I've been curious about the air intake temperatures on my stock ls3 since it seems the air intake mostly draws in under hood air. I bought a Taylor indoor outdoor remote thermometer on line for $20. I placed the outside temp. sensor centered right in front of the air filter intake. I placed the outside sending unit below the right headlight unit under the hood. The display unit sat in the cup holder.

The outside temp was at 50 degrees when I started and the cars temp. display stayed at 50 during my 20 mile test. To my surprise the temperature sensor from in front of the air intake stayed between 49.8 and 50.9 during any time the car was moving. When stopped at short stop lights the temp went about 5 degrees. While stopped at a long light the temp. reached 60 degrees.

Each time after moving from a stop the temp would go back down to 50 within a mile. I will try this again when the weather is warmer but I was happy to find out that at least while moving our cars are getting the same temp air as outside... Makes you wonder if those air boxes really help any.....

Location of the sensor (white arrow)



Location of sending unit..


Outside temp before starting..


Air intake temp after 20 mile run... Bottom temp..


Dash display after 20 miles..

 

thanks for the info. I have read that the ls3 intake is just as good as any after market unit. I was considering the Killerbee with the behive but now I thinking if the Behive will fit the stock ls3 system might be the way to go. The behive is supposed to keep the engine heat away from the filter but your test shows this to be the case with ls3 intake. You might have saved me $500. Thanks

 

Good info. I knew that the timining would suffer at the redlight, because of under hood temps, but didn't know that it would be exactly the same on the run. I always figured that even on the run that your timing would suffer. ....thanks.
Larry

 

I performed the following on my 2008 Corvette which keeps IAT's down in city driving and provides ram air effect at highway speeds using the stock intake.

The Beehive will not fit the stock intake, but with a little cutting it will! I am currently running the stock intake with the two cut outs at the bottom of the shroud for cold air. Also, I cut the Beehive Shroud to fit the stock intake by using a cardboard template. Here's how: Make a cardboard template with the stock intake installed, using the retainer holes for reference points. Then, tape the template to the Beehive and using a jigsaw with a fine blade, cut the shroud to enlarge the intake bridge hole. After cutting, file the edges for a smooth and clean finish. Secure the intake on top of the shroud with the stock retainers. The finish product came out perfect! Now you have a cold air box with the stock intake and 400+ dollars in your pocket!

 

The way he explained it I am thinking the temp. at the intake filter.

 

The 72.5 was the cabin temp. The temp at the air intake never went above 60, and that was at a long cycle red light. The outside temp was 50 and while moving the intake temp never went above 50.9, even at speed below 25.

Its going to be near 70 the next few days, I plan to do another test...

 

My observations are a little different so I'll post them up.

On 3/9/07 I scanned a C6Z06 with HP Tuners (which gives you the actual IAT the car is using for its calculations). The Z has a similar system as the LS3 but it has a little scoop on the front that feeds a little cool air to the filter so it should be a little better than the LS3.

On a 79 degree sunny day (verified via DragTimes.com), the Z had IAT of 135 when he started the car - it went up to 156 degrees after 2 minutes in the staging lanes at the drag strip. It stayed at 150 + until the run started. By 80 mph, 3rd gear, 4 seconds into the run, it went down to 106 degrees, and by 13 seconds into the run, at 133 mph (he ran it out past the finish line) it was at 100 degrees. On the return road it stayed about 104 degrees, 25 degrees above ambient that day.

Meanwhile on the same day, my Vararam equipped car started out at 93 degrees when I started the car, stayed there until the run started, and was down to 84 degrees 6 seconds into the run where it stayed, or 5 degrees above ambient.

Here's the kicker. At 156 degrees IAT, the stock tune of the Z06 was pulling 10 degrees of timing....that's about 1/2 of the commanded timing the car! It was running 13 degrees of timing in the upper RPM ranges on the scan. The car calls for 23 degrees of timing there - I just pulled up the stock tune and checked.

My car's stock tune does NOT pull any timing at 86 degree IAT, not 10 degrees (though at 158 degrees, like I would have seen with my factory intake, my car would have been pulling 12 degrees). My scan showed 23-24 degrees of timing at the upper range, right what my tune was calling for.

That's why the Vararam gets the results that people see on the track. Lowering IAT, particularly with a stock tune, gives you up to 10-12 degrees of timing and that's a LOT of horsepower you are leaving on the table with a factory intake.

On cool days, you don't have this effect, which is why everybody's car feels so much faster on cool days.

Also, that factory IAT spark reduction table is the first table tuners either zero out or make much less aggressive, which is one easy way you get such better horsepower with a tune. Give the car back 10-12 degrees of timing and see what a nice result that is on a dyno (or SOTP meter).

OP I'd be curious to see what would happen if you tried your experiment on a warmer day and see if your results are different.

 

Joe_G... On the LS3 where is the IAT reading taken from, the Mass Air Flow sensor? If so I could try to put my temp. probe inside the air bridge near the MAF to see what that reads.

My reason for putting the probe just in front of the filter was to see if the car was pulling warn air from under the hood or outside air from the openings under the car. Just so every one understands, the shrould below the air intake is closed...

 

Yes the car reads IAT from a sensor integrated with the maf.

You can get free cai by propping the bottom of your shroud open by the way...do a search for pics if you are interested.

 

I have tried that.... The car bucked and surged the whole time it was open...

 

Needed to be tuned! MAF sensor is very picky in LS3

 

I did a similar test scanning my IAT's this summer. I found that the temp rose 3-6 degrees stopped at a light, but within a couple hundred feet, it was back to ambient. I think the air bridge where the MAF resides gets a little heat soak from the radiator and upper radiator hose..
I have a K&N CAI, vette-air, insulated shroud, beehive and I also insulated the underside of my air bridge with some of that reflective heat shielding you can buy at summit or autoparts stores.

 

Thanks