I was wondering how bad the intake air temperature effects the performance of the engine. I ran a 8.95 in the 1/8th mile (high 13 second 1/4 mile), when the ambient temperature was 65 degrees (IAT showing about 75-80 degrees) and at that I didn't have traction (didn't have posi traction installed). Just today, I ran again, with posi traction. This time the temperature outside was 95 degrees (putting the IAT at about 120 degrees the whole run). I couldn't do better than a 10 second 1/8th mile (mid 15 second 1/4 mile)

Just wanted to get everyone's take on how the temperature outside effects the performance of a turbo charged engine

 

i dont think temp should effect the perfromance that bad. But im a nitrous guy non turboed. Miight be somethin else. Mayeb misfire or spark plugs. I know spark plugs will make one run like crap. How u keepin up with iat and everything, via hptuners or efi live?

 

I'm no expert neither, but it definitely sounds like somethings wrong, is your CEL on? We can start from there.

 

I can definitely feel a difference when it gets hot. Doing the math with PV=nRT, you get 8% less air mass with an increase from 75 to 120 IAT, so you can see its a decent amount. Also, if your IAT table is aggressive it will pull timing once things heat up so that will reduce power too.

 

the stock timing iat table will pull a lot of timing at 120. 6* or so I wanna say. So if your timing is already conservative you can loose a lot of power. This is where meth comes in handy.

 

yep, IAT advance table is pulling timing. Plus if it is hotter outside that usually means everything else is hotter too. Like the engine temps. There is an ECT advance table as well.

6* is a ton of power.

 

I'm keeping track of the IAT's using an aeroforce interceptor. It was nelson tuned back when I didn't have an intercooler (and I told him that). I'm not sure what he did as far as IAT tables, but the past couple times I went to the track I've had the intercooler on (the time I went 8.95 and just yesterday the really slow time). I'm still waiting on the new nelson tune. I was planning on getting them to tune it in person, but every time I call it seems like they are closed

The CEL is on, but the engine will idle rough about once a day for about 10 seconds causing the CEL to come on throwing P0171 and P0174 (lean codes)

 

i know when ever i get a retune from nelson it always seems like it has a learning curve to it or somethin. The more u drive the truck the better the tune becomes. Does he do this, so his tune can kinda learn the truck since he is tuning kinda blind? Just curious.

I didnt know the air temp could affect perfromance that much. I guess u learn somethin new everyday. Have u relocated your iat closer to the intake mani. away from all that heat yet? they say that helps, i planned on doin this to mine.

 

yeah, I'm running the KB racing kit so my MAF/IAT is right in front of the throttle body

 

check if your O2 sensors are working fine... i remember those codes came up when they wernt working.. i lost a whole second because of that!