Topic: 3.91 rear differential on LNF kappa?

[ophidia31]

Since our cars are already irs, id be going for more of a street/road course setup and go with the lower final. If it was going to be for the strip, id be tossing the irs and fab up a solid rear and a 4 speed. (that id like to see) Thats just my opinion though. I dont think gm had drag racing in mind when it came to the design of our cars. 

[snaponbob]

IRS + drag racing = suckage. BUT, if that is what one is going to run, limited camber and plenty of spring and shock compression. Or, just get a Chevelle, slap in some torque

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BWAHAHAHAHAHAHAHAHAHAHAHA !!!!!!!!!!!!!!!!!!!!! 

[NormSky]

You should consider tire diameter and rpms along with 1/4 mile trap speeds. Make sure you will not run out of 4th gear.

[ophidia31]

Just imagine that but a kappa.  Brings back memories. I can just smell the cherry scented exhaust from the radically cammed big block now. 

[Bottoz]

IRS + drag racing = suckage.

I had an IRS Cobra that pulled 1.8 60fts... it didn't feel like it sucked!

[Critterman]

I have a 3.91 without the torque arm and a little bit over stock power.  I have to launch in the 2-2.5k range to keep from boiling the tires and the shift to second is immediate.  2nd to 3rd comes quick as well, but with my long !@$$ 3rd gear I can read the newspaper to the traps because I will still be in 3rd.

I have a 7k redline and I can honestly tell you I don't know what it tops out in 1st as I don't have time to look.  2nd is 61-2 and 3rd is over 100. don't know about 4th or 5th.

[idkfa]

Thanks for this conversation.  I've been eyeing a CTS diff for my 2006 since it's still an open diff (i know, i know).  Are those that have a torque arm incompatible with an 06?

[snaponbob]

Thanks for this conversation.  I've been eyeing a CTS diff for my 2006 since it's still an open diff (i know, i know).  Are those that have a torque arm incompatible with an 06?

Given that ridiculous jump from 2nd to 3rd, why not get a transmission from an 07 or later?

[Bottoz]

I have a 3.91 without the torque arm and a little bit over stock power.  I have to launch in the 2-2.5k range to keep from boiling the tires and the shift to second is immediate.  2nd to 3rd comes quick as well, but with my long !@$$ 3rd gear I can read the newspaper to the traps because I will still be in 3rd.

I have a 7k redline and I can honestly tell you I don't know what it tops out in 1st as I don't have time to look.  2nd is 61-2 and 3rd is over 100. don't know about 4th or 5th.

7000 Shift, 245/45-18, 3.91
1st 37
2nd 62
3rd 103
4th 142
5th 194

[Critterman]

7000 Shift, 245/45-18, 3.91
1st 37
2nd 62
3rd 103
4th 142
5th 194

255/45x18 is the only difference in the equation

[Bottoz]

Add about 1 MPH to each gear.

[Critterman]

if that