Cold air intake..

[azhodge]

Air density is the key.. has anyone fabricated a true cold air intake system? or know of one for the 3.2??

[76FJ55]

Do you have working A/C?
If yes, replace the rear deck lid condenser with a rear wheel well condenser.
If no, you're already done.

[azhodge]

I have a rear wheel well condenser as well as the deck lid condenser. any intake that is taking air from inside the engine compartment is not a true cold air intake. I could always turn off the acc for maximum cold airness. but who has made one? I cannot be the only one on the planet who recognizes the value of a true cold air intake on a 3.2

[HaroldMHedge]

You could mount an early whale tail that has a separate intake for engine cooling/AC.





Images from Pelican and the web.

[aread]

There's always what Singer did to their new DLS... although probably outside most of our 'snack bracket'

[76FJ55]

with the amount of air the engine fan is sucking through the engine bay and blowing out the bottom It would be pretty interesting to actually measure intake air temp (with no A/C running) and compare it to the outside air temp, just to see how much heat is really being picked up off the engine.

[Steve@Rennsport]

Originally Posted by 76FJ55

with the amount of air the engine fan is sucking through the engine bay and blowing out the bottom It would be pretty interesting to actually measure intake air temp (with no A/C running) and compare it to the outside air temp, just to see how much heat is really being picked up off the engine.

I've done that many many times on a variety of 911's.

Once in motion, intake and cooling air is at ambient temperature.

Temps do rise during "heat soak", the 45 minute period following engine shutoff, but return to ambient once in motion for a few minutes.

After spending a LOT of time fabricating different 'cold air' intakes for various street & race cars, I've not found any benefit from such arrangements.

Now,....the newest Singer system as used in their 500BHP model is something altogether since the outside air is picked up in a high pressure zone.

[Coastr]

If a cold air intake made extra power then Porsche would have fitted it to at least 1 performance model.

The fact they never did makes me believe there is no benefit. Unlike most engine bays, cold air is being continually drawn into the engine compartment. It's a big cooling fan that moves a lot of air.

[Nick Triesch]

If you install any type of cold air intake on your 911, the only thing that will happen is cold air will go into the intake . It is all make believe. No power gain whatsoever. How can it? The science is not there. Only thing that works is Turbocharging or supercharging.

[Steve W]

Originally Posted by Coastr

If a cold air intake made extra power then Porsche would have fitted it to at least 1 performance model.

The fact they never did makes me believe there is no benefit. Unlike most engine bays, cold air is being continually drawn into the engine compartment. It's a big cooling fan that moves a lot of air.

That's what I thought the side scoops on the Boxsters and Caymans, and the big ram air decklid scoops on the 997 and 991 GT3, and the big side scoops on the GT4 and 991 GT3RS were for, no?

[Steve W]

Originally Posted by Nick Triesch

If you install any type of cold air intake on your 911, the only thing that will happen is cold air will go into the intake . It is all make believe. No power gain whatsoever. How can it? The science is not there. Only thing that works is Turbocharging or supercharging.

Cold air is a good thing for the intake of at least the 3.2s and 964s on. The 3.2 and 964s have an intake air temp sensor in the air flow meter that will trim down the overall ignition timing by as much as 4 degrees if it senses the intake air as being hot, such as on a hot day with the AC on, sucking in that hot air after the AC condenser, reducing your overall output power.


Interesting thing we've found over the years dyno tuning 911s. Blowing at intake area with a squirrel cage blower usually makes about 7 hp more at the wheels at full throttle. Whether that's from more fresh air going to the motor, or reducing the air pressure drop due to the intake air suction, your guess is as good as mine.

[pmax]

Originally Posted by Steve W

Cold air is a good thing for the intake of at least the 3.2s and 964s on. The 3.2 and 964s have an intake air temp sensor in the air flow meter that will trim down the overall ignition timing by as much as 4 degrees if it senses the intake air as being hot, such as on a hot day with the AC on, sucking in that hot air after the AC condenser, reducing your overall output power.


Interesting thing we've found over the years dyno tuning 911s. Blowing at intake area with a squirrel cage blower usually makes about 7 hp more at the wheels at full throttle. Whether that's from more fresh air going to the motor, or reducing the air pressure drop due to the intake air suction, your guess is as good as mine.

Hmmm, heater blower is close to the intake.

[azhodge]

the science is definitely there. air temperature has a direct correlation to air density. if it were not so then why does altitude effect performance? porsche just went to all turbo chargers to deal with it.

[Steam Driver]

Actually there is a distinct advantage to cold air boxes but it probably depends a lot on the engine and intake configuration.

Back in the (really) old days I was a Corvair Driver, when the cars were new. I owned two of the turbocharged cars - both the 150 and 180 hp varieties. I street-raced and autocrossed both these cars, quite successfully with the later car.

At the time there was a great book on Corvair performance “How to Hot Rod Corvair Engines,” by Bill Fisher. He mentioned on P.20 (I still have the book) that HP output can go up as much as 1% for every 2 degree drop in intake temperature. That figure of course assumes adjusting the mixture to match, something not possible in carburetor days. But even 1% per 2 degrees would be good so I decided to try it.

I put a length of dryer hose over the turbo air cleaner’s snout and ran it around into the air intake grille behind the rear window (second generation Corsa). I didn’t have dyno access, but I did have a “test hill.” Pass a specific point at the bottom in a specific gear and RPM and stand on it. Have passenger start watch. When passing another point at the top and stop the watch, noting RPM increase. Voila, college car enthusiast dyno.

Doing this repeatedly there was a measurable and palpable definite performance improvement for little expense, so the mod stayed on the car for the five years I had it. I noticed no downside as far as carb ice or drive ability issues even in Midwest winters.

There was one amusing malfunction with my setup. Since the hose was round and the snout rectangular I sealed around it with shop towels stuffed into the cavities. One day when I was on it hard I heard a noise followed immediately by sharp deceleration and a lot of exhaust smoke. I limped home.

What had happened was one of the shop towels had gotten sucked into the air cleaner snout and sucked up against the filter element! Getting it out wasn’t easy; I don’t think it could have been packed in more tightly with a jack hammer.

In any case cold air boxes do work, at least in some applications.

[azhodge]

Banks says it all. watch the whole thing and learn many cool things from a true master.

https://youtu.be/eMusa5hZxtk

[Nick Triesch]

Cold air does nothing except really look cool in an engine bay! The shiny tubes! The cool K&N ! Looks really fast. I bet if I added to my 911 I could go 0-60 in about 5.6 seconds!!

[azhodge]

So if cold air intake made power then Porsche would of used it you say ??? check out this 2009. a TRUE cold air intake..

[clutch-monkey]

yeah except the water cooled cars do not have a giant fan sucking air through the grille and engine compartment.. of course they need to actually put the air intake more directly into the air stream.

[Jack Olsen]

I've measured it. As Steve W points out, with our air-cooled engine's blower working, temps go right to ambient under throttle. Idling, they go up -- but no one cares if they're losing some power while the engine is idling. I doubt the AC condenser makes any meaningful difference with the volume of air moving at high RPMs.

Water-cooled engines are another story.

[azhodge]

Jack I respect your and steve's opinion. it is nice to see facts backup a statement. Thanks, Atlanta... PS. your you tube videos are inspiring.!!