Zero10

I think in definition that MAKES it a failed rennlist project

Bastiaan

Trying to revive this tread.

Colin, maybe it's worth looking here:

http://www.968-tuning.de/

Site isn't fully updated, but they are still active with the 968 (still raced in 2008 on the ring). They seemed to have made similar modifications that you are thinking about and increased revs and power output.

McLovin69

TRUST THE PORSCHE ENGINEERS A LITTLE BETTER

THE 996 CAN RUN 10K RPM WITHOUT BLOWING UP. THE 968 SHOULD BE FINE FOR SHORT RUNS UP TO 8500

IT SHOULD ONLY BE A MATTER OF FINDING SOMEONE TO PROVIDE YOU WITH THE FUEL DELIVERY PROGRAM TUNED UP TO 8500

100 HP PER LITER ISNT UNREASONABLE ON A NA CAR. OR THE 3.0L 968 SHOULD BE GOOD FOR 300-300HP WITH JUST SOME TUNING.

NOW IF YOU WANT TO RUN IT FOR A LONG TIME YOU MAY WANT TO LIGHTEN AND STRENGTHEN EVERYTHING. YOU MAY ALSO CONSIDER BLUE PRINTING AND PORTING EVERYTHING.

Chads996

I agree that this is achievable:

968 high compression motor:

Lose the VarioCam system
New more aggressive cams
Solid lifters vs hydraulic (yes, they will need adjusting)
Heavy duty valve guides
Lightweight valves (possibly Ti)
Higher compression, lightweight pistons
Forged lightweight rods (possibly Ti)
revised / lightened crank
Dry sump oil system
Improved fueling system (possible increase in fuel pressure)
Revised intake manifold to supply more air
Revised ECU to accommodate the air/fuel differences

$10-20K+ later - done.

C.

V2Rocket

im sure its doable but you would need alot of money to get it to work. like i said before i wonder if you could get something similar to a 997GT3's valvetrain to work on the 968. that itself is good to around 8500RPM and probably goes higher than that without failing.

you would need to exactly balance the (knife-edged to the max) crankshaft, you'd need to make new (hollow?) cams that will work at that speed, you'd need probably all hollow-titanium valves, possibly the timing chain we talked about a loooong time ago, probably delete the balance shafts and get a superlight flywheel. the bearings would all need to be very strong and solidly in place, you'd need to revise the oiling system (cross-drilled everything), new airbox, new fuel system, new computer (stock computer will barely compute that high).

in the end youd probably have a 350-HP, 10,000RPM 968 engine that only makes power from 7000-up, makes no torque and cost you $50,000.

and for that money id rather buy a 996GT3 that will rev just the same and still give me more power.

McLovin69

dont scare the man, he isnt building a competition race car, he just wants more power. I doubt he will be running at 8500 rpm for a 3-4 hour race session. just short runs in traffic and autocrossing.

Start with remapping the ECU. the 250$-500$ for the custom program will be a good start. later one you may find you need the larger injectors and enlaged air way, but not nessisarily. as a follow on effort, put in a lightened rotating assembly will free up hp. send the head off and have it ported and flow benched can free up some more.

you could even try boring the 3.0l out to lets say 3.4l. that will shorten the bore stroke relationship facilitaing even higher revs and more power.



battisann is right, check out http://www.968-tuning.de/ !!! its a good place to start. 5000 euro (7000$) will get to to or beyond where you want to go. \


Bottom line, its your toy. play with it.

McLovin69

one more thing

the prices on the http://www.968-tuning.de/ include the 16% VAT in germany

since you are in the states you shouldnt have to pay it

Geo

Dude, you should not be commenting on techincal stuff that you know very little about.

Clearly you have zero clue about custom mapping and what it takes. For that kind of money, I wouldn't put that chip in your car. Hell, the dyno time to tune a high revving 968 to make 100bhp per liter would likely cost $1-2k with someone who knows what the hell they are doing.

Low mass flywheels and cranks do NOTHING to hp. I repeat, low mass flywheels and cranks do NOTHING to hp. They might (and that's a BIG maybe) lower the harmonics enough to allow a little more rpm, but more rpm by itself won't necessarily get you more power.

Punching out the bores will in all likelihood lower the rpm limit due to the higher mass pistons.

Lots of monkey poo being slung here.

AX993

One thing I haven't seen stressed much in these discussions is the bottom-end of the motor.
Seems like I remember Porsche factory people saying in interviews is that, this was what the limiting factor on this engine family was . There was a recent article in one of the Porsche magazines about a guy named "Ott" I think, who modded his 928 motor for much more HP (the 944 4 cyl engine is SIMULAR to 1/2 of a 928 V8). This Ott fellow put in crank scrapers, fabricated a more rigid oil pan (to help prevent the block from cracking) with baffles (to prevent oil starvation from oil slosh), installed an Accusump unit, and many other mods that I can't remember right now.

Besides which, I think the BOTTOM END was what NineMeister was asking about in the FIRST place, back at the begining of this thread. Way back in 2004 !

I wonder if NineMeister is even still following this thread, what with almost everyone going on about the valve train, chips, etc, etc.

Geo

Crank scrapers are a realy good idea with these engines. A good friend of mine is an automotive engineer and is well connected in OEM, aftermarket, and racing. He knows the guy who owns crankscrapers.com and this guy told him the 944 is in serious need of on. He installed a small camera in the block of a 944 and the oil was all foam and froth before installing a scraper. It's welll known that this engine also needs good baffling in the pan. I will be installing both along with an Accusump in my engine.

I'm surprised to hear there are issues with the lower end considering the crank girdle and the balance shafts.

There are issues with the top end for sure when it comes to making power. The ports are not all that great from what I understand (although apparently there is one casting number that is noteably better than the others) and the cam blows goats. The cam is the main factor why the usual performance mods don't do much on the 8v 944.

McLovin69

Before you start being rude. the bosh system limits the rpm through the fuel delivery curve, cutting back on the gas as it get to the redline. Change the curve move the redline. Remove the curve and blow up your engine. 1-2k$ isn’t a bad price compared to the 50k people want to sling around. Lindsey sells a replacement programmable ecu for 2400$, but having a professional work with you is probably worth the money.

I never said lightening the rotating bits added hp. Much like removing the a/c it simply frees up what is already there and helps the engine hold together at higher RPM.

Have the crank Nitrided (hardened), lightened, and balanced

Of course there are risks, but if he had the big $$ he’d have just bought a 20k turbo’s race engine

V2Rocket

yup.

the 944 engine was designed for optimum mid-range torque, something you could easily use around town or for passing someone without revving the crap out of the engine. the cam profile is designed accordingly.

thats why were saying that the cams would need to be changed in a high-rpm engine, the stock ones simply wouldn't flow enough air.

Geo

Wrong again, but thanks for playing.

Says who? Some years back I invested heavily in building a very high output NA engine for my car (not a 944). I could have bought a factory turbo engine and massaged it, or simply just built a turbo engine since this was a complete top to bottom, inside and out total rebuild. But, I wanted a high output NA. I did the turbo route with a later car (same engine). It was fun and all, but I really like the visceral enjoyment of a well tuned and built NA. So don't think people just spend money on turbo engines. Some people like the technical challenge of building a well optimized NA.

Geo

Actually, I think the cam sucks because of tuning for emissions control. Remember, the 944 was designed in the early 80s when emission controls were nearly still in their infancy. I think this manifested itself in the lack of overlap in the cam (among other things).

Chads996

I'd love to see the results. Post the specs, build cost and what was done. I think that info would be great to see.

C.