acasanova

Hey everyone, i decided to go perform a few tests on underhood air temperatures and found very interesting results. I got a hold of a digital Temperature probe normaly used for measuring ambient temperatures inside my PC. Decided to place it right on the filter and measure Temps both while in motion and idle. The results where very interesting.

Temp: http://home.comcast.net/~miamiprep1/pic_2.jpg 81.2 high humidity South FL.

Location of probe: http://home.comcast.net/~miamiprep1/pic_1.jpg

Temp of air on filter while idle for 2 minutes hood down of course http://home.comcast.net/~miamiprep1/3.jpg

Took the car out, and as soon as speed increased past 15mph temp started to drop rapidly temperature under the hood around the filter area is actually almost as cool as the outside air when the vehicle is traveling past 44mph

http://home.comcast.net/~miamiprep1/5.jpg at 60 mph : http://home.comcast.net/~miamiprep1/4.jpg it is just as cool. After a bit of heavy acceleration and stopping, i let the car idle for 5 minutes these were the temps on the surface of the filter. http://home.comcast.net/~miamiprep1/8.jpg . I understand these conditions are far from ideal ,fairly cool 80 degrees and not under controlled scientific parameters but it gives me an idea of what goes on under the hood as far as Temperatures. The short ram while at speed should perform very similarly to the CAI, especially on a cool night. Although temps soar when idle as soon as the vehicle is in motion temps drop rapidly. Also placed the Probe in the fender area where the CAI filter would rest. Temps in the fender also rose but where more stable about 10 to 15 degree difference.

Dr_Isotope

iTrader: (1)

I'm using a ScanGauge, which can show the Intake Air Temp (IAT) as taken from the factory IAT sensor. With the OEM air intake equipment, the IAT will show 2-3º above ambient while cruising, and 8-12º above ambient when temps rise above 100º. Same heatsoaking issues at idle. The only way to prevent that would be to draw air from outside the car, and to wrap all of the underhood piping in heatwrap to prevent any soak from occuring there.

It's as I've said before: the advantage of the CAI is in the tuned length of the pipe, not in the temperature of the air it provides. The same goes for the shortrams. Bottom line-- at least for me-- no CAI or SRI without CARB approval is worth $200+... and with a peak gain of 5-6hp, the $$$ per HP ratio isn't very good.

jrv2000

So then would the CAI be better since it is constantly sucking in cooler air, unlike the SRI that only gets cool air when you are moving?

acasanova

It should do better but the fender area was also quite warm . But cooler by 10 to 18 degrees. I would try the CAI but i live in south FL seen the puddles?

The_Instigator

That makes no sense at all. Why woudnt they call it a tuned length intake then if that was so important. Its not like tuned length headers that actually do make a difference. Cold air makes more power and that has been proven ad nauseum. Intake length may have some difference, but if tuned length was important, why would every intake manufacturer advertise as having cold air intake? Another point is that SRI and CAI make the same amount of power (within 1-3 hp) which is negligible. If length mattered so much, there should a much greater difference in hp between the two.

TheScionicMan

I've been meaning to run a similar test on the xB. Very interesting...

part of it depends on what type of driving you're doing. If you're auto-xing or track racing, the SRI will work just as good, but think about the 1/4 mile. Lot's of idling waiting to get staged. Pull up to the line, engines hot. That's when that CAI is going to help you out more, IMO.

as a formula, the peak hp gain per $$ may not equate, but the difference is pull across the power band is worth it to me. Plus it looks good when the hood is popped.

Dr_Isotope

iTrader: (1)

They advertise it as a cold air intake because the buying populace, by and large, knows nothing of how a part benefits their car. The buyer tends to like nifty annodized aluminum tubing.

And there is that much of a difference-- along pipe CAI will often peak at double the production of an SRI, while their average gains may be very much the same. AEM has made their fortune off of that famous "hump".

I look at the intake as an entire system; you can't just replace 2 feet of piping and expect the world to pass by in a blur. The breathing of a motor is only as free as the most restrictive point. You can do very little on the upstream side of the TB-- it all comes down to how fast you can cram air through that opening. Long pipe air velocity is faster than short pipe air velocity. Tuning the length is tricky, and is dependent on so many variables that it's nearly impossible to sell a product that can back it's manufacturers claims. Any variable, from ambient temp to spark plug gap, will adversely or positively affect the output.

The best option for an intake is one that draws from the cowl. Aside from old skool muscle, how many cars do you see drawing from the cowl? Air temperature is a fine and dandy point to throw around when trying to sell an intake... when performance wise, it doesn't even really matter-- especially to those of us making 140whp. It will have some impact at higher HP ratings, but take a look at track cars. They care little about intake temp, and entirely about intake volume. 3-5hp is variance. Even 10-12hp on a car making 300+ could be attributed to an underinflated tire or a bad plug.

Don't try to confuse manufaturer claims with mechanics. They want to sell products. The CAI, in 90% of instances, offers a 1-5% increase in peak HP, with a dramatic increase in the chance of hydrolock. It's not worth it.

I watch air temp because higher temps = better fuel economy, but too high of temps rob both power and fuel. Finding the balance is important.

apexjr

For one, the price of the TC intakes is insanely to high for the small amount of power given.

While this data is pretty cool, it really is showing that the placement of the SRI while the car is moving is pretty good. The CAI would be good for the track because your temp differences in the fender will help. If I recall correctly, you gain a HP or two for every 7-8degrees of intake charge cooling.

Another thing I want to have noted is that with my CRX I had a SRI with a polished tube. Under normal driving and idling the tube would heat up from the heat in the engine. I don't know if it really made much of a difference, but there was a move in the industry at one point to make the tubes from some type of plastics, which was said to not conduct the heat as much.

Just some food for thought. It looks to me that a SRI on the TC for normal driving while underway would seem to be fine. If you are tracking the car, or dragging, and you want all the power you can for a short period of time then the CAI would be a better choice. If both cost the same, then CAI all the way anyways.

The_Instigator

Im willing to bet that in the quest to maximize profit, the manufacturers figure out the easiest way to route the pipe with the least amount of materials and call it done. I would put money that K&N or WeaponR or Injen did not spend an extra second "tuning" the length of thier intake. Im sure it was more like.

Does it fit? ... Check
Any HP improvements?... Check
Is the profit margin right? ... check

Off to market where we buy it like crazy.

Im also willing to bet that any one of the intakes available would make no more or no less power than a one off custom tuned intake built exactly to your specific mods, climate and altitude. In the situation of an F1 car that is on the bleeding edge of perfomance where every hp matters...of course. Thats where the hundred million dollar budgets come in...but in an economy minded 4 cylinder...no way.

Harman

Thank you, dude.

It is a very interesting results as well as observation.

Harman

Incorrect. The longer the pipe, the less air the pipe will be able to push through because of the pressure loss inherited in the inner wall friction. The velocity of the air in the pipe depends on the amount of pressure difference on both end of the pipe and the cross sectional area of the pipe. The longer the pipe, the slower the the air flow because of pressure loss. THe larger the cross sectional area, the lower the air flow, given constant pressure difference.

Back to both SRI and CAI. SRI has the advantage as it is shorter in length and has less elbow and so it is less "restrictive", but we are only talking about a few feet, so the difference is negligible. Air temp while importance, as reflect in the data, 10-15 F does not make a real difference, so it is negligible. So, the most decisive factor is the filter cone that is on the intake. Most of the pressure loss does come from the factory filter element setup. By using SRI or CAI, we remove the most restrictive part (filter)of the intake system and give us the most gain, as aftermarket filter cone is a lot more free flowing. The rest are just a matter of preference.

toastbox

just an addition to what you are saying Harman,....
the baffled intake tube is also extremely restrictive on the stock setup. That's why a polished pipe makes a difference, smoother flowing air.

TheScionicMan

I wonder why they would use a baffled pipe there when if what you say is true, they could just use a smooth plastic tube. I'd like to think there are other factors in play here. These guys couldn't spend all that R&D money and then just quit testing things before they finished the intake tubing and just said screw it, save a buck?

I'd like to think it would be quite easy for these well-known and reputable companies to spend a few bucks on some tubing and some time on their flow meters and other testing measures to find something that fits AND works.

Injen could've just lengthened their SRI and stuck the filter into the fender, but they went a different route. Why? Just for show or because they find it works better?

Mid-range power, not peak HP...

toastbox

I'm not sure why....possibly to further trap contaminents that get past the filter? Maybe because baffled pipe = less airflow, = less air = less gas, = better economy? But almost every car I've had, with the exception of performance cars, have had baffled intake tubes.

acasanova

It can also be used for sound suppression purposes among those.

toastbox

good point, I didn't think of that.