Author Topic: et change with engine temp  (Read 440 times)

Offline wideopen231

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et change with engine temp
« on: October 21, 2018, 02:25:08 PM »
Wondering what kind of change in et most are seeing if engine temp increases 10,20 or what ever make change in you combo when running alky?
Relecting obama is like shooting right foot because it did not hurt enough when you shot left foot

Offline gregm784

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Re: et change with engine temp
« Reply #1 on: October 22, 2018, 02:32:31 PM »
We've been hung out on the starting line a few times.  Each time, we seem to pick up the same.  a 30 second extension  equates to about a 1/10 of a second pick up.  Hot = flyin fast.    We generally try to turn on the top stage light about 140-150*  I don't know how much heat that 30 seconds produces, but i know it's gonna fly down track and i best be ready. :)
Greg
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Offline JrFuel Hayden

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Re: et change with engine temp
« Reply #2 on: October 23, 2018, 12:37:04 AM »
To stage your car at the perfect temp, depends on your combo, Greg has alum heads and I don't know if he runs water in his heads/block.
My JF engine must use iron heads & block, and we always run water because not only does it even out the temps around the two center cylinders but it does make more HP because water supports the clynders better and has better ring seal. also cuts down on the cyclinders from having harmonics [ like ringing a bell] , I've seen it on dyno pulls. OK enough on that subject.
We don't have a temp gauge on the car, I juse a infared temp gun to check the temps on the front of my heads just before it pulls into the lights, and I like 160-170 so it's up to 180-190 at the top bulb. alky fuel likes a hotter engine, it burns better. When I check the head temps after the run it can be 200-220.
I had another engine in another teams JF car and they did not run water, so I kept the temps around 150
I know of an ex NE-1 [ 7.60] team that fine tuned their car with engine temps , like if they ran a 7.55, they would run the engine cooler, like 10, I think,  to run 7.600.
You'll need to find the temps your engine likes, of course all that can change if you burn some nitro, I don't run any nitro, Heritage JF rule is pure alky only.
BTW when I have helped other JF teams staging and checking temps some take way too long to get any temp, because they did not lean the barrel valve enough, I set mine at 18% using a cylinder leak down gauge.
Jon   
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Offline wideopen231

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Re: et change with engine temp
« Reply #3 on: October 23, 2018, 05:33:27 AM »
Jon,
  Thanks for info .As always very informative.  I agree water makes more power and higher temp will almost alway make more power. WHen we where behind performance wise with our TA car I would have driver make sure to build as much heat as possible,longer burn outs,take time lower body and what ever else I could do to get little more heat in motor. While water works in most cases its not going to help me either heat or cooling with solid block and billet heads. Then I don't haver to worry much about cylinder support.LOL 
 Everyone,
What I am trying to get is baseline idea for now,refine later. If engine temp is 10* or 20* hotter than I want at stage is cr going to pickup .05 or .10.Yes its a combo based true answer. I figure if I know what it will do I can adjust my driving to compensate on top end.I will be bracket racing it and will have to dump the extra before finish line.  Just collecting data for the old memory banks to use later in case I do't have exact data base and need to take a SWAG to save the run. From info I have gotten from here and cpl other forums it seems .05  for 10* after 160 if a running average.. I have temp gauge wired to 3 positions switches that allow me to flip switch from rt. head to left head to oil to trans in two seconds. I figure all of these will have effect.Maybe minor but in game where .001 can make or break your run minor counts.

MY  biggest problem separating the driver from tuner when its time for the driver to not think. Most driver only don't have problem of that. LMAO The tuner is laughing by the way.
Relecting obama is like shooting right foot because it did not hurt enough when you shot left foot