Performance issues..
Thread Starter
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Joined: Jul 2001
Posts: 182,997
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From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Performance issues..
Raced at the Corvette Challenge today..
There was little time between passes and the engine and tranny ran 210 - 230 degrees.. The car got 3 mph slower every pass..
My first pass was 119 mph and my 3rd pass was 113 mph...
Could that bad performance be caused by the engine being hot?
The A/F was ok (12.2 - 12.4) but still rich (after I re-jetted last night)..
Still made it to the semi final.. but I wonder if there could be anything wrong with the engine?? Could the hot engine and tranny be responsible for a 6 mph loss (and .6 slower ET) between passes?
There were no noises etc. from the engine to indicate that there would be anything wrong... The traceion also sucked today and my 60' times were .2 slower than usual..
Anyway, gonna change all the fluids on the car tomorrow, pull the valve covers etc. and will check for anything wrong...
There was little time between passes and the engine and tranny ran 210 - 230 degrees.. The car got 3 mph slower every pass..
My first pass was 119 mph and my 3rd pass was 113 mph...
Could that bad performance be caused by the engine being hot?
The A/F was ok (12.2 - 12.4) but still rich (after I re-jetted last night)..
Still made it to the semi final.. but I wonder if there could be anything wrong with the engine?? Could the hot engine and tranny be responsible for a 6 mph loss (and .6 slower ET) between passes?
There were no noises etc. from the engine to indicate that there would be anything wrong... The traceion also sucked today and my 60' times were .2 slower than usual..
Anyway, gonna change all the fluids on the car tomorrow, pull the valve covers etc. and will check for anything wrong...
Melting Slicks
Joined: Dec 2004
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From: pr, frederick md.
i cant see hot engine oil being a problem, and engine over temp would cause detenation and you said it made no noise, so thats not it. hmmm, possibly the trans fliud ( if auto ) getting hot could cause low pressure and create slight slippage. do you run a tranny cooler? and ice down the manifold between runs. alot of guys run fuel lines thru cool cans and hit the can with nitrous simply by strapping a plate system to the can. how was track conditions? could have been the track too.
Thread Starter
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
Originally Posted by redc3
i cant see hot engine oil being a problem, and engine over temp would cause detenation and you said it made no noise, so thats not it. hmmm, possibly the trans fliud ( if auto ) getting hot could cause low pressure and create slight slippage. do you run a tranny cooler? and ice down the manifold between runs. alot of guys run fuel lines thru cool cans and hit the can with nitrous simply by strapping a plate system to the can. how was track conditions? could have been the track too.
I run a tranny cooler but it still ran up to 230 degrees...
It felt like it was slipping a bit....
The track conditions were bad.. 60' times were horrible, but they shouldn't affect my mph... My concern is a 6 mph loss in mph within minutes
Melting Slicks
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From: pr, frederick md.
since you dont have time between runs, put a fan on that tranny cooler. high temp is a trannys kryptonite.. do you run your lines to the cooler only, or do you route thru the rad cooler first and then to the aux. cooler?
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
Originally Posted by redc3
since you dont have time between runs, put a fan on that tranny cooler. high temp is a trannys kryptonite.. do you run your lines to the cooler only, or do you route thru the rad cooler first and then to the aux. cooler?
Melting Slicks
Joined: Dec 2001
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From: Billings MT
Oliver: I have not noticed much difference in MPH based on tranny temp. It will typically run from 180-210 degrees, as hot as 260 degrees if I try to make 3 consecutive runs on a hot day.
What tranny fluid are you using? I run Redline High-Temp ATF, won't burnish.
What tranny fluid are you using? I run Redline High-Temp ATF, won't burnish.
Thread Starter
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
Originally Posted by VETDRMS
Oliver: I have not noticed much difference in MPH based on tranny temp. It will typically run from 180-210 degrees, as hot as 260 degrees if I try to make 3 consecutive runs on a hot day.
What tranny fluid are you using? I run Redline High-Temp ATF, won't burnish.
What tranny fluid are you using? I run Redline High-Temp ATF, won't burnish.
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
"Could that bad performance be caused by the engine being hot?"
why not....a hot engine will heat up the fuel and incoming air decreasing the quanitity you get of both resulting in lower speeds
why not....a hot engine will heat up the fuel and incoming air decreasing the quanitity you get of both resulting in lower speeds
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What did RPM do in the traps? Was it down that much too..or is trans slipping/converter dying? If RPM was the same and speed is down...one of them is wounded.
Otherwise, I wouldn''t expect that much MPH drop due to heat. With time progressively getting slower that fast, I'd do some searching before anything bad happens.
JIM
Otherwise, I wouldn''t expect that much MPH drop due to heat. With time progressively getting slower that fast, I'd do some searching before anything bad happens.
JIM
Thread Starter
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
Originally Posted by 427Hotrod
What did RPM do in the traps? Was it down that much too..or is trans slipping/converter dying? If RPM was the same and speed is down...one of them is wounded.
Otherwise, I wouldn''t expect that much MPH drop due to heat. With time progressively getting slower that fast, I'd do some searching before anything bad happens.
JIM
Otherwise, I wouldn''t expect that much MPH drop due to heat. With time progressively getting slower that fast, I'd do some searching before anything bad happens.
JIM
First pass, I trapped at 6300 RPM
Second pass, I trapped at 6150 RPM
Third pass, I trapped at 6000 RPM
I noticed that my oil pressure was pretty low too... It always goes down when the oil gets very hot... However, I have never run the car that hot before...
Another thing that I did could've affected performance, but I doubt it..
After my first pass, I had to put some gas in the car and the 110 octane pump wasn't working, so I had them put 2 gallons of 112 leaded and 1 gallon of 100 unleaded into the car... Don't really think that this could've made a difference...