try autofarm (see link in my previous post).

Paxton boost
 

There's boost at idle. That's the big difference between SC and turbo it's always on. The hp loss has to be minimal at 6psi. It's certainly not an ac compressor.
It would be interesting to compare the hp/torque curves with a turbo. My guess is the turbo probably has more slope left at the top end of rpm curve.

Re: Paxton boost
 

The HP loss is not minimal at 6 psi. The Eaton is one of the worst superchargers. Here is a power required to drive the supercharger:
http://www.magnusonproducts.com/images/mp90g2.jpg

I once had a catalog for the Whipple superchargers. The HP draw was quite a bit less, but was still around 20-30HP.

Dunno about the Paxton. I'm not arguing the superchargers make great power. I'm arguing the HP loss is not trivial. The real question, as alertmike pointed out, how much HP do you gain using the turbocharger vs. the supercharger. Given the Eaton uses up to 50 HP, the turbocharging probably will not give more than 20-30HP more than the supercharger. That's just a wild guess. After all, the turbocharger does take power through exhaust backpressure. How much, is the question.

I think we all need to donate money to Mark Hargett, so he can test two identical engines with turbos and superchargers. :)

Nice thread. Old ideas rehashed, but still good for arguing and learning.

Jurgen

Nobody has brought this up, so I will. The 3.2 motor is known to have "weak" rod bolts, from the factory. 7mm, reduced from 8mm on the previous engines as I recall.

What is the effect of added HP and Torque WITHIN the same RPM range on bottom end stresses, as opposed to higher RPMs? This is the area that keeps me from "hopping up" my stock 3.2, more than any other. (Then there's $$$$$$, in a close second place these days...)...:cool:

The intake valve springs are lubricated by the engine oil that ends up runnnig down the return tubes. If the intake runners have pressure on them and if the valve guides and seals are worn, isn't it at all possible that some of that pressure could make it's way up the valve guides, past the seal and into the valve cover area where it could pressurize the crank case? This may not be the only source but it may contribute.
I installed a turbo system on a 914 a few years ago and had excessive blowby. Since I had already installed total seal rings (with limited benefit) I had the valve guides replaced and the blowby was reduced significantly. A leak down test will not identify this leak path, you would have to pressurize the runners with the intake valves closed to really check it (carefully).

The oil tank vent is normally connected to the air box or at least to the air intake system before the turbo or supercharger so it won't see boost.
if this is not the way it is set up that very well may be the problem and must be corrected.
BTW if you think Porche engines tend to leak oil check one out that has a significant possitive crankcase pressure. Niagra freaking falls.

For you guys in the Bay Area contact Peter at Porsche BMW Restorations in Crockett (510)787-3301. I've seen several supercharged cars in his shop. I had him rebuild my 3.0 liter and have been very satisfied with his service.

FWIW, if you look on autotrader there is an older 911 for sale ($20K) in Albuquerque, NM, which has a sc and seems to make ~300 hp.

Mike,

First off the major flaw in your argument is " 345 would make me quite happy!". As an ex-930 owner you know that you will never be happy - more is always better in the HP game.

But, if you want to make a road trip to visit Tennessee, well I am there. Just give me a couple of days to rearrange my work meetings (yawn) and we can do a day trip. Nothing like a good excuse to drive!

Problem is....after 4 hours in Blkbrd, my measly 345 hp will feel pretty anemic! FYI, my 87 Turbo was 320 hp and was about 200 lbs heavier than my Carrera....it was plenty fast to scare the ***** out of me without much effort. 345 in the Carrera should do me just fine. I'm sure it's track behavior will be totally different too....can't wait to find out.

I've pretty much made up my mind to do this. Now trying to decide if I should make it a DIY project or drop it off for the wrench to do. There's a mechanic in Duluth that I've known for a number of years that recently installed a TPC Supercharger on a 964. I spoke with him about it today and am considering going that route. Either way, I'm going to wait until after the Barber DE. The way work is these days, I'm concerned that it'll take me months to find time to get it done....add three kids to the mix and it might take years!

Sure will be fun to be able to keep up with you...or at least try.

Ha! Must be an omen. This is my 911th post and it fell in this thread (not on purpose...really). Not very superstitious normally but I guess this seals it. No turning back now. :D


Did I say that???

Since this is a topic that interests so many of us on the board, if only in curiosity if nothing else, please keep us informed. I can't help to still contemplate this route as I continue to plan for a 930. It may not be simplier, but would keep the cost from continually to spiral upwards into HP Junkies' arena.

Keep us abreast of the install and afterwards. TIA

not as much as you'd think. higher rpms put far more stress on the engine. get youself some turbo books.........

Mike, did the install ever happen?

Olivier

Silver4C:
The rod bolts went from the SC's 10 mm to the Carrera's 9mm.

However, the crank, and rod bolts were the same for a 3.2 Carrera as they are for a factory Turbo...so.....

---Wil Ferch

Wil,

Are they made out of the same material? Same Specs?

Mike, have mercy man! What is going on?

RickM...I believe they're identical....
maybe we'll look into PET tro find out for sure..but I am quite sure the 3.2 Carrera used the 3.3 Turbo engine case, the crank, and the con-rods/bolts....all the same. The only difference was the 2 extra mm diameter of the piston and lower compression of the turbo.
---Wil Ferch

Dr. Steve put one of those on a 3.6 swap
http://instant-g.com/Cars/BlauCarrera/DSCN2109.JPG

Mike ended up going the 3.6 swap route. I think he has a thread on it somewhere around here...

I think you are better off with a Proto Stage I Turbo system/ At about 8500 installed, it provides a reliable 360 BHP with a proven track record.