Tom

I'm not at home or I'd give you the part number from a catalog, PET, or by finding a receipt for one I bought. However, the 3.3 and later Turbos, plus all of the 964 based engines would have had to use the short tube.

I suppose cutting and welding would work if done right, as it has some reserve strength: The tube is stronger than the end of the intermediate shaft (at least than a 30 year old one): connecting rod bolt fails and rod cap bashes and jams oil pump, splined end of IS breaks off as if machined.

Walt

ROUND TWO
 

I can get my hands on a factory GT2 (993) twin inter-cooler at a decent price.

Do you recommend going that route or rather manufacturer our own twin intercooler? Do bear in mind that I have access to some very experienced engineering people who have in the past made some SERIOUS coolers for Porsche racing cars - BUT it is going to be way more expensive...

What kind of power will the 993 cooler 'permit' on something like a 3.0 with small twin-turbo's???

Tom

1) What pistons (and supplier) do you recommend. First I was going with the 3.0 option, but now somebody recommended 98mm p/c? (must then fit 3.0 crank!). JE, Mahle, Andial? If going with new PNC, yes increase size. 7.0 Either one of the three you mention would be fine.How about ceramic coated with dry lubed skirts.

2) Is the 74.4 crank a must or can I stay with the (like new) 70.4 I have? Stay with one you have, Either way, machine shop work required after you buy PNC.

3) We were planing on using a 964 PLASTIC intake manifold with adapters - securely fastened. Comments?
Yes or go with a 3.2 intake if have to buy one or the other

4) I am running twin-spark, 102.6 fuel, what is your suggested max compression?
7.0 . Keep boost at 1.0 bar

5) Would a factory 964 cam be nice in this setup?

Yes

6) Yes on IC shown above

What about flame ring. New rods? Twin plug/port/Flow/CC Heads High output Fuel injectors/pump

Boost and CR can be increased, but I wouldn't in order to not give up reliability at same time. What ever you decide have fun. Good luck. Be safe.

Regards,

Bernard,

Thanks alot. You bring up a new issue.

What's the take on ceramic coating on this board. Some people coat 'everything', some coat exhaust ports and piston tops only and some say leave it as Porsche did.

Bear in mind that I'll run relatively low boost, it's a track car and I have plenty air / oil cooling.

Any input on the intercooler ??? Anyone...

Tom

It makes a difference for FA on the pistons. Not for Porsche heads. It also goes back to how much bang for your buck would you get out of it. I beleive there is a value to it.

That IC is very good for your application.

If you want a set of bolt-on headers for a Twin Turbo setup, contact Todd Knighton at Protomotive. He'll give you a good price. Tell him I sent you. I know Todd well.

Thank you guys,

I'll post some pictures soon. Just received my new 7.5:1 935 style pistons, etc - phew.

Will check out the Protomotive stuff but have also got the option on a local set - will get more detail.

Keep the ideas coming please.

Tom

I know of people who have used the 993 NA headers for a twin turbo setup. This typically mounts the turbos (usually Garrett T3 Super 60's) at the rear of the engine, like the 935's, gravity drain the oil into the chain cover housings, with the two exhaust dump pipes out under the middle of the bumper. Looks and sounds MEAN! If yours is just a track car,this would be a good setup. It's functional and those turbo's would spool really quick with no muffler :D

Have the two 40mm or 46mm Wastegates dump to atmo too :cool:

any photo? thanks in advance.

Sure, here you go :cool:

http://forums.pelicanparts.com/uploa...1126654158.jpg

All you'd need to do is fabricate a J pipe from the collector portion, mounting the two small turbo's in front of the respective chain housing covers.

Get the oil feed from the oil pressure switch at the top of the engine, and gravity drain the oil back into the lowest point in the chain housing cover.

The only problem with this configuration is it's difficult to use a muffler, however, if the car is purely track, you can dump straight out the rear :D

No silencer - no need to.

What is your take on the manifold length? From you pic it is clear that the 993 exhaust manifold is VERY uneven.

On NA cars exhaust tuning is key - what's the story on Turbo's?

I happen to have a 993 system here, so it really sounds like an idea.

Tom

T3-60 are souped up Garrett T3's. Pretty cheap turbochargers. They usually flow around 260hp worth of air a piece.

Much cheaper option is buying two used units from Volvo 740 Turbo or early SAAB 900/9000 turbo. They are oilcooled and can be had for <100$ a piece. integrated wastegates (no need for external ones). Base boost is often set @ 0.45 bar for SAAb units. They flow around 230hp of air but spin up sooner. Clearly a cheap alternative.

Re: ROUND TWO
 

I think custom intercoolers are better idea. Factory intercoolers were always quite bad. By fabricating your own, you can customize it so it fits your engine bay. 993 intercoolers are compromise made to fit 993 engine bay.

Here's one pix of custom IC on a car i'll be working at next spring:

http://www.itsfun.nu/itsfun2/itsfun2_198.jpg

WOW! What sort of tail is going to house THAT monster IC beepbeep? I hope that IC is easily removabe for servicing etc? :eek:

cookie porsche - ideally, for a TT setup, u would want to have short primaries (shorty headers) for optimum spool-up, but if you want to do a TT setup on the cheap and are not worried about looks, the 993NA headers have worked quite well. Just ask Mike Rombotis (mike the mechanic) who lurks around on these boards.

He's actually running a pair of Garrett Hybrid T3/T4 Turbo's :eek: AND he said they spool up very quick! Well, quicker than what his single T04B use to ;)

Thanks for the details on the 993 stuff, Merv.

Tom, after glancing at this post I believe that you are worried unnecessarily about how to reach 450bhp.
First of all your 3.0 crank is stronger than a 3.2/3.3 crank.
Second:a 3.2 intake flows enough air to give you well in excess of 600 hp at reasonable boost levels and will not necessitate any adapters.
Third: the 964 cams will give you all the power you want, but fall off well before the 7000rpm you are hoping to achieve. Best choice here is to have your heads ported and have them subsequently flowbench tested and contact one of the better cam grinders to recommend one of their grinds so you can achieve the powerband you are looking for.
Fourth: mill your heads 1mm to increase your compression to help your off boost power and transition coming out of turns.
Fifth: a GT2 intercooler set up will work out fine for your requirements.
Lastly: 55lbs/hr injectors can easily support 550bhp and when sizing exhaust headers don't get sucked into large diameter pipes. 1.5in will give you the power you are looking for as well as good throttle response. Larger will make more power but sacrifice response.

Good luck, Oliver

P.S.: as far as I am aware the 930 oil pump is the biggest pump Porsche ever made, but a 964/993 pump will work almost as well, just don't forget to put the factory top end oil restrictors on your motor to give a bit more oiling to the bottom end considering twin Garrett or Turbonetics turbos use upa large quantity of oil.

Wow - it took you guys a little time to wake up but now we're cookin'... thanks all. SmileWavy

The reason for the 450bhp was the assumption that to be competitive and RELIABLE for races lasting up to one hour, pushing the bhp too far may cause other problems. I have a big oil tank and huge oil cooler so that no problem - more worried about sustained use? A road car may accelerate under 100% load a few times every week but a race car does so almost full time.

The reason for the 7000rpm was that our gearbox is 'geared' to fit a powerband btw 4000-6500. The thought was that for those few extra-long straights that last 500rpm would allow max speed.

The car is already fast with the current NA engine - so I can only imagine what's to come...

UPDATE: The heads have been flowed, new valves, guides, twin spark and ceramic coating.

What should I do to the cylinders (Nikasil). I have cut a small 'eye-brow' for better case flow - but should I do anything else :confused: . The cylinders do have a ring-groove - what type of ring should I use?

Keep it coming ;) .Tom