Converter Temp Effect on ET

[Dean Feiock]

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??

[ALMACK]

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.

[Dick Butler]

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?

[Michael Beard]

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.

[Greg Hill]

Originally Posted by Dean Feiock

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??

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.

[Mike Taylor 3601]

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

[Robert Simpson]

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.

[FED 387]

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

[David Lee]

Originally Posted by Robert Simpson

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.

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

[Dean Feiock]

Originally Posted by Greg Hill

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.

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?