Good Shift Point for Auto LT1?
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Le Mans Master
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Good Shift Point for Auto LT1?
What should be a good point for an auto LT1 to shift at? A friend came over the other day and when in Drive at WOT his '92 shifted at 5100 rpm according to Diacom. That seems kinda early to me for an LT1. Should the TV cable be adjusted to make it shift around 5500 or so?
What does everyone think?
What does everyone think?
Safety Car
Joined: Jun 1999
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From: Southern California
Re: Good Shift Point for Auto LT1? (tntcorvette)
Your friend's car is having the same problems as mine. My car shifts at 5,000rpm. I have a raised limiter at 5850 so i'm 850 short. You can't adjust the wot shift points with the t.v. cable so don't go this route. You need a B&M governor modifier kit ($27). It comes with the springs and such.
Safety Car
Joined: Jun 2000
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From: Long Island, NY
Re: Good Shift Point for Auto LT1? (Goody)
Do a dyno run for his car and adjust shift points with that data in hand for best results.
But, 5000 rpm is too low, most TPI's shift at about 4800 - 5000 rpm. So the LT1 should be atleast 5500 - 5700 rpm.
Vic
[Modified by Vic'89, 3:31 PM 1/9/2002]
Burning Brakes
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From: Chicago, IL
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Re: Good Shift Point for Auto LT1? (Vic'89)
According to my Tach at least mine shifts at Redline which I believe is at 5900RPM or so. 5000 is too early. I've seen my Tach in the red before it kicks.
Racer
Joined: Feb 1999
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From: Sellersburg Florida
Re: Good Shift Point for Auto LT1? (Marcho Polo)
Craig, try with the car not running, depress the gas pedal to the floor, and have someone under the hood manually trying to open the throttle to w.o.t., if the throttle opens more you can adjust your t.v. cable to maximize your throttle. This will get your t.p.s. (throttle position sensor) the right info to relay to your e.c.m.
Your cars t.p.s. is only seeing partial throttle, while your foot is through the floor! In return the e.c.m., which controls the transmissions shifts points is not getting the info of w.o.t. status. This could alter your shift points, and be holding back some power. I have seen a few LT1 vettes with this prob.
Good luck
Your cars t.p.s. is only seeing partial throttle, while your foot is through the floor! In return the e.c.m., which controls the transmissions shifts points is not getting the info of w.o.t. status. This could alter your shift points, and be holding back some power. I have seen a few LT1 vettes with this prob.
Good luck
Le Mans Master
Joined: Apr 2000
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From: Manassas VA
Re: Good Shift Point for Auto LT1? (CROOZN)
Craig,
The 92 has the 700 trans in it and full throttle shifts are controled by a govener and not the computer. This seems to be a problem with 92 and 93 vettes. I have wondered if replacing the govener would fix this (considering they have springs and pivot points that could wear) or if it is necessery to install one of the b&m kits that Raysur is talking about. Good luck, and keep up posted with what you find out!!
The 92 has the 700 trans in it and full throttle shifts are controled by a govener and not the computer. This seems to be a problem with 92 and 93 vettes. I have wondered if replacing the govener would fix this (considering they have springs and pivot points that could wear) or if it is necessery to install one of the b&m kits that Raysur is talking about. Good luck, and keep up posted with what you find out!!
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Re: Good Shift Point for Auto LT1? (Red 86 4+3)
My 93 shifts at 5,000(don't know if the tach is accurate though).
The rev limiter is at 5850.
The rev limiter is at 5850.
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Thread Starter
Le Mans Master
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Re: Good Shift Point for Auto LT1? (Vic'89)
Do a dyno run for his car and adjust shift points with that data in hand for best results.
I think we have enoigh LT1 cars on this forum to find out the stock shift points on the Auto Tranny, no need to dyno yet.
But, 5000 rpm is too low, most TPI's shift at about 4800 - 5000 rpm. So the LT1 should be atleast 5500 - 5700 rpm.
I think we have enoigh LT1 cars on this forum to find out the stock shift points on the Auto Tranny, no need to dyno yet.
But, 5000 rpm is too low, most TPI's shift at about 4800 - 5000 rpm. So the LT1 should be atleast 5500 - 5700 rpm.
Yeah, my L98 shifts at 5150 according to Diacom. That might be a bit early for my car. His LT1 shifted at 5050 I think. I was thinking we need to get his car to go at least 5500.
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Re: Good Shift Point for Auto LT1? (Marcho Polo)
My '92 will actually get into the rev limiter (about 5800 RPM?) before the 1-2 shift! I sometime have to back off the throttle just a bit in order for the tranny to shift. Is this a TV cable problem? Car only has 26K miles and there are no other apparent problems with the tranny. Shifts are firm and no slippage.
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From: Former NCM Drag Racing coordinator, National director Corvette Challenge Spring Hill, Tennessee: Whiting, New Jersey
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Re: Good Shift Point for Auto LT1? (Marcho Polo)
When my motor was stock I had the shift points set at 6,000.
Now with the mods it shifts at 6,800.
Now with the mods it shifts at 6,800.
Drifting
Joined: Jun 2000
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From: na
Re: Good Shift Point for Auto LT1? (mackeyred96)
Consider leaving it alone unless you have a budget for repairs. My used 92 came with a "beefed" up tranny as the seller called it! It would shift at the red line on the 1-2 and the 2-3 shift. With this setup the car would really accelerate fast.
Then is started to come apart. I put in a SRTA (GM rebuilt). Now I have a tranny that upshifts 1-2 at 4,800 rpm and 2-3 at about 5,500. I took it right back to the dealer and they said that it's just right and that there is nothing they can do! Of course I have a 50K or 3 year warrantee to consider.
So if I need to go all out I manually shift 1-2. It's a little faster than letting the tranny do it considering the low up shift RPM.
I am just living with it and saving up for the next breakdown.
Then is started to come apart. I put in a SRTA (GM rebuilt). Now I have a tranny that upshifts 1-2 at 4,800 rpm and 2-3 at about 5,500. I took it right back to the dealer and they said that it's just right and that there is nothing they can do! Of course I have a 50K or 3 year warrantee to consider.
So if I need to go all out I manually shift 1-2. It's a little faster than letting the tranny do it considering the low up shift RPM.
I am just living with it and saving up for the next breakdown.
Team Owner
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From: Former NCM Drag Racing coordinator, National director Corvette Challenge Spring Hill, Tennessee: Whiting, New Jersey
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Re: Good Shift Point for Auto LT1? (Don Martin)
Consider leaving it alone unless you have a budget for repairs. My used 92 came with a "beefed" up tranny as the seller called it! It would shift at the red line on the 1-2 and the 2-3 shift. With this setup the car would really accelerate fast.
Then is started to come apart. I put in a SRTA (GM rebuilt). Now I have a tranny that upshifts 1-2 at 4,800 rpm and 2-3 at about 5,500. I took it right back to the dealer and they said that it's just right and that there is nothing they can do! Of course I have a 50K or 3 year warrantee to consider.
So if I need to go all out I manually shift 1-2. It's a little faster than letting the tranny do it considering the low up shift RPM.
I am just living with it and saving up for the next breakdown.
Then is started to come apart. I put in a SRTA (GM rebuilt). Now I have a tranny that upshifts 1-2 at 4,800 rpm and 2-3 at about 5,500. I took it right back to the dealer and they said that it's just right and that there is nothing they can do! Of course I have a 50K or 3 year warrantee to consider.
So if I need to go all out I manually shift 1-2. It's a little faster than letting the tranny do it considering the low up shift RPM.
I am just living with it and saving up for the next breakdown.
My trans is 100% stock, not even a shift kit and is just now starting to slip but that woith 96,000 mile and 700+ 1/4 mile passes. I let the computor shift mine. It's still more consistance than me even after 35 years of racing.
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From: Somers NY
Re: Good Shift Point for Auto LT1? (mackeyred96)
When my motor was stock I had the shift points set at 6,000.
Now with the mods it shifts at 6,800.
Now with the mods it shifts at 6,800.
We have it easy, just set it and forgetit :)
Team Owner
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From: Former NCM Drag Racing coordinator, National director Corvette Challenge Spring Hill, Tennessee: Whiting, New Jersey
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Re: Good Shift Point for Auto LT1? (Red96Coupe)
We have it easy, just set it and forget it :)
Thank you Ron Popiel :D
