C4 shift point 85 versus 86
Thread Starter
Instructor
Joined: Jun 2010
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From: Webster Florida
C4 shift point 85 versus 86
I have an 85 and 86 Corvette, both with 5.7 TPI engines, and both with an automatic. I just got the 85 and noticed that the 85 shifts out of 1st into second at 4000 rpm while my 86 shifts out at 5100 rpm.
The 85 has a shift kit the 86 doesn't. the 86 has a hypertech chip, the 85 doesn't.
I've done the self adjust on both.
what can I do to adjust the shifting of the 85 to 5,000 rpm or is this difference because of the hypertech chip. I've already ordered a hypertech for the 85... the two computers are different.
thanks in advance,
Robert
The 85 has a shift kit the 86 doesn't. the 86 has a hypertech chip, the 85 doesn't.
I've done the self adjust on both.
what can I do to adjust the shifting of the 85 to 5,000 rpm or is this difference because of the hypertech chip. I've already ordered a hypertech for the 85... the two computers are different.
thanks in advance,
Robert
Race Director
Joined: Apr 2003
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From: moraga ca
Shift points on a 700r4 are determined by the weights and springs in the governor, not the computer. Buy a B&M governor weight kit and change to lighter weights. This will delay the wot shift points.
Thread Starter
Instructor
Joined: Jun 2010
Posts: 116
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From: Webster Florida
Thank you... actually I found a new governor on this web site:
http://www.transmissioncenter.net/highperf700r4.htm
search on 700R4 Corvette governor on the page to find it. it was only $38 and is made for a WOT shift at 5200 RPM.
Robert
http://www.transmissioncenter.net/highperf700r4.htm
search on 700R4 Corvette governor on the page to find it. it was only $38 and is made for a WOT shift at 5200 RPM.
Robert
Last edited by rrwebster; Sep 13, 2010 at 11:30 PM.
Thread Starter
Instructor
Joined: Jun 2010
Posts: 116
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From: Webster Florida
Does the Governor cover just pop off? (pry off) and can it be removed and replaced without dropping the exhaust? it looks like it but I hate to try getting it out and not be able to.
thanks in advance!
Robert
thanks in advance!
Robert
Race Director
Joined: Apr 2003
Posts: 17,699
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From: moraga ca
I could get the cap off on my car without taking the exhaust off, but I had left the spring clip off and had a different exhaust from stock. I used a large screwdriver and hammer to remove the cap and an old bar type torque wrench to tap the cap back on. I still have a scar or two on my forarms from the burns (kidding),
Race Director
Joined: Apr 2003
Posts: 17,699
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From: moraga ca
No, I think some of the caps had a spring clip on the outside which was a pita. Some of my trannies came from non c4 stock so maybe the camaros or passenger cars used the clips. If you don't have it, all the better. The governer just rotates and pulls out.
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Thread Starter
Instructor
Joined: Jun 2010
Posts: 116
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From: Webster Florida
I got the new govenor installed... no problems... used to do the 1-2 shift at 4200 rpm now it shifts at 3900... 2-3 and 3-4 are shifting at 5200 though, what could be causing this????
Safety Car
Joined: Sep 2001
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From: Glenbeulah Wi
Too much spring pressure and not enough weight. The springs have a greater effect at low road speed and the weights have more effect as the speed increases.
Thread Starter
Instructor
Joined: Jun 2010
Posts: 116
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From: Webster Florida
same topic... shift points same transmission... 700 r4 now i'm working on my 88 gta with a 5.0 tpi engine... put a b&m shift kit in it... it's shifting better but unless I leave it in 1st gear and let it shift out to 2nd, it's shifting at around 20 mph.... 2200 rpm whether I'm accelerating normally or at WOT. My cable adjustment is correct based on everything I've read... it's fully extended at WOT and the normal shift points are what I've read however no downshift to 2nd when below 20 mph and the low rpm shifting at WOT.
I'd love this tranny to shift like my vettes... would a servo and govenor from a vette do this? Is there something I'm missing in the TV cable adjustment now that it has a shift kit?
I've called B&M and all they say is check the pressures.
I'd love this tranny to shift like my vettes... would a servo and govenor from a vette do this? Is there something I'm missing in the TV cable adjustment now that it has a shift kit?
I've called B&M and all they say is check the pressures.
