1 tuff z Posted August 30, 2004 Share Posted August 30, 2004 hey all, i did a few searches to see what the current opinion is on what diff ratio to use with the t56 ls1 swap and came up with...nada. anyway, phantom, mas280 & others that have already logged some drive time with the swap i'd like to hear your thoughts as to which...3.9, 3.7, 3.54 or? thanks! finally got the donor car...'01 firebird ws6, 20k miles, wrecked and nervously waiting to have it's heart pulled out! Quote Link to comment Share on other sites More sharing options...
Tim240z Posted August 30, 2004 Share Posted August 30, 2004 Well...no LS1 here, but with the 94 LT1 and T56 and 3.54:1 gears, I think it's great. The T56 has a really low 1st anyways, and I have to be careful not to spin, and in 6th at ~1500 rpm I'm exceeding the speed limit on the freeway. Something to chew on until someone that knows what they're talking about chimes in....... Tim Quote Link to comment Share on other sites More sharing options...
Phantom Posted August 30, 2004 Share Posted August 30, 2004 I have the 3.70:1 R200 LSD. Depending on what you're running for tires the 3.70 may be too much. My 225/50-16 Yokohama S306's were totally overwhelmed in 1st and challenged in 2nd. The 215/55-16 Kumho Supra 712's I'm running now do better. With the 3.70's a 2nd gear start for daily driving is commonplace. It's easy and doesn't challenge the clutch, etc. When it comes time to go then 1st is a real screamer. If you build the engine a bit it might be better to go with 3.54 or 3.36 or you'll be hitting the quarter needing a shift to 5th. I'm over 5,000 in 4th now and expect it to go up some. For croooked track driving I'd stay with the 3.70's. Give you more response in each gear and still be able to carry any top speed the car can handle. Quote Link to comment Share on other sites More sharing options...
Savage42 Posted August 30, 2004 Share Posted August 30, 2004 Since the C5 Vette runs something around a 3.3, I figured I'd follow suit with the 3.36 LSD. We'll see how it works. Quote Link to comment Share on other sites More sharing options...
1 tuff z Posted August 31, 2004 Author Share Posted August 31, 2004 perhaps i should've given a bit more info. i've only gone down the strip once...about 10 years ago and it was an 1/8th in north carolina when i was stationed at cherry point. since then my driving is a combination of street [fun!], autocrossing [fun+] and on track driving at schools [most fun++!] and plan to continue. home track-watkins glen international. swap going into my 73 240z. jim cook racing supercharged L28 coming out. i don't anticipate doing much to the engine above it's stock condition. Quote Link to comment Share on other sites More sharing options...
1 tuff z Posted September 3, 2004 Author Share Posted September 3, 2004 more searching on the www i found the following; for the tremec 6spd [1st] 2.66 [2nd] 1.78 [3rd] 1.30 [4th] 1.00 [5th]0.74 [6th]0.50 Stock GM axle ratio is 3.42, curb weight approximately 3400 lbs. so if my 240 weighs around 2500 lbs, has a 3.9 and the 83 na zx 5spd [5th is about the same ratio as the t56], it looks like a 3.36 or 3.54 diff would work pretty well. if i keep the 3.9, i'd think that 1st gear would b pretty useless, except for cleaning old rubber off the tires... i'm no engineer so if someone has some input, i'd certainly appreciate it. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.