Regarless of the intake temps ram air will give you more power. I ran last summer about 80 timed runs at the drag strip. I did this on several different set ups.

lets take the rx7 fashion box first. exact same setup consistent runs without ram air I ended up with around a 104-105 trap consistently. with the ram air I had a consistent 110 trap.

Infact, I had a setup that was the bolt ons with a highflow cat, but with the stock IC. The stock IC was modified to have ram air.

I had the rx7fashion cold air box installed (without a ram air) and I got a midpipe, 1200 CC secondary injectors and a fuel pump and guess what? My trap dropped by 1 MPH. When I put the ram air on my cold air box I gained 5 MPH again...consistently.

So go ahead and argue about cold air temps vs hot air temps, but the amount of air you ram into the car makes a difference.

 

This quote: "I never understood a cold air intake on a turbo when you are feeding it into a red hot turbine" doesn't imply that the intake air goes through the exhaust side?

The fact remains that the turbos will generate X amount of boost easier with colder air than with hot air. If nothing else, turbo life will be extended. Not to mention the side benefits, such as not having air pumps die due to sucking in hot air.

In the end, this is like an abortion debate. There are some people who think that hot-air intakes are fine and some who don't and neither group will easily change their mind.

 

Should I keep my stock ast or eliminate it?

(Im just joking, I thought it would be fun to start another endless argument).

 

Sorry I misworded my first post, shoulda been compressor housing... and several times I mentioned not talking about a ram air setup.. but ya, its two schools, I agree. After my own research and investigation I found it didn't really matter on my last turbocharged project - Wether the filter was bolted to the turbo, right behind the head, or dropped down to catch air from under the car, there was no difference in IAT temps.

I dont understand how its easier for a turbo to compress colder air though.. Colder air=denser air= more work has to be done by the turbo I would think. Regardless of the intake temp, the compression factor raises the charge air temperature by X amount, and the heat soak from the Y-pipe, upper IC piping on the FD ( My crossover pipe gets HOT) adds to that by a small factor... The question is- is a cold air intake, by reducing intake temps by say 30 degrees (sound reasonable) all that effective when measuring at the throttle body? From my findings it is negligible, if at all.

RAM Air however is completely different - this is where you are forcing more air into the turbo inlet than it can take on its own. I wholeheartedly agree that RAM air is a good thing. But simply bathing the filter in ambient air does not achieve this.

No flames, I love a good discussion, and hope I don't sound insane

 

Well if , as you say, 30 degrees doesnt make a difference, try running your car on a 100 degree day and again on a 70 degree day (Like Florida, where i live) There is a noticeably difference in teh way teh car runs in the 70 degree weather....

 

Not that I have seen, actually. I live in So Cal so we have similar climates other than humidity - which may enter into your experience, but here my cars run the same day/night doesnt matter. I don't have a Power FC yet, so I can't check the IAT on the FD, but as soon as I do Ill do some back to back experimentation

 

My car definately runs better on cooler, slightly humid nights.

 

The HKS J-Spec kit would qualify as a ram air setup, correct? Would this be superior/inferior to the M2 cold air box?? Thanks,
Seldon

 

Save lots of money for a V-mount knight Sports setup and you get cold air to airpump, intake, radiator, and IC

Oh yeah Rotary Extreme also have the V-mount setup.
I think V-mount should be the best Cold Air setup!!!

 

Ditto... and RE-V Mount "Kit" comes with Cold air, that'll fit most hoods, and Battery kit so you can keep stock location...

-DC

 

How about this example:

It's a cool day. 50 degrees out. You have been driving your car hard. Water temps 220. You are now stuck in traffic, heat soaking your engine compartment and everything in it. You come up to a stop light, and the guy next to you wants to race. Do you want 250 degree air from under the hood, or 50 degree air from a cold air intake, coming into your intake?

Don't try to fool yourself (or anyone else) into thinking cold air intakes are worthless.

I modded my stock airbox to work just like the M2 and other expensive CAI's. I would wager that it works at least as well.

 

BTW, for you guys talking about "ram air", the only intakes on the market that work this way (without modification) are the stock box, Racing Beat duct, and the PFS intake. Of course, the only negative is that those setups supposedly can suck hot air back through the intercooler during high boost, low speed situations...although my mechanic's testing didn't support that theory.

 

ok a 200 degree inlet temp difference, I concede...

I don't think i said worthless, just negligible differences from my own experiences. My other car doesn't get 250 under the hood, so perhaps it is not the best comparison. Hell, my water temps in that car at full boost (22psi) never get above 92C, IAT's is in the 30-50C range through the pull.

That being said, I guess we can kill this...When I get a PFC I'll do some tests and post the results



V Mount and vented hood all the way though - we all agree on that one

 

And just when you thought a thread was going to die....

The reason I put "ram air" in quotes is because nothing is a true ram-air system unless it positions the intake in an aerodynamically high pressure area (such as a leading edge of bodywork) and the intake runner and airbox are completely sealed (which the stock airbox intake runners-- including the RB duct and the PFS intake-- are not) in order to pressurize the airbox. The interior of the intake nacelle (where the radiator and stock intake duct resides) isn't really a high positive pressure area, especially since there a leakage points all inside that area, up to and including the IC and battery cooling duct.

 

My 2 "ram air" hoses are set up like this.

Hose 1 is where the oil cooler duct is on the drivers side (No oil cooler). I have the opening of the duct completly sealed and a hose connects to that. That hose goes into the intake box and is placed within an inch of my K&N for the primary turbo.

Hose 2 is under the nose of the car where the air gets rammed into the radiator duct and is routed to my secondary turbo much the same way.

I'm hoping...actually I'm praying that my car meets your definition of ram air. Thanks and waiting to hear back (crosses fingers).

 

There will be a noticable difference, because of extremes in temp difference, but keep in mind, those air temps are not exclusively hitting the intake(s)- your intercooler is getting them too.

 

um, no.
If you start with colder air, you'll end up with colder air all else being equal, simple as that.

The complication with our cars is finding a large enough cold air source so as not to be restrictive, and heat the intake air up, due to the turbos working harder to produce the same boost. Its a balancing act, and theres alot of different opinions out there as to what the best balance is.

But saying that you don't need cool air, or it won't help simply because you have an intercooler isn't really correct. What you want is cool air, with minimal restriction in a perfect world.

 

Heh...well, more so than any stock-based equipment. At least you're taking a direct feed of airflow and redirecting it to the airbox. If your hoses are completely sealed to the airbox, then yeah, it is. The stock airbox/intake setup (as well as the PFS intake) is in no way a "ram air" system. The term defines itself; you're "ramming" air into the intake.

 

YES!! YES!!!!

I got a ram-air and you dont, na-na na-na na-na!!!

 

This thread is funny. Everyone is so busy arguing about cold vs. hot AGAIN and ignoring Seldon's question...

Seldon - No the HKS kit does not qualify as a ram air setup.

The only cold air type setups (that I know of) are:
1. M2 cold air box - m2performance.com
2. RX7fashion cold air box
3. PFS intake system
4. Crooked Willow cold air box - http://www.crookedwillow.com/intake.htm
5. Stock air box

If you look at how these systems work, you will notice that they are actually enclosed air boxes that use the round/conical K&N filters with one filter for each turbo inlet. Except for the PFS or stock airbox that use one large round K&N for both filters or the stock air box that uses a flat panel filter. Now compare those to the Apexi intake or HKS or Greddy type of intake where its just a filter at the end of the turbo intake pipes in the engine compartment.

Because the filters are enclosed within the "cold air box", they will suck air from whatever opening the air box uses. The M2, CWC and RX7 fasion boxes suck air from the ~1" space between the radiator and the chassis under where the stock air box is now. Left, front side of the car. Between the enclosures and the heat shield that goes down besides the radiator, this keeps the car from sucking in all the hot air from inside the engine bay. We can all agree that when sucking in air from this area especially at idle the air will be cooler than the air under hood.

You following?

Now lets talk ram air.

Ram air has already been well defined in an earlier post. Some people have made ram air type of modification by using hoses to direct airflow from openings in the front of the car to the air filters. The faster you go, the more air gets directed and forced toward the air filters. Obviously this air is going to be cooler than the air under in the engine bay.

Now the decision of what you want to use on your car is up to you. For me, I decided to use the stock airbox with the adam_c type mod for the following reasons:

1. I spend a lot of time in traffic (daily driver) and I believe the vented stock air box will get cooler air than an open element filter setup.

2. I'm in NY so we have hot summers and cold winters. On my old Turbo IIs, I used to switch back to the stock airbox in the winter to decrease boost spikes.

3. Its a street car. I'm not after all out power. I barely have a chance to wring it out beyond 2nd or 3rd gear till I hit some traffic anyway.

4. I'd rather spend $400 on something else.

5. Zerobangers tests on the drag strip confirm that the differences are not that much between using the stock airbox, vented and rammed vs. an expensive cold air box from other makers. For me using my 7 primarily on the street and driving often in traffic, I'll put the $400 in my pocked and won't miss a few extra HP as much as the cash.

 

Thank you alberto_mg... That really clarified the issue, and I think I'll save the money for a PowerFC until the car reaches a higher level of modding.
john

 

check out nick's setup.

http://www.rotaryracing.com/rr_intak...old_air_FD.htm

its kinda like pettit's and n-tech engineering, but has a top like the M2......well, with rotary racing and reliability's logo on it. i was gonna get this before i decided to go single. they can also have the panels powdercoated any color you want.

 

I did all this research when I was messing with my set ups.....I tried the apexi but I had to go with the pettit set up in order to fit my intercooler. There is no way pettit draws any cold air into those filters from that radiator crack with a stock hood. So, I am working on a mod similar to zerobangers--the best of both worlds IMO. FWIW the apexi was much better than the pettit (build, flow,temp, quality, noise) but I doubt it would fit with very many aftermarket intercoolers.

I think that pettit's system flows more than others...so, is it better to flow more air even though it's hotter? or less air when it is colder......I think the net result is the same.

The other box style intakes (m2 etc..) dont draw air any better than the pettit.....they just have a duct that forces air to be drawn in through that radiator hole. Pettit and Apexi draw air from where ever they can.

My mod...pegasus brake duct mounted into the passenger oil cooler intake slot. The hose will be routed up behind the headlight and dump out to the left of the headlight through the slot cut in the frame. At seven stock a guy actually cut this opening out and routed one of the pettit filters down behind the headlight.

 

http://f1.pg.photos.yahoo.com/ph/key.../lst?.dir=/rx7

The vented hood made a huge intake temp improvement. I think that in addition to hot air venting out when stationary, more cold air is actually drawn up past the air filters. Im working on some ducting to ram air past the filters and out through the vents.

 

i agree...i wanna do some ducting!
i cant see how they draw air from that little area there