[bbailey]

With the new PCA rules for the GT classes for 2008, it seems that the normally aspirated 944/968 series cars have a renewed opportunity to be competitive in those classes where they really weren't before, especially the 3.0L in GT3 versus the 2.5L 944 Turbo's.



I've found a few threads discussing higher output engines but nothing definitive, just curiuos whats been done out there as I'm getting ready to start building a 968 for GT4 under the new PCA rules.



I know Kelly Moss built a 968 to run in World Challenge back in '93 that made around 365 hp. Jon Milledge has done work on these engines as well. And I think RSBarn has started working on stome stuff.



Thinking we're going to need ITB's, a more aggressive cam, some serious headwork, and a substantially lightened and balanced bottom end, with standalone engine management.



Thinking about this purely from a track perspective. I'm not at all worried about the streetability of these modifications, only interested in a useable powerband of between 1500 and 2500 rpms.



Thoughts?



Brian Bailey

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[Eric_K]

Go for it! I don't think we have seen too many 300+ hp n/a cars though. You going to have to get real aggresive in weight reduction too. You can run at 2550 w/driver by my calcs. Getting a 968 into the 2300's will be hard but probably doable. Won't be a cheap project.

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[bbailey]

[quote name='Eric_K' post='43866' date='Nov 21 2007, 12:46 PM']Go for it! I don't think we have seen too many 300+ hp n/a cars though. You going to have to get real aggresive in weight reduction too. You can run at 2550 w/driver by my calcs. Getting a 968 into the 2300's will be hard but probably doable. Won't be a cheap project.[/quote]



Agreed, won't be cheap. 2526 lbs to be precise.



Kelly Moss has already told me they could do it but were unsure they were interested in the project because most people that go down this road aren't willing to commit the necessary funds and want it done on the cheap (which would result in a very unreliable finished product which they don't want their name on).



9meister had posted in a thread several years ago on 968.net that they had already built a prototype ITB that they got good results with and were working to build a high reving 3.0L. I've send them an email to see whatever became of that project.



Anyone else? RSBarn maybe? This seems right up your alley. ITB's and an aggressive cam would complement the headwork you're already offering. Would just need to lighten, balance, and beef up the bottom end from there.

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[Eric_K]

For ITBs hit up http://www.haywardperformance.com



Lance said he could make them for the 968, but I don't believe anyone has stepped forward to pay for it. I think he has posted to a thread here.

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[bbailey]

[quote name='Eric_K' post='43868' date='Nov 21 2007, 01:24 PM']For ITBs hit up http://www.haywardperformance.com



Lance said he could make them for the 968, but I don't believe anyone has stepped forward to pay for it. I think he has posted to a thread here.[/quote]



Thanks Eric, I'll get in touch with Lance and let everyone here know what I find out.

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[banditsc]

[quote name='bbailey' post='43870' date='Nov 21 2007, 02:59 PM']Thanks Eric, I'll get in touch with Lance and let everyone here know what I find out.[/quote]







Take a look at the pics in this thread, there is a 951 with ITB's in it, I wouldn't think it would take to much engineering to adapt the 951 ITB setup to the 968. The manifolds would bolt up, just need tuning.



http://www.968forums.com/index.php?showtopic=4640

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[RS Barn]

Hum!!!

Interesting you bring this up

I'm building a car for NASA GT something this winter. We're doing the chassis, cage now and next is the motor.

I'm going to move forward with throttle bodys at some point soon I hope.

I'm not familiar with Kelly Moss engine producing 365hp. That seems a bit high even for them and lots of money.

I know of a 325HP @ 8500 rpm carb engine that is in a 1800LB Trans Am 951 chassis. Yah it is fast!!!

I'm calculating my engine around 310-320 @7500 Hp with ITB's and Stand alone. It would have a 2500-2800 power range. I am looking to build something that has a powerband and would last

Call me to talk

Pete

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[bbailey]

[quote name='RS Barn' post='43872' date='Nov 21 2007, 02:06 PM']Hum!!!

Interesting you bring this up

I'm building a car for NASA GT something this winter. We're doing the chassis, cage now and next is the motor.

I'm going to move forward with throttle bodys at some point soon I hope.

I'm not familiar with Kelly Moss engine producing 365hp. That seems a bit high even for them and lots of money.

I know of a 325HP @ 8500 rpm carb engine that is in a 1800LB Trans Am 951 chassis. Yah it is fast!!!

I'm calculating my engine around 310-320 @7500 Hp with ITB's and Stand alone. It would have a 2500-2800 power range. I am looking to build something that has a powerband and would last

Call me to talk

Pete[/quote]



Pete, I assume you're thinking 310 to 320 rwhp? I'm 99% sure that the 365 that KMR mentioned to me was at the crank, not the wheels. So you'd both be in the same ballpark. Ideally, I'd like to see 335 at the rear wheels which should be attainable with an aggressive enough camshaft, high enough compression, and enough revs. Won't last forever, but if I can get 20 hours between teardowns I'll be happy.



Lets talk after the holidays when things slow down next week.





[quote name='banditsc' post='43871' date='Nov 21 2007, 02:02 PM']Take a look at the pics in this thread, there is a 951 with ITB's in it, I wouldn't think it would take to much engineering to adapt the 951 ITB setup to the 968. The manifolds would bolt up, just need tuning.



http://www.968forums.com/index.php?showtopic=4640[/quote]



Thats Jon Milledge's intake. Only one way to get one of those and thats to have him build your motor top to bottom. He consulted on my 450 rwhp 2.5L 944 turbo build and knows his stuff. Last I heard he had retired. I'll have to check and see if thats true or not.

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[RS Barn]

I'm talking engine HP @310-320

Even to get there you are talking solid lifters and removing variocam to use more radical cams.

I'm not worried about engine hours being a problem-It would be the missed shift that would be very costly.

I have a 12-1 compression engine I'm waiting to dyno. It wouldn't work with much cam though. I would need to make custom pistons for that.

Pete

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[333pg333]

I am getting this done now as we speak. That is, ITB's on a 16v Porsche head. That this is on a turbo car is incidental, to a degree. My advice is to contact Dave McGrath at http://www.customengineeredperformance.com/ and have a talk to him.



Patrick

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[Torbjorn968]

Sorry for my ignorance but ITB means? Question to Pete: is it worth ditching variocam for extra power if you look at it for track only purposes.



best



T

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[banditsc]

Individual Throttle Body. There are a few long threads on here about it.

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[RS Barn]

Tborjn (sp),

I think up to 300hp or so Variocam is still worthwhile. This would let the engine make good power from 3K on up. Not that you'd need low end driveability but package would be very docile.

Over 300hp you really are looking at a race engine with a 5K to 8k powerband and nothing below. Vario isn't really functioning there.

With all the new rules and potential racing applications I've been looking at altering the Variocam to work better with higher rpm applications.

Pete

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[LHP]

[quote name='RS Barn' post='48732' date='Mar 5 2008, 08:34 PM']Tborjn (sp),

I think up to 300hp or so Variocam is still worthwhile. This would let the engine make good power from 3K on up. Not that you'd need low end driveability but package would be very docile.

Over 300hp you really are looking at a race engine with a 5K to 8k powerband and nothing below. Vario isn't really functioning there.

With all the new rules and potential racing applications I've been looking at altering the Variocam to work better with higher rpm applications.

Pete[/quote]



The higher the performance wanted from the engine, Normally Aspired that is,

the higher the comp ratio, and as such,

limited room for the vario cam movement,

which is oriented to lower parts of the rpm band and street drivability.

Carefull fitment of piston to valve movement.



But hey, ITB's could open up that power band too,

And then you can get more aggressive with the cam profiles.

Individual throttle bodies make aggressive cam profiles more drivable.



LHP

www.haywardperformance

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[FRporscheman]

Oh man, I thought it meant "in the butt"..... I have to reread the whole thread now.

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[Cloud9...68]

I'm sure this is completely unfeasible, but I have to ask anyway. Gradually, makers of high-end cars, primarily Audi and Cadillac for now, are beginning to introduce fuel injection systems that inject the fuel, under very high pressure, directly into the combustion chamber, as opposed to into the port. For the 968 owner who has discovered he's Warren Buffet's long-lost nephew, is this something that could conceivably ever be implemented on an after-market basis? The car manufacturers claim a 5-10% horsepower boost from direct injection, though I can imagine it would be very tricky to figure out how to fit a high pressure injector within the 968's head. Just daydreaming...

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[LHP]

[quote name='Cloud9...68' post='48764' date='Mar 6 2008, 06:34 PM']I'm sure this is completely unfeasible, but I have to ask anyway. Gradually, makers of high-end cars, primarily Audi and Cadillac for now, are beginning to introduce fuel injection systems that inject the fuel, under very high pressure, directly into the combustion chamber, as opposed to into the port. For the 968 owner who has discovered he's Warren Buffet's long-lost nephew, is this something that could conceivably ever be implemented on an after-market basis? The car manufacturers claim a 5-10% horsepower boost from direct injection, though I can imagine it would be very tricky to figure out how to fit a high pressure injector within the 968's head. Just daydreaming...[/quote]



The head has to be configured/designed for this type of thing.

Not something that could be considered feasable in the aftermarket.

And the ECU would be out of this world to setup, let alone not affordable.



LHP

www.haywardperformance.com

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[RS Barn]

Lance,

Manifold on the way.

Pete

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[Cloud9...68]

[quote name='LHP' post='48783' date='Mar 7 2008, 10:44 AM']The head has to be configured/designed for this type of thing.

Not something that could be considered feasable in the aftermarket.

And the ECU would be out of this world to setup, let alone not affordable.



LHP

www.haywardperformance.com[/quote]



Thanks, I figured that was the case. Plenty of cars make amazing power with port injection, anyway. And I checked - no sign of Warren Buffet anywhere in my lineage. Not even Jimmy Buffet... <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" />

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[am914]

Haven't been lurking for a while so didn't see this thread. Yes, 325 HP at rear wheels normally aspirated is do able. We have been doing for 3 or 4 years running GT2 in SCCA. 3 liter block, 968 head, custom cams, solid lifters, dry sump, etc. Intake is 55DCOE webers on custom manifolds. We are looking at doing ITBs with fuel injection for a friendlier power curve. Bearing life is an issue. Even modified stock crank doesn't oil well over 8000 rpm.

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