Shifting rpm range
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Joined: Jan 2020
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From: New Jersey
Shifting rpm range
We have a built 700r4 with a 2600 stall convertor how can you get the car to shift higher without manually shifting it..I think stock shift points are hurting our ETs i think 4800 to 5200 is stock shift points I'd like 5500 or a tad higher..thanks for any help
Le Mans Master
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From: Texas
Try shifting at a LOWER rpm and see what happens. You want to maximize the effect of the torque converter, so you want to keep the rpm's in the fattest part of the power curve at the shift.
I had my 96 heads/cam LT1 impala set to shift at 5200 at the 1-2 shift and 6000 at the 2-3 shift. I had a program back in the day, some drag race simulator program, that suggested this. I THINK it was called Desktop Drag. You used Desktop Dyno to build a dyno graph of your engine combo, and then fed that into the Desktop Drag tool along with your car's weight, gear ratios, and torque converter data, and the software would predict your ET's. It suggested to lower our 1-2 shift points, and dang if it wasn't correct.
I had my 96 heads/cam LT1 impala set to shift at 5200 at the 1-2 shift and 6000 at the 2-3 shift. I had a program back in the day, some drag race simulator program, that suggested this. I THINK it was called Desktop Drag. You used Desktop Dyno to build a dyno graph of your engine combo, and then fed that into the Desktop Drag tool along with your car's weight, gear ratios, and torque converter data, and the software would predict your ET's. It suggested to lower our 1-2 shift points, and dang if it wasn't correct.
Race Director
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If 93 or older do not adjust shift rpms via tv cable.
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From: New Jersey
Try shifting at a LOWER rpm and see what happens. You want to maximize the effect of the torque converter, so you want to keep the rpm's in the fattest part of the power curve at the shift.
I had my 96 heads/cam LT1 impala set to shift at 5200 at the 1-2 shift and 6000 at the 2-3 shift. I had a program back in the day, some drag race simulator program, that suggested this. I THINK it was called Desktop Drag. You used Desktop Dyno to build a dyno graph of your engine combo, and then fed that into the Desktop Drag tool along with your car's weight, gear ratios, and torque converter data, and the software would predict your ET's. It suggested to lower our 1-2 shift points, and dang if it wasn't correct.
I had my 96 heads/cam LT1 impala set to shift at 5200 at the 1-2 shift and 6000 at the 2-3 shift. I had a program back in the day, some drag race simulator program, that suggested this. I THINK it was called Desktop Drag. You used Desktop Dyno to build a dyno graph of your engine combo, and then fed that into the Desktop Drag tool along with your car's weight, gear ratios, and torque converter data, and the software would predict your ET's. It suggested to lower our 1-2 shift points, and dang if it wasn't correct.
Team Owner
Joined: Dec 2000
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From: Phila., PA burbs
I remember a few good threads from back in the day about the time consuming process of messing with the weights in the governor. Sounds like a TON of trial and error, testing, filing, etc. I should have done the same thing years ago in my car as it also shifts too early. Unfortunately I never got around to it and now I almost never take it to the track so it'll probably never happen at this point.
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From: New Jersey
I remember a few good threads from back in the day about the time consuming process of messing with the weights in the governor. Sounds like a TON of trial and error, testing, filing, etc. I should have done the same thing years ago in my car as it also shifts too early. Unfortunately I never got around to it and now I almost never take it to the track so it'll probably never happen at this point.
Team Owner
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From: Park City Utah
I had my 96 heads/cam LT1 impala set to shift at 5200 at the 1-2 shift and 6000 at the 2-3 shift. I had a program back in the day, some drag race simulator program, that suggested this. I THINK it was called Desktop Drag. You used Desktop Dyno to build a dyno graph of your engine combo, and then fed that into the Desktop Drag tool along with your car's weight, gear ratios, and torque converter data, and the software would predict your ET's. It suggested to lower our 1-2 shift points, and dang if it wasn't correct.
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From: New Jersey
I agree. 4800 is too low for you combo, I feel. Do you have a dyno run of the engine?
You want the most average hp under the curve, so with the OP's combo, lowering the RPM isn't likely going to accomplish that.
Are you sure you don't have that backward? I can see a 6k 1-2 shift due to the wide 1-2 ratio spread of the 700R4...and then a more conservative 2-3, since they're closer together. Ideally, you want to shift above the HP peak....how much depends on the shape of your tq curve and your gear ratios.
You want the most average hp under the curve, so with the OP's combo, lowering the RPM isn't likely going to accomplish that.
Are you sure you don't have that backward? I can see a 6k 1-2 shift due to the wide 1-2 ratio spread of the 700R4...and then a more conservative 2-3, since they're closer together. Ideally, you want to shift above the HP peak....how much depends on the shape of your tq curve and your gear ratios.
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Team Owner
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From: Phila., PA burbs
I really don’t know. My car is sort of an anomaly, as dyno runs showing it making power all the way to 5500 RPM. I’ve posted the scans on here and everyone was baffled. I think it’s a fairly similar build to yours except with ASM runners instead of First setup. It has gone 11.8x at 114 and normally sees 60’s in the mid 1.5 range. This is with the trans shifting at the stock shift points so I really think bumping it up 500 RPM or so would yield better times.
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From: New Jersey
I really don’t know. My car is sort of an anomaly, as dyno runs showing it making power all the way to 5500 RPM. I’ve posted the scans on here and everyone was baffled. I think it’s a fairly similar build to yours except with ASM runners instead of First setup. It has gone 11.8x at 114 and normally sees 60’s in the mid 1.5 range. This is with the trans shifting at the stock shift points so I really think bumping it up 500 RPM or so would yield better times.
I messed with timing and air fuel too I forgot to mention that lol the shop set it to 38 degrees wot and he set air fuel to 13.0 wot this is on a set of 113 heads done by tpis..someone said these heads like alot of timing I moved the wot timing to 34 degrees and I set air fuel to 12.7 wot.. and we have nittos not the best tire my wife had to roll off she couldnt launch it hard it would spin..i have MT drag radials she wants to try the nittos one more time..she has gone 1.67 60ft so I think it has low 1.6s to high 1.5s with a good launch I'm sure this is heavier then your vette too..I think shifting it might help a little too we are 0.38 tenths away from 11.99 lol...wonder if she'll get there ?
Le Mans Master
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From: New Jersey
You have any data logs? That'll make it easy to see if the shifts are right or not. You'll see mph and rpm increase them the shift, follow the mph line. If it isn't changing slope when the shift happens you can push it further. In the same breath if when you are in the next gear and the mph slope is flatter and then noses up more, your rpms you shifted into are lower than they should be too. Obviously it'll look different through a stalled auto but you should be able to see the trend.
With your intake you should be shifting in the 5k range. Even my stock CFI manifold doesn't start to really hurt my performance until the 5k range. I'd say bump it up some... or use your edi setup to control a swap in 4l60.
With your intake you should be shifting in the 5k range. Even my stock CFI manifold doesn't start to really hurt my performance until the 5k range. I'd say bump it up some... or use your edi setup to control a swap in 4l60.
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From: New Jersey
You have any data logs? That'll make it easy to see if the shifts are right or not. You'll see mph and rpm increase them the shift, follow the mph line. If it isn't changing slope when the shift happens you can push it further. In the same breath if when you are in the next gear and the mph slope is flatter and then noses up more, your rpms you shifted into are lower than they should be too. Obviously it'll look different through a stalled auto but you should be able to see the trend.
With your intake you should be shifting in the 5k range. Even my stock CFI manifold doesn't start to really hurt my performance until the 5k range. I'd say bump it up some... or use your edi setup to control a swap in 4l60.
With your intake you should be shifting in the 5k range. Even my stock CFI manifold doesn't start to really hurt my performance until the 5k range. I'd say bump it up some... or use your edi setup to control a swap in 4l60.
Le Mans Master
Joined: Sep 2013
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From: near the thumb in the mitten
If you replace or rework governor, you can raise WOT shift rpm. With the 1-2 gear split depending on axle ratio, it maybe be worthwhile to let transmission make 1-2 shift. Then manually make 2-3 and 3-4 although it is about consistency. You can try different techniques to find the best results.
Race Director
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I heard years ago, shift 10% above max Horsepower (corrected, sorry about that). Problem is the 700R4 has a such a wicked first to second drop.
In my LT1(396), I put car in 2nd, let it shift where it needs to , then manually shift into 3rd.
In my LT1(396), I put car in 2nd, let it shift where it needs to , then manually shift into 3rd.
Last edited by krackenvette; Oct 22, 2020 at 01:27 AM.
Team Owner
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From: Park City Utah
^THat doesn't sound right at all. 10%?? So if your peak tq is at 3200 (typical stock TPI, then you should shift at 3200*.10=320+3200=3520 RPM?? I would have to see that work best, to believe it....because I don't believe it.
OP, If you can get it on a chassis dyno, then it'll be easy to calc the ideal shift point, knowing your trans gear ratios.
OP, If you can get it on a chassis dyno, then it'll be easy to calc the ideal shift point, knowing your trans gear ratios.
Last edited by Tom400CFI; Oct 21, 2020 at 11:52 PM.
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From: New Jersey
If you replace or rework governor, you can raise WOT shift rpm. With the 1-2 gear split depending on axle ratio, it maybe be worthwhile to let transmission make 1-2 shift. Then manually make 2-3 and 3-4 although it is about consistency. You can try different techniques to find the best results.
Race Director
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From: United States
^THat doesn't sound right at all. 10%?? So if your peak tq is at 3200 (typical stock TPI, then you should shift at 3200*.10=320+3200=3520 RPM?? I would have to see that work best, to believe it....because I don't believe it.
OP, If you can get it on a chassis dyno, then it'll be easy to calc the ideal shift point, knowing your trans gear ratios.
OP, If you can get it on a chassis dyno, then it'll be easy to calc the ideal shift point, knowing your trans gear ratios.
Le Mans Master
Joined: Mar 2006
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From: Texas
This is in a 89 iroc it's a 383 stroker,lpe219 cam,first performance intake,D port 113 heads fully worked, 36 lb injectors all controlled by a holley hp efi only thing is an old school 700r4 I think it needs to shift a little higher and I'm afraid to mess with the governor and hate to rely on manually shifting but if we have to we will...car went 12.3s at 109 with 1.6x 60fts I know there is more left in the table with it just shifting at stock shift points .
Le Mans Master
Joined: Mar 2006
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From: Texas
Are you sure you don't have that backward? I can see a 6k 1-2 shift due to the wide 1-2 ratio spread of the 700R4...and then a more conservative 2-3, since they're closer together. Ideally, you want to shift above the HP peak....how much depends on the shape of your tq curve and your gear ratios.