Effect of inlet temp at air filter on power

[Sleeper1987]

Is it worth trying to lower inlet temps pre turbo? Ive been observing underhood inlet temps near 125* while driving wondering if moving the airfilter into the stream of cooler air will help in hunting for small power gains.I would search but it keeps telling me server not found or something.


TIA for any input

 

[vader87]

Oh yea! The colder the better. Yea the air heats up leaving the turbo but if you put in hot air into the turbo, it will only get hotter. My intake is behind the front bumper, no problems and it sounds really cool also :biggrin: .

 

[Razor]

Nope.

At 80 MPH what is the temp? At 90 MPH what is the temp?

Who cares at idle or 20-30 MPH.

Test at a track and observe performance .. now if your looking for bling.. the kits sure look pretty.

 

[Sleeper1987]

Nope.

At 80 MPH what is the temp? At 90 MPH what is the temp?

Who cares at idle or 20-30 MPH.

Test at a track and observe performance .. now if your looking for bling.. the kits sure look pretty.

The temp remained pretty constant between intown and 55-70 with maybe a 10-15* drop.Im just looking to reduce it in my primary driving range.Not really wanting any bling just every tiny bit of power i may be giving up on things like inlet temps etc.
right now it just has a k&n cone under hood.

 

[441120]

Get a cold air kit! Like stated above hot air in hotter air out. The cooler the air the more O2 you have per CFM, the more O2 the more power. With the cone under the hood you are just sucking all the heat right out of the radiator, not good for hp, detonation anything.
Keep cool
Never seen intake air temps more that 10* above ambient

 

[VadersV6]

My intake air temps dont get very high, and my filter is under the hood. Ive got the filter right behind the headlight and out of the way of radiator air. Late model cars are very picky when it comes to MAF signal....a cold air setup can really make a disaster out of the MAF signal curve, but I havent read anything where it seems to affect TR's in the same way.

 

[Sleeper1987]

Well guys ive messed and played around with several differant ways to run this air intake tube. and the butt dyno does seem to feel a differance.


Here is a before picture

ATS 125-135* idle-45 mph i did see it get to 118* at 75mph

 

[Sleeper1987]

and the after picture it was mid 80's today


added a few pieces to the old setup and put the filter behind the parking lamp on the driver side. for comparison i left the ATS in the same location.


ATS 88-95* through out the driving range. up to 75mph

 

[Gary Wells]

http://psmbuick.com/index.asp

This makes for very interesting reading and graphics, but after reading what Razor had to say, I am going to refrain from making any hasty judgement. I was just getting ready to buy this kit, too. If you think about Razor's analogy, it would only seem to make sense regarding underhood temperature versus behing headlight terperature versus speed. There was a very interesting thread that I came across a while back involving some serious drag racers, and they seemed to be of the opinion that for racing purposes, they did best with a bare K & N cone filter over by the cannister, out of the way of the radiator. Interestingly enough, the same racers were of the opinion that for street racing, which we should not do, a cold air system such as the PSM might work slightly better. They thought that it might be possible that was due to the fact that after some hard runs down a track, the temperature coming off of the track could almost equal the temperature underhood.

 

[Sleeper1987]

http://psmbuick.com/index.asp

This makes for very interesting reading and graphics, but after reading what Razor had to say, I am going to refrain from making any hasty judgement. I was just getting ready to buy this kit, too. If you think about Razor's analogy, it would only seem to make sense regarding underhood temperature versus behing headlight terperature versus speed. There was a very interesting thread that I came across a while back involving some serious drag racers, and they seemed to be of the opinion that for racing purposes, they did best with a bare K & N cone filter over by the cannister, out of the way of the radiator. Interestingly enough, the same racers were of the opinion that for street racing, which we should not do, a cold air system such as the PSM might work slightly better. They thought that it might be possible that was due to the fact that after some hard runs down a track, the temperature coming off of the track could almost equal the temperature underhood.

thanks for the input and link lots of info there

 

[ChrisCairns]

Some years ago a thread came up with this very subject.

I "think" it was Carl Ijames who did a herd of calculations as to whether it was more efficient to have higher inlet temps from drawing air in from under the hood but with less suction required....or to draw cooler air from in front of the radiator through a longer tube but requiring more suction. (Slightly less air.)

I believe the conclusion was that using hotter air but with less suction was better.

Perhaps Carl will see this and comment.

 

[Gary Wells]

I must have thought about this too long. As much as I respect Razor's opinion, I think that for a general street car, a cold air package such as PSM's or Mark Hueffman's is best for all around playing. And as much as I respect Mark Hueffman's (BucikGN)'s products, the stealth look of the PSM unit has me hooked. I think that will be going on the car shortly. Almost looks stock, huh?

 

[GNguy]

just get an alky kit and be done with it.......

 

[Sleeper1987]

just get an alky kit and be done with it.......

I could, but i dont like to give up "free" power if it can be had i like to try to optimize things.

an alky kit is in the works but not untill i move past a few other things.

 

[Gary Wells]

just get an alky kit and be done with it.......

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I got a Razor's Alkycontrol kit. Been sitting on the shelf in the garage for about 3 months now. Got lazy and put a tankful of 100 octane unleaded V.P. at $ 5.79 a gal. Love the stuff. But the alky kit will go on someday. It's easy to just go fill up with 100 octane. I get 22 lbs. of boost with absolutely no knock retard indication. Gotta love the smell of that race fuel.

 

[Fuelie600]

The straightest, smoothest shot of air to the turbo will yeild the best results with the least restriction. Try to have as few bends as possible. Pay attention to all adapters and transitions, as to have the smoothest flow possible. Blunt edges and tapers from Home Depot plumbing fixtures/adapters, 90* bends, and poorly designed filters all disturb/inhibit air flow. I run a 3 piece an "Intense Performance" air filter w/ inverted cone end, and a exchangable gentle taper filter to intake tube transition, and leave the filter under the hood.This filter will flow 1300cfm. I have designed a heat shield to deflect as much heat as possible from the filter area, and feed outside air to the filter thru 5" ducting. Can't say it's the best way to go, but I did alot of research and brain picking last year, and came up with what I run now. Thru the years, I have used Kenne Bell, and other cold air set ups, and my design is an improvement over all of them. Tried posting some pics, but they won't reduce enough. If I can, I will try again this eve. Brian

 

[441120]

The straightest, smoothest shot of air to the turbo will yeild the best results with the least restriction. Try to have as few bends as possible. Pay attention to all adapters and transitions, as to have the smoothest flow possible. Blunt edges and tapers from Home Depot plumbing fixtures/adapters, 90* bends, and poorly designed filters all disturb/inhibit air flow. I run a 3 piece an "Intense Performance" air filter w/ inverted cone end, and a exchangable gentle taper filter to intake tube transition, and leave the filter under the hood.This filter will flow 1300cfm. I have designed a heat shield to deflect as much heat as possible from the filter area, and feed outside air to the filter thru 5" ducting. Can't say it's the best way to go, but I did alot of research and brain picking last year, and came up with what I run now. Thru the years, I have used Kenne Bell, and other cold air set ups, and my design is an improvement over all of them. Tried posting some pics, but they won't reduce enough. If I can, I will try again this eve. Brian

Would love to see the pics as I have thought about the same thing. Cone type filter on the MAF pipe for max flow, but contain the filter in a large enough housing so there is no restriction and feed the housing with cold outside air, the best of both. Insulate the filter housing so no heat soak from radiator or exhaust. Filter flows like open element but in outside enviroment.

 

[ijames]

Some years ago a thread came up with this very subject.

I "think" it was Carl Ijames who did a herd of calculations as to whether it was more efficient to have higher inlet temps from drawing air in from under the hood but with less suction required....or to draw cooler air from in front of the radiator through a longer tube but requiring more suction. (Slightly less air.)

I believe the conclusion was that using hotter air but with less suction was better.

Perhaps Carl will see this and comment.

Uh, weren't me . Maybe John Estill? You definitely want the least restriction possible, and the coldest air. Restrictions mean a pressure drop and so to get the same boost out of the compressor the pressure ratio has to be greater, which usually pushes the efficiency down and outlet temps up. On top of that, the turbo is going to cause basically a fixed temp increase (so long as the boost doesn't change, just comparing inlet plumbing here), so hotter air in translates directly into hotter air out, and hotter air into the intercooler means hotter air out there as well, and so hotter air into the motor. Roughly every 40 deg F drop in air temp at the intake valve equals one extra octane number equivalent, so getting the air from 120 F to 80 F is the same as bumping the octane from 93 to 94, and we all know what to do with extra octane - crank the boost .

I guess I disagree with Razor on how important the temp is sitting still. I don't like the idea of having everything heat soaked up to some high temp on the starting line, especially for a fast car launching at high boost and expecting to be at full boost basically before the car moves. That hot intake air will slightly slow the spoolup and limit how much boost you can run in first gear, and it will take a little time for the plumbing to cool down once the cooler air starts flowing. Can't say if it matters 0.01 sec or 0.1 sec, but theoretically it has to matter .

 

[JDEstill]

Man, you guys are good... I did contribute a little something about 3 years ago:
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Basically you want the highest air density right at the turbo inlet. To increase the density you have to get the air colder or increase the pressure. Most cold air kits do great at the temperature part of it, but do so by adding a lot of length and bends to the intake system. This extra restriction in turn decreases pressure at the turbo suction.

So it's a case by case thing - what setup gives you the best combination of temperature and pressure?

Take two setups. One gives a 3" Hg vacuum at the turbo suction with an 80F air temperature, the other gives a 2" Hg vacuum at the turbo inlet with a 130F temperature. Which is better?

Air density at 3"Hg and 80 F = 0.066 lb/cuft
Air density at 2"Hg and 130 F = 0.063 lb/cuft
In this case the cold air/lower pressure would be better since it gives a higher density.

But suppose instead that the cold air kit gave a 4" vacuum instead of 3", and the low pressure setup gave 110F air instead of 130F air. In that case the straight shot would be better.

So, it just depends... If you have a TA type turbo, with the inlet bell that has the port on it, it is pretty easy to measure the vacuum your turbo draws, and make a judgement on which way is better. TE style turbo is a little more difficult, but I'm sure something could be rigged up.

John
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Took a while to find the thread, it was this one:
http://www.turbobuick.com/forums/showthread.php?t=92947

Hope that helps

John

 

[VadersV6]

Isnt more vacuum at the inlet indicative of a restriction? The closer to zero the better. You dont want a vacuum state in the intake tube. A vacuum says you have a flow problem. I can wrap a plastic grocery bag around my air filter, and that will bring the vacuum at the turbo inlet wayyy up. Is that better? No. If you think you're flowing less air into the intake because the temps are higher, then just increase the size of the filter and intake tube.
Naturally cold air is better, but I think some people stress way too much over this.