Help choosing dif gear ratio for my setup
11-11-2018, 12:47 PM
#1
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Thread Starter
Help choosing dif gear ratio for my setup
Hi all, not a gm truck but driveline is GM tho.
Its a 1994 F150 lightning.
-GEN4 5.3L
-Procharger D1 14-15 PSI at 6200 RPM
-Meth injection
-91 oct fuel
-6L90E transmission
-im dialing in the tune but currently truck is doing 12.7 on 1/4 mile
-Currently truck has the stock 4.10 gear ratio.
-Running 28/10/17 Hoosier tires
What would be a better or correct diff gear ratio for my setup?
thanks
Its a 1994 F150 lightning.
-GEN4 5.3L
-Procharger D1 14-15 PSI at 6200 RPM
-Meth injection
-91 oct fuel
-6L90E transmission
-im dialing in the tune but currently truck is doing 12.7 on 1/4 mile
-Currently truck has the stock 4.10 gear ratio.
-Running 28/10/17 Hoosier tires
What would be a better or correct diff gear ratio for my setup?
thanks
Last edited by 400ss; 11-11-2018 at 04:23 PM.
11-11-2018, 02:06 PM
#2
How’s it running with the 4.10? Does that make the first gear to low? I know the stock trucks using that trans have like 3.42 rear gear. You getting to the OD gears in the 1/4? Rule of thumb in the 1/4 is you end up redlining in your 1.1 trans or 4th gear in yours which is 1.15.
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400ss (11-11-2018)
11-11-2018, 04:18 PM
#3
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Thread Starter
How’s it running with the 4.10? Does that make the first gear to low? I know the stock trucks using that trans have like 3.42 rear gear. You getting to the OD gears in the 1/4? Rule of thumb in the 1/4 is you end up redlining in your 1.1 trans or 4th gear in yours which is 1.15.
Fisrt time i took it to the track it did 13.1, installed the converter and it did 12.9, it was hitting limiter on some shifts, the last time i took it to the track i did some work on the trans tune and it shifted good, it did 12.7, but on the logs i can see it shifts to 5th gear before the end wich means it is shifting to OD gear... on the street 1st gear is pretty much useless to be honest, i can make it start from 2nd gear for daily but i im interested more in the correct gear ratio for the 1/4 mile, should i go 3.73 or 3.55?
thanks for your time, apreciate it
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400ss (11-11-2018)
11-11-2018, 09:25 PM
#5
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400ss (11-11-2018)
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11-12-2018, 08:34 AM
#8
what mph are you at? 106ish?
3.73 would be more fun on the street but if you turn it up much more you're going to be back running out 4th gear in the 1/4.
id say 3.55 or even 3.42
3.55 with 28x10 should be real close to my yukon with 4.10s and 32" tire as far as final ratio. mine traps almost 103 would have to look at a log to see actual rpm tho but it's comfortably in 4th 5600rpm+
with 3.42/32" i would run out 3rd and trap around 100-101 with shifts set at 6500 though
3.73 would be more fun on the street but if you turn it up much more you're going to be back running out 4th gear in the 1/4.
id say 3.55 or even 3.42
3.55 with 28x10 should be real close to my yukon with 4.10s and 32" tire as far as final ratio. mine traps almost 103 would have to look at a log to see actual rpm tho but it's comfortably in 4th 5600rpm+
with 3.42/32" i would run out 3rd and trap around 100-101 with shifts set at 6500 though
11-12-2018, 09:55 AM
#9
Teching In
Thread Starter
what mph are you at? 106ish?
3.73 would be more fun on the street but if you turn it up much more you're going to be back running out 4th gear in the 1/4.
id say 3.55 or even 3.42
3.55 with 28x10 should be real close to my yukon with 4.10s and 32" tire as far as final ratio. mine traps almost 103 would have to look at a log to see actual rpm tho but it's comfortably in 4th 5600rpm+
with 3.42/32" i would run out 3rd and trap around 100-101 with shifts set at 6500 though
3.73 would be more fun on the street but if you turn it up much more you're going to be back running out 4th gear in the 1/4.
id say 3.55 or even 3.42
3.55 with 28x10 should be real close to my yukon with 4.10s and 32" tire as far as final ratio. mine traps almost 103 would have to look at a log to see actual rpm tho but it's comfortably in 4th 5600rpm+
with 3.42/32" i would run out 3rd and trap around 100-101 with shifts set at 6500 though
11-12-2018, 05:22 PM
#10
Just do the math to help you decide, we've kinda already said what mph you'd be at with a certain size tire.
Look up one of those online calculators that you can put tire size, engine rpm, rear end gears and transmission ratios to help you pick the perfect gear ratio.
It's likely that you need to stay around 3.42's so you can be in 4th gear all the way through the end of the 1/4 mile.
Look up one of those online calculators that you can put tire size, engine rpm, rear end gears and transmission ratios to help you pick the perfect gear ratio.
It's likely that you need to stay around 3.42's so you can be in 4th gear all the way through the end of the 1/4 mile.