Porsche Enthusiasts Club Forum

After a few measurements have decided that I wish to keep the 16V head on the S2, especially seeing that a 2.7 8V head which is a straight fit to the 3Litre block come very expensive, the only one I could find, they wanted £450+VAT & shipping for
Also seems silly to downrate the engine then tune it.
So centrifugal superchargers are much smaller & are in fact what 9Meister used on their 968 car. So have just won this on E Bay! These are around 10x10x8 inches so not much bigger than an alternator, they can also provide much more boost than a Roots style blower off a Mercedes.

So next step will be some engine management, probably megasquirt & then the project can start in earnest, well Chatham anyway



http://tinyurl.com/39tt34

I'm looking forward to seeing how this goes Jim as I know of another S2 engine being supercharged at the moment using an Ebay supercharger but being installed by RPM Porsche near Leighton Buzzard.

Are you planning to lower the compression of the engine at all or keeping it standard and only using a small amount of boost? I have heard of a few people lowering compression on an S2 by simply using a thicker head gasket

As regards Comp ratio I'm a bit undecided at the mo. according to the calculator here http://www.superchargersonline.com/hp_c ... p?submit=1

I can go to around 8psi boost on standard, a fair bit more with an intercooler. I don't intend building some mega track only demon so that takes me to around 300bhp which is "adequate"
I may skim a small amount out of the pistons & a clean up of the head should give me a few cc's. As you say a thicker head gasket will give me a little more.

keep the info coming, i'm interested in the outcome and the work involved

That seems to be the general consensus for a standard compression ratio. I know the initial 9Meister conversions on 968s ran at 7psi boost and they claim 360bhp after custom mapping, but remember that is on a Variocam 968 engine with a MAF as standard.

Our S2's have the barn door AFM which restricts airflow so figures would not be as good (still over your 300bhp target I reckon). However the car being done at RPM already has a Scivision MAF and is going to use a piggyback from http://www.maxhpkit.com/ so that a custom map can be written.

Here's a good thread from Ninemeiter on Rennlist:

http://forums.rennlist.com/rennforums/s ... p?t=352011

Whoo hoo the Vortech has just arrived, bought by a nice Parcel Force man this AM!

Just spent the afternoon writing excel to calculate maps & gearing etc...
Looks to be 300BHP easy with the potential to go to much more
Peak revs are 65,000RPM! Potentially 800BHP!

Whoo, 800bhp!, how the hell are you gonna keep it on the black stuff?

what sort of gear ratio will you need for 65000 rpm ?

The black stuff will be the trail , maybe 25 yards long , left behind the car with the odd bit of metal sticking out of it, when this supercharger is employed anywhere close to its maximum effect

Interested in the Maxhp kit to correct the map in my lux. Not sure why it's so far out except that it may have the early engine & cam. It's half the price of similar piggyback computers available here.
Supercharger looks interesting Keep at it Jim!

OK I need 31,500 RPM on the blower to give 300BHP which will be at 4.2PSI of boost with an intercooler. This RPM will equate to 5,800RPM in terms of engine RPM. Internal blower gearing is 3.48 or thereabouts so Crank pulley to blower needs to be 1.56:1 so a pulley of around 85mm.

These units can provide in a peak of 25PSI moving 800 CFM of air! that would be at it's peak of 65,000RPM.

Data sheets are here, this is a V5 G trim which is a good match for an 944 S2.
http://www.capa.com.au/vortech_data.htm

Nah I'm not being greedy, I'm looking for around 300BHP on super unleaded, intercooled & standard compression ratio. Although a similar unit on the 9Meister car is doing 460-480BHP. The great thing is that to get more horses (than 300) all I need to do is change the pulley & the mapping & if you go beyond around 8PSI then you need intercooling & beyond 12PSI probable compression ratio reduction.
The whole point is that this thing can shift enough air flow to make 800BHP!
In fact geared for 60,000RPM at the blower, the excel shows that you'd be at 550BHP at 21.5PSI boost on a 944 S2.

So a 944 head / valves will allow that increase in charge flow and exhaust flow , what about the cooling , brakes etc ? if you are going for what , compared to the quoted potential of this unit , is such a modest improvement , is it worth the outlay and the risk . The problem with superchargers is that they require energy to drive , the more you try to squeeze out of them your energy losses mount very quickly compared to output . which is why everybody turbo's , cos its free . If you don't have the space often it would be possible to compound turbo , may require some cunning plumbing , but interesting . However I would think that you will run out of puff through that head long before you get anywhere startling in output terms , just a guess , dont know the engine very well , shouldnt think its much different to many other engines I have seen suffering that fate though still good luck , hope you have a spare motor . (what would be really cool would be for some of these tuning people took a look at producing something to enhance the scavange side of enhanced induction ?)

Not sure where the question is coming from but...
Yup 300BHP is not such a big target, why am I doing it, because I can! Will my car support that, yes it already has S2 brakes & suspension, which is effectively 220BHP Turbo spec. & it'll be tweaked further whilst this lot is being fitted. Can you support 500BHP in a 944 yes of course you can, 9Meisters 68 is close to that in track form & the works cars were running near that 15 years ago. Lindsey racing have a road going turbo that runs 50BHP, pack your credit card away & go to http://www.lindseyracing.com ! Blower HP to support 550 BHP is 97BHP, to support 300 is 10BHP. Supercharger BHP are very different to Turbo ones, a turbo is peaky a supercharger makes the engine appear bigger than it is. Converting a 944 to a Turbo looks to be much more complex than going supercharged.




The only things that I know that run compound turbos are tractor pullers & they run very complex set ups for short periods of time, head limitations on the 944 are not so much of an issue with non-NA tuning hence lindsay,
powerhaus.com etc. The factory did a few 968 turbo's running big BHP but binned them because they would have literally blown the existing 911 models into the weeds.

Why would I want a spare engine? I don't intend breaking this one
300BHP isn't pushing the envelope with a 3Litre.

Edited to add quote tags

Beauty of these cars is that they are so over engineered. Nowadays they look at a part & say "How cheap can we make it?" But with the '44 it was "How strong we can make it?" Fitting a supercharger is a great idea on a 944. Realativly cheap horsepower. Sure you can make it work. And 300 horses is fairly conservative. With massive midrange grunt it should be a lot of fun.