Turbo'ing the S2

[Neil Haughey]

Guys loads of talk over recent months about 3.0L conversions for the 951, why not just start with an S2. As an idea my path of least resistance approach would be similar to what I believe Baz Hartech has been doing i.e.
- S2 bottom end
- 2.7 head
- 951 manifolds and some sort of KKK turbo
- custom rods or if at possible an off the shelf one with the right parameters from one of the UK rod specialists.
- if at all possible some form of off the shelf cosworth / Mahle etc. piston with the right parameters.
- if at all possible standard 951 fuel/ignition components to replace the S2 bits where required.

I would keep it basic and aim for around 300 Bhp or so but with monster torque.

Has anyone other then Baz done this and what are the pros cons involved and likely costs? Didn't Andial or someone stateside do a kit that had a lot of the suitable parts?

 

[Lemon]

You could always just bolt a supercharger on.

Ninemeister in Warrington do a bolt on one I believe which would give at least a 100 bhp extra, so would give you a ball park 300 to 320 bhp with very little effort and not a lot of mods to your excisting engine.

They were fitting various 968's with them last time I was there with one of them having a 420bhp kit[]

Just a thought anyway

 

[Fen]

Why start with an S2 and add Turbo manifolds, ignition, fuel and possibly the turbo (plus I assume ECUs), then mix it with a 2.7 head and custom or aftermarket rods and pistons? Basically you have an S2 block and crank left from the donor car, plus a donor chassis with softer suspension, smaller brakes, open diff etc.

Better to start with a Turbo surely?

The supercharger kits look expensive to me - even in the 968 you have the same small brakes, open diff and soft suspension to deal with and you only get to 350 bhp or so for £5k+. I've also heard tell of one such 968 not exactly keeping its owner happy with its manners when compared to equally powerful Turbos. the 420bhp car was the yellow one. Colin told me that they wouldn't supply a customer car at that power in case it went bang and they lost reputation through it. They sold the car but with the wick turned downhence people keep being unimpressed when they see it on track.

 

[Diver944]

Baz is doing that to a car that was already a Turbo so it already had exhaust, manifolds, crossover, wastegate, ECU, turbo etc and he is dropping in an S2 block with 2.7 head. I spoke to him about it when he supplied the crankshaft for my engine and he was planning to keep the standard KKK 26/8 turbocharger just to see what difference the up in capapcity would do

 

[Neil Haughey]

I was thinking more along the lines of what I would do to my own S2 when the time comes (not to far of me thinks maybe in a years time) to rebuild the engine. She still goes like a stink but is gradually burning more and more oil. Since 944's in any guise are so cheap as to be almost disposable items I don't see a problem in getting loads of donor parts as long as someone is prepared to collect them as and when things become available. Something tells me that with an increasing number of rough cars out there I can only see more 944/951 getting broken up and the parts getting cheaper.

 

[Neil Haughey]

ORIGINAL: Fen

The supercharger kits look expensive to me - even in the 968 you have the same small brakes, open diff and soft suspension to deal with and you only get to 350 bhp or so for £5k+. I've also heard tell of one such 968 not exactly keeping its owner happy with its manners when compared to equally powerful Turbos. the 420bhp car was the yellow one. Colin told me that they wouldn't supply a customer car at that power in case it went bang and they lost reputation through it. They sold the car but with the wick turned downhence people keep being unimpressed when they see it on track.

ISTR not changing the bottom end. There is no way in a million years I would add forced induction to an engine with a CR as high as the S2/968. Must drop the CR down to 9:1 or lower. This means that for me an SC conversion is a nonsense, it would be cheaper to cobble together used 951 parts for what goes outside the engine, and accept that the engine internals must be rebuilt with different pistons/rods.

What is the difference between starting from a 220 turbo or an S2?

 

[Fen]

I guess it makes sense if you want to use your exisitng car though it might still be cheaper to sell it as a good S2 and start with a ropier (but not rusty!) Turbo if you're going to refresh components. You'd then have all the awkward bits like hubs etc. that you need.

 

[Neil Haughey]

Problem is my S2 has a shed load spent on mechanicals but looks like a ropey S2.

 

[Fen]

Fair enough. A 220 Turbo and an S2 are similar to start with as you suggest, but you wouldn't buy a 220 Turbo specifically as the base for this sort of project.

 

[333pg333]

You can do it of course but you need new rods, pistons, turbo, intake, ems, and the cams aren't really that good for turbocharging and head could use a little work. We have been toying with doing the S2 and keeping it 16v but I keep looking at having to do too many things to make it work properly. Of course you could just get a John Milledge bullet proof engine for about $40K US but he's retired.
It seems easy enough with quick observations to do this but it will cost much more than you initially anticipate.
If you really want to know, contact Dave McGrath (Evil 944 on various sites)and ask him about costs involved. He builds engine with Neil Harvey of Performance Developments (ex BMW F1 when they were winning). To do it properly starts to really get scary expensive.

 

[DivineE]

In the early 1990's when the 968 turbo was being produced Porsche were recording something like £10million in profit per year and they decided to stick with the 8v head for the turbo engine... This to me is a BAD sign about the difficulties and costs you might incur?!

Regards,

Ben

 

[Neil Haughey]

Hence why I feel it makes more sense to use the 2.7 8v head and all the stock 951 manifolds. Why make life difficult when the aim would be to make a nice driveable motor with loads more poke then an S2, rather then trying to break the 500 horse barrier.

Also a little concerned about the flange/s on the S2 head around where it mates to the block. Looks a bit thin to me compared to what one tends to see on engines designed from the outset to take the heat energy load from turbocharging. This may be part of the reason why Porsche used the 2.7 8v type head to make the 968 turbo s.

 

[Fen]

I believe Porsche used that head as the 968 Turbo S was built for a specific race series with a 350bhp power limit and they could easily get there with 8 valves, so why engineer a 16v turbo engine when they had done an 8cv already.

 

[Neil Haughey]

BTW forgot to add I will not be paying someone else to do this if I do it next year (or after). To long since I got my hands properly dirty as they say and I would divide the build up with my brother, or possibly pay him a little to do some of the work. His last engine build was a 380 horse cosworth turbo. I can't get that excited about paying someone else, even someone as nice as Jon to do it, where is the excitement in that?

Honestly cranking over your newly built motor is one of the most stressful and then hence pleasurable experiences out there. You feel like Dr Frankenstein.

 

[333pg333]

ORIGINAL: Neil Haughey

BTW forgot to add I will not be paying someone else to do this if I do it next year (or after). To long since I got my hands properly dirty as they say and I would divide the build up with my brother, or possibly pay him a little to do some of the work. His last engine build was a 380 horse cosworth turbo. I can't get that excited about paying someone else, even someone as nice as Jon to do it, where is the excitement in that?

Honestly cranking over your newly built motor is one of the most stressful and then hence pleasurable experiences out there. You feel like Dr Frankenstein.

Queue thunder and lightning and a good "MWUHHAHAHAHAHAHAHAHHA"!!!!!!!!!!