Supercharging the 944?!

[Will1981]

Whilst my car has been away in the body shop I've been looking into the possibility of supercharging it, there isn't much info available but I'm led to understand the 968 kit will fit with some modification to the slam panel.
There is a chap on the 968 forum selling his 9m setup but as I'm not a member so I can't pm him and if it won't fit them I'd rather not waste his time.

I'm taking the car into my workshop for winter so I have plenty of time to do it, any advice or ideas would be great!

 

[edh]

Get in touch with Peter Empson - you should be able to find him on here (or he might find you first...)

Peter has supercharged his S2 engined lux with a similar setup (speed force racing centrifugal charger?)

Personally, for forced induction I think you're better buying a 944 turbo based track car and throwing some money at Promax or JMG [] Unless you're really attached to your car that is. Do you have a torque / hp target?

 

[Mike_Pollock]

Peter Empson on here has supercharged his 3.0 S2 engined track car, the only one I know of.

Very quick! He took me around Silverstone GP a couple of years ago.

Cant remember if he did a build thread, but he may respond to a PM.

Edit - Beat me to it Ed!












































+

 

[Will1981]

Cheers guys, looks like a tidy install. I'd like 300hp and prefer the idea of supercharging than buying a 944 turbo, I think it will be better suited and keeps the linear power delivery.

Everything else is sorted on the car so more power seems the next step....

 

[John Sims]

ORIGINAL: edh

Get in touch with Peter Empson - you should be able to find him on here (or he might find you first...)

Peter has supercharged his S2 engined lux with a similar setup (speed force racing centrifugal charger?)

Personally, for forced induction I think you're better buying a 944 turbo based track car and throwing some money at Promax or JMG [] Unless you're really attached to your car that is. Do you have a torque / hp target?

Agreed all round. There is a great deal more to blowing an engine than just bolting on a Supercharger.

I could see some merits in swapping off a Turbo for a blower though.

 

[Will1981]

ORIGINAL: John Sims

ORIGINAL: edh

Get in touch with Peter Empson - you should be able to find him on here (or he might find you first...)

Peter has supercharged his S2 engined lux with a similar setup (speed force racing centrifugal charger?)

Personally, for forced induction I think you're better buying a 944 turbo based track car and throwing some money at Promax or JMG [] Unless you're really attached to your car that is. Do you have a torque / hp target?

Agreed all round. There is a great deal more to blowing an engine than just bolting on a Supercharger.

I could see some merits in swapping off a Turbo for a blower though.

Indeed, and at no point did I say it would be a simple task to 'bolt' a supercharger on.

I only asked the question to see if it's possible or any potential problems others may have had.

 

[edh]

And here's a similar view from dear old Fen [] http://www.tipec.net/_forums/viewtopic.php?f=25&t=2079

I think Will that if half your fun is in the journey, then go for it... but if you want a sorted 300hp, 350lbft 944 track car for spring next year, maybe a turbo is a better bet.

Of course the best option is an LSx swap.... - how much more would that cost?

 

[Copperman05]

It think it depends of what price you are giong to pay. Most of what I have read on rennlist and other sources if that the S2 lump is not really suitable to supercharging or turbo charging due to is high compression pistons, 16v, etc. It appears you can get around it by running low boost but then it kind of defeats the point IMO, especially when a new SC costs $6000.


Edd

 

[bmnelsc]

ORIGINAL: Copperman05

It think it depends of what price you are giong to pay. Most of what I have read on rennlist and other sources if that the S2 lump is not really suitable to supercharging or turbo charging due to is high compression pistons, 16v, etc. It appears you can get around it by running low boost but then it kind of defeats the point IMO, especially when a new SC costs $6000.


Edd

I believe the key point here is the S2 is a high compression engine which means the boost must be kept low (IIRC around 6-8 lbs). I don't know what difference 16 valves vs 8 would make other than more expensive to overhaul when the time comes as the boost offsets the benefit that extra valves provide for NA engines. IMHO, if this meets the power expectations, it might be a reasonable alternative as I believe the low boost is less stress on the engine and so it might live longer....

I have driven a 2.5 boxster with a TPC supercharger installed. Unfortunately I haven't driven a regular 2.5 so can't comment on the difference it made although based on road tests, etc. that I have read, I'd say the supercharger made a significant difference in torque and power delivery was very smooth from start to end. Actually, didn't notice it "getting on the cams" as is apparent even in the regular S2.

One of our club members has an LSx conversion for racing - bought it already done. I don't know if the engine has been modified for more power but apparently the clutch/transaxle is pretty easy to break even with soft treatment - low end torque is hard to manage apparently.

 

[Will1981]

Interesting stuff thanks, so if the S2 lump isnt ideally suited to forced induction what differences are there in the 968 lump as that seems to be a better starting point and after speaking to RPM regarding there other 944 with that engine is a relitively straight forward job to swap.
I'd prefer supercharging as I love the power delivery and had numerous costly problems with my Audi's which has put me off turbo's for a while, although I have read the Audi 20vt 5 pot fits []

The other option is to use this car until next summer and then go for a track prepared 968 and supercharge that?

 

[edh]

I'd suggest you have a trawl through the rennlist forums - there are plenty of people in the US doing this sort of stuff.

I don't believe there's anything fundamentally different about a 968 that makes it better for forced induction - maybe the rods are better but I don't know. Any n/a motor will only run moderate levels of boost. Mind you, supercharging a 3.0 lump at 6-8psi will give you a hefty increase in power.

I would have thought the issues associated with forced induction are quite similar whether you turbocharge or supercharge. Heat is the main enemy, particularly on lengthy track sessions.

Buying and supercharging a 968 would definitely be more expensive than dropping an LSx into the 944 []

 

[bmnelsc]

968 vs 944 - I understand the differences to be vario cam timing (which was good for 28hp over the 944 3 ltr), hydraulic timing belt tensioner vs the S2 spring style and IIRC the 968 has piston cooling oil jets built into the crank webs ala 911s. There are some articles on Rennlist (and a machine shop that advertizes) about adding these to a 944. I'd suggest the only significant benefit to the 968 lump is the piston cooling jets as I think the benefit of boost would negate the vario cam.

 

[colin944]

I can understand the desire for a bit more power on a 3lt 16v.But I would like to go down the throttle body route.I recon 260-280 bhp could be got by going down this route.Also a naturaly aspirated engine will always be more responsive to drive and would take a turbo car with another 50-60hp on tap to keep up with it.

 

[PSH]

ORIGINAL: colin944

I can understand the desire for a bit more power on a 3lt 16v.But I would like to go down the throttle body route.I recon 260-280 bhp could be got by going down this route.Also a naturaly aspirated engine will always be more responsive to drive and would take a turbo car with another 50-60hp on tap to keep up with it.

Hmmm sorry Colin but I have to disagree with that statement, I agree that an N/A car will be more responsive than a forced induction engine but even that is getting marginal these days with modern turbo applications. However where the turbo really comes in is higher up the range, so even if you have for arguments sake a 300bhp N/A car it won't keep up with a 300bhp forced induction car. Yes it will pull off quicker but it will soon be overhauled by the forced induction car, N/A cars power tails off the higher you get up the speed range, forced induction holds that power for as long as it's set for. A forced induction car will always beat an N/A car, hence why when running in mixed classes the N/A car will be allowed 3 times the capacity of engine just to keep up. The F1 series will soon be returning to turbo charged cars, they will be 4 cylinders. 1.6 ltr engines and capable of double of todays F1 power outputs.... enough said I think...

Pete

 

[edh]

ORIGINAL: PSH

ORIGINAL: colin944

I can understand the desire for a bit more power on a 3lt 16v.But I would like to go down the throttle body route.I recon 260-280 bhp could be got by going down this route.Also a naturaly aspirated engine will always be more responsive to drive and would take a turbo car with another 50-60hp on tap to keep up with it.

N/A cars power tails off the higher you get up the speed range
Pete

Pete - that's not right is it? Power doesn't tail off with speed, but you need a lot of power to accelerate strongly at speed (100+)

yes, forced induction can produce more power from the same capacity, no argument with that, but given the same power, I'd rather have an n/a (on ITB's yes please [])

There's no doubt you get wodges of torque in forced induction & for me the turbo scores in that midrange effortless torque, but I think there's more pleasure in high revving motors - vtec, BMW M etc..

 

[Will1981]

Is there an off the shelf ITB kit available for the S2, would love to see some pictures!

I agree on the high revving n/a, the best engine I've had in any car was my E46 M3 it was an absolute peach.

 

[edh]

Nothing really - apart from this
http://imamotorsport.net/IMA_Performance_Products.html
very very expensive

Lindsey racing have been talking about one for ages but I don't think they have ever done one

 

[PSH]

I probably haven't explained myself well enough Edd, well I did have SWMBO screaming at me to get off the PC and go shopping..lol
What I meant was an N/A car's power tails off , it looses it's torque and thus acceleration in comparison to forced induction, so an N/A car's acceleration from mid to high end will decline and although it may be able to get to a similar top speed it will take an awful lot longer to get there, does that make sense?..... Basically whereas an N/A car will be slowing down in acceleration from mid to high speed a forced induction will still be accelerating at a far higher rate of knots.

Pete

 

[JamesO]

ORIGINAL: edh

I'd suggest you have a trawl through the rennlist forums - there are plenty of people in the US doing this sort of stuff.

I don't believe there's anything fundamentally different about a 968 that makes it better for forced induction - maybe the rods are better but I don't know. Any n/a motor will only run moderate levels of boost. Mind you, supercharging a 3.0 lump at 6-8psi will give you a hefty increase in power.

I would have thought the issues associated with forced induction are quite similar whether you turbocharge or supercharge. Heat is the main enemy, particularly on lengthy track sessions.

Buying and supercharging a 968 would definitely be more expensive than dropping an LSx into the 944 []

The rods are actually a weak point and according to the WSM the early 968 rods are to be replaced if the engine comes apart.
Oil squirters, the valves are bigger, variocam, MAF and pistons are different I believe.

 

[colin944]

I think I know what you mean Pete. I think you are talking about relitive engine speeds. The thing is though that a S2 motor comes on "cam" at around 5000 rpm.If the car is running well it feels like you've added another dod of power or that the engine is on a second wind.An 8v engine doesn't really do this the same way that a 16v engine does.That's why Porsche themselfs never Turbo charged a 16v 4 cylinder car.Even the 968 turbo had an 8v head. Turbo chargers are not suited to the 3lt 16v engines as they deliver their power in an unlinear way.The reason people go for superchargers is because of the linear boost delivery on a charger.I however don't like the noise of a supercharger or the fact that you loose some of the gained power and responsivness through the charger it's self needing a fair bit of power to operate.
I have not seen a suitable throttle body kit on the market,and to be honest for me half the fun is making one myself rather than fitting a kit.
I also feel that if you let an S2 engine breathe easier you would gain a bit of power ( I don't think you could get above 260-280 bhp without having to do major internal changes) even if you could get it up to 250ish it would be soo much more responsive and pleasant to drive than a standard Turbo.
I always remember years ago having a 16v VW GTi. It had the mechanical k jet tronic fuel injection system and was so much more responsive than the later digi fant motronic 16v GTi's.It always felt quicker and more urgent than the later cars.This is what I would want to try to build into an engine.Rather than just going for big power I would be going for responsiveness and drivability.