What is the average gain from a cat back exhaust system with down pipe, CAI, and DC headers (i believe those are the best headers right?). I am new to the scion, I had an audi TT 1.8T so I know everything there is to know about the 1.8T engine. Not so much for the VVT-i. Any help will do. Thank you.

 

Im not a 100% sure but I'm thinking anywhere in the neighborhood of 15-20whp possibly depending on what you buy and what type of tranny you have. I have Injen CAI, DC header, Invidia S-pipe and Magnaflow cat back and you notice a pretty good difference in it. I havn't dynoed it yet though so I don't know what it's giving me right now.

 

PLEASE DON'T QUOTE ME ON ANY NUMBERS...

From the other posts that have dyno numbers (that i can remember):

Ingen CAI = 8whp
Tsudo cat-back claims = up to 6-7whp
DC Headers = 10-13 whp
Down-Pipe = (i've seen it somewhere but can't remember gains) i figure 3-5 whp

Even though these number all added up to give you well over 30 whp, when all are combined they usually don't give as much WHP as they say, so you'll probably see 20whp MAYBE more but i DOUBT it.
But it will be enough for you to feel a difference that for sure.

To answer your question about the headers...
DC is IMO the best 4-1 headers, but the best overall is MMW 4-2-1 headers+s-pipe...
I've had/have both on my car so i know from experience, and since you have a 5spd you'll probably see/feel more of the power.

 

At the wheels, you will see MAYBE 10hp. If you start removing your catalytic converters and such and making the car illegal, you'll get more gains, but a chain is only as strong as it's weakest link...

 

^^nah, u'll get more than 10whp from an I/H/E combo with a catback exhaust especially. I'd say with a good CAI + DC Header (as u stated at first) + Catback exhaust...ur lookin at around the 20whp range

 

I agree 10whp is about as realistic as it gets here. Not to mention it will be in one part of the band, so you arent seeing a huge gain overall.

 

I just want to see some dyno numbers. Anyone have access to one (or some spare cash to get some time on a dyno)?

Not that the gains will be that significant, but I'm really curious as to what they are.

 

I'm planning on doing on within the next month hopefully. only 65 bucks for 3 pulls. And I like your sig..."Trust me. I'm a professional" LOL

 

Duh, I don't know why I forgot to mention that. The power isn't going to be where it is most desired. It will be in the high end and the cost of low end power. Good point engifineer.

 

Looking forward to the printout amd!

And I AM a professional! Just nothing to do with automobiles :D

 

Yeah, everything you add that isn't a turbo loses low end and gains high end. Since I spend a good amount of my time up in that range I'm good to go However, I just put on my DC header and Invidia s-pipe today and it actually feels like it smoothed out my power band some. When I just had the CAI and magnaflow on at about 3.5k you could feel it actually pull, no lie. Now with these two additions it mellowed out that "pull" area as far as I can tell so far and gave me almost unbareable rasp...time for resonators LOL.

Kuo just send me a PM to remind you or I'll forget.

 

wow, 10-12whp is not what i was expecting. These parts are going to cost me over a $1,000! My car is bone stock right now, so I think I will just save up and get the TRD Supercharger for $2500. Or maybe even a turbo kit depending on how much they run. I am still trying to keep my car under warranty and with an aftermarket turbo I doubt I will still have my warranty. Thanks guys

 

Not over $1k if you buy used :D Some good, lightly used parts out there for the taking. That and what's your final goal? Are you going to do some competition with it or do you just want lots of horses?

i/h/e keeps me in STS for autox.

TRD super is good and stays under warranty but is rather mild in the boost arena. Aftermarket may void warranty (if it's the cause of failure) and you have to consider buying gauges and supporting mods (clutch, LSD, brakes, etc.) if you're wanting to put it all on the ground. Just stuff to consider.

Keep an eye on the classifieds either way! That's the cheapest way to get quality parts.

 

10-12 at the wheel

 

Dynos are posted here:

https://www.scionlife.com/forums/viewtopic.php?t=89753

You will be lucky to get 15whp from I/H/E. And that's peak, as mentioned you may be sacrificing low-end hp for high-end. Problem is, although you're replacing stock restrictive parts with higher-flowing parts, you're still at the mercy of the ECU and its fuel maps and sensors, especially the MAF.

To get the most out of I/H/E you would need to buy a piggyback controller (Emanage, Camcon, etc.) - which will set you back about $300 - then shell out mucho $$ for professional tuning and dynamometer time. Someone here on SL squeezed another 12whp from their setup with Camcom + 4 hours on the dyno.

If you work at a shop or can somehow get free dyno time that's one thing, for the rest of us it becomes prohibitively expensive for the small gains.

 

On the intake side, "less restrictive" also is a moot point after a bit, since you are not maxing out the system. This is why a CAI gives practically no gain at all in application in our car. The stock intake design is sufficient for the flow our engines create. As for a header, this writeup can explain it better than I can:

http://www.yoursciontc.com/informati...kpressure.html

Most dont truly understand what header design is all about, and the purpose of designing a different type of header for an engine. You are mostly moving power around the band, not gaining power overall. Especially in the newer cars with the engine design tools that exist today. And VVT-i puts more of a hamper on header design as well.

As for exhaust, I have seen cars that benefitted ok from a catback, but most (especially newer) cars already have the exhaust design down pretty well.

As the saying goes, power costs money, so dont expect cheap bolt ons to provide stellar results.

 

^^That is a good article.

And, for those that don't already know, the ECU variable-valve timing schemes are not just on Toyota/VVT-i & Honda/VTEC. Article in August "Road & Track" describes how almost every manufacturer from Ford to Ferrari has some form of it now.

I understand that AEM will be marketing a controller for the tC that allows you to map under all conditions - not just open-loop WOT - but it will cost in the thousands of $$.

Wonder if there be any more-affordable "ECU hacks" on the horizon for our car.

 

I have seen a few i/h/e setups gain 20whp over stock. It is very possible. You also have to remember, we put down 140whp stock, so 20hp from bolt ons is not bad, thats a 15% increase in power. As for the power curve, it depends on your application, though you trade up a little bottom end for the increase on top, you still increase your theoretical output. Yes, I know a case may be made that peak hp is not as important as a power curve, but nonetheless, by no means do you "loose" power. You guys make seem as if it's almost detrimental to upgrade with bolt ons. If you want to take real world application; 15.6-15.8 is 1/4 mile stock run, with bolt ons you are taking it down to 15.1-15.3. Also, engifineer, how do you figure there is no benefit to CAIs in our cars?

 

Detrimental to the city/street drive ability of your car, your car may perform better at WOT from launch and in "spirited" highway driving. But for those that mainly drive city stop and go traffic full bolt ons may "SEEM" to make your car lose power since the low end TQ is the first thing to take a hit in our car...

As far as the CAI thing, our intake flow is limited to the throttle body's flowing capacity(unless you got a turbine cramming air in lol ) so a CAI really won't make a world of difference on its own.Once again our stock air box is not as restrictive as aftermarket manufacturers would like you to believe, it actually works similar to a CAI and with a K&N drop in your about 80% there.

I do believe the combination of I/H/full exhaust together will net you about 15 to 20 whp but i drive 85 to 90% highway and its all in the high end, on city streets i can feel a substantial low end loss.

 

Yea, I know you may have to press the gas slightly more to roll from a stop, that's a given. It's also not that drastic though, we are just accustomed to our torquie tC, even with the slight back pressure loss, we still out torque a lot of cars in our class.

As for CAI, even thermodynamics aside, if you get a short ram you are still increasing the volume of air going into your throttle body. Throttle body is not the bottle neck, its the stock box coupled with the filter. Yes, there are ways to hack it, or you can invest in an after market setup so it's aesthetically pleasing as well.