BC

That's not a 2.75 rear end, is it.

Anyone have a gear chart for a 2.2?

Jim bailey - 928 International

80 mph in a 2:75 should be 3,000 rpm something is off...

BC

The transmission will be off soon! This is an interesting discovery, unless the Speedo or the tach is off (don't see how if they are working)

Seriously - I'll pull this one, put the 78 trans and TT I rebuilt in there, and rebuild this set and put it in the 78. (or "fix" whatever I did when I lost 2nd on the "test drive" - the rest of the trans was rebuilt)

I could do that swap in a day with some help and be on the road the next.

I think, unless something else is off, that Devek put a 2.2 trans in this thing when they rebuilt it.

Jim bailey - 928 International

Might have swapped in a later box rather than spend the money having the early one rebuilt.... take a look at the numbers on the trans.

BC

It doesn't show that in the receipts, but you never know. If this is true this is a great thing. I was wondering why the car wasn't as peppy as the 80 I drove at your store.

6.0-928S

My auto, 2.20 was around 2200rpm at 75 mph. So taking into account for converter slippage I'd say a manual would fit your criteria.

Hammer

Jim bailey - 928 International

80 mph is about 2400 rpm on the 2.20 with stock tire diameter anything taller and it really changes

dprantl

I was about to say, if you are turning exactly 2,000RPM at 80mph, then at 6,000RPM you would be going 240mph!! Are you sure you read that right?

Dan
'91 928GT S/C 475hp/460lb.ft

BC

I will do 80 on the way home and double check.

Jim bailey - 928 International

try for 160 !!

dprantl

Just checked and the 5th gear ratio on a 2.2 pinion box is 33 1/3mph per 1,000RPM.

Dan
'91 928GT S/C 475hp/460lb.ft

BC

Well, no 160, but verified that at 80, I have right at 2200rpm. So now its time to get under there and see what the 28/0x is. Methinks its like an 83 or 84 usa 2.2, but not the borg warner 2.2

no doubt

Wow! 2000 RPMs in my '88 auto is just 60mph.

dprantl

AFAIK the '83-'84 US 5-speed only had the 2.36. With that kind of 5th gear RPM at 80mph you must have a 2.2. Since it's a 5-speed, it can only be '85-'88 US. Unless of course it was taken apart and messed with.

Dan
'91 928GT S/C 475hp/460lb.ft

BC

maybe you have the 89 2.64 rear?

Well, I will get under there in the morning and see for sure.