DVC

Very nice build, Tom. Are you still running through single 3.5" exhaust?

968ls1

I have 2 exhausts, my street is a 3.5" with 3 mufflers two bullets and a Magnaflow, quiet but a little restrictive. My track exhaust is 3.5" to 4.0" with 1 4" Magnaflow race muffler. The track pipe is really not too loud just cruising, but when you step on it hard it is pretty loud.

TonyG

Getting back to the original question...

You are correct... the S2 gearing is way too short. The 968 gears are too close together for the V8's massive TQ curve (shifting wastes time), which would result in a lot of useless shifting.

The best solution is the 951 box. I run the hell out of mine on the track with zero problems. The gearing is perfect on the track. Combine that with a Guard GT LSD, some GKN Motorsport Axles, a real oil cooler/pump setup, and you're good to go for a long time on the track as long as you're not launching the car off the line.

Good luck,

TonyG

Frank@Work

Thanks a lot guys!

A lot of usefull info.

I'm going to replace the R&P in the S2 gearbox with a 951 R&P! According to my calculations the first 4 gears will be the same as the 951 transmission and the 5th will be extra tall for a good MPG on the highways.

TonyG

It would be far easier to replace 5th gear in a 951 trans than to replace the ring and pinion in an S2 trans due to the big hassle of having
to shim the pinion correctly to get the lash right. This is assuming that you even have the correct assortment of shims to use in the first place.

If you track the car, the 951 5th is perfect for the V8.

Good luck,

TonyG

Frank@Work

I'm not going to track the car.
At the moment I have a S2 transmission, not a 951 transmission. The S2 transmission will be rebuild (by pro's (I hope)). I will contact the rebuilders and let them know your concerns. If they agree I will be on the lookout for a 951 transmission.

Thanks again!

TonyG

Just as an FYI...

When you replace the R&P you have to shim under the pinion gear to get the proper lash (wipe pattern) between the R&P.

To do that, you have to blue the ring gear, then assemble the entire transmission, rotate the ring gear, then pull the cover and check the wipe pattern. If it's not correct, which it 99% of the time won't be, you have to disassemble the transmission to get the pinion gear back out to change the shim underneath it, then repeat the process all over again. It's very very time consuming and just the time to set the pinion gear height can easily cost more than a good used non-LSD 951 transmission.

And if your mechanic doesn't get it right... ultimately you will get a howl, and/or have a worn out pinion bearing, and/or have a screwed up R&P gear... all of which typically take a good 10k + miles to show up. $$$

With a good used non-LSD transmission, you can replace the differential without having to touch the pinion gear height as long as you use the same ring gear, side plate, and side plate bearings. So the swap is fairly trivial.

Swapping the 5th gear between the transmissions is a fairly trivial thing as well which can be done by simply pulling off the rear cover and doesn't require much disassembly.


TonyG

333pg333

Sounds like a plan. I've seen my mechanics do just that process Tony mentions and it is time consuming. You could probably sell or swap the S2 tranny for a 951 box and go from there.

Olli Snellman

Frank,
you can also consider Audi A8 6-speed. More or less the same trans as 968 one. Should be quite easy to locate from the Netherlands.

Frank@Work

Ok, I probably can swap my S2 LSD box for a 951 LSD box.

Will go from there!

Thanks again.

333pg333

Report back when you're done.

porshhhh951

Just as a fyi. i've seen about a dozen or so ls3's come from LG motorsports making 530+rwhp with cam+bolt ons.

968ls1

How big is the cam? I have seen 6C Z06 427 vette's make 530rwhp with heads and cams, 530rwhp would be exceptional for a 376 LS3 unless the cam was really wild.

odurandina

does anyone know the dimensions of a 968 manual transmission?

(don't feel like getting under my car with all the mud out there).

DEMETRIOS

HI THERE
I turbocharged an s2 3.0 motor and put it in my 89 951.I ve kept the intake stock
using a 930 turbocharger with 60 m.m impeller in the passegers side.I drive the electronics off a tec3r .Any way , at 1,6 bar i get 516 rwhp@6800 and 62 kg @4000 .I blast 3,4,5 gears with no transmision issues.The first and second gears in 951s trannies are shot pinned but i never blast them anyway because even in fifth i brake trackion I GOT 5000KM with this set up with no engine m or tans, problems(the motor is all stock exept for gasket spacer and raceware studs)