Need Advice on G50 swap in RSR project

[andy s]

Good Morning;

I am close to getting my rebuilt 3.8 back into my 90 C2 RSR backdate project and fortunately I have a couple trans options, but I need advice.

I have the stock (If my numbers are correct but over the years I have done a bunch of trans swaps in various cars..) G05/01 with additional stampings of 74H 12/0778, which is presently set up with the '90 C2 nose cone and this trans came out of the car.

I also have the G50 out of my wife's race car (I know... I know...) that I think I could put in this project for the time being (and build her a new trans later).

Reason for doing this is her trans is a short geared (155 mph, new syncros, tapped for external cooling, 80% lsd, etc...) full on fun box.

the numbers on that box are (very faded so I'm kinda guessing0 G50/03 2 606007

the issue and question is the race box and the C2 box don't have the same nose cone on them, although I looks like the bolt pattern is the same, so swapping out the nose cones should be pretty easy.

However, it looks like the shifting rods are different length.....?

How hard and what parts do I need to complete this swap, if its worth the effort?

Thanks

I am willing to upload photos if that will help

Best

Andy

[Matt Monson]

What kind of poweband and red line on the 3.8?

[andy s]

Have not dyno'd it yet, but

The motor has Pauter rods, P&P heads, cams, Euro RS 993 varioram etc... and I am running Motec M84... If it is anything like Colin's motors at neinmeister (who I got the wire harness from and I highly recommend him), I'd think we should realistically hit about 365hp, with a red line at 7000 - 7200 be my best guess.

[Matt Monson]

If it were me, I would put the G50/01 back in. It will be fairly well geared for the revised engine. Her race box will be too closely spaced for the broader powerband of your 3.8. Plus it already has an LSD in it, so you aren't gaining anything with her LSD. A lot of hassle to convert her box over with the rod change.

[andy s]

Thanks for the input Matt!

I am pretty sure that her box has one of your LSD's in it, so no question its a better product with just the LSD!

My noodling this issue is based as much on having a trans that really runs short and within a realistic level of speed for the street, but no question that if this was just about swapping out nose cones, I would just try if for fun, but it I need to make significant changes inside the box, the time and expense might not be worth the hassle....

[andy s]

Unlike the race cars where its about keeping it "On the Pipe" at all times, this is a street project (maybe some trackdays), where I was thinking that shorter gears could make for some funner spirited driving on the street... no?

[Matt Monson]

155mph is SUPER short, though I would want to see the actual ratios that are in there before going too far down the path of saying it is a bad idea.

However, stock 1 & 2 are pretty nice on an /01. 3rd is a bit leggy, but it really depends on where you drive. Will it wake the car up? Sure it will, but how much more often will you be shifting with the short gears? It can also become tedious versus fun. If it were me, I would see how much the new engine wakes up the car with the stock gearbox and go from there. I always say that nothing is permanent.

[Bill Verburg]

I agree w/ Matt M.

1) the 3.8 will have a lot of torque and less need for super short gearing, factory RSR in the shortest geared version had ~160mph top speed

2) 155 is a very short legged box

g50.01 will have decent gearing, certainly better than g50.03 which is better than a g50.05 butt you said the .03 was regeared so that doesn't matter

[andy s]

Bill;

Thanks for the input.

. Ok, to keep the project moving I'll stick with the c2 box I have (then again, now I can't remember if that box still has the stock gears in it as over the years we've changed so many...) and now that I think about it, we did take that car to Road America, so its got to have stock gears in it...

Thanks guys!