Tranny governor mod - shift point corrected..
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
Tranny governor mod - shift point corrected..
When I analyzed last weeks track video, I noticed that the 1 - 2 shift still occured at 5200 RPM with my modified governor (cut down weights on the governor).
see also this video (from last week)
http://www.corvetteforum.net/c3/gran...desoto1114.wmv
Initially, I bought a brand new governor with reduced weights on it and a softer spring and when I went to the track, the shift wouldn't occur at all before hitting the rev limiter at 7000 RPM...
So, what I initially did was to install the spring from the old governor into the new governor and the shift points changed, especially on the 2 - 3 shift.. The old spring in the new governor got the shift points to 5200 for the 1 - 2 shift and 6000 RPM for the 2 - 3 shift..
I'm now shifting 2 - 3 manually, so I'm mostly concerned about the 1 - 2 shift.
Yesterday, I ended up putting the soft spring, which initially was in the new governor, into the old governor.. So, I was using the unmodified weights but a softer spring.
Went to the track today and the 1 - 2 shift is now occuring at about 6200 RPM!! It's not quite where I want it but it's a huge difference from 5200 RPM... Unfortunately, I couldn't take advantage of the better shift point because the car was hesitating... I suspect a carb issue... Initially, it would run like crap and when I rev'd up the engine a few times, it would get better, but the car still hesitated during the entire trip down the track.. I'll have the carb checked out.. I'm pretty sure that it's a fuel delivery issue...
BTW - I still ran 3 passes in the 11.24 - 11.29 range at 119 - 119.63 mph range... (my reaction time was in the .02 - .07 range
.
I'm finally getting used to launching that beast
Without the hesitation, I will be VERY close to 10's... I hope that it's just an issue with the carb and not any other problem...
BTW - temperature was 88 - 90 degrees with a heat index of 98 - 100 degrees...and sunny skies...
see also this video (from last week)
http://www.corvetteforum.net/c3/gran...desoto1114.wmv
Initially, I bought a brand new governor with reduced weights on it and a softer spring and when I went to the track, the shift wouldn't occur at all before hitting the rev limiter at 7000 RPM...
So, what I initially did was to install the spring from the old governor into the new governor and the shift points changed, especially on the 2 - 3 shift.. The old spring in the new governor got the shift points to 5200 for the 1 - 2 shift and 6000 RPM for the 2 - 3 shift..
I'm now shifting 2 - 3 manually, so I'm mostly concerned about the 1 - 2 shift.
Yesterday, I ended up putting the soft spring, which initially was in the new governor, into the old governor.. So, I was using the unmodified weights but a softer spring.
Went to the track today and the 1 - 2 shift is now occuring at about 6200 RPM!! It's not quite where I want it but it's a huge difference from 5200 RPM... Unfortunately, I couldn't take advantage of the better shift point because the car was hesitating... I suspect a carb issue... Initially, it would run like crap and when I rev'd up the engine a few times, it would get better, but the car still hesitated during the entire trip down the track.. I'll have the carb checked out.. I'm pretty sure that it's a fuel delivery issue...
BTW - I still ran 3 passes in the 11.24 - 11.29 range at 119 - 119.63 mph range... (my reaction time was in the .02 - .07 range
.I'm finally getting used to launching that beast
Without the hesitation, I will be VERY close to 10's... I hope that it's just an issue with the carb and not any other problem...
BTW - temperature was 88 - 90 degrees with a heat index of 98 - 100 degrees...and sunny skies...
Last edited by GrandSportC3; Aug 21, 2005 at 12:44 PM.
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Just a little bit closer and you will be there. Hopefully the hesitation is something easy to work out.
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St. Jude Donor '03, '06, '17
Originally Posted by Eddie 70
Just a little bit closer and you will be there. Hopefully the hesitation is something easy to work out.
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Oliver - I have an new extra 6800 rpm gov never opened from Art Carr. It was something like $68 bucks. Make me an offer and I'll send it to you if your interested. It was for my 700R4, but I think that it's the same as a 200.
What I found with 700R4 and 4.11 gearing that it's easy to overpower the tires on the 1-2 shift. I watched your vid. it sounds like your spinning on the 1-2 because your rpm didn't drop after the shift.
What I found with 700R4 and 4.11 gearing that it's easy to overpower the tires on the 1-2 shift. I watched your vid. it sounds like your spinning on the 1-2 because your rpm didn't drop after the shift.
Last edited by gkull; Aug 22, 2005 at 10:31 AM.
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St. Jude Donor '03, '06, '17
Originally Posted by gkull
Oliver - I have an new extra 6800 rpm gov never opened from Art Carr. It was something like $68 bucks. Make me an offer and I'll send it to you if your interested. It was for my 700R4, but I think that it's the same as a 200.
What I found with 700R4 and 4.11 gearing that it's easy to overpower the tires on the 1-2 shift. I watched your vid. it sounds like your spinning on the 1-2 because your rpm didn't drop ofter the shift.
What I found with 700R4 and 4.11 gearing that it's easy to overpower the tires on the 1-2 shift. I watched your vid. it sounds like your spinning on the 1-2 because your rpm didn't drop ofter the shift.
Thread Starter
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St. Jude Donor '03, '06, '17
Originally Posted by gkull
I watched your vid. it sounds like your spinning on the 1-2 because your rpm didn't drop ofter the shift.
The 2 - 3 shift should also drop to 4200 RPM but it only drops to 4800...
Gotta love a high stall speed
Last edited by GrandSportC3; Aug 21, 2005 at 02:40 PM.
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Man, you make me feel so guilty. I "almost" got energetic enough to take mine to the track yesterday, but it was too hot to have any fun.
I gotta hand it to you.....you are working that dude hard and getting it dialed in. You have it pretty darn consistent. When cool weather comes you're going to fly!
Shift points up near 7000 rpm would be a good thing. Keep after it!
About all I could manage today was a 50 mile drive to hang out with some Vette buddies and some cruising in the country. Even just doing that was pretty warm...sitting in staging lanes would be brutal!
JIM
I gotta hand it to you.....you are working that dude hard and getting it dialed in. You have it pretty darn consistent. When cool weather comes you're going to fly!
Shift points up near 7000 rpm would be a good thing. Keep after it!
About all I could manage today was a 50 mile drive to hang out with some Vette buddies and some cruising in the country. Even just doing that was pretty warm...sitting in staging lanes would be brutal!
JIM
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Originally Posted by 427Hotrod
Even just doing that was pretty warm...sitting in staging lanes would be brutal!
JIM
JIM
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Originally Posted by GrandSportC3
The temperature was VERY hot, even for Florida standards... I always try to race in the morning, because afternoons are even worse...
been this way for 2 months now....humidity to match...
sux....
and there is allmost no blow either.....
GENE
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St. Jude Donor '03, '06, '17
Originally Posted by mrvette
tell me about it...try working in this weather...outside that is...
been this way for 2 months now....humidity to match...
sux....
and there is allmost no blow either.....
GENE
been this way for 2 months now....humidity to match...
sux....
and there is allmost no blow either.....
GENE
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Why don't you just shift manually? Or get an air / electric shift solenoid for the 1/2 shift? Those are a hell of a lot easier to dial in.
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St. Jude Donor '03, '06, '17
Originally Posted by BSeery
Why don't you just shift manually? Or get an air / electric shift solenoid for the 1/2 shift? Those are a hell of a lot easier to dial in.
I also need the tranny to shift automatically for the bracket events that I race at.. Automatic shift is usually more accurate than manual shift... Air shifters or electric shifters are not legal in the NO ELECTRONICS class that I race in..
