968gene

With a 3.0L turbocharged engine, what is the preference? A 951 5sp or a 968 6sp? Assume stock ratios for both.

EliteThink

whichever has the tallest top gear! :-)

seattle951

I have had both. The 6 speed helps with turbo lag, but in my opinion, there is too much shifting. I am running 320 to 350 RWHP depending on the boost setting.

I installed the 6-speed to deal with the lag. Later, I changed turbos. If I had to do it all over, I would have started with my current turbo (GT30), the stock intake manifold and stayed with the 5 speed.

I am sure it is prohibitively expensive, but it might be interesting to increase the gear separation on the 6-speed.

bumflick

I have a 6 speed sitting in the basement, and have not installed it yet. You lose top end compared to the 951, assuming stock ratios for both. On the other hand with more gears, there is less rpm drop with each pushing, so depending on the power band for your engine, that could be good or bad.

When I win the lottery, or my last kid graduates from college, I will pay someone to tear the 6 speed down, install new synchros, LSD, strengthened R&P, and taller 6th gear. There are a couple threads about using the gearset from a Euro front wheel drive diesel audi to swap into the 968 tranny, but it seemed pretty expensive to me. Still looking at options.

333pg333

I would spend the money elsewhere. I've tried both and preferred my 5 speed in terms of actual shifting. If you track your car you can also swap out the S2 r&p into the 5 speed and that really livens the car up, but not so great for Hwy cruising.

Thom

I voted 6 speed but that's because I run the 968 gearbox with taller gear ratios which would be the equivalent of the 951 5 speed with a super tall 6th gear. Makes for the perfect gearbox for a 3.0T engine, and for relaxed cruising at 150+ mph.
I also prefer the feel of the 951 gearbox, which is faster between gears than the 968, even with new synchro rings.

If using stock ratios, stick with the 951 gearbox.

968gene

I own both. Both have LSD. The 6sp is stock. The 5sp has a long 5th gear.

What about clutch, flywheel, and pressure plate costs and choices?

User 52121

Ok so I haven't driven a 3.0 car to know how it compares to mine but...

My car, with a DBB T04E 50-trim (with -8 replica hot side)... I have an *S2* gearbox and it is AWESOME. IMO they should have sold it from the factory this way. Less lag, car overall feels snottier, but 5th gear isn't too far off from the stock 951 box.

All the videos I've seen of turbos with 968 boxes, the guy is shifting a LOT. Ideal on a race track if you have a peaky power curve and need to stay up in the revs. But I think it's too much shifting for the street on a torquey motor.

blown 944

I'm of the mindset that the gearing is too short on the 968 trans. Howevee, first is too short on the 951 box too.

In stock form, I'd stay with the 951 box. I just wish it was as strong as the 6 spd.

jmj951

Depends on what the torque curve looks like. If you have a wide-enough band of RPM's to support a 5-spd, stick with the 5-spd.

thingo

Myself I think the 968 shifts better, not much difference in the top speed compared to a stock 951. Changing the clutch is much easier with the 968 tt more pressure plate choice, but less so for the clutch disk. Better lsd in the 968.

bumflick

" I voted 6 speed but that's because I run the 968 gearbox with taller gear ratios which would be the equivalent of the 951 5 speed with a super tall 6th gear. Makes for the perfect gearbox for a 3.0T engine, and for relaxed cruising at 150+ mph."

Thom, can you share the details of the details of your modified 6 speed? What ratios, and where did you get them?

RajDatta

968 turbo S transmission. Has the best of both.

Kris H

How about 951 5spd vs 944S2 5spd as somebody mentioned? I have those, and if it makes sense, i may swap them between the cars..

azbanks

Your choice in gears/gearbox really depends on what you want to use the car for and the power that car makes.

The S2 and 968 have lower gear ratios which get you into the power band sooner but also cause you to hit red line sooner which means more gear changes. The S2 and 968 needed the lower gears since they make their power higher in the rev range.

My 3 liter turbo will have a 5 speed AOR trans out of an 89 Turbo with the factory ring gear. I will replace 5th gear with the longer 5th gear from an early 944. That will drop the rpm's while cruising and potentially give me a higher top speed.