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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,289
I've never had it on a Dyno so I don't know how much HP it's making.
I installed new Mahle 3.3 pistons and cylinders last spring and they only have around 800 miles on them so far.
The heads are 1975 930 heads that have been milled down .018" with new valve guides and valves in them. The valve seats were reground with 3 angles.

I carefully opened up the intake manifold holes and intake ports to 40mm ID to match the 40mm aluminum injector blocks I used. I posted pics of all that last spring so you probably remember all that.
It has 964 cams timed at 1.26mm intake valve lift at TDC before the intake stroke.
Exhaust ports are the 1975 930 stock 34mm ID. Only the 1975 930 heads had 34mm exhaust ports. From 1976 on they were all 32mm... I guess that was to get lower emissions with the air pump injection.
I would have opened up the exhaust ports to 36 or 38mm but they match the B&B header flange tubes that insert into them around 8mm the way they are so I left them.
I could have cut them off the header flanges so the flange would fit flush to the exhaust ports but they are there for a reason (probably over engineering) and I was concerned it might have exhaust leaks at the flanges under boost if I did that. I probably I could have done that and not had exhaust leaks with new gaskets because other headers don't have those and they don't leak.

It has B&B headers with a B&B muffler with all the internal baffles and flow directors cut out. It still has the 1" of stainless steel packing around the inside diameter wall but that doesn't restrict flow it just makes it a little quieter.
I put a summit racing 2.5" electric exhaust butterfly valve with a short turn down tail pipe on it over on the passenger side of the the muffler that opens or closes by pressing a momentary rocker switch. It probably lowers backpressure a little and definately makes the exhaust louder as it opens.

It all works nice. It runs perfect and I can only guess how much horsepower it's making.
I have adjustable boost with a boost presure regulator feeding the top of the wastegate and it's set to 1.1 bar. I also have water methanol injection on it but that doesn't make any more horsepower that I can feel while switching it on or off, it just lessens the chance of detonation or pinging under boost.

I would guess horsepower is around 400 at the flywheel at 1.1 bar boost. Maybe a little more... I don't know.
Old 11-16-2014, 07:54 AM
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