Cool down between run? PROS/CONS
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Senior Member
Joined: Jan 2003
Posts: 5,097
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From: DETROIT, (formerly Eaton County, Michigan)
Cool down between run? PROS/CONS
i was thinking of this today.
Is it actually better to let your truck completely cool down between runs? I think NO.
why?
when you first start your truck, the PCM retards the timing and the PCM is using different fuel tables, then when it is at normal operating temperature.
So if you make a run and let it cool down to a temperature below or well below normal operating temperature, your truck is not running optimally. and your run will (should) be slower.
Everyone knows hotlapping is NOT GOOD,
the engine is HEAT Soaked (so is the tranny and the tranny fluid). the A/F mixture is richer, because the air coming into the engine is HOT (less dense).
What to do?
After the run, let it cool down to perhaps the normal operating temp or a little BELOW IT.
why below it?
while you are sitting in line, waiting to make your run, your truck is going to heat up a little..
which brings me to my next point.
I've done this and I'm sure others have also. I take a run down the track, turn off the truck, , put ICE on the intake, turn on the E-fan to cool it down.
Then you after it is all cooled, you head for the track, and wait in line for 5-10 minutes, meanwhile your engine is heating up. (and dripping melted ICE on the pavement (maybe tires)
What's the secret to getting a good run, while using normal fuel tables and timing.?
thoughts? comments? No gripes!
Is it actually better to let your truck completely cool down between runs? I think NO.
why?
when you first start your truck, the PCM retards the timing and the PCM is using different fuel tables, then when it is at normal operating temperature.
So if you make a run and let it cool down to a temperature below or well below normal operating temperature, your truck is not running optimally. and your run will (should) be slower.
Everyone knows hotlapping is NOT GOOD,
the engine is HEAT Soaked (so is the tranny and the tranny fluid). the A/F mixture is richer, because the air coming into the engine is HOT (less dense).
What to do?
After the run, let it cool down to perhaps the normal operating temp or a little BELOW IT.
why below it?
while you are sitting in line, waiting to make your run, your truck is going to heat up a little..
which brings me to my next point.
I've done this and I'm sure others have also. I take a run down the track, turn off the truck, , put ICE on the intake, turn on the E-fan to cool it down.
Then you after it is all cooled, you head for the track, and wait in line for 5-10 minutes, meanwhile your engine is heating up. (and dripping melted ICE on the pavement (maybe tires)
What's the secret to getting a good run, while using normal fuel tables and timing.?
thoughts? comments? No gripes!
Senior Member
Joined: Jul 2004
Posts: 463
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From: Midwest
You should always make your runs/pulls at normal operating temps.
You run richer after hotlapping because the PCM pulls timing due to the extra heat to prevent detonation. Cooler air temps will yield more timing, at least on a stock PCM.
You run richer after hotlapping because the PCM pulls timing due to the extra heat to prevent detonation. Cooler air temps will yield more timing, at least on a stock PCM.
Senior Member
Joined: Jun 2003
Posts: 1,123
Likes: 0
From: Paradise
I ran 12 1/8th mile runs back to back one night in Immokolee with only 1/10th time down and only 1 mile per hour in difference. I lost them both in the fifth run and they held consistent.
Not sure if that adds anything of value to the post, but I thought it was interesting considering all the talk I have heard about, cool downs and their advantage.
D-Day
Not sure if that adds anything of value to the post, but I thought it was interesting considering all the talk I have heard about, cool downs and their advantage.
D-Day
