Rebuild or replace

[ROWSC]

I'm sure I'll hate myself in the morning but I thought I would ask the group:

What is the best way to increase the performance of an SC? I have a quote from a WELL respected engine builder that promises 260-280 streetable hp from my long-block. But, we are talking $22,500 including Motec injection.

Would one be better off replacing the stock engine with a 3.6 for a third the price? What is required for this conversion? What are the pluses and minuses?

What about a low mileage 3.3 turbo?

[tight as a bull's ass]

I would take the $22,500, sell your car the way it is now, and buy a 1987-1989 930 Turbo.

You'll get the same power plus factory originality

[ROWSC]

Selling this car isn't an option. There is too much sentimental value. Keeping it as a daily driver and buying another car has crossed my mind. My wife, however, does not see the advantages of owning two 911s. I have tried to convince her that a 2002 C4S would not be like owning two of the same car but she fails to understand. Wives, you can't live with them and they are too expensive to get rid of.

[KTL]

You'll get similar HP out of a 3.6 and the 3.6 is built from the factory to withstand the added HP. There's always a trade-off for increased HP when you build up your existing motor. More HP = probably less drivability and less reliability (in the long run).

Good background on the 3.6 swap here:

3.6 SWAP

Wait 'til JackOlsen and widebody911 reply. They'll give you their personal experiences about the job.

[John Brandt]

my thinking would be that the only reason to pack the cannon with that much money into your exising engine is so you are competitive in a given racing class. you'll get the same results with a Jack-O style transplant without the outrtageous investment. reliability and drivability will probably be better too.

[dickster]

is it cause you're starting with an sc thats its so expensive??

you can get 335hp with the 3.2 for $5k to $6k.

i personally would like to keep my 3.2, but if it really costs that much for an sc its not an easy decision.

[makaio]

Dickster, how can you get 350HP out of a 3.2 for that little $$$$.

Go for the 3.6 transplant! I'm seriously thinking about it, when my 3.0 gives up the ghost in 7-10 years.

[John Brandt]

This would be a perfect time for George to chime in!

[dickster]

makaio - promotive's bog std stage 1 turbo kit sells for around $5,500. it goes where the cat./premuffler is, and so is out the way and hardly noticable - apart from the 335hp quoted!!!

sounds like a great deal from a reputable company, but for the sc i'm not sure.

[KTL]

I was thinking about tossing in the SBC recommendation! Didn't want to offend anybody. Gotta agree though. Detroit iron can pump out a boat load of HP relatively cheap (compared to Porsche hardware). To each his own. I'm sticking with P power.

[StuttgartDavid]

I have to caveat the Dickster's suggestion here:

There is a big difference between momentary peak hp quoted for a turbo conversion and the reliable factory hp (turbo or NA) that can regularly maintain full throttle for long periods under heavy loads without compromising longevity.

The bolt-on turbo that you mention uses the stock 3.2 high compression ratio pistons, which are the max the factory felt acceptable for an NA motor! Yes, the converter shops motronically richen it up and retard the timing. This might hold together and be a good solution for the street wanker who thinks that high performance is a momentary burst of power out of the onramp. However, for the continuous full throttle use that comes with track events, it is something you should think twice about. Detonation is serious business. Also, read the rules before you do this if you ever may want to compete - a turbo puts you into the mega$ class where everything else had better be optimized.

If you're going to have to restore your engine with new pistons/cylinders anyway, why not have it enlarged to 3.2 or even 3.4 liters? You could get close to 250 HP that way without the use of a Turbo. More economical and reliable than an aftermarket Turbo kit.

Of course there's also the 964/993 engine transplant as others have recommended.

[Early_S_Man]

Rich,

While the Motec engine would be spirited in the best sense, I believe it is at a price point well beyond the point of dimenishing returns! And, Turbo engines do not rev or behave in a manner that I call 'SPIRITED,' which is in the character of quick responding, high-revving Early 'S' and RS engines!

What I suggest is an engine based on your own, with Andial-Mahle 98 mm/9.5:1 pistons and cylinders, giving 3.2 liters, and PMO carbs, with GE-60 cams to orchestrate the music ... with SSI's and a stainless Dansk mufler to play the tunes! That combination should give 240 hp and the same reliability as any other rebuilt SC engine ...

A 7:31 ring & pinion from an early 915, installed in your 915 with a ZF limited-slip would be the perfect match for that engine! And, I suggest, just as much fun as any Turbo engine, and far more usable in all driving situations, despite the apparent hp deficiency!

[Jack Olsen]

$22,500 for 260-280 hp?

I think some shop-owner's kid must have just got accepted to Stanford...

[KTL]

Factory 3.6 Oooomph

Maybe have some $$$ left from your $22,500 quote/budget to put in your piggybank when you're through with the install?

[Bill Verburg]

For ~$22,500 you could easily transplant a 350hp 3.8 w Motec. Of course you would still need to do the brakes and suspension.

As I have stated before a properly modified n/a big motor(in this case 3.6-3.8) will beat a properly modified n/a small motor(2.7-3.4) every time in any measurable manner that you may choose.

[widebody911]

Hell, for $22.5, you can do the 3.6L, new brakes, suspension, maybe even interior and paint!

[R22tech]

wouldn't this be a better way to spend that kind of cash
http://www.eisoftwareinc.com/andy/911.html

[Bill Verburg]

Thom, notice the 3.8 & Motec; unstated was the cams, rods, valve springs, retainers, and various bolts. I have seriously priced these components (just in case ...)

R22tech, that is a nice car, The weaknesses are rear brakes and carbs though.

[dickster]

I have to caveat the Dickster's suggestion here:

There is a big difference between momentary peak hp quoted for a turbo conversion and the reliable factory hp (turbo or NA) that can regularly maintain full throttle for long periods under heavy loads without compromising longevity.

The bolt-on turbo that you mention uses the stock 3.2 high compression ratio pistons, which are the max the factory felt acceptable for an NA motor! Yes, the converter shops motronically richen it up and retard the timing. This might hold together and be a good solution for the street wanker who thinks that high performance is a momentary burst of power out of the onramp. However, for the continuous full throttle use that comes with track events, it is something you should think twice about. Detonation is serious business. Also, read the rules before you do this if you ever may want to compete - a turbo puts you into the mega$ class where everything else had better be optimized.

calm down, calm down

i live in the uk and the compression ratio i have is usa spec so is down on what porsche thought was acceptable for a na motor here in euro land. thats why i thought turbo (or sc) was a good route for me - i'll be starting with lower comp ratio.

the 3.2 has the turbo bits and bobs inside (crank etc)

na, the 3.2 produces more power than the turbo, so should be better off boost??

i haven't bought one yet but i'll bear your comments in mind if i do.

ROWSC mentioned buying a 3.3t as one of his options!

my comment weren't entirely relevant as hes got an 3.0 sc.

chill out