m0t03

I was just wondering which is better to go with a cold air intake or a open air intake? My car has catback, DP, MP. Any suggestions would help. My car is stored right now and I am planning on putting everything on over the winter.

Mahjik

iTrader: (1)

Honstly, I really don't think it matters since you have a mid-pipe. Supposedly, with open air intakes, you run the risk of bringing in too much warm air causing the air pump to fail prematurely.

Some people say cold, some people say open. Without an air pump or upgraded Intercooler, I don't think you'll see much difference between the two.

I've heard of some unhappy people going with Pettit's TKT Cold Air intake, so if you are looking at a cold air intake, you might want to look at M2.

rx7eaven

I have heard that without an intercooler upgrade then going open air will overload your stock ic.

RX7 RAGE

iTrader: (22)

open intake if you have a good intercooler

3rdGenLuvr

So the consensus is if you have an airpump AND stock IC go w/ the cold air?

maxpesce

Cold Air - You want the intake air to be as cold as possible & The colder the air you start with the colder it will be going into the engine, regardless of your IC Setup. I modified my Stock airbox by cutting some holes on the bottom and adding a Baffle/Duct to bring in cold air from beside the radiator (remove the foam between Rad & Body) I also retained the stock air duct and am planning to add a baffle to the IC Ducting to seperate Intake & IC air flow.

lenny

hmmm..... can anybody with power FC or some other way to monitor intake air temps post their temps?

i see around 40-50 degrees celcius with outside temp around 70 degrees with a RE amemiya intake, greddy SMIC, efini y-pipe and downpipe

what is the ideal intake air temp?

7 eleven

Colder is always better, But at what price ? In a turbo Car the intake temp To the inlet side of the Turbo is Not very important compared to a NA Car. When you compress air it heats up, Right? I 'm sure one agrees here. The part most miss is that it is not proportional. For example it the turbo takes in 70 degree air and compresses it to X psi it will heat it up to say 110 degrees. Now say it takes in 30 degree air, Your thinking ok 70 - 30 = -40 degrees from the 110 degrees so it's now down to 70 degrees and rule of thumb is 11 degrees equal 1% increase in output so a Lightly modded 7 making 300hp gets roughly a 9hp(Of course you get some hp due to less restrictive filters but open filters get that to so it equals out) increase due to the (NO names here) say 485 dollar intake. You pat yourself on the back and show it off to your friends, right? Well if only you got that much bang for your bucks.
When air is compressed by a turbo it's a nasty messy affair, so your Cold 30 degree air is heated to within say 10 degrees of the Hot 70 degree air on the outlet side of the turbo. So now your 9hp gain is a 3hp gain and you could have got a 200 dollar intake and blow the other 285 on strippers or what ever. At least that way you could tell every body you spent 285 on strippers and feel better than saying you paid 285 on 3hp.
Sorry it was so long but hey it's free.

13BAce

With my T-78 and 70-80 degree F temps I was seeing temperatures no higher than about 40 degrees C. I had a FMIC and some screen over my turbo inlet.

13BAce

Now that it's colder--50-60 degrees F--my intake temperatures don't go above 30-35 degrees C.

maxpesce

My cold air mod cost me $0.75 worth of scrap Aluminum sheet a couple feet of Aluminum Duct Sealing Tape and about 1.5 hr of my time to cut & fit the baffle and cut out the bottom of the Air Box with a Carbide Cutter in my Die Grinder. Now I just need $55 to get a K&N Drop in from Summit and I am all set with clean free flowing cold air.
The outlet temp from a turbo IS Directly proportional to the inlet temp, the amount of compression, and the Effiency of The turbo. but the effiency changes depending on the compression ratio (inlet/outlet) and in general the colder/denser the inlet air the higher the efficency (lower compression ratio) for a given fixed outlet pressure. Large Marine diesels use Precoolers on the inlet air as well intercoolers & aftercoolers on the compressed air. (technically our cars have aftercoolers - Intercoolers are between staged low/high pressure Compressors)

m0t03

so I shoud go with the cold air intake if I'm running a stock intercooler. Otherwise I was going to go with the Blitz SUS. Now I'm leaning towards the M2 cold air system.

13BAce

If you can get cooler air into the motor then it will always be better. I would have made a cold air intake for my car, but I"m lazy. When I re-do my IC piping and gain the space I'll do it.

7 eleven

I have to disagree with maxpesce; there is a thermal limit to the outlet temp of any compressor. This is due to the bleed off of heat by the compressor housing pipes etc. as the temp differential between the inside and out side increases the amount of heat lost also increases. After a point of which the loss equals any increase. Now we don't want hot air so we don't run our compressors/turbos this high (like 20 psi+ on stockers) Around this point loss of density loss do to increase in temp out weighs flow increase and we have a stale mate of power. What this illustrates is the lower the differential temp (delta t) across the turbo less heat is rejected into the housing pipes etc. so it remains in the air stream causing a loss of effinciy that would otherwise be gained. The precoolers are used on apps. that absolute efficieny is the only thing that matters not Max HP. The 5g's they spend on all that cooling in a marine diesel will pay it's self hundreds if not thousands of times over the millions of hours the motor runs at a constant power setting plowing water. Once again "colder is always better but at what price?" you're not going to make your money back by the better fuel efficieny because of your cold air intake like those large marine diesels do. The Home made cold air set ups work pretty good for the bang for the buck, but How far do you plan to go? The k&N panel Filter will cause a big restriction @275rwhp and up.

Mahjik

iTrader: (1)

Well, I'm not going to comment on whether to go cold air or open air as 7 eleven pretty much has said all there is to say.

I would say just go with whatever you like. I liked the "look" of the open air intakes verses the cold air intakes. The Blitz just looks great under the hood, unfortunately I couldn't get my hands on one.

Here is a comparison of some open air intakes:

http://www.gtrowner.com/induction.html

The power gain is pretty much the same all across, you'll never notice any difference. Keep in mind, that test is not an actual "road test" but a simulated test. You really can't go wrong with any of them.