Mike, I gotta think a simple heater back-date would be the solution.

Mike, I'm heading down the same slippery slope with my 78SC. However, I'm leaning turbocharger vs. supercharger. I feel a turbocharger is less likely to damage parts, because the boost is occuring at a higher rpm. This is just my totally inexperienced opinion. You can make more power with less stress with a turbo, right? I mean, if it costs more power to turn the supercharger vs. spool the turbo, you will be stressing the engine more to make XXX HP and XXX lb-ft. Like you, I think a shot of 7-10 psi would make any 3.0-3.2L an absolute haularsemobilewetherpantiesfast man of a machine.

Boost away!!!

Jurgen

I saw first-hand RFNG's unit, and it looked very nice, and very simple. He doesn't like to quote hp figures, but 300 hp doesn't sound too far off if the SC engine is in good shape.

The upside: simplicity and the price is very reasonable.

The downside: can't use the SSIs or heat exchangers. Have to update to standard SC exhaust.

I agree with those about the downside toward the supercharger. It takes power to make power, while the turbo is, for all intended purposes, free.

Not positive on this, but don't those wipple SCer's make some boost at idle? If so that might be why since the motor is not under a load but positive pressure is going in, wouldn't that create blow-by on a perfectly good motor? Just throwing a dart in the dark here.

There would be positive pressure at the blower's exit but the butterfly's would create the same "normal" vacuum at the intake valve. Otherwise the increase in air would make the motor rev higher.


Wayne

dont forget the heat issue with a turbo - thats the biggest enemy.

just came across this http://www.autofarm.co.uk/car.php3/993eng.html

dd74,

I'm no expert...quite the opposite but....the fact that it takes hp to turn the supercharger seems like a moot point. If it takes 5hp to turn a supercharger that delivers 120 additional hp, it seems so negligible as to be unworthy of consideration. On a 911 SC, I've heard that the pistons are not the same as the later Carreras and may be more subject to problems...don't know the details though, but I know it's been done with some success.

Jurgen,

I owned a 930 and never liked the "feel" of the lag. The SC runs cooler and delivers down low....where my 3.2 needs it most. That's why I'm leaning toward SOK. I see you're in TN....have you though about paying SOK a visit to discuss things? I thought about driving up there when the day comes, to buy the kit and talk to Paul and company to learn more about the installation. Also, never hurts to put a face with a name...especially if I need to call him during the install to ask questions. Let me know what you decide to do. If you go with an SC, it might be fun to work through the process together. I've got two DE's to do in October. As of now, I'm planning to start the process immediately after.

I wonder...is there a need for additional oil cooling (over the Carrera fanned cooler) with an SC installed? I don't believe it's part of the kit and haven't heard it mentioned.

I have a Paxton SOK kit install on my 3.2. It was done by Powertech in New Jersey 5-years ago. Intercooler followed and just got the heat back via a turbo type setup last winter.
Produces 323hp at the wheels with 6psi. The paxton unit has a definite whistle when applied but less audible with the B&B headers etc. It has done 135 on the back straight at Pocono.
Runs with 964 cams and those are the only motor mods. It has been autoX'd and DE'd but it's no track regular.

How has it held up? No problems? I've heard there is a propensity to foul plugs and keeping the unit in tune is a bear.

I wana play
 

Well i'v been looking at sc my 85 now for some time and the 2 places in the UK that I have contacted are just not interested in supplying sc's for Porsches, even though they have done in the past!! so if there is any one in the UK that can put me in touch with some one that wants to supply me with a supercharger please let me know.
Cheers Steve

If the engine does not have any noticeable blow-by before the supercharger but does afterwards I would not susprct the rings. Sounds more like intake valve guides. On a N/A engine they run in a vacuum but when boost is applied they run under pressure. If they are worn the resultant boost will show up as blow by.

Rings on the other hand are always under either vacuum or pressure no matter what kind of aspiration method is used, the only difference is that the pressure will increase under boost. I would not think that is the problem because pressure helps to seal rings, right up to the point where they break.

I could be wrong, whoever heard of a 3.2 having valve guide problems? ;)

Does sc fowl plugs?
 

The only time it had plug problems was at another Pocono DE when the head temp sensor failed and resulted in the motor running so rich it fowled 4 plugs.
It is set up to run a bit rich to avoid problems with higher compression and running hot.
In the early days it broke a belt and that prob has been solved.
Just like a turbo, it is NOT a bolt-on-no- brainer. If you don't get greedy with boost you get plenty of hp.

That wouldn't explain the pressurized crankcase though would it?
-Chris

Since the crankcase breather is hooked to the oil tank and there is also the large hose running from the intake to the oil tank neck, wouldn't the crank case get pressurized as soon as pressure is seen in the intake (ie under boost) unless some modification is made to this hose routing (ie providing a separate oil catch tank for the crank case breather?

I may be off base here but just a thought

Todd

What is "blow by?" What are its characteristics?

There appears to be a bit of confusion running here....the crankcase is seperate to the cylinder......the only way that pressure can get from the intake/cylinder is past the piston. If there is pressurisation caused by worn valve guides they would have to be like matchstick! As Chris saisd it would not explain the crank pressure. The butterfly will also reduce the pressure in the intake and reduce the unlikely event of this happening.

If blowby is occuring it could be caused by badly worn rings, broken ringsor glazing of the ring or cylinder wall. Likely causes are overly rich or heat.

Alertmike, Does the power come in gradually or is is constant and easy to drive.

Cheers

Mark.....

I believe the Paxton is supposed to deliver power much like a Turbo. Not as much punch at the bottom (like the Autorotor or Whipple) but builds strongly as rpm's rise. Alertmike....sound right?

are you referring to the hot turbo sitting beneath the apron or heat from compression?

No expert here either, but I have read online the Eaton blowers fitted to a Ford t-bird (might be another model) drew in the neighorhood of 30-55HP , depending on the boost level. The whipple is going to be more efficient, but it still uses LOT more than 5 HP. Nevertheless, SoK is quoting 325-350HP. That is still quite good. The power from a turbo at the same boost is probably more, but at this HP level you are already walking away from 3.6L transplants. :)

Mike, you're actually closer to Knoxville than I am. It's a good 6+ hours to Knoxville from Memphis. Plus, I'm still trying to figure out the best path to 300HP.

It seems like the supercharger is a good intermediate power adder. A supercharger + good engine = 325 rear wheel HP. :) From what I've seen, there are few intermediate turbocharger setups. If guys go turbo, the HP is staggering (HP Junkie Juan comes to mind). There is little information out there regarding a mild 6-10 psi turbo system on a stock 3.0 or 3.2L, making it hard to figure out the magic combination to keep the engine in one piece. Perhaps rfng is going to change things with his 3.0 turbo kits. Hey, Richard, do you need a test pilot for your first production turbo kit? :) A fresh 83 3.0L awaits with willing participant. :)

Jurgen

The positive displacement super chargers take way more than 5hp to turn. The Eaton I ran was rated to need 50hp at full boost. The Whipple is more efficient than that but still probably 30-40. A turbo (to make the equivalent boost levels) would require much less than either. To make a given amount of boost, today’s turbos are very efficient and will always produce “x” amount of increased power for less power loss than a SC.

The heat of a turbo is an old wives tale. The only heat issue of a turbo is the surrounding area (burning things from heat soak). It is not relevant to the intake air temp. The intake air doesn’t stay in the turbo (or SC for that matter) long enough to heat up. The rise in intake temps on forced induction motors is from the air being compressed, not from heat transfer from the turbo or SC.

The whole discussion of blow-by and crank case pressure increases with SC is ridicules. No motor can tell whether a turbo or a SC has compressed the air. Also, a SC does not produce boost at idle because there is a by-pass valve that opens when the motor is in a vacuum state.