hot-J

Again, out of curiosity, why not go with a 968 box? Gears are just as short, and supposedly stronger.

TonyG

1) It's not any stronger.

2) The gear ratios are too close together for anything but a peaky narrow power band engine (like a honda S2000 or 968, etc...)

The extra shifting involved costs too much time on the track.

It's faster to have a wider gear ratio and shift less.

TonyG

Dubai944

I have the same setup except for a turbo 5th gear. The Guard diff is awesome, the S2 ratios are great. I prefer it over a 968 6 speed which I have also run. It's already plumbed for an external cooler. Great price. Someone should buy it! If I didn't have to pay for shipping I might have bought it as a spare.

Thom

I would have thought that the significantly larger differential bearings helped the 968 box being stronger?

TonyG

I've never measured the bearings to compare. No matter... the diff bearings on the 951/S2 box aren't a weak link are are more than strong enough to run well over 500HP without problems.


TonyG

hot-J

Interesting. So would a S2 R&P be a good match in say an 951s AOR trans?

TonyG

It would be as good as a 951 5th gear installed in a S2 trans.

TonyG

333pg333

Search in here about this. Quite a few of us have done this in the past and in 9 out of 10 cases it's a great way to go. You can access so much more of the meat of the motor's performance with a shorter final drive ratio. The only downside is hwy cruising. You will feel like you want an extra gear. Apart from that it's a great mod for a track focused car.

JET951

very surprised no one has jumped on this. this is a great mod to do to any 951.

docwyte

I'd buy it in a heartbeat if I had the space in my race budget for it. Great way to get an uber expensive diff with basically a free transmission.

nick_968

Not knocking the box you have for sale, its a great deal.

However on the 968 box, the ratios were good enough for Porsche to use them with the same final drive on their turbo RS so they cannot be quite as bad as you suggest. They also had a 2nd version of the 968 RS spec box with even shorter 5th and 6th. What you probably need is a very fast spooling turbo to make the most of the short ratios i.e. full boost powerband from 3000 - 6500 rpm.

To say the NA 968 is a peaky engine is not strictly true, it has a pretty flat torque curve from mid range rpm with the variocam giving it a wider spread than it would otherwise would have been. All IMHO.

acorad

Nick, are you aware that Tony's running a Chevy V8 with gobs of torque?

I'm running a (weak, compared to Tony) Chevy LS1 V8 and a 951 trans and I'd love wider gearing.

nick_968

Yes I am aware but I took it that the comment was made to 951 owners in general, my mistake if it was only aimed at V8 conversions.

TonyG

1. Porsche wasn't running a V8. They were running a laggy turbo 4 that had to be kept above 4000+ rpms

2. Porsche wasn't racing against 911's with sequential no-lift shift gear boxes.

3. Porsche ran multiple different sets of gear ratios depending on the track, many of which were custom made gear sets.

4. A 968 with 236HP and 225TQ at the crank can hardly be described as having a "fat" torque curve... or even much of a torque curve at all. The only way the thing moves at all is to keep it above 5500rpms.

Driving a 968 is an exercise in rowing a boat. It's nothing but constant shifting.

Every time you let off the gas to shift... the sequential box 911 pulls 1/2 of a car on you.


TonyG

TonyG

Taken...

Just know my aim is 100% at racing, no matter the engine.

And if you have a fat torque curve, whether it be from a V8 or from a small turbine turbo 4, wide ratios are faster around the race track.

TonyG