Gear change or not?
08-07-2018, 01:46 PM
#1
Instructor
Thread Starter
Gear change or not?
Getting ready to have my rear differential rebuilt do to gear noise, currently I have 3.90 gears which were installed when car was still naturally aspirated now car is supercharged so was wondering if I should now go with 3.73's or even go back to the 3.42's?
Car is an occasional go out and play car, I've done one track event 1/4 mile. Car current sits on CCW sp500's 19x10 & 19x11's rear tires NT05 dr's. During the track event did no burnout, staged left off idle and managed a 11.20 @ 128
Looking at getting a set of Weld RTS 71's 17x5 & 17x10's with a 305-45-17 dr
Sitting at 720rwhp @ 9psi
Car is an occasional go out and play car, I've done one track event 1/4 mile. Car current sits on CCW sp500's 19x10 & 19x11's rear tires NT05 dr's. During the track event did no burnout, staged left off idle and managed a 11.20 @ 128
Looking at getting a set of Weld RTS 71's 17x5 & 17x10's with a 305-45-17 dr
Sitting at 720rwhp @ 9psi
Last edited by te-44; 08-07-2018 at 01:49 PM.
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CorvetteBrent (08-10-2018)
08-07-2018, 06:05 PM
#2
Burning Brakes
I have found a degree of gear noise with the motive 3.90 from the get go despite being properly set up. Hasnt become any worse. If it is, then there is a problem. Few seem to know how to set up these rears properly. I had a lot of issues with mine.
I went with the 3.90s as the rearmounts are a bit laggy. Should be less of a problem with the cerntri.
If it is spinning too much at launch, 1st and second Then back off on the gear. You have enough power to go with a lower [numerical] ratio.
You can calculate how any change will affect your shift points and MPH per gear
I went with the 3.90s as the rearmounts are a bit laggy. Should be less of a problem with the cerntri.
If it is spinning too much at launch, 1st and second Then back off on the gear. You have enough power to go with a lower [numerical] ratio.
You can calculate how any change will affect your shift points and MPH per gear
08-08-2018, 12:53 AM
#4
I had 4.10's in an m12 with 611rwhp and did not like it. Drag radials is what I had to run on the street to use 2nd...1st still got no traction and 2nd wasn't great.
I just increased the power and did the trans. and went back to 3.42's.
The 4.10's were fine when it was a cam only car, but too much once blown. Sounds like you are where I was not long ago. I went 3.42's
I just increased the power and did the trans. and went back to 3.42's.
The 4.10's were fine when it was a cam only car, but too much once blown. Sounds like you are where I was not long ago. I went 3.42's
Last edited by Water_Walker; 08-08-2018 at 10:56 AM.
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08-08-2018, 11:01 AM
#5
What is the car used for? Maybe that needs to go into the decision making equation.
Some good info here:
http://www.badasscars.com/index.cfm/...rod/prd398.htm
https://xse.com/leres/z06/calculator.html
Some good info here:
http://www.badasscars.com/index.cfm/...rod/prd398.htm
https://xse.com/leres/z06/calculator.html
Last edited by Water_Walker; 08-08-2018 at 11:02 AM.
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CorvetteBrent (08-10-2018)
08-08-2018, 11:21 AM
#7
Melting Slicks
Personally I’d use the 3.42 if its a street car. Makes it easier to cruise the highway and put your power down in the lower gears.
The following 2 users liked this post by Turpid porpoise:
CorvetteBrent (08-10-2018),
Pekka_Perkeles (08-08-2018)
08-08-2018, 11:36 AM
#8
Instructor
Thread Starter
The 3.90's aren't bad at all rolling down the highway in 6th at 70-75 only turning 1800-2000 r's
But yes on some roads in 3rd at 70 you lay into she will light up the rears
But yes on some roads in 3rd at 70 you lay into she will light up the rears
08-10-2018, 01:32 AM
#9
Racer
I have a buddy here in San Antonio with a 03z that is motor only.
the car has 53k miles. Might be interested in a trade for his stock z06 3rib 3.42.
I just went with a 2.66 tr6060 with the close ratio 5th and 6th for my fi build plan to be around 650 tire for now
thanks Jason
the car has 53k miles. Might be interested in a trade for his stock z06 3rib 3.42.
I just went with a 2.66 tr6060 with the close ratio 5th and 6th for my fi build plan to be around 650 tire for now
thanks Jason