I am currently building a 4.2L stroker motor with a greddy twin turbo set up. My goal is to end up around the low to mid 700's RWHP.

I am having trouble choosing a LSD. I want a streetable setup that will give me better traction on start up (out of the hole) and prevent as much wheel spin during hard acceleration and gear switches.

Id appreciate your opinions, I am currently looking at two models, the Carbonetics/ATS Carbon diff, and the Quaife.

And another question is , Do I really need this, or can I get away with the stock vLSD. (my car is 35th anniversary model)

 

Quaife is the best for street use.

 

id definitely upgrade if your running those types of number. I believe a stock lsd is only rated to a certain number and your numbers definitely will exceed that. Quaife is nice but I hear the ATS is da **** but i might be wrong. chow!

 

Either would work great, Carbonetics will be less expensive though since there are no extra parts to buy, Quaife will require new output shafts/bearings/seals to work on a car that has factory VLSD

 

Stock differentials can handle a lot of power belive it or not. VLSD actually wouldn't be such a bad idea because it usually takes a lot of initial torque to get those to lock, but seems like that won't be a problem especially with the numbers your making. I'd say wait it out, see if the VLSD gives you the grip you want, THEN decide

 

I know I will have a hard time nevertheless, but I still want to find a way to get the best traction I can get (other than the obvious....drag radials). If you guys have any other suggestions, I would appreciate them.

 

I should have my Carbonetics which i bought from Forged Performance on by tomorrow.. Ill give you my review..

 

I run a Quaife in my Z (autocross/drag) and it is smooth, quiet, and very effective. I am only putting down about 250hp, but,

"What kind of horsepower can the Quaife differential handle?

The QUAIFE differential is engineered to take just about as much horsepower as you can throw at it. In almost any given transmission or rear axle, the QUAIFE ATB Differential will not be the limiting factor. If you have any questions regarding this, please feel free to contact us. "

The above quote is from their website: http://www.autotech.com/quaife/index2.htm

 

Are you going to change your FD from a 3.5 to a 3.3? If I were you I would do it due to your hp plus the lower gearing would help take advantage of the power and help somewhat with traction. Look at Alberto's review of the 3.3FD in the F/I Section and if you decide to go with that, the Carbonetics does not fit with the 3.3FD but the quaife will. If you decide to stick with the stock 3.5FD i would go with the Carbonetics.

 

Did you buy a complete pumpkin from Sharif, or did you ship one up to him to be assembled?

Any idea what an empty pumpkin costs from a dealer? Maybe it's better to look for one in a junkyard.

 

Since you have a VLSD car, I would pick the Carbonetics. The Quaife, as Adam mentioned, requires that you purchase a set of base model stub axles which run about $300 for the pair.

You'll really enjoy the Carbonetic. The car will hook up more consistently in a straight line, and be extremely controllable in the corners as well.

 

I have to say the Nismo VS Carbonetics is night and day!!! Carbonetics is super quiet!! I havent really tried to go WOT but this diff is way better!! I feel like the rear wheels are way more responsive and I dont get any of that loud clacking I had from the NISMO LSD.. This LSD is super quiet in comparison to the Nismo.. I have to say although I had to spend 4k for my damn diff to be fixed.. Having the Carbonetics is almost worth the 4k..

 

I am getting very close to purchasing a 3.9 FD and new Carbonetics LSD. I found the following break-in information on the Carbonetics web site. (I highlighted the red area.)



Do those of you with the Carbonetics LSD actually break them in by driving in a figure 8 for over 187 miles and change the diff fluid every 1,870 miles? That's changing the diff fluid twice every oil change.

That might be a bit too much for me...

 

Pick up some of the motul diff fluid, you should be good for 6k-10k miles with that stuff.

 

Yea wow that Carbonetic LSD oil change is pretty ridiculous. Off topic but if someone wants to go with a 3.3 F.D what are the best LSD to use?

 

No, your drive it in figure 8's for 15-20 minutes continuous.. Change the oil... Then change it every 3000 miles.. Those are the instructions from Carbonetics/Sharif and Im sticking with them!!

 

when you're doin the break in, pick a nice open area with no light poles or objects. i got dizzy pretty fast. rofl. but you'll notice the center of rotation on the Z is like right around where your shoulder is. that was neat.

 

I'm shopping for the same thing- probably Quaif.

I have an enthusiast roadster, so will I need any additional parts (output shafts/bearings/seals/base model stub axles/etc)?

Around how much should it cost to install the quaif?

 

we offer a complete bolt in kit for a Quaife into an Enthusiast/Touring and Track:

http://www.z1auto.com/prodmore.asp?m...ne&prodid=2349

install will vary shop to shop since labor rates vary, but around 4-5 hours should cover it.

 

I know that you sell all three LSDs and that you have a Cusco RS in your car that you are happy with. If you had it to do over again now, what would you get/recommend?

I like the Carbonetics, but I'm not sure I would keep up with the heavy maintenance.

I like the Quaife, but I have a G with VLSD, so it would cost a fortune to swap to the Quaife.

I like the Cusco RS, but wonder how it will wear and how noisy it will be.

Any thoughts? I am probably leaning towards the Cusco RS.

ps: Do you keep the 3.91 gears in stock?