Final Drive Ratio, wheel, and WHP changes

jchammond · 10-30-2017, 03:12 PM

One thing is for sure; You should be able to get an accurate whp/tq with 4.08’s...as it won’t over speed the Dyno in 5th gear (1:1)
Your 4th is 1.27:1 & an auto is 1.41:1,
Some tuners avoid 1:1 in these cars because of the higher speed @7500+ R’s
Good Luck & post some #’s ... as 5th will yield higher ones than 4th gear,
And don’t be surprised if your #’s Dropoff a tad; because it’s easier for the engine to turn 4.08’s vs. 3.69 or 3.36’s

chuckie311 · 10-30-2017, 11:33 PM

Quote:

Originally Posted by jchammond

One thing is for sure; You should be able to get an accurate whp/tq with 4.08’s...as it won’t over speed the Dyno in 5th gear (1:1)
Your 4th is 1.27:1 & an auto is 1.41:1,
Some tuners avoid 1:1 in these cars because of the higher speed @7500+ R’s
Good Luck & post some #’s ... as 5th will yield higher ones than 4th gear,
And don’t be surprised if your #’s Dropoff a tad; because it’s easier for the engine to turn 4.08’s vs. 3.69 or 3.36’s

There is not much of a power difference doing a dyno in 4th or 5th gear with the 4.08 you yield just about the same numbers..
I was at 320whp with the 3.36 and with the 4.08 301whp

In the link below post 4 it has my dyno comparison. It has a fourth gear pull a fifth gear pull in the 4.08 gears compared to the fourth gear in 3.36 gears

https://www.myg37.com/forums/ecu-tun...-new-dyno.html

10-30-2017, 03:12 PM	#1 (permalink)
jchammond A True Z Fanatic Join Date: Nov 2014 Location: South Carolina Age: 59 Posts: 15,204 Drives: 13’ 370Z TS 7A/T Rep Power: 2684396	One thing is for sure; You should be able to get an accurate whp/tq with 4.08’s...as it won’t over speed the Dyno in 5th gear (1:1) Your 4th is 1.27:1 & an auto is 1.41:1, Some tuners avoid 1:1 in these cars because of the higher speed @7500+ R’s Good Luck & post some #’s ... as 5th will yield higher ones than 4th gear, And don’t be surprised if your #’s Dropoff a tad; because it’s easier for the engine to turn 4.08’s vs. 3.69 or 3.36’s SS_Firehawk likes this. __________________ MazWorx built long block \| FI-TT-100 Stage 2.75 \| IPT built 7A/T http://www.the370z.com/members-370z-...s-musings.html

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