Hybrid GSR tranny for A/M GSR. - Honda Forum / Acura Forum

uoboarder · 06-25-2004, 10:04 PM

Here's the scoop: I'm taking my GSR tranny and dropping in a JDM ITR Final Drive. I'm pulling the GSR 5th and swapping it with a LS 5th for good freeway rpms. This will turn my GSR tranny into a JDM ITR tranny (for the most part) and then I have low revs on the freeway.

The question... When swapping the LS 5th for the GSR 5th do I need the LS 5th from the countershaft only or only the mainshaft? Or do I need to swap in the LS 5ths from both the countershaft and the mainshaft?

I already know I need to buy new bearings (upper and lower) for the Quaife LSD I have. I was planning on using the shim that's in the GSR tranny with the Quaife... can I do that?

This GSR engine I have is built pretty comprehensively. CTR pistons, Skunk2 Stage 2 cams, Portflow valvetrain, Hondata, Skunk2 IM, 68mm TB, and a few more goodies. Help me out with this tranny stuff.

CRVTEC0WNZJ00 · 06-26-2004, 04:13 AM

I don't know what to tell you but this is just my 2 cents worth of info.

"The question... When swapping the LS 5th for the GSR 5th do I need the LS 5th from the countershaft only or only the mainshaft? Or do I need to swap in the LS 5ths from both the countershaft and the mainshaft? "

I say you need the LS 5th gear from the countershaft and the mainshaft...it only makes sense to swap it totally out. If you really want the right answer look at each piece carefully to see if they're different at all even by a tooth...but someone needs to give you more info...I wouldn't go on just what I say

uoboarder · 06-26-2004, 09:27 AM

That's kind of what I was thinking. The part numbers for the both sets of LS and GSR 5ths on both shafts are all different. 4 different part numbers. I kind of thought also that I would need to swap out both.

Here's the thing. The gear from the countershaft touches/connects the final drive and the mainshaft. Wouldn't changing just the countershaft change it all? I'm going to try and call a couple of shops soon that works in hybrid trannies. This is something totally new to thought. I love the idea of making your own tranny.

blueSI · 06-26-2004, 12:37 PM

switching out the final drive will nowhere be close to a type r, the gears are too different, the itr 2nd is like a 2.1something the gsr 2nd is like a 1.9something that a pretty big gap,even if you put in a 4.7 final drive and ls 5th gear the ls is only .767 and a gsr is .8somethin not that big of a difference, save ur money both of those and get an ats4.9 and get the quaife, that would work out better for you in my opinion plus ats give u all the parts u need to put in the final drive all the stuff and so does quaife.

CRVTEC0WNZJ00 · 06-26-2004, 02:53 PM

I dunno dude, I'm not to thrilled about the transmission thing, especially since I'll be learning to tear down 3 different kinds and put them back together and they have to work...for school...

uoboarder · 06-27-2004, 12:42 PM

My brother ran a JDM ITR tranny in his car for a while. Before I came up with my idea he and I both didn't like how short 2nd and 3rd were. We also didn't like how short 5th was. Knowing that... The GSR 1st, 4th, and 5th gears are the same as the JDM ITR. It'll be perfect with the longer GSR 2nd and 3rd cause then you're not getting unequal percentage drops in rpms like you would with a full JDM ITR tranny. The GSR tranny has excellent percentage drop differences between the gears all the way up. That allows for even power delivery as you go down the track. The ATS 4.9 FD is so freaking short! I visit the track maybe 5 times a year and I don't autox. Oh and the Quaife LSD doesn't come with bearings or shims or anything. Its just the unit.

blueSI · 06-27-2004, 01:36 PM

gsr gears are so long though, all honda b series 1st gears are the same and im not too sure that the 4th and 5th are the same, it just seems a waste to me to buy a ls 5th gear, too much trouble, but if it works ouit good i would like to know what rpm u shift at the revs fall down too.

uoboarder · 06-27-2004, 07:54 PM

GSR gears are too long for all motor setups. However the GSR ratios are perfect for turbo setups. Now change out the final drive on the GSR tranny and you suddenly have a great set of ratios. I'll be shifting somewhere between 9000 and 9600. I don't know where yet.

Yes, the GSR 4th and 5th are the same as the JDM ITR 4th and 5th. Take a look: http://www.bseries.net/html/specs/btrannyspecs.php

The reason I want to put in the LS 5th is cause the JDM ITR 5th is so short that at 70mph you're turning about 4400rpm. Now drop in the LS 5th and you're turning about 3800 rpm. That's a good freeway gear. Since I won't be getting into 5th on the drag strip its sensible to put in the LS 5th.

blueSI · 06-27-2004, 08:18 PM

oh ok turbo setuo ok i wasd thinking allmotor,yes yes then that combo sounds good for turbo, but i see some wrong info on that site, i see a few gears that are wrong.

CRVTEC0WNZJ00 · 06-27-2004, 11:39 PM

http://www.allmotorhonda.com/techpag...anny_specs.htm b-series gear ratios.

96teg · 06-28-2004, 09:52 AM

I have a stock gsr and When I'm at 70 my rpm is at 3400..??

uoboarder · 06-28-2004, 04:02 PM

Quote:

Originally Posted by 96teg

I have a stock gsr and When I'm at 70 my rpm is at 3400..??

Yep. That's about right. My stock GSR tranny turns about 3400 or 3500 rpm at 70mph. The JDM ITR tranny turns about 4400 rpm at 70 in 5th. Then if my calculations are close with the LS 5th and a JDM ITR final drive the rpms will be about 3800 or so at 70mph.