100+ degree IAT affect performance?
Thread Starter
Launching!
Joined: Aug 2002
Posts: 231
Likes: 0
From: Ontario, Canada
100+ degree IAT affect performance? 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?
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?
Thread Starter
Launching!
Joined: Aug 2002
Posts: 231
Likes: 0
From: Ontario, Canada
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?
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?
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
^^^ 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*
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*
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...
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.
Trending Topics
Thread Starter
Launching!
Joined: Aug 2002
Posts: 231
Likes: 0
From: Ontario, Canada
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!!
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!!
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
