LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

performance when hot outside

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Old Jun 19, 2006 | 06:23 PM
  #1  
wyldcdn's Avatar
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From: Fairhope AL
performance when hot outside

Camaro runs very strong in cooler weather (85 and below) If its hot out; say mid noon 95ish and high humidty, power just falls off big time. Anyone else find away around this? Or simular problems. I'm allready running 160 thermostat, and reprgrammed to have fans come on at 170 ish. car won't run really over 170-180 no matter how hot it is outside, really would like to have that, *SNAP* in throttle like i have in the evening and at night. Can't let those little rice rockets catch me on bad day
Old Jun 19, 2006 | 07:09 PM
  #2  
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Re: performance when hot outside

Yeah. On a hot day the engine will get heat soaked no matter when your fans come on.
Old Jun 19, 2006 | 07:45 PM
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Re: performance when hot outside

Yes heat will affect your performance, but if it's an M6 I think the main problem is when our clutches get to hot, wish they had something to cool down the clutches. Mine seems to slip when it's hot outside. Loose alot of power.
Old Jun 19, 2006 | 07:52 PM
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Re: performance when hot outside

Having the AC does not help either..
Old Jun 19, 2006 | 07:57 PM
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Re: performance when hot outside

Most of it is due to the air being hot, hot air + humid air =less % oxygen and its less dense when its hotter to, thats where the real power loss comes from. On a hot summer day down here at sealevel, the D/A can be 3000+ ft, if you don't know what that means it means its like being 3000ft above sea level.
Old Jun 19, 2006 | 08:24 PM
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Re: performance when hot outside

Yeah, temps make a big difference. Every 10 degree drop in temp will get you about 1+ mph in the 1/4 mile, given roughly the same humidity. Lower humidity is better. Barometric pressure also makes a big difference. High pressure is better.

Just last week, guys started to trap 1-1.5 mph better at the end of the night when the air cooled down 10+ degrees versus the heat of the day.

I always calculate my DA every time I race so that I know how I can compare my times to other track times with different weather. The best DA I've had is 1500. The track I go to is 688 ft. above sea level.

Dan

Last edited by stereomandan; Jun 19, 2006 at 08:27 PM.
Old Jun 19, 2006 | 08:29 PM
  #7  
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Re: performance when hot outside

Yea the heat has alot to do with it. Plus the IAT Sensor is always reading alot hotter than it is outside. Here in TX it really sucks, kills my car, my car runs fine around 180 and the car hits 200 and the car looses alot of power. I need to go to 160 stat and a fan switch but I'll still loose power to density. I'm running 180 stat now but this 388 and LT's are producing alot of heat.
Old Jun 19, 2006 | 11:00 PM
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Re: performance when hot outside

what if i was to route the IAT behind a cooling fan (or an area to provide some cooler air?) Somewhat false reading? Thanx everyone, for your input makes me feel at ease that we're all in the same boat
Old Jun 19, 2006 | 11:26 PM
  #9  
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From: Columbia, Pa
Re: performance when hot outside

SLP makes a plug-in that hooks to your IAT sensor to trick the computer into thinking its cooler out, I bought one a few years ago



Air-Temperature Module, Various V8 Applications

--------------------------------------------------------------------------------
This module plugs in between the air temperature sensor and its harness connector. It tells the PCM air to provide maximum spark advance (usually a 1 to 2 degree increase). Proper knock sensor and other engine sensor functions are not compromised. SLP suggests the use of premium grade fuel with this modification. A 5 to 7 horsepower increase is possible. Call for the most up to the minute vehicle applications. This item works on stock or modified engines HOWEVER it is NOT for use with custom PCM calibrations with advance spark timing. NOT legal for use on pollution controlled motor vehicles.

NOTE: For use with stock MAF sensors and stock tuning.
Old Jun 19, 2006 | 11:33 PM
  #10  
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Re: performance when hot outside

yup, I've noticed it too......the heat around here lately is not kind to me.
Old Jun 20, 2006 | 12:24 AM
  #11  
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From: virginia
Re: performance when hot outside

have yall done the t/b bypass its just a little but it may help alittle. afew degrees is a few degrees.
Old Jun 21, 2006 | 12:36 PM
  #12  
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From: Ocala, Florida
Re: performance when hot outside

Originally Posted by wyldcdn
what if i was to route the IAT behind a cooling fan (or an area to provide some cooler air?) Somewhat false reading? Thanx everyone, for your input makes me feel at ease that we're all in the same boat
The air that a cooling fan blows out into the engine bay is 150+ degrees.
Old Jun 21, 2006 | 04:53 PM
  #13  
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Re: performance when hot outside

The IAT sensor heat soaks pretty badly in the stock location. To get a more accurate reading on temperature, relocate the IAT sensor closer to the CAI filter. I drilled a hole in the metal can on my K&N cone filter, put a rubber grommet in the hole and pushed the IAT sensor into it. Add some wire to the harness, and connect in the new location.

There is speculation that the mysterious 3deg of ignition advnace that normally appears on a scan (compared to the value in the ignition advance tables) is related to the IAT sensor reading, and disappears at higher IAT temperatures.
Old Jun 22, 2006 | 12:27 PM
  #14  
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From: Saginaw, Michigan
Re: performance when hot outside

Originally Posted by Injuneer
The IAT sensor heat soaks pretty badly in the stock location. To get a more accurate reading on temperature, relocate the IAT sensor closer to the CAI filter. I drilled a hole in the metal can on my K&N cone filter, put a rubber grommet in the hole and pushed the IAT sensor into it. Add some wire to the harness, and connect in the new location.

There is speculation that the mysterious 3deg of ignition advnace that normally appears on a scan (compared to the value in the ignition advance tables) is related to the IAT sensor reading, and disappears at higher IAT temperatures.
Good info. Thanks. I think I'll try that. Any ideas what a loss of 3 degrees of advance will do to power output on a stock, or bolt on LT1?

Dan
Old Jun 22, 2006 | 12:31 PM
  #15  
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Re: performance when hot outside

I don't even race my car @ the track over 75*, period! I eace myself just for the best times & I know I won't get a good time at temperatures over 75*. I've lost .5 - .6's and 4 mph EASY on a hot, humid day/night.
Mike
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