special tool

Albeit a friend with a temporarily overextended toy budget.....

David Floyd

I know that problem all to well.

TRWright

I know, I know! I cheaped out and used a fairly new stock PP. Big mistake. Even with the 6 puck copper metallic disc, the clutch spins at around 400 hp or so.

John has something for me, but it will be winter before the car comes apart again.

Understatement of the year. . .

SoloRacer

I don't doubt your kevlar disc was slipping but how do I know if mine is? The vendor told me it's good for 400 rwhp and the guy is reputable. I have no evidence of it slipping yet but that doesn't mean it won't at some point in the future. How did you know when yours was slipping? Was it the usual rapid RPM rise with the smell of burnt clutch? Or was it something more subtle? I really don't want to do a clutch job right away if I can help it - especially since there is no proof that it is slipping on my car.

On another note, during the rebuild of my engine the crankshaft and flywheel were lightened. Then the entire rotating assembly was balanced - including the pressure plate. I noticed on the pressure plate that there were a couple of holes drilled to remove weight from it. Can I replace this pressure plate with one off the shelf (say a KEP plate)? Or do I have to get it balanced to match the one that comes off the car?

SoloRacer

This is probably the smartest post of the whole thread. Getting the power that ST and others have is not as easy as just bolting on xyz turbo. It takes a lot of additional work and you have to run higher boost with exotic fuels. This is often beyond the average joe. However, many read the posts here and assume that 400 rwhp is a drop in the bucket. When I posted I fully expected some people to blast the numbers as being either wrong or horribly low (which they did) when in fact the dyno sheets I posted should be thought of as being the norm. It's the other high horsepower sheets that are the exception. If John hadn't been so forthright on telling me what to expect and all I had to go on was the results posted here I too would have been mad as hell. Instead I'm pleased with the numbers and I will work to push them further up. I've come to realize that our cars have limitations that are lower than others. For example on the same dyno my friend with an RX7 put down nearly 400 rwhp on pump gas and 15 psi. I have another friend on a different day put down over 500 rwhp on pump gas on his RX7. For us to get there on our cars it would be very expensive and very difficult, if not impossible, to do. The Vitesse Stage 3 is the last turbo I will buy for my 951 because I don't expect anything out there to be better.

I too was impressed with the air fuel ratios out of the box. With my APE chips the maps were rich in one spot and very lean in others. The Guru chips were a bit better but nowhere near as tight as the ones from John.

fast951

SoloRacer, I wonder if the lighter fluwheel, crank (rotating asembly) does not help in loading the engine on the DynoJet.. On the street they are fine!
Before declaring your clutch is slipping, more testing is needed. Ted W. didn't think his clutch was slipping, but I could tell it was from his dyno chart. As I recall, when we were dynoing David Floyd's car, his kevlar clutch slipped at 13psi 330rwhp.. So having a certain type of clutch does not mean it is not slipping, at the same time without additional data we cannot declare your clutch as slipping.
If your are making 1 bar boost in 4th at the same RPM as 5th (or 4th same as 3rd) Or if the RPM is higher in a higher gear, I would suspect the clutch..

With the Stage 3, no exhaust leaks, and a dual port WG you can expect 12-15rwhp with each psi increase (on race gas).. Up to 400-420rwhp any hiher and you need head work, cam etc...

What octane rating were you using for the dyno?

300-330rwhp/tq with a broad power band is nothing to complain about. Assuming 15% drivetrain loss, this is 352-388 crank HP..

SoloRacer

John: I was using 91 octane as that is the premium fuel up here. I just got back from making a few pulls on the highway to see at what RPM I get 1 bar of boost. The results are as follows:

3rd Gear: Approx 4000 rpm (could be 3900 because of the time it takes to look at the boost gauge and then up to the tach)

4th Gear: Approx 3600 rpm

5th Gear: Approx 3400 rpm

I did notice that it took no time to get to 14 psi but the last 1 to 15 was taking a lot longer. I'm wondering if this is due to the set up of my boost controller. I know the gain dial sharpens the wastegate response and I have it set a little softer at the moment. If I change the gain the boost is more on/off at 15 lbs.

special tool

You have an exhaust leak

TRWright

I concur.

fast951

Exhaust leak or WG opening up too soon...

On 91oct I wouldn't run more boost unless you have a way to detect knock. The latest software you are using now has 2 ignition maps. One map is fairly conservative to support 91oct.. The second timing map is more aggressive and designed for race gas (it can be used for 93oct pump gas up to 1bar boost, but not recommended).

On 91oct gas, fixing the exhaust leaks will gain you some torque and more HP.. On 91oct you will not be able to make the power that can be made on 93oct...

Mike B

Hey Erik...A handful of Mohawk gas stations offer 94 octane. I don't have the list but if you email their customer service they'll tell you the locations.

Edit: Here is their email
customerservice@huskyenergy.ca

porshhhh951

300hp and 280tq is kind of low. I would check for leaks and make sure things are in order. Go back and lean it out some run it to 6500 and post up the new chart.

I ran 4 more psi than you on a much smaller turbo and pump gas and make the same hp and 51 more lb ft of tq.

Something is not quite right. Even at 15psi and pump gas I would think you would be all over 320hp and 330-340tq.