Converter causing trans slipping on 1-2 shift?
03-20-2005, 07:05 PM
#1
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Converter causing trans slipping on 1-2 shift? I was at E-town yesterday. A good time.
I put a 3800 stall Vig in my car. Now my car is hitting the rev limiter on the 1-2 shift.
It didn't do this before the converter?
The shift point was set at 44 mph with the rev limiter set at 6800 rpm.
After it hit the limiter on 3 out of my first 4 runs I decided to lower the shift points by 2 mph.
With the shift point now set at 42 mph (basically 300 rpm lower) I figured all would be fine?
I only ran two more times but the limiter still hit on one of the passes? Why would this happen?
It wasn't bad, just one Bap! Then it shifted right away?
I have the line pressure raised only at WOT. It has worked this long?
(I have gone 11.25 @ 127 with no problems before, on N2O?)
I don't have a shift kit, I was told they are not necessary.
Do I need one?
These runs were all NA. No squeeze that day.
Again the only change was the higher stall converter from 2800 to 3800.
Does anyone have an idea of what might be up?
Is this normal with higher stall converters?
Thanks in advance.
I put a 3800 stall Vig in my car. Now my car is hitting the rev limiter on the 1-2 shift.
It didn't do this before the converter?
The shift point was set at 44 mph with the rev limiter set at 6800 rpm.
After it hit the limiter on 3 out of my first 4 runs I decided to lower the shift points by 2 mph.
With the shift point now set at 42 mph (basically 300 rpm lower) I figured all would be fine?
I only ran two more times but the limiter still hit on one of the passes? Why would this happen?
It wasn't bad, just one Bap! Then it shifted right away?
I have the line pressure raised only at WOT. It has worked this long?
(I have gone 11.25 @ 127 with no problems before, on N2O?)
I don't have a shift kit, I was told they are not necessary.
Do I need one?
These runs were all NA. No squeeze that day.
Again the only change was the higher stall converter from 2800 to 3800.
Does anyone have an idea of what might be up?
Is this normal with higher stall converters?
Thanks in advance.
03-20-2005, 07:45 PM
#2
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The 3800 may need you to lower the MPH a bit more.
You will be running a few hundred RPM higher for the
same MPH under load / acceleration. Figure if it were
1:1 on the converter stall you would be turning 1000
RPM higher. Of course that's not how converters work
at the top end exactly, but you only made a -5% change
in MPH (which I guess would equate to maybe 300RPM)
and may need to take out a bit more.
You will be running a few hundred RPM higher for the
same MPH under load / acceleration. Figure if it were
1:1 on the converter stall you would be turning 1000
RPM higher. Of course that's not how converters work
at the top end exactly, but you only made a -5% change
in MPH (which I guess would equate to maybe 300RPM)
and may need to take out a bit more.
03-22-2005, 03:30 PM
#3
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Originally Posted by jimmyblue
The 3800 may need you to lower the MPH a bit more.
You will be running a few hundred RPM higher for the
same MPH under load / acceleration. Figure if it were
1:1 on the converter stall you would be turning 1000
RPM higher. Of course that's not how converters work
at the top end exactly, but you only made a -5% change
in MPH (which I guess would equate to maybe 300RPM)
and may need to take out a bit more.
You will be running a few hundred RPM higher for the
same MPH under load / acceleration. Figure if it were
1:1 on the converter stall you would be turning 1000
RPM higher. Of course that's not how converters work
at the top end exactly, but you only made a -5% change
in MPH (which I guess would equate to maybe 300RPM)
and may need to take out a bit more.
03-22-2005, 06:05 PM
#4
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By the 2-3 you are not running the RPM up anywhere
near as fast, so don't need to "lead it" by as much. But
too, on my car the 2-3MPH was a bit short originally, I
moved it up a lot more than I moved the 1-2.
near as fast, so don't need to "lead it" by as much. But
too, on my car the 2-3MPH was a bit short originally, I
moved it up a lot more than I moved the 1-2.
03-24-2005, 04:49 PM
#5
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Originally Posted by jimmyblue
By the 2-3 you are not running the RPM up anywhere
near as fast, so don't need to "lead it" by as much. But
too, on my car the 2-3MPH was a bit short originally, I
moved it up a lot more than I moved the 1-2.
near as fast, so don't need to "lead it" by as much. But
too, on my car the 2-3MPH was a bit short originally, I
moved it up a lot more than I moved the 1-2.
The problem with that is, with the gear spacing there is a much bigger drop off from 1-2 then 2-3. It really pulls the motor down out of its power range.
On my 2-3 shift the car still stays in its power band.
You never mentioned if you thought a shift kit would help?
Thanks