your muffler off. Also that review was written by experts who know quite a bit more than you.

Why aftermarket exhaust systems are good!

Produced by, and sponsored by- An aftermarket exhaust manufacturer!


???????

that link is filled with so much miss information. 18 PSI of back pressue would blow your muffler off. Too funny and you need some backpressure in any non-WOT type of driving where all street cars spend 99.9999% of the time. You get a 5-10 HP at max from a Scion due to a better exhaust with current cams NA, and more of course forced induced. Don't believe me just unbolt your exhaust after the factory header and let me know how "drivable" your ride is with .5 PSI less backpressure....

I think they explained it pretty clearly:

+++++++++++++++++++++++++++++++++++++
"An old hot-rodder's tall tale: Engines need some backpressure to work properly and make torque. That is not true. What engines need is low backpressure, but high exhaust stream velocity. A fast-moving but free-flowing gas column in the exhaust helps create a rarefaction or a negative pressure wave behind the exhaust valve as it opens. This vacuum helps scavenge the cylinder of exhaust gas faster and more thoroughly with less pumping losses. An exhaust pipe that is too big in diameter has low backpressure but lower velocity. The low velocity reduces the effectiveness of this scavenging effect, which has the greatest impact on low-end torque."
+++++++++++++++++++++++++++++++++++++

Makes sense to me.

Why aftermarket exhaust systems are good!

Produced by, and sponsored by- An aftermarket exhaust manufacturer!

:doh: uh.... the article is about building your own exhaust system?

that link is filled with so much miss information. 18 PSI of back pressue would blow your muffler off. Too funny and you need some backpressure in any non-WOT type of driving where all street cars spend 99.9999% of the time. You get a 5-10 HP at max from a Scion due to a better exhaust with current cams NA, and more of course forced induced. Don't believe me just unbolt your exhaust after the factory header and let me know how "drivable" your ride is with .5 PSI less backpressure....

I think they explained it pretty clearly:

+++++++++++++++++++++++++++++++++++++
"An old hot-rodder's tall tale: Engines need some backpressure to work properly and make torque. That is not true. What engines need is low backpressure, but high exhaust stream velocity. A fast-moving but free-flowing gas column in the exhaust helps create a rarefaction or a negative pressure wave behind the exhaust valve as it opens. This vacuum helps scavenge the cylinder of exhaust gas faster and more thoroughly with less pumping losses. An exhaust pipe that is too big in diameter has low backpressure but lower velocity. The low velocity reduces the effectiveness of this scavenging effect, which has the greatest impact on low-end torque."
+++++++++++++++++++++++++++++++++++++

Makes sense to me.


It makes perfect sense because the information is factual and accurate,unlike the information that some self proclaimed experts here in this forum spew.

I've been thinking lately of running a larger diameter exhaust system. I have the Borla axleback but I want to get headers and run custom tubing from the headers to the Borla axleback. Am I going to have to worry about my sensors freaking out and dash lights coming on?

thie means i have to get a new exhaust system when i turbo my car?!?!?!


man...

It makes perfect sense because the information is factual and accurate,unlike the information that some self proclaimed experts here in this forum spew.


Yeh here is the quote: “Some stock mufflers and exhaust systems have up to 18psi of choking, power-robbing backpressure. In direct contrast, a well-designed, high-performance street exhaust system typically has about 2 to 6 psi of backpressure. “


How much is 18 PSI? Well lets see um stock muffler is say 1 foot in diameter cylinder, 2 feet long, Area is PI x Diameter x length = 905 sq inches x 18 PSI = 16290 lbs of pressure pushing out of the case or a little more then 8 TONS. Want me to calculate the CFM flow through the engine to pressurize the exhaust system to that? I think not. Oh and how much backpressure is the “guru” talking about if say I put my hand in back of the exhaust system? 2.25 / 2 sqaued x PI x 18 PSI = 72 pounds of pressure, that is what this “guru” is saying is being run in the pipe and cause of the gas law this is through the whole pipe – some small pressure drop needed to actually flow this from source to sing. LOL too funny!

You want me to calculate the amount of HP loss to 18 PSI of back pressure or how about torque? OK Torque lets see 18 PSI means the piston has to force 18 PSI out the exhaust so um that is
3.48 bore / 2 squared x18 PSI = Force on piston top x moment arm of crank which is idealized as ½ of 3.78 = torque needed to drive piston up the bore against 18 PSI of backpressure or => or 26 ft-lbs. We are not talking torque gain because of better cylinder savaging which most headers and exhaust systems do, we are talking direct pumping loss. I personally think I’d notice +26 ft-lbs across the entire range, but please unbolt your head pipe and drive around for a few days and let us know if you find +26 ft –lbs across the torque range which is 26 HP @ 5250 or 52 HP @ 2700 RPM or 104 HP @1350 RPM BTW. Spanking.

Here is a working model feel free to play with it:
http://www.maxcooper.com/rx7/how-to/fuel_system/why.html

Yes I see that the author probably over exaggerated the restrictions, but this is a much older turbo RX7 TURBO which can use and does need a bigger exhaust.

Um and I’ve used this type of performance gauge and it goes upto 8 PSI!

http://shop.store.yahoo.com/bradystools/exbaprgaotc7.html


Oh and my old favorite is David Vizard here!

http://www.installuniversity.com/install_university/installu_library/back_pressure.htm

street/race car should be at or below 2.2 psi of exhaust backpressure. At anytime if the cumulative back pressure is above 5 psi, the exhaust system needs serious modification.


Like I said in the first post any street legal after cat exhaust system normally aspirated with current cams will show at best .5 PSI Well I did not say it that way but I should have. Point being 18 PSI is completely and totally laughable, which I did say.

Um yes with turbo you should look into something and really I'd start from scratch and do a 3" depending on the turbo and what you are going to do, even at 2.5 (2.75 pipe is not common) you would be butting heads with the exhaust, 3" you would be good to some crazy levels of power. Just my thoughs I've had 2.5 on turbo 4 bangers before most much smaller then 2.4 liters and each time the performace was much better uncapped after the down pipe.

Supercharger to sane levels say 250 BHP, header, 2.5 mandrel is good enough.

For me if I supercharger I want quite, so stock exhaust for me or maybe that cool header with the CAT, but really I don't want anybody knowing I'm packing under the hood. good upto say 225 BHP, after which the exhaust should be address stem to stern.

My point was only that Magnaflow is all over the web page,
and all througout the article.

Convienient that.

thie means i have to get a new exhaust system when i turbo my car?!?!?!


man...

From the charts on the magnaflow site and depending on HP 2.5 should be fine.

thie means i have to get a new exhaust system when i turbo my car?!?!?!


man...

Only if you want to maximize performance.

that link is filled with so much miss information. 18 PSI of back pressue would blow your muffler off. Too funny and you need some backpressure in any non-WOT type of driving where all street cars spend 99.9999% of the time. You get a 5-10 HP at max from a Scion due to a better exhaust with current cams NA, and more of course forced induced. Don't believe me just unbolt your exhaust after the factory header and let me know how "drivable" your ride is with .5 PSI less backpressure....

18psi will not blow your muffler off. Also that review was written by experts who know quite a bit more than you.

For sure magnaflow is interested in telling everybody that backpressure is BS since they want to sell as many low restriction exhaust systems as possible. Right?

Now, since you call them EXPERTS, it would be nice to put them (Magnaflow) in contact with TOYOTA so that way they can tell the SCION Engineers in Japan how wrong they were regarding exhaust systems and how little they know about cars design. Probably Toyota will recognize the big mistake they did.

:rofl:

It makes perfect sense because the information is factual and accurate,unlike the information that some self proclaimed experts here in this forum spew.


Yeh here is the quote: “Some stock mufflers and exhaust systems have up to 18psi of choking, power-robbing backpressure. In direct contrast, a well-designed, high-performance street exhaust system typically has about 2 to 6 psi of backpressure. “


How much is 18 PSI? Well lets see um stock muffler is say 1 foot in diameter cylinder, 2 feet long, Area is PI x Diameter x length = 905 sq inches x 18 PSI = 16290 lbs of pressure pushing out of the case or a little more then 8 TONS. Want me to calculate the CFM flow through the engine to pressurize the exhaust system to that? I think not. Oh and how much backpressure is the “guru” talking about if say I put my hand in back of the exhaust system? 2.25 / 2 sqaued x PI x 18 PSI = 72 pounds of pressure, that is what this “guru” is saying is being run in the pipe and cause of the gas law this is through the whole pipe – some small pressure drop needed to actually flow this from source to sing. LOL too funny!

You want me to calculate the amount of HP loss to 18 PSI of back pressure or how about torque? OK Torque lets see 18 PSI means the piston has to force 18 PSI out the exhaust so um that is
3.48 bore / 2 squared x18 PSI = Force on piston top x moment arm of crank which is idealized as ½ of 3.78 = torque needed to drive piston up the bore against 18 PSI of backpressure or => or 26 ft-lbs. We are not talking torque gain because of better cylinder savaging which most headers and exhaust systems do, we are talking direct pumping loss. I personally think I’d notice +26 ft-lbs across the entire range, but please unbolt your head pipe and drive around for a few days and let us know if you find +26 ft –lbs across the torque range which is 26 HP @ 5250 or 52 HP @ 2700 RPM or 104 HP @1350 RPM BTW. Spanking.

Here is a working model feel free to play with it:
http://www.maxcooper.com/rx7/how-to/fuel_system/why.html

Yes I see that the author probably over exaggerated the restrictions, but this is a much older turbo RX7 TURBO which can use and does need a bigger exhaust.

Um and I’ve used this type of performance gauge and it goes upto 8 PSI!

http://shop.store.yahoo.com/bradystools/exbaprgaotc7.html


Oh and my old favorite is David Vizard here!

http://www.installuniversity.com/install_university/installu_library/back_pressure.htm

street/race car should be at or below 2.2 psi of exhaust backpressure. At anytime if the cumulative back pressure is above 5 psi, the exhaust system needs serious modification.


Like I said in the first post any street legal after cat exhaust system normally aspirated with current cams will show at best .5 PSI Well I did not say it that way but I should have. Point being 18 PSI is completely and totally laughable, which I did say.



Here is another article on the whole backpressure issue. Note this is a naturally aspirated engine unlike you other interactive example which was a turboed engine. The whole issue is backpressure (negative flow) its not necessary ,rather gas velocity and the correlation between pipe size and scanvenging . Thats the key to performance.


Here the link:

http://www.miata.net/garage/KnowYourCar/S4_Back.html.

that link is filled with so much miss information. 18 PSI of back pressue would blow your muffler off. Too funny and you need some backpressure in any non-WOT type of driving where all street cars spend 99.9999% of the time. You get a 5-10 HP at max from a Scion due to a better exhaust with current cams NA, and more of course forced induced. Don't believe me just unbolt your exhaust after the factory header and let me know how "drivable" your ride is with .5 PSI less backpressure....

18psi will not blow your muffler off. Also that review was written by experts who know quite a bit more than you.

For sure magnaflow is interested in telling everybody that backpressure is BS since they want to sell as many low restriction exhaust systems as possible. Right?

Now, since you call them EXPERTS, it would be nice to put them (Magnaflow) in contact with TOYOTA so that way they can tell the SCION Engineers in Japan how wrong they were regarding exhaust systems and how little they know about cars design. Probably Toyota will recognize the big mistake they did.

:rofl:


Our exhaust systems are built to be quiet and perform adequately. They are not designed to be highflowing, this would result in the obvious tradeoff noise. Why do you think aftermarket exhaust systems perform better than the OE units. The engineers at Toyota know this their priority is a balanced system. Before you post make sense and have some sort of valid argument :loser:

that link is filled with so much miss information. 18 PSI of back pressue would blow your muffler off. Too funny and you need some backpressure in any non-WOT type of driving where all street cars spend 99.9999% of the time. You get a 5-10 HP at max from a Scion due to a better exhaust with current cams NA, and more of course forced induced. Don't believe me just unbolt your exhaust after the factory header and let me know how "drivable" your ride is with .5 PSI less backpressure....

18psi will not blow your muffler off. Also that review was written by experts who know quite a bit more than you.

For sure magnaflow is interested in telling everybody that backpressure is BS since they want to sell as many low restriction exhaust systems as possible. Right?

Now, since you call them EXPERTS, it would be nice to put them (Magnaflow) in contact with TOYOTA so that way they can tell the SCION Engineers in Japan how wrong they were regarding exhaust systems and how little they know about cars design. Probably Toyota will recognize the big mistake they did.

:rofl:


Our exhaust systems are built to be quiet and perform adequately. They are not designed to be highflowing, this would result in the obvious tradeoff noise. Why do you think aftermarket exhaust systems perform better than the OE units. The engineers at Toyota know this their priority is a balanced system. Before you post make sense and have some sort of valid argument :loser:

I don't want to make sense MORON, I just want to have fun with people that knows nothing about engineering and do modify their cars losing quietness, LOW RPM TORQUE, and making the iddle rougher in a perfectly working car, just to gain a few horses that show up only in the dyno but that are hard to notice in real world driving.

Probably your car runs always between 4500 and 6500 RPM. Enjoy your ponies. Save money for a new engine.

I am tired on being non-sense. To make sense I am going to stop this by turning off the computer.

Do that makes sense to you? I don't care

:rofl: :rolling: :rofl:

Yes and a Mx-5 likes 2.25 for maximum WOT performance, says nothing about the 99.99999% of the time I just want to drive down the road. I agree with the article but this is NOT the article you posted which clearly stated the 18 PSI was the back pressure of the exhaust and how straight through exhaust is going to get me some big numbers.

The basic fact is most of us have had little Honda 4 bangers with exhaust, intake and larger rims, and most of us have lost to grandma's Accord, Camry whatever too. That blab blab straight through no back pressure exhaust does NOT work where the rubber hits the road and it may barely work in WOT applications that rarely happen.

The Scin tC has a large well flowing OEM exhaust and barring huge cams, headers etc NA, or the above mentioned forced induction there will be little gained but noise from any type of in back of CAT type system, and even a stem to stern optimal build is going to get 15 WHP with stock head and cam NA. This has already been shown with an uncapped race header at WOT. A CAT Header then you are down to say 12 WHP, toss in the optimal exhaust and you are at 10 WHP gain from: header with cat, 2.5 mandrel low restriction exhaust, high flow cat for $1200. While you could save the money and buy a supercharger with a warranty and have buku torque and no blab balb blab sound either. For me I’m waiting for the supercharger, and then maybe a header with CAT. I may give up say 10 to 15 WHP by not running a $1200 system from header back. But the thrill of packing in a sleeper is well worth that. I for one don’t like the blab blab drown of a “performance” exhaust and every performance car I’ve owned I’ve gone through great lengths to have an optimal quite exhaust, which luckily I have bone stock on a tC.

I love the bit about “straight through” core being so much better with flow, yet my favorite packed muffler the dynomax hemi super turbo is the old convoluted path design and no only does it work to quite the exhaust system down to stock Camry levels it has far less backpressure then these straight through jobs that ALLWAYS do a poor job at part throttle drone. You would think this great “straight through” technology doing wonders every OEM would run one especially like say a Z06 Vette and BMW M3. But nope, we all know the OEM runs reverse flow baffled and packed mufflers because they are the only type that work in terms of sound deadening and drone reduction. The day I see an OEM “straight through” design that sounds quite, is the day I’ll change my mind. I see OEM with Iridium and platinum plugs, and syntactic oil, but alas the one of the magic wonders of the automotive world ““straight through” mufflers, goes with the spiral intake turbo, the slick 50, and the Zmax.. Sure straight through mufflers have less back pressure, they also have less sound dampening, and hence are called resonators by the OEM used in conjunction with a normal muffler to dampen harmonics mid stream. Not as a primary rear muffler which is baffled, will always be baffled, has always been baffled.

http://www.dynomax.com/superturbo.stm

and yes that is 410 cfm at 20 inches of water or about .5 PSI and you think you can get less drop / more flow from a "straight through" muffler? The only reason there are fart can mufflers out there is because the is a perception that noise makes power. For me my turbo Integra made 350 Wheel HP with a muffler on it and yes it was Camry quite, my Jetta made 300 ft -lbs to the wheels and yes it was near Camry quite and it used the OEM exhaust with my own hand made down pipe. My Scion tC will be just fine with the factory exhaust upto my listed 225 BHP.

The whole reason for the backpressure thing is that high rpm cams (like in our cars) have longer intake/exhaust valve overlap.

At high rpms this is great for power, but at low rpms you end up sucking some air/fuel out the exhaust.

A limited amount of backpressure will stop so much air/fuel from
flowing out the exhaust, and create slightly more pressure in the cylinder.

This will improve low/mid rpm torque, iddle, emmissions, and fuel mileage at the
expense of high rpm power, unless the restriction is removed at higher rpms.

FOR THAT REASON the muffler in our cars does incorporate a valve that opens at high RPMS reducing backpressure exactly when the engine needs it.

Now, please stop saying that the people at Magnaflow are EXPERTS because it trashes all the hours that REAL and EXPERT engineers have put in designing a nice car, besides the fact that it sounds silly, poor informed and NON-SENSE.
:wink:

but dont the engineers work towards

FUEL EFFIENCY, AFFORDABILITY, OPTIMAL POWER, CARB LEGAL?

all in one?

so when toyota designed the exhaust system wouldnt you think that they made the stock exhaust 2.5 inches to meet all of those?

while an aftermarket exhaust burns more fuel making it INEFFIENT, yet it produces more power it will be harder to legalize and the noise level would be TOO MUCH for the average driver.

so what if toyota did it on purpose?

no mean to flame...

i see the importance of backpressure but i also believe to much will restrict HP/TQ

but dont the engineers work towards

FUEL EFFIENCY, AFFORDABILITY, OPTIMAL POWER, CARB LEGAL?

all in one?

so when toyota designed the exhaust system wouldnt you think that they made the stock exhaust 2.5 inches to meet all of those?

while an aftermarket exhaust burns more fuel making it INEFFIENT, yet it produces more power it will be harder to legalize and the noise level would be TOO MUCH for the average driver.

so what if toyota did it on purpose?

no mean to flame...

i see the importance of backpressure but i also believe to much will restrict HP/TQ

It is much more complex than that. Actual diameter helps maintain a good escape velocity for the gases. If you increase the diameter of the pipe then you end up reducing the speed of the gases, which is not good. A too small diameter for the pipe would be too restrictive hurting the car's performance.

I agree with you regarding design trade-offs. They have to comply with many restrictions accross the country and specially the ones in California for emmisions and sound levels, but the car is designed to comply with regulations and still perform "sporty" at high RPMS. As a matter of fact the tC qualifies as a low emissions vehicle.

I like my car being quiet, but that is just a matter of tastes.

right agreed and the compromise is the exhaust after the stock header is sub 10 WHP, which is fine.

The header is OK from the factory and I see maybe 5 to 10 WHP with an optimal header and CAT, once again the factory compromise some HP for a cooler quiter cheaper factory header (twin wall design). I'm sure OEM it was an expensive header to build. Repacement headers may offer 5 to 10 WHP at a cost of $400+ bucks and will run hotter and will be louder due to their single wall design.

So the factory of course has compromises, but it is really a well engineered piece for a $16,000 car. The Scion is HEAVY runs on plain fuel and is just slightly slower then my GS-R Integra which was way lighter, way more expensive and needed high test fuel and was a masterpiece of design.

The Scion is a very impresive piece all in all, and the compromises were few and far between. Any atempt to gain compromise HP will result in louder and for me that is a no no. I don't want noise.

I see the stock exhaust as a near perfect piece, even upto mild supercharger.

A bit of Googling brings up a number of examples (e.g. beater cars) with measured exhaust backpressure >= 15 psi. Scary to think about but I live one sound wall away from the I-5 and every night I hear plenty of excessive backpressure.

I'm not saying this article will qualify Magnaflow for a Nobel prize but it's the first explanation I've read that jibes with my understanding of fluid dynamics, (If you must know, I got a C+ and that was 18 years ago ...) in particular the Bernoulli equation. It also explains the "observed reality" of wide-open exhausts hurting low-end torque.

So if it's all that easy why don't we see aftermarket exhausts bench-tested this way? My tinfoil-hat theory ... only a few companies can afford that kind of testing, and their marketing departments would rather sell exhausts with technical witchcraft.

Guys, the key is the proper balance. Too much backpressure takes away from performance, just as too little does. You need bigger exhaust in a non-naturally aspirated engine to allow for the increased air flow. But too little backpressure does have a negative impact.

Magnaflow's reasoning does not address engine dynamics as the effect of having a high revs engine in whick intake and exhaust lobes overlap for higher rpm performance, they assume the engine behaves the same at any number of RPMs, but the truth is that flow dynamics at low RPMs are different than flow dynamics at high RPMs. For that reason the model they propose is flawed.

For sure they are going to present a theory that backs-up their products, don't they want you to buy their products? is all marketing tactics.

They are just telling half of the truth and manipulating it so that way people believe in their products, something like.... ooohh, how I didn't realize this before?

They play with the ignorance of the people by putting together a writeup that only very few with enough technical background would argue. Result: minimum bad word of muth regarding their products.

Yes, there are gains in horsepower, but everything comes at a price.

If somebody is expecting to install a low restriction exhaust system, being concious of the price (not cheap), low horsepower gains and drawbacks (torque, iddle, noise) then is fine.

At the end... The Beauty is in the eye of the beholder.

:wink:

yep

Guys, the key is the proper balance. Too much backpressure takes away from performance, just as too little does. You need bigger exhaust in a non-naturally aspirated engine to allow for the increased air flow. But too little backpressure does have a negative impact.

agreed :clap:

If somebody is expecting to install a low restriction exhaust system, being conscious of the price (not cheap), low horsepower gains and drawbacks (torque, iddle, noise) then is fine.
wtf its cheap as hell, take off your muffler and get a muffler shop to make a turn down... $40

idle noise isn't a problem, sure there is some "noise" but if you have the radio on you can't even hear it.
as for low rpm torque "loss", that’s what a manual transmission is for. I highly doubt peak torque has dropped since having no muffler, and I highly doubt peak BHP has increased.
I am an audiophile. I love sound. For me, the noise the car makes now makes driving this car an even bigger joy.
beauty is in the eye of the beholder

For those interested, I’m going to post some sound clips later tonight (probably close to 11pm PST).

If somebody is expecting to install a low restriction exhaust system, being conscious of the price (not cheap), low horsepower gains and drawbacks (torque, iddle, noise) then is fine.
wtf its cheap as hell, take off your muffler and get a muffler shop to make a turn down... $40

idle noise isn't a problem, sure there is some "noise" but if you have the radio on you can't even hear it.
as for low rpm torque "loss", that’s what a manual transmission is for. I highly doubt peak torque has dropped since having no muffler, and I highly doubt peak BHP has increased.
I am an audiophile. I love sound. For me, the noise the car makes now makes driving this car an even bigger joy.
beauty is in the eye of the beholder

For those interested, I’m going to post some sound clips later tonight (probably close to 11pm PST).

We never talked about high RPM torque. The loss of torque with a low restriction system occurs at LOW RPMs.

Again, if people don't mind losing torque on the low end for a gain at the high end, then is OK.

In real life (your car moves) your tailpipe is spewing exhaust into the low-pressure wake of your car ... a cutout spews exhaust into the high pressure air cushion created by lift under your car. Not sure how significant this effect is but it's something a dyno can't simulate.

We never talked about high RPM torque. The loss of torque with a low restriction system occurs at LOW RPMs.


I never said anything about high rpm torque as well. I said I highly doubt PEAK (or the MAX) torque has dropped.

a cutout spews exhaust into the high pressure air cushion created by lift under your car.
VERY interesting point. Gotta find some math guru friends and ask them about that...

We never talked about high RPM torque. The loss of torque with a low restriction system occurs at LOW RPMs.


I never said anything about high rpm torque as well. I said I highly doubt PEAK (or the MAX) torque has dropped.

a cutout spews exhaust into the high pressure air cushion created by lift under your car.
VERY interesting point. Gotta find some math guru friends and ask them about that...

ok

max torque is at 4000 RPM, don't know about you but 95% or more of my time is spent below that range going here and there. Low end torque will go down. I agree with the rest of your statement in general terms.

Yes you can make a cut out for little money, but you ain't even getting a decent tip nor a shop to put on a high quality axle back for $40.00. I can build my own exhaust and have done so. The Scion axle back is um very difficult, you can just go straight back but room for the muffler is limited to some bullet type "straight through" which will be a droner for sure. Or you can go thru a complex curve travers muffler and then a complex curve out, an expensive setup that if not done perfect will rattle. Or you can get a TRD setup with the T muffler. There are some expensive side in side out chamber mufflers too. All in all it ain't cheap to do it right hence IMO the TRD offers the best compromise and minimal WHP IMO.

Look max pressure at the front of the car is say .5 PSI at 120 MPH. Rear trail vacuum is less then that. At say 50 MPH it will drop to immeasurable readings unless you have a namometer. Under the car is a low pressure area too. I would not suggest an exhaust pipe facing straight forward, but there is really no gain from any type of air movement extractor design despite what some tips makers claim. But yes at high speed with the proper placement there is so minimal gains, rule of thumb just don’t face them forward!

How much is 18 PSI? Well lets see um stock muffler is say 1 foot in diameter cylinder, 2 feet long, Area is PI x Diameter x length = 905 sq inches

Actually, Area of a cylinder = PI x Radius ^2 x length. So your example here starts @ 864 sq.in.

How much is 18 PSI? Well lets see um stock muffler is say 1 foot in diameter cylinder, 2 feet long, Area is PI x Diameter x length = 905 sq inches x 18 PSI = 16290 lbs of pressure pushing out of the case or a little more then 8 TONS. .

oh my god, have you ever heard of Pascal's Law?

you're a science-moron..

JLTD Actually, Area of a cylinder = PI x Radius ^2 x length. So your example here starts @ 864 sq.in.


JL, actually that's the volume here it is:



The volume of a cylinder equals the (area of the base)*height = r2h


http://www.aaamath.com/geo79-volume-cylinder.html

Simple mistake, I make them all the time.



Tamago oh my god, have you ever heard of Pascal's Law?

you're a science-moron..

First off Tamago means egg in Japanese. FWI So that means: I’m not only a science wiz, I can weld, make exhaust systems teach graduate level science course and um know Japanses too. Can’t write but hey.

Now to you:

http://www.aaamath.com/B/geo79x10.htm

Here The surface area of the side is the circumference times the height or 2 PI r h

two PI radius Height = PI diameter height = PI diameter length if the cylinder is laying flat which it is.

As I already calculated. QED

Oh and what does Pascal's law have to do with simple area calcs? NOTHING . Obviously I’ve have correctly applied ye old Pasal’s law to the internal surface and just as Mr Pascal stated the pressure is EVEN within the muffler – some minor pressure differential due to restriction and flow propagation heat rejection via the muffler body. Pascal’s law applied correctly to the area of the cylinder not the volume as the previous poster INCORECTY tried to do by squaring the radii.

I WOULD SAY YOU JUST GOT OWNED!!! :ttth:

Here’s Pascal’s law: http://www.britannica.com/ebi/article?tocId=9312902 and I should note it deals with working media: ONLY in a sealed container, not moving hot air with an entry and exit, and is NOT entirely true.

How much is 18 PSI? Well lets see um stock muffler is say 1 foot in diameter cylinder, 2 feet long, Area is PI x Diameter x length = 905 sq inches x 18 PSI = 16290 lbs of pressure pushing out of the case or a little more then 8 TONS. .

this is sooooo flawed..

8TONS OF PRESSURE??

how does 18PSI EVER CREATE 8TONS OF PRESSURE? 18PSI is 18PSI.

there is 18PSI pushing on each and every surface of the supposed muffler, not 8tons.

using your theory, if i blew into a balloon til i reached 3PSI, that the air would somehow intensify to TONS OF PRESSURE, the balloon would explode and kill me..

FORCE = PRESSURE X AREA, not PRESSURE X VOLUME

i think you just OWNED YOURSELF

How much is 18 PSI? Well lets see um stock muffler is say 1 foot in diameter cylinder, 2 feet long, Area is PI x Diameter x length = 905 sq inches x 18 PSI = 16290 lbs of pressure pushing out of the case or a little more then 8 TONS. .

this is sooooo flawed..

8TONS OF PRESSURE??

how does 18PSI EVER CREATE 8TONS OF PRESSURE? 18PSI is 18PSI.

there is 18PSI pushing on each and every surface of the supposed muffler, not 8tons.

using your theory, if i blew into a balloon til i reached 3PSI, that the air would somehow intensify to TONS OF PRESSURE, the balloon would explode and kill me..

FORCE = PRESSURE X AREA, not PRESSURE X VOLUME

i think you just OWNED YOURSELF

As much as I hate to get into all of this:

He did not say TONS of PSI, he said tons of pressure. There is a difference depending on what you are relating the pressure to. And yes, Force = Pressure X Area... that would be SURFACE area inside of a volume.

But, as many who have actually built and tested motors know, backpressure does make a difference, so calculating all the results is redundant, and of course Magnaflow is going to give you answers that support their products. Common sense. Now stop bashing each other over something so completely ignorant!!!

How much is 18 PSI? Well lets see um stock muffler is say 1 foot in diameter cylinder, 2 feet long, Area is PI x Diameter x length = 905 sq inches x 18 PSI = 16290 lbs of pressure pushing out of the case or a little more then 8 TONS. .

this is sooooo flawed..

8TONS OF PRESSURE??

how does 18PSI EVER CREATE 8TONS OF PRESSURE? 18PSI is 18PSI.

there is 18PSI pushing on each and every surface of the supposed muffler, not 8tons.

using your theory, if i blew into a balloon til i reached 3PSI, that the air would somehow intensify to TONS OF PRESSURE, the balloon would explode and kill me..

FORCE = PRESSURE X AREA, not PRESSURE X VOLUME

i think you just OWNED YOURSELF

As much as I hate to get into all of this:

He did not say TONS of PSI, he said tons of pressure. There is a difference depending on what you are relating the pressure to. And yes, Force = Pressure X Area... that would be SURFACE area inside of a volume.

But, as many who have actually built and tested motors know, backpressure does make a difference, so calculating all the results is redundant, and of course Magnaflow is going to give you answers that support their products. Common sense. Now stop bashing each other over something so completely ignorant!!!

there's STILL NOT TONS OF PRESSURE..

how else is pressure measured?

Oldman, engifneer, and niguels seem to get the big picture here. If you want a race car, build a race car! If your starting point is an Xb you're ____ing in the wind. Disapointment will be your fate. All these HP figures measured at the brochure are not worth the ink it took to print them. Try all these great ideas and report your findings back to us all so we can benifit from your ignorance. If you truly understand physics and internal-combustion engine dynamics you will understand, If your knowlege consists of a stack of brochures you read and reapeat at will, I would suggest some proper education. Just a thought.

Thanks for the clarity. I should add I’m not bashing anybody, I politely corrected somebody who incorrectly thought I made an error. My calculations were as usual precisely correct. I should point out that Tamago started with the name calling and I for one don’t like to be called a “moron”, especially by somebody who obviously has a tenuous grasp of physics and the application there of. I was more the proper with my reply and will continue to do so. IMO you go around calling your peers “morons” you better have your act together.

We all agree that backpressure effects engine performance, a dynomax superturbo can flow 410 CFM of air at .5 PSI of backpressure, be quite as stock, cost $50.00 and cost to install including a crush bent 2.5 inch pipe and a neat slash tip is sub $100.00. Power gain over stock OEM non-TRD um safe to say less then 5 WHP, IMO maybe ½ that, and only in the upper RPM ranges. System would flow enough for even mild turbo applications I ran one on my T04e Integra GS-R, stock quite, brutal HP even capped, 350 WHP capped up plain fuel, 400 WHP+ uncapped at the down pipe 3” with race gas. Big gains in response uncapped but loud too (even with the turbo).

there's STILL NOT TONS OF PRESSURE..

how else is pressure measured?

sighhhh...... 10PSI applied to a 10 Sq Inch surface = 100 lbs of force.... It is not measured differently, and I am not trying to validate or invalidate the calculations. What I am saying is that 18PSI does not mean that the system has 18lbs of force on it. It is 18lbs per every sq inch of surface area.

exactly. i agree. there are 18PSI pushing on each and every surface of the canister..

now :) factor in atmospheric pressure :)

exactly. i agree. there are 18PSI pushing on each and every surface of the canister..

now :) factor in atmospheric pressure :)

Ok, you are making no logical sense at this point, so I will let you guys argue it amongst yourselves now. Have fun.

Call me crazy but I think I'll trust the opinions of the 2 engineers (engifineer, oldman). :D

i'm an industrial hydraulic engineer, and believe me, what we're talking about is VERY relavent in industrial hydraulics

exactly. i agree. there are 18PSI pushing on each and every surface of the canister..

now :) factor in atmospheric pressure :)

Ok, you are making no logical sense at this point, so I will let you guys argue it amongst yourselves now. Have fun.

can someone please expain the 8TON THEORY to me first?

then we'll talk about atmospheric pressure.

Dude, pounds or 2,000 pounds = 1 ton have been used in traditional lingo aka common everyday plain simple easy to understand English to be a unit of mass and a unit of force. So pounds or tons of pressure x area does indeed = force which can be measured in POUNDS or TONS since it would still retain this unit of measure and also retain the units of time squared.

Look at my exact words: 16290 lbs of pressure pushing out of the case

Obviously this is FORCE I have even included the vector of said force being the summation of the normal angle out of the case. QED

YOU HAVE BEEN OWNED ONCE AGAIN :loser:


Right from a definition page on Physics:

pound force (lbf) convert
A unit of force. Traditional measuring systems did not distinguish between force and mass units. Pound force is the gravitational force experienced at the Earth's surface by a mass of one pound. Following Newton's law F = ma; one pound of mass is 0.453 592 kilogram multiplied by the acceleration due to gravity 9.806 65 meters per square second equals 4.448 221 615 newtons. The symbol lbf should be used for the pound force to distinguish it from the pound of mass.


The “8 ton theory” is that if there really were 18 PSI of pressure, which is above atmospheric just for Tamago’s FYI, in the exhaust system as backpressure. Then the force on large exhaust system components would be so incredible that it would blow them up, (being made out of cheap tin gauge steel and all). Since you don’t see mufflers, CATs, composite exhaust gaskets and the like just flying apart all over the road. You can rest assured there is NOT 18 PSI in the exhaust system.

I have blown up many mufflers with my 440 Mopar. But ahem that is another story.

Tamago :ttth:

The 18psi thoery makes sense if there were no outlet to the muffler but since there is, there's no way that much pressure could build up in the exhaust. I'd imagine no exhaust could be so restrictive to allow that kind of pressure build-up. So if you plugged your muffler to allow such a build-up of pressure, something would blow.

Like with an air compressor, it builds pressure because the air has no place to go. But if you open the release valve, the pressure would drastically drop and never build. 18psi in a tire is capable of holding up a 2ton automobile (yes I know the avg 30psi). So Tamago, since you work with hydraulics, what would the dimensions of a hydraulic cyclinder be to lift 8tons with 18psi?

Now I'm no engineer nor am I a physics major, this is just what I'm gathering from this conversation.

Dude, pounds or 2,000 pounds = 1 ton have been used in traditional lingo aka common everyday plain simple easy to understand English to be a unit of mass and a unit of force. So pounds or tons of pressure x area does indeed = force which can be measured in POUNDS or TONS since it would still retain this unit of measure and also retain the units of time squared.

Look at my exact words: 16290 lbs of pressure pushing out of the case

Obviously this is FORCE I have even included the vector of said force being the summation of the normal angle out of the case. QED

YOU HAVE BEEN OWNED ONCE AGAIN :loser:


Right from a definition page on Physics:

pound force (lbf) convert
A unit of force. Traditional measuring systems did not distinguish between force and mass units. Pound force is the gravitational force experienced at the Earth's surface by a mass of one pound. Following Newton's law F = ma; one pound of mass is 0.453 592 kilogram multiplied by the acceleration due to gravity 9.806 65 meters per square second equals 4.448 221 615 newtons. The symbol lbf should be used for the pound force to distinguish it from the pound of mass.


The “8 ton theory” is that if there really were 18 PSI of pressure, which is above atmospheric just for Tamago’s FYI, in the exhaust system as backpressure. Then the force on large exhaust system components would be so incredible that it would blow them up, (being made out of cheap tin gauge steel and all). Since you don’t see mufflers, CATs, composite exhaust gaskets and the like just flying apart all over the road. You can rest assured there is NOT 18 PSI in the exhaust system.

I have blown up many mufflers with my 440 Mopar. But ahem that is another story.

Tamago :ttth:

18PSI is 18 PSI.. there is 18 pounds of pressure per square inch of surface area in the muffler. this number is not additive. you cannot multiply 18PSI (which is POUNDS PER SQUARE INCH) BY THE VOLUME OF THE CYLINDER MUFFLER AND GET ANY USEABLE NUMBER.

i will give you an example of your theory being incorrect..

ready?

ok.. water hose.. 1/2" ID
water pressure. 40PSI
water hose length: 50 ft

according to your theory, there would be .. let's see.. .5X.5X.7854 (the easy way to find area) X (50 X12) 117.81 LBS OF FORCE pushing out on the interior of the hose.

now.. what if the hose is 2,000 feet long?

your number is now 4,712.4 POUNDS OF FORCE pushing out on the interior of the hose.

so.. my garden hose is now 3FT in diameter to withstand the 2.3 TONS of force being exerted against it?

:rofl: :rofl: :rofl:

i bow to your superior brain power :bow: :bow: :bow:

So Tamago, since you work with hydraulics, what would the dimensions of a hydraulic cyclinder be to lift 8tons with 18psi?.

Force = Pressure X area

so.. we know force and pressure

16,000 / 18 = 888.89 SQUARE INCHES.

(SQRT of (888.89 /.7852) = 33.64
with 18 PSI and no fudge factor for friction, a 33.64" diameter cylinder with 18PSI would lift 8tons.

Thanks for answering, so based on circumstance you're both technically right. oldman's is right but his calculation is based on a closed cylinder. So based on your answer if you had a hydraulic cyclinder roughly the size of the muffler in his calculation then technically it's feasible to exert 8tons of force. So in this case oldman is stating that it's impossible to build 18psi in an exhaust which is also technically right. Since the exhaust is open, the pressure cannot build that high, so therefore 18psi of backpressure is not happening.

:yawn:

-THE DON

Thanks for answering, so based on circumstance you're both technically right. oldman's is right but his calculation is based on a closed cylinder. So based on your answer if you had a hydraulic cyclinder roughly the size of the muffler in his calculation then technically it's feasible to exert 8tons of force. So in this case oldman is stating that it's impossible to build 18psi in an exhaust which is also technically right. Since the exhaust is open, the pressure cannot build that high, so therefore 18psi of backpressure is not happening.

no. you cannot exert 8 tons of force with a muffler. there is not 8 tons of force pushing out on a mufller wall.. there would be 18PSI

now, to totally throw this ENTIRE ARGUMENT OUT, there wouldn't be 18psi AT THE MUFFLER ever anyway.

the only place that would feel the 18PSI woudl be at the exhaust manifold...

thanks Miller, and just about everyone else,

um Tamago :ttth:

The Don I agree Oldman :yawn:

Thanks for answering, so based on circumstance you're both technically right. oldman's is right but his calculation is based on a closed cylinder. So based on your answer if you had a hydraulic cyclinder roughly the size of the muffler in his calculation then technically it's feasible to exert 8tons of force. So in this case oldman is stating that it's impossible to build 18psi in an exhaust which is also technically right. Since the exhaust is open, the pressure cannot build that high, so therefore 18psi of backpressure is not happening.

no. you cannot exert 8 tons of force with a muffler. there is not 8 tons of force pushing out on a mufller wall.. there would be 18PSI

now, to totally throw this ENTIRE ARGUMENT OUT, there wouldn't be 18psi AT THE MUFFLER ever anyway.

the only place that would feel the 18PSI woudl be at the exhaust manifold...

So basically you agree with everything I just said.

um Tamgo :ttth:

poor old man.. you know i'm right.

It wasn't explicitly stated that 18psi was measured at the muffler ... I'd imagine that could have been measured anywhere downstream of the collector. 18psi overpressure x 3.14 x (2.5/2) ^2 = 88.3 lbf.

And a lot of the discussion here seems to center around principles that apply for (purely theoretical) incompressible fluids at rest in thermal equillibrium ... sure, it's easy to predict the behavior of an ideal situation at rest with Discovery Kids-level science, but hot, compressible exhaust gases in motion are another matter entirely. Maybe I should just STFU and leave it to "real" engineers. ;-)

Tamago, you should have paid more attention in school! It is not 18PSI X Volume = force it is SURFACE AREA X PRESSURE. Would you believe that 9PSI would crack the wing of a 747? You bet! surface area X pressure. But basicly the moral of the story is that while some people think HP gains are cumulative of brochure numbers added at will, reality dictates that there was not a lot of "free" HP left on the table when Toyota designed the powertrain of our cars and you would be hard pressed to make any significant gains cheaply.

[quote="Tamago"][quote=jmiller20874] Since the exhaust is open, the pressure cannot build that high, so therefore 18psi of backpressure is not happening.

read what you wrote backpressure.

it is possible to have 18psi of backpressure..

let's say my 2.4L compressor makes 430 CFM..

and i allow 120CFM to escape through my 25FT exhaust with a 1" diameter.... (which, btw would create a 1/4PSI pressure drop

what would be the pressure at the HEAD of the exhaust line..

ZERO?

no.. the compressor is filling the "tank" faster than i can get rid of it.. i will not push 430 cfm through the 1" tube without a rise in pressure, because line velocity and friction will dictate so.

ok, here's an easy one for you..

go to your water hose.. turn it on, and watch the flow come out of the hose.. it goes maybe 3 ft right? what is the pressure inside the water hose AT THE FAUCET?

now.. put your thumb over the end of the hose, and allow only a small portion of water to come out..

it goes a LONG way!!!

what is the pressure inside the hose AT THE FAUCET NOW?

higher, right? this is how you can create backpressure in an exhaust system. (and i'll bet that Magnaflow used some V8 from the 80's with two dinky 1/1-2" exhaust pipes and huge restrictive mufflers to get their 18 PSI, which IS a pretty high number)

although the theory is about water, it does apply to air as well, minus factoring in the compressibility of air....

Scott: true dat, amen brother.

Dude, you know where you can put that hose. I was making an arguement in your favor in case you didn't realize it. I know pressure is highest at the faucet, my god man what the hell do you take me for? Of course I know 18psi is possible at the manifold.....ah fu@# it, I give up.

Tamago, you should have paid more attention in school! It is not 18PSI X Volume = force it is SURFACE AREA X PRESSURE..

Scott, you really should have paid attention when reading my responses. i never once said that FORCE = pressure X VOLUME. in fact, i said the exact opposite. i was trying to figure out how oldman thinks there are tons of pressure pushing out on the walls of a muffler.

force = surface area X pressure.. let's play with that..

if i take a ball with an inside surface area of 100 sq inches, and pressurize it to 10 psi, am i creating 1000 POUNDS of force? no! i am not!

Of course I know 18psi is possible at the manifold.....ah fu@# it, I give up.

you just got done saying that 18PSI backpressure is not possible.. now you agree with me?

cool :rofl:

Of course I know 18psi is possible at the manifold.....ah fu@# it, I give up.

you just got done saying that 18PSI backpressure is not possible.. now you agree with me?

cool :rofl:

I meant at the muffler, damn, blow it out your exhaust :D.

the muffler is too close to the atmosphere to ever see 18PSI .. but we all know that, and we should realize that's not what magnaflow was trying to say.

Tamago, you should have paid more attention in school! It is not 18PSI X Volume = force it is SURFACE AREA X PRESSURE..

Scott, you really should have paid attention when reading my responses. i never once said that FORCE = pressure X VOLUME. in fact, i said the exact opposite. i was trying to figure out how oldman thinks there are tons of pressure pushing out on the walls of a muffler.

force = surface area X pressure.. let's play with that..

if i take a ball with an inside surface area of 100 sq inches, and pressurize it to 10 psi, am i creating 1000 POUNDS of force? no! i am not!

Actually, yes you are... it is distributed over the surface. the overall force does equal that... but since we have a little thing called equilibrium, nothing bad happens. Simple physics.

the muffler is too close to the atmosphere to ever see 18PSI .. but we all know that, and we should realize that's not what magnaflow was trying to say.

thats wat jmiller said,

Tamago, you should have paid more attention in school! It is not 18PSI X Volume = force it is SURFACE AREA X PRESSURE..

Scott, you really should have paid attention when reading my responses. i never once said that FORCE = pressure X VOLUME. in fact, i said the exact opposite. i was trying to figure out how oldman thinks there are tons of pressure pushing out on the walls of a muffler.

force = surface area X pressure.. let's play with that..

if i take a ball with an inside surface area of 100 sq inches, and pressurize it to 10 psi, am i creating 1000 POUNDS of force? no! i am not! YOU should have paid more attention to the last sentance of my post! Now go sit in the corner till I say you can come out! :rofl: Go buy yourself a bushel of magnaflow mufflers and give them out as Christmas presents for all I care, but you still won't have a race car . :rofl: PS- save the money from one of those muffler purchases and buy a good physics book! :lalala: :rofl:

Gentlemen, you all, please calm down. The situation is getting out of control and the thread is getting away from its initial purpose.

The goal here, IMO is to put pieces of information together so that way everybody can find a benefit from colective knowledge.

Then, once people is educated, it is possible to perform a critic reasoning in order to tell what is the truth, what are convenient half truths and what are lies.

When I write for this thread my intention is not to tell the people not to buy a certain brand. What I try to do is to give others arguments that can help them to make an informed decision.

Please, for everybody that is going to keep posting to this thread, bring information that sheds light over the main issue of the thread. If anybody has actual data, INDEPENDENT NUMBERS OR GRAPHICS, please share it with us.

If somebody has a relative or friend that is actually working in an engineering position for any car manufacturer, please invite him/her to share what they know with us and know the truth "from the horse's mouth"

Thanks for reading :idea:

that link is filled with so much miss information. 18 PSI of back pressue would blow your muffler off. Too funny and you need some backpressure in any non-WOT type of driving where all street cars spend 99.9999% of the time. You get a 5-10 HP at max from a Scion due to a better exhaust with current cams NA, and more of course forced induced. Don't believe me just unbolt your exhaust after the factory header and let me know how "drivable" your ride is with .5 PSI less backpressure....

18psi will not blow your muffler off. Also that review was written by experts who know quite a bit more than you.

For sure magnaflow is interested in telling everybody that backpressure is BS since they want to sell as many low restriction exhaust systems as possible. Right?

Now, since you call them EXPERTS, it would be nice to put them (Magnaflow) in contact with TOYOTA so that way they can tell the SCION Engineers in Japan how wrong they were regarding exhaust systems and how little they know about cars design. Probably Toyota will recognize the big mistake they did.

:rofl:


Our exhaust systems are built to be quiet and perform adequately. They are not designed to be highflowing, this would result in the obvious tradeoff noise. Why do you think aftermarket exhaust systems perform better than the OE units. The engineers at Toyota know this their priority is a balanced system. Before you post make sense and have some sort of valid argument :loser:

Did you read my post titled "BACKPRESSURE-Final Words"

http://www.scionlife.com/forums/viewtopic.php?t=47877

Read it and tell me now who do you think knows more about cars design, the TOYOTA ENGINEERS or the HALF TRUTH TELLERS AT MAGNAFLOW.

:wink:

mygod people, did this turn into math class?

i almost forgot what the topic of this thread was.

And the point of digging up this thread was??? :ponder:

And the point of digging up this thread was??? :ponder:
so that I could bump it a year and a half later.

so 2.5 is ok with n/a?.....people here are too smart we only need simple answer yes or no...

I've been thinking lately of running a larger diameter exhaust system. I have the Borla axleback but I want to get headers and run custom tubing from the headers to the Borla axleback. Am I going to have to worry about my sensors freaking out and dash lights coming on?

If you pay attention to what the article says, it's basically saying for N/A keep smaller diam piping and use a straight through design, rather than Larger piping.

Just trying to point that out.

Yes, 2.5 inch exhaust is all you should need for NA on this car, or for almost all turbo setups on this car as a matter of fact.

If you go more than 2.5" on an N/A, you will LOSE power.

If you don't think backpressure is important, run open headers and go to a dyno. Maybe then the ricers on this board will shutup.

All the people who already know this, thank you for raising the intelligence level on these forums! Maybe one day everyone on this board will be educated. :)

And the point of digging up this thread was??? :ponder:
so that I could bump it a year and a half later.

WTF?? :rofl: Put the stirring stick away...

Well, since this thread has been rehashed by Most Hated Local Boy...

Why would anyone believe an article products that was written by or published or whatever by a company that produces said products? Would you believe Phillip Morris if they put an article on their webpage that smoking prevents lung diseases & cancer, and promotes healthy breathing? How about a study concluding that drinking excessively doesn't make you drunk and its okay to drive by Segrams or whoever? Folks just don't understand that you can't believe everything you read on the internet.
For those that do, I've got a product that will give you 20% more fuel efficiency just by creating a 'tornado' in your intake tubing! Available today only for a low introductory price of $128, introducing the Turdnado! But wait, that's not all. Order in the next 12 hours and I'll send you *two* Turdnados so you can double your fuel efficiency!

LoL... :rofl: ...At the Turdnado's!!!

I could tell a huge difference in torque down low when I ran open downpipe on my 240sx, more horsepower up top. It felt dead until I got above 4k.

Just what I've felt with my ___-dyno though.

wow what a sh*tty thread...