Mat

I know that sounds like a stupid question..

Basically, we had a dyno session yesterday and it was about 90 degree's out with humidity in the 60% range and my scans showed my IAT at over 100 degree's on the dyno.

I pulled 315/330 last year with just a lid/exhaust on the car. Now I've got Pacesetter LT's, TSP 3" catted Y, and did a complete VE tune and also adjusted the PE tables slightly (1.175). On colder days/nights the car pulls like a monster compared to what it used to do.

At the dyno yesterday I made 320/335 and I'm thinking this was because of the poor air quality vs. last falls pulls in 58 degree weather? I was still getting a full 28 degree's of timing...

At any rate just figured I'd ask all of yah and see what you think. Go ahead, slap me, I know I'm asking a silly question and I'm pretty sure I know the answer.

To further my point, a buddy who dyno'd 320/330 last fall on the same 58 degree day did 303/314 yesterday with absolutely nothing changed on his car. I think that alone answered my own question right?

HumpinSS

iTrader: (1)

yes 100+ iat will pull anywhere between 1 and 3* of timing

Mat

Interesting. However my scans showed the motor was getting the full 28 degrees the timing table commands. Does it pull the timing but still report that it's there?

I was thinking because hot air is less dense and carries less oxygen (thus affecting the burn) you make less power then with cooler more dense air?

mrr23

iTrader: (3)

i would say the PCM pulled fuel due to less dense air.

horist

^^^ yes, hot air you make less power due to not the same amount of oxygen in a unit.

I just checked a stock 2000 .bin and looks like 104* will pull 1* of timing at 100kpa
then 113 will pull 2 degrees at 95 and 100kpa
and then starts to pull more at lower KPAs as temp goes up


ECT pulls alot more timing... it pulls a lot once you get to 230*

Pro Mouse

iTrader: (15)

Yep just like Horist said ,Hot air = Crap for power ,It has been really Hot and Humid here in Mich.My Car feels like it has lost 30+HP Infact I know it has.In cooler temps you will see an hp increase...

Black02SS

iTrader: (36)

I have personally zero'd out the IAT and ECT tables and the car still runs lean. I normally see ECT's in the 180-190 range and IAT's under 90*, today IAT"s were in the 140's with ECT's 210's. Hot weather sucks and will make the car run lean.

Mat

Gotcha!

That's what I figured.. my budy looks to have lost 17 rwhp and 18 or so rwtq as a result of the temps/air that day as he had nothing changed on his car between our fall runs and this summer one. Quite disconcerting to say the least!!

At any rate, at least our thoughts make sense and the fact that I'm still getting full timing actually means nada since it's the air itself and the level of oxygen in it that is killing the power capabilites!

At least I feel better knowing the 1000+ bucks I spend on longtubes/exhaust/tuning software hasn't gone to waste!

IAT's in the 140's! Yikes!!