2.8SS or 3.0SS
 

Dear sir
I have a 3.0 turbo engine want to rebuild, so I am consider 2.8 ss(95mm) or 3.0 ss(98mm), it will use EFI ITB.

Another question is, If I want to use the engine for s short curve track(max speed about 210Km/hr), 915 better or short bell house 930 trans?
PS. the engine and trans will install in a 1987 930.
Need you guys input. Appreciate!!

I am working on the same thing… 2.8SS on 3.0 turbo case. The engine came with 95mm nikasil cylinders with the groove cut for the sealing ring. I've read that these can't be bored to 98mm. So I'm going to stick with 95mm to make a 2.8.

Do you have cylinders yet? If you will buy them new, I'd go for 98. If you go used and the nikasil is good, stay with 95mm to save money. If they are 3.2 cylinders and need replating, then boring to 98 is not much extra.

cheers,
dug

Hi Dug
Thanks for your import, I am thinking use 3.2 cylinders replaying and 3.2 header, EBS tell me I can go 98MM. I just want to know how much benefit I can get.

Displacement is one of the cheapest power sources. All other things being equal, the 3.0 should make more power.

So this is for normal aspersion?

Yeah, NA for me anyway.

The 3.0 turbo engine cases (and the 75-76 3.0 Carrera which are even rarer) came with the 6 bolt crank like the 2.0-2.7 engines, but with the larger bore, stud spacing and valve sizes of the 911SC and 3.2 Carreras. Which means you can run the 66mm crank to make an engine that doesn't shake loose the flywheel like the 70.4 stroke crank at 8000 rpm. You don't really need/want the wild cam necessary to get 8k rpm while running a turbo. Although the 956 2.8 engine was a 66 stroke too, but now you're talking factory race engine:)

cheers,
dug