Supercharged 2.5 944 project.

Supercharged 2.5 944 project.

Author
Discussion

ihatesissycars

Original Poster:

951 posts

203 months

Monday 27th August 2007
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Hi all,

I've got money burning a hole in my pocket and I need more power!

I have an n/a 2.5 944. It is thouroughly sorted in the suspension and brakes dept along with some nice wide cup wheels and it genereally excellent!

Other than the engine.

Now, I have a nitrous oxide kit kicking around and I'll probably run it with that for a laugh but I want a permanent wpoer fix.

I can't afford to insure a 944 turbo or 3.0 s2 so tuning my one it is.

I did consider an ls1 v8 conversion but that would've been too much of a project which elave the supercharger kit thats available from the states.

Its supposed to be a bolt on conversion hardware wise and with a pre programmed a/f controller that goes inline with the ecu to control fueling and spark.

That sounds nice but its mapped for a USA car with a 9.5:1 c/r whereas mine has a 10.6:1 c/r so I'll no doubt get det problems and going by my past experiances with mapping megasquirt ecu's this is something I want to avoid mapping myself or get someone else to do it.

What should I do?

I was thinking of getting all the hardware to mount and drive the blower as well as the blower itself from the states and doign the rest myself that being get a 944 turbo ic (same as what they use in the kit) from over here and mouting that myself to save some pennies and getting an emerald ecu to control it all and have dave walker map it.

This could be done for less than 3k.

OR shall I find a way of lowering my c/r and using the complete US kit. This could be done by way of decompression plates but won't this affect the bet lengths and so on?

I forgot to add that I do have the added advantage of 99ron fuel over here unlike their 93.

All help appreciated!

Gav

tribbles

3,980 posts

223 months

Monday 27th August 2007
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You really should inform the insurance company of the change though - if you get caught without declaring it, then you could find yourself really screwed.

Apart from that, it sounds like an interesting project - good luck!

Boosted LS1

21,188 posts

261 months

Monday 27th August 2007
quotequote all
Gav, decompression plates are a bodge imo, don't go there! You could machine the heads slightly to lower the c/r a tad and/or take a smidgen from the piston bowl and rebalance afterwards. If you want, give me a shout I've worked on 944's before.

Boosted.

ihatesissycars

Original Poster:

951 posts

203 months

Monday 27th August 2007
quotequote all
Don't worry the insurance company gets told about everything!

Mr Boosted!

There seems to be very little info on these engiens when it comes to mods, probably because nobody bothers. . . . .

Anyways, machining the pistons bowls is possible according to some fella's in the states and i'm sure theres gotta be some meat in the heads that can be removed however I believe Porsche went to alot of bother with engine balance on these, am I opening a can of worms by messing with that?

Turbo pistons will fit but lower the c.r by wuite a bit, 8:1 iirc plus they're sized individually to piston bore unlike the the rv8 which I'm used to so swapping pistons is out of the question.

Does anyone know how strong the pistons are?

I have another spare engine so it makes sense to prep that for action meaning I can take my time over it without disabling my car.

Give me a chance to uprate the clutch too. . . .

Anymore brainstorming ideas?

Boosted LS1

21,188 posts

261 months

Monday 27th August 2007
quotequote all
Hi Gav,

These are very strong engines, built and engineered well. The balancing is also spot on. The engineers did the internals whilst the monkeys got to lob all the ancilliaries at the block.

Boosted.

stevieturbo

17,272 posts

248 months

Monday 27th August 2007
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I wouldnt worry too much about the bore sizing on a used block or used pistons.

Subarus are the same, but Ive swapped A's and B's many times with no problems.


As for their 93 PON fuel.....it would be on par with Tesco 99 RON.

Different octane ratings...same fuel. 93 is not as bad as it first sounds.

Mave

8,209 posts

216 months

Monday 27th August 2007
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Have you got an insurance quote for modified S/C vs standard Turbo? I would have thought the turbo would have been cheaper!

ihatesissycars

Original Poster:

951 posts

203 months

Monday 27th August 2007
quotequote all
STEVIE! small world!

I guessed as much as if my info is correct pork motors don't have over size pistons available, I'm guessing because the bores aren't bore out-able and then re-coatable or some what.

While I'm on about the bores it obvioulsy makes sense to replace the rings whilst I'm in there but what do i do about bore prep?

Back to the charger kit the yanks use a replacement afm kit swapping the oe flapper for a hotwire jobbie but if I were to use en emerald ecu i'll be junking this or ordering the bits I need from their kit without the afm, sound good? Boost is an completely new world for me so I have to ask! In thinking about it a map sensor like what the emerald uses seems to make more sense, please correct me if I'm wrong as I need to learn!

Ref the c/r what would be a good one to aim for? It needs to be future proof and allow further boost increases. I have upto 17psi available according to the yanks, anything more requires too large (!) a bottom pulley that simply won't fit in the space!

ihatesissycars

Original Poster:

951 posts

203 months

Monday 27th August 2007
quotequote all
No a stock 944 250hp turbo was £3000!!!!!!!!!!!!!!!!!!!!!!!! Adding Nos or a charger was another £200 for me.

I did think about the turbo option but there was none out there with the trim adn colour I wanted plus they've all done 150k so I'd need to refurb the brakes, suspension etc etc which is what I've done to my 2.5 which only cost £800 to start with. I then went and bought a mint 924 with a mint black porsche logo'd interior for £200 which is now in mine. I LOVE it and is perfect other than lack of grunt which is kinda a good thing as i get to play and make stuff anf get them working which ticks another box, buying a turbo would be too easy but WAAAAAAAAAAAAAAY too expensive!

Boosted LS1

21,188 posts

261 months

Monday 27th August 2007
quotequote all
ihatesissycars said:
While I'm on about the bores it obvioulsy makes sense to replace the rings whilst I'm in there but what do i do about bore prep?

Ref the c/r what would be a good one to aim for? It needs to be future proof and allow further boost increases. I have upto 17psi available according to the yanks, anything more requires too large (!) a bottom pulley that simply won't fit in the space!
I can prep the bores so long as they aren't outside tolerance, or you could leave them alone if not scored. .005" oversize rings were/are available but may be hard to get. I did a turbo build for a customer who supplied a lindsey racing composite head gasket and he said he was using 16 psi (thats what they all say). He pushed the gasket sideways into the water jacket so he must have got some detonation. He used their big turbo kit and injectors so be careful and don't aim to high. Use a cometic head gasket.

stevieturbo

17,272 posts

248 months

Monday 27th August 2007
quotequote all
Rings should be easy ??? Total seal do make a huge range ? or do coated bores have specific requirements ?

As for bores...no idea, but Mike seems to know how to sort them.

Id be inclined to think you could still do a quick DIY hone if necessary ?? purely to clean up the surface ?

What blower do you intend to use ?

Boosted LS1

21,188 posts

261 months

Monday 27th August 2007
quotequote all
Hi Stevie,

These are alusil blocks, aluminium saturated with silicone particles rather like a hypereutectic piston. Basically it's glass so to reface them you use a slightly different approach. I've used TS rings but they came in a Deeves pack. They didn't survive the head gasket failure. In fact they were all broken and in several places but the bores survived so it must have been instant failure, detonation. I'll stick with porsch rings from now on. Internally these are very nice engines and the cranks forged as well which is nice.

Oh, I can fit lighter pinssmile

Boosted.

ihatesissycars

Original Poster:

951 posts

203 months

Tuesday 28th August 2007
quotequote all
Cheers for the info and thoughts guys!

I've fogotten to mention option no 2, fit a 968 engine. Any good are they? I know where there is one with all the bits to make it work for £2000.

Tam Lin

694 posts

254 months

Tuesday 28th August 2007
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ihatesissycars said:
Cheers for the info and thoughts guys!

I've fogotten to mention option no 2, fit a 968 engine. Any good are they? I know where there is one with all the bits to make it work for £2000.
Interesting options there..me I just lightened the thing.

With a 968 (or an S2 3.0) the tricky bit AFAIK is the engine wiring harness and the flywheel sensor, both of which are different from the 8v. I must say, the relative complexity of the vario-whatsit on the 968 engine, and the relative lack of BHP advantage over the S2 3.0L would make me tend towards the latter engine for a swap.

With the supercharging, the thing that worries me is why so few people seem to have done it this side of the pond. I know Colin Belton does superchargers for 968, and not sure, but possibly the S2 too, but I wonder why he has avoided the 8 valves, unless it's a cost-of-upgrade-to-cost-of-car-thing.

ihatesissycars

Original Poster:

951 posts

203 months

Tuesday 28th August 2007
quotequote all
Well I've been offered a complete engine, loom, ecu etc etc a bolt in job for £2k.

It should in theory at least be a bolt in job with just some electrical component relocating and maybe jiggery pokery with the airbox and so on.

240 hp.

Its tempting! It'd also be a better place to start if I wanted to charge it that being more power made for the same amount of effort.

ihatesissycars

Original Poster:

951 posts

203 months

Monday 3rd September 2007
quotequote all
Well I went for the 968 engine, if I'm going to make it go fast I'm better of starting with the best engine for it.

Tam Lin

694 posts

254 months

Tuesday 4th September 2007
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ihatesissycars said:
Well I went for the 968 engine, if I'm going to make it go fast I'm better of starting with the best engine for it.
Good stuff, let us know how it turns out (out of more than passing interest in my case) smile

ihatesissycars

Original Poster:

951 posts

203 months

Thursday 22nd November 2007
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Would there be any benefit to using a 944 turbo head instead of my ealry 2.5 n/a head?

wildoliver

8,790 posts

217 months

Thursday 22nd November 2007
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On an s2/968 engine? Neither of your heads will fit that engine.

wildoliver

8,790 posts

217 months

Thursday 22nd November 2007
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On another note assuming you haven't started this conversion I would really suggest you consider selling all the bits you have and just buying an s2, rough and ready ones (but needing a hell of a lot work than what your proposing) start at 2k.

Plus you get better brakes/suspension the later interior (assuming yours is an early car) nice wheels as standard and on and on, plus when you come to sell it it will have a value. A 2.5 with an s2 engine is worth nothing.