I did another air intake test with the weather being a little warmer. The outside temps were between 59 and 62 degrees during my 22 mile test drive.. During the drive I stopped at 9 redlights and 5 stop signs. Speeds were from 30 mph to 65 mph. This was all done on my stock 08 A6 car.

For this test I put the temp probe in the air bridge, between the MAF and the throttle blade. The engine was cold at the start of the test. The highest temp reading I saw during the 22 miles was 65.9 degrees which was about 3 degrees above the outside highest temp of 62.

For the second part of this test I parked the car in the driveway with the hood closed. After about 20 minutes the temp sender in the air bridge recorded a top temp of 147.7... With the engine now heat soaked I went for another drive. The outside temp was now at 63 degrees. Within about the first 1/8 mile the temp dropped to 110. At the 1 mile mark it dropped to 93. It took about 4 miles of driving at 45mph to bring the temp in the airbridge back down to 66.4 degrees, about 3 degrees above the outside temp the same 3 degree difference I saw with an cold engine.

What I draw from the test is, that unless you open up the shroud (like for the Vara Ram) your not going to get any cooler air to the air intake from any of the "cold air intake systems" that are after market. More air flow maybe but not cooler air.

I plan on trying this again when the temps are in the 80's or 90's but that might be a while...


Location of the temp. probe. (White Arrow)

 

well depending on what you're looking for 4 miles is a long time to wait.

in a 1/4 mile you'll be completely heat soaked from waiting in line, and in a 1/4 mile blast you'll see no cold air benefit.

If you have a CAI you'll get instant cold air. when i had my vararam i saw temps +1 deg above ambient any time the car was moving.

 

During the 22 mile drive I sat at 9 red lights. The Temp in the airbridge never went higher than 3 deg above ambient....

 

you'll typically spend 45 min to an hour in line at the track.
It's closer to your "letting the car sit and heat soak" test than a 30 second stop light.

 

I never let the car run the entire time in line so that theory is out the window. It runs for about 2 mins at a time then I shut it off and wait for the line to move.

 

I figured he had shut the engine off for those 20 min, not left running in the drive way.

Which was it pettvette?

 

The engine was off for at least 20 minutes. I went for the second drive after the temp stopped rising in the air bridge while the car was off. It topped out at 147.7....

I think your missing the reason for my temp test. If you install a CAI and NOT cut the shroud, where does the aftermarket air intake get its so called "cold air". It will be pulling in the same air the factory unit is using. Which in both of my test was within 0-5 degrees of ambient.

Keep in mind on my second drive that took 4 minutes to cool back down to 3 degrees above ambient, was at only a max of 45 mph and with 2 redlights and 1 stop sign. I'm sure with a greater throttle opening it would have cooled down much quicker....

 

If you don't cut the shroud then it isn't a CAI, it's just a filter change.

 

What would be INCREDIBLY informative would be if you propped open your shroud with the stock intake and did the same test to check the Free CAI mod, which I have done with my K&N and see very good results.

 

Would also love to see the results with the cold air mod!

 

I love when someone takes the time to run these tests! Thanks! Does this mean that the only improvement a real CAI generates is in the 1st 4 minutes after it's been parked?

 

Yes, but if you are running the 1/4 mile, most complete it in under 4 minutes.

 

Thank you for posting your results!

When I first got HP tuners I ran the same test. I tested the Callaway and the Vara Ram. Cold air intakes (that you cut shroud) will record a lower air intake temp very close to ambient temp. Any other air intake which replaces the stock unit and takes air from the engine bay is not a CAI.

The propped shroud also works. I have also seen the stock air system modified with a cut shroud on each side to allow cool air in.

Unfortunately, the stock intake will heat soak when you get stuck in the staging lanes for any long period of time.

About now we should be hearing from some CF members who installed a CAI and were very pleasantly surprised at the new found performance in the cooler weather.

 

I should make a macro for this post I've made it so many times.

Here's why CAI's work.

Look how much timing is being pulled at your 147 IAT...10 degrees.

That means you're going to run 14 degrees of timing in your quarter mile.

A CAI gives you back those 10 degrees of timing to your otherwise commanded 24 degrees and that's what gives you .4 in the quarter mile. In the winter, with super careful controls, (i.e. pushing the car up in line) on a private test day (nobody burning you down on the tree, etc.) you can keep this heat soak from happening. In real world conditions the CAI is a much easier solution.

 

So, is there any real gains on a road course?

 

I have an '07 LS2. I installed a VetteAir ram and built a beehive type cold air box with a K&N filter. Engine runs about 3 - 5 degrees about AAT when moving. On a recent cross country trip, it was constant at 2 degrees above AAT for hours.

At the drag strip, AIT was 116 at launch, 100 at 60' and 90 degrees at 1/8 mile. Ambient air was 78 degrees.

 

Interesting info on CAI's and air temps.

Is there any truth to the story that opening the shroud with a stock filter on a "08 LS3 will cause surging?

 

I think that what he is trying to prove is that the vettes that are not used on the track do not benefit from a cai.
Thanks you just saved me $600

 

I propped mine open when I fits bought it and never experienced any problems with that. Now I have a Vararam on it.

 

Whats up guys. When I had my dodge charger I would hang around the 300c/charger forums. There was much debate over cai. We finally got together to put the cai to the test. Stock, kn, afe, and a few more other brands were all dynoed. The results.. The afe and some other one came out on top. Some lost hp. The over all gain was only a few hp. We came to the conclusion the only reason you should get a cai is not for performance, but for an increase in sound. I can't speak for the corvette but with the 6.1 hemi the cai would make the intake GROWL ( a good thing ) on WOT.