GM Drivetrain & Suspension Chassis | Transmission| Driveshaft | Gears/Rear End/Differential | Traction Aids

4.10 to 3.73 am i downgrading?

Old Mar 1, 2012 | 05:34 PM
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Default 4.10 to 3.73 am i downgrading?

Trying to figure out if this is the right way to go.

Truck spends about 1.5seconds only in 1st gear at WOT from a dig and shifts into second. HPTuners log tells me that the truck isnt hitting full boost/load in this gear, just like what would otherwise happen when your tires are spinning, the very short 1st gear mimics a spinning tire even with 100% 4x4 traction.

So besides the added load (hp) by switching to a 3.73, the truck is getting some 100rwhp worth of mods, and a 2800stall triple disk converter for a little torque multiplication and 3rd gear lockup.

just so you know how short the gears currently are, I have to shift twice to get to 60mph.
http://www.youtube.com/watch?v=GAe8e...1&feature=plcp
(video before weight reduction and further tuning)
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Old Mar 1, 2012 | 06:03 PM
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if your gonna do a gear change, why not go to 3.42s?
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Old Mar 1, 2012 | 06:08 PM
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3.42's
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Old Mar 1, 2012 | 06:10 PM
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That only applies to turbos... With a roots, once you open the throttle, you have all boost instantly. The concept of load is not the same.
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Old Mar 1, 2012 | 06:17 PM
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Originally Posted by smokeshow
That only applies to turbos... With a roots, once you open the throttle, you have all boost instantly. The concept of load is not the same.
I know its not load thats spooling a turbo here, but even an NA car would behave the same, if you're wheelspinning you will hit a low g/cyl area by looking at a log, the same thing happens to me in 1st gear, which is calculated to be about 680hp at peak, and does 720hp in 2nd/3rd/4th so on using calculated output torque and RPM to figure horsepower.
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Old Mar 1, 2012 | 06:19 PM
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Originally Posted by smokeshow
That only applies to turbos... With a roots, once you open the throttle, you have all boost instantly. The concept of load is not the same.
I'm aware. I just don't see the need for such high gearing with the instant torque, cam/stall not varying.
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Old Mar 1, 2012 | 06:25 PM
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Originally Posted by CC05
I'm aware. I just don't see the need for such high gearing with the instant torque, cam/stall not varying.
My shift times are down to about 150ms or so, and the transition from 1st to second gear is instant you cant even feel the transmission shifting, I dont want to step down to the stock 3.42 because I could feel that alot of the acceleration is coming from the 4.10s torque multiplication, another reason why I got a tight 2800 circle D converter.
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Old Mar 1, 2012 | 06:30 PM
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Originally Posted by ayousef
My shift times are down to about 150ms or so, and the transition from 1st to second gear is instant you cant even feel the transmission shifting, I dont want to step down to the stock 3.42 because I could feel that alot of the acceleration is coming from the 4.10s torque multiplication, another reason why I got a tight 2800 circle D converter.
Meaning that you'd experience a shorter first gear,obviously, which you wanted to rid due to the fact that you weren't reaching full boost.? Have you got the converter in yet and went from there, after dialing things in?
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Old Mar 1, 2012 | 06:35 PM
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Ok, long as we're on the same page. Are you MAF or SD tuned?
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Old Mar 1, 2012 | 06:41 PM
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Sure enough, man. You wondering if I'm MAF or SD, or Ayousef? If you were asking me, I'm working on going SD. I ran a card-style MAF and pretty much had no complaints, but the whole MAF thing has its limits, as you know.
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