I have heard of a few aftermarket 4.9 final drives, are any of these compatible with the ls tranny or would a different differential be absolutely necesary? if so its not really worth it IMO... a 4.9 final drive would nicely give the ls similar gearing to a stock r.

 

4.9? That's a bit too much.....stock USDM Type R's have a 4.400 Final drive. There are race companies and such (check the Type R forum that have different FD gear sets for the Type R tranny)

Anyway....for the LS tranny, here's what I did. I put a GSR 4.400 final drive on it since I had to mate it with the Type R LSD I installed. In order to do so, the countershaft has to be a 4.400 countershaft, NOT the 4.266 countershaft that the stock LS tranny uses.

Basically, you can't just throw in another FD gear unless you mate it with the same ratio countershaft.

If you want to do that, get yourself a 4.400 FD gear and 4.400 countershaft and slide your LS gears on. It's like a medium between LS and GSR gears. Performed well in my turbo setup.

As for something as crazy as a 4.9 FD.....like I said, ask around in the Type R forum, there are some nuts in there that have some weird FD's. Just remember, a 4.9 FD will give you a pretty damn low top speed. In 5th gear at 80mph, you'd probably be hovering near 6Krpm. And a LS motor doesn't rev that much higher.

 

Good post, thanks!

I am torn between just slapping an R tranny (LSD is my biggest need) on my LS or keeping the LS tranny - the car now does a legit 145 on the highway - 5th gear at 6000 sounds scary

Also scared of Phantom Grip.... thinking the Honda unit is the way to go.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 96IntegraRS &raquo;</TD></TR><TR><TD CLASS="quote">Good post, thanks!

I am torn between just slapping an R tranny (LSD is my biggest need) on my LS or keeping the LS tranny - the car now does a legit 145 on the highway - 5th gear at 6000 sounds scary

Also scared of Phantom Grip.... thinking the Honda unit is the way to go.</TD></TR></TABLE>

No problem.....I asked the same question a long time ago when I needed to do the swap, and someone helped me out. HT

Anyway....the Honda differential is indeed good, but it also depends on how much power you are putting down. When I heard people say that it maxes out at about 300whp, I didn't really believe them.....until I literally grenaded the LSD.

I see that you have a JSRC, ask around the forced induction forum and ask whether or not the ITR LSD holds up well. Mine didn't in a high boost turbo application.

Even if they say it does hold up well....remember it is, in fact, a stock unit made for the ITR which is a measly 195-200hp, much less at the wheel. You don't want to unload and load the differential very hard, in other words, don't slam gears and go WOT, don't go over bumps in a turn WOT while boosting, etc. You get the point. Things like that will damage the LSD.

In any case, ask the Forced Induction forum....good info there.