Converter Temp Effect on ET
 

Has anyone seen drastic changes in ET due to changes in converter temperature?
If so, do you think is a product of the type of fluid or the converter design?

I ask because last weekend, my car magically picked up ET again. Had a bad pairing in round 2 so we had a quik rerun. I cooled my car some but engine temp was actually warmer on the second run that it was on the previous run. No other changes. Runs were made within 15 minutes of each other.

The first run in round 2, the ET was 11.918, run out the back door.
The second run in round 2, the ET was 11.843, and I lifted some.

My car always seems to gain ET when back to back runs are made. I believe I have this narrowed down to converter temp but I don't know why it's happening.

Ideas??

Re: Converter Temp Effect on ET
 

I have a bracket car that does the same thing.
It doesn't pick up as much as yours did, but it keeps picking up as that big c-6 trans gets warmer.

Re: Converter Temp Effect on ET
 

Is the first round run on a cold car? Do you get the motor and trans and rear end run at all before the first run? Are you using any heavy oil anywhere which might be taking the extra time to thin out? Does the 60 ft show the change also or is it throughout the run? Is this something NEW for your combination? Do you have another Converter to try back to back?

Re: Converter Temp Effect on ET
 

Get a transmission temperature guage. I find that when the trans goes over 150, it's worth .015 to .02 in the 1/8th mile (so, obviously more in the 1/4) and how much change you see may depend on the type of fluid.

If you're running a thick oil, you may see more of a change as well in hot lap conditions.

Re: Converter Temp Effect on ET
 

I can tell you why it happens. As Raymond King who worked at TCI years ago once told me, an automatic transmission operates properly at180 degrees. Also warmer fluid makes your converter flash a little higher and your 60 ft. Picks up.

Re: Converter Temp Effect on ET
 

X2 on Michael's & Greg's comments,I had auto w/temp gauge mine would pick up .07-.08 when fluid got to 190+.
I was using regular old type F fluid I'm sure there is difference in fluids.
My conv. was a little too tight I could leave off dead idle and run fastest but could'nt hit tree,bring up to 2000 on line and hit tree but slow down .20 in 1/8,then with fliud 190+ could pickup another .07-.08. due to conv. flashing more due to fluid thinned out.
Mike Taylor 3601

Re: Converter Temp Effect on ET
 

Not to highjack the question. But where do you put the temp probe in the trans? The pan? or somewhere else? I have one in my pan and no matter how much I hot lap it, it has not gotten over 150deg. I run a cooler and Semi-Synthetic oil. I am curious about this also.

Re: Converter Temp Effect on ET
 

Robert--best place is in the trans pan---second best location is in the trans output to cooler line as close to the trans as possible

Re: Converter Temp Effect on ET
 

What if you reduced the size of the cooler, thus less area to permit less cooling

Re: Converter Temp Effect on ET
 

Thanks for all the replys.

That is the same conclusion I had come to. Which is an indication that the converter is to tight for my every day routine.

The question becomes, do I run the transmission warmer all the time or do I get a looser converter?

Re: Converter Temp Effect on ET
 

Dean your car will be more consistent if you run it at the same temp every time. Trans temp is a variable that can be controlled. Get a gauge and a pan heater.

Re: Converter Temp Effect on ET
 

I had a customer that had stock sprag go out in his tranny. He replaced it with one that had more elements. That was the only change he made. Before the change his car was deadly consistant. The change seemed to cause the ET to be "off" on the first pass. He figured out he had to warm it up to a higher temp to make it run the number without throwing out the first pass. He was running a hyd fluid and I've always thought it was more about the fluid than anything else.

Re: Converter Temp Effect on ET
 

What type of trans temp gauge is better, electrical or mechanical? And full sweep vs short sweep?

Re: Converter Temp Effect on ET
 

Digital

Re: Converter Temp Effect on ET
 

An electric gauge makes for easier transmission removal.

Re: Converter Temp Effect on ET
 

I drilled and tapped trans above pan where temp gauge came down through top of case into fluid in pan, you could pull gauge probe and not lose fluid,also had plug could be put in if trans was going to be tilted while removed or transported.
Mike Taylor3601

Re: Converter Temp Effect on ET
 

I've got a mechanical trans. temperature gauge mounted in-line on the pressure side of the cooling lines. I've got one of those extruded aluminum coolers mounted underneath the right floor pan with a Auto Meter temperature manifold to accept the gauge. Works great and don't have to mess with it during trans. changes.