sounds like you might be pushing some boost into your coolant system. take a peek at the headgasket. look between the head and the oil tank on passenger side.

 

engine is down as we speak, will be looking, thanks for the tip

 

My heads were like bananas probably form too much boost but have found the studs werent tightened at 60Nm as per manual but some at 72 or others in the low 50s, was going to install new raceware studs and cometic hgaskets but found something even worse

Seems my engine builder didnt tightened correctly the cam sleeve too and both the sleeve and cam but also the superior part of the heads got damaged, take care guys.

Guess these engines are just amazing as the car runs like this since 2013

 

Steve Ott makes some great clutches. I highly recommend contacting him at driver source in race town USA ( Houston ).

 

I recently purchased a 996 turbo with ACarbonetics/ATS triple clutch. This is a high horsepower clutch designed for the track. I replaced with a more street able clutch as I will not be tracking my car. The ACarbonetics clutch is $4k new. My clutch has ~500 miles on it and is essentially new. Make me an offer. Gehren@charter.net after researching.

 

I have ACarbonetics/ATS triple clutch designed for high horsepower track applications available for sale. ~500 street miles on this $4k clutch. Pm me with an offer if interested. Gehren@charter.net. I just bought my 2001 996 turbo and will not be tracking and am in progress of detuning.

 

cant see how the heads were warped with only 700 or so hp. as for torque the 12mm are torqued to 90 ft/lbs with no warpage at all. sounds like the torque sequence was done improperly and many of the studs backed out. even racewear torques their studs to 60 ft/lbs with no warpage. spec 45 ft/lbs just isnt enough to hold the heads when making more than stock boost

 

Car did 2.2bar at 2.0bar dynoed 916whp and 1015Nm

 

on stock head studs?

 

No. Raceware 10mm and cometic gaskets

 

racewear are supposed to be torqued to 60 ft/lbs then 2 complete heat cycles then retorqued to 60 ft/lbs again if any sign of the studs backing out is present. looks like they were undertorqued from the beginning. also stock gaskets are recommended for 10mm applications. when you use the 12mm studs then custom cometics are used

 

Who says stock is better than cometic? I guess the cometic should be slightly better and I have my reasons to believe that, unless some proof will keep my opinion. The idea is I have pushed way too much with a lot of timing and boost and gas was only a mix of 94 with 50meth up to 50/50% 94/109 and 100%meth, did also 1-1.3bar of brake boost for 60-130 for like 50-100times.. there was no mercy showed till it gave away. I am sure bellow 1.8-1.9bar the car was very reliable, 1.8bar was the advice I got from Markski for this setup, was my problem I didnt listen.

But yes, if will go ever again for 2+bar will use 12mm studs, in the meantime I have built another car for high power

 

i didnt say they were better . they are recommended because cometics are a multi layer gasket and at only 60 ft/lbs of torque they tend to separete under boost. tim941nyc, prodigy both run over 1000 hp with stock gaskets.
i have seen a host of cars running 10mm studs lose head gaskets due to loosening at close to 1000 hp. seems to be more common if the car is driven hard on a regular basis. the 12mm studs seem to have solved this since with more surface area and more threads per mm the torque is increased a huge amount and no retorque is needed

 

Sean told me that the 12mm studs have higher tq values but clamp the same as the 10mm. The added tq value is a result of the size or resistance of the larger parts and not because of tighter clamping force. So the clamp is the same, just the 12's wont stretch.