ARP Sell a larger washer, I would not recommend using the stock one as its thin.
ARP washers are about 3mm thick.
3 years of pushing water gone now once I did this. 2bar on e85 all day. 520 wheel HP.

 

Finally tuned the car again on a different dyno, made 360kw at the wheels at 32psi if dynos read the same made a 65kw increase, didn't push any water, also did a 10.94@129 1/4

 

Nice job.

 

FYI, ARP changed the spec on the washer included in the standard head stud kit at some point last year. I had started to re-use the OEM washers when I opened an ARP package and found a much larger (OD) washer. They also revised the recommended torque spec down from 80ft.lb to 65ft.lb.

 

FYI if its of use, our heads are at 80-90ft/lb, anything less when going for 5-600BHP, gasket issues.

 

Hmm. I'll be testing this pretty soon, mine are at 65 ft*lbs with a calibrated wrench and I'll likely be over 500whp. I hit 490 something whp last year and didn't lift a head, but should be well above that with my new setup.

 

Pmax is directly related to ignition timing. Enrichment has a negligible impact on Pmax. It is common that Pmax will increase as you decrease load from WOT (at the same engine speed) simply due to the additional IG advance.

 

 

I've had zero issues since using the bigger washers and high torque on the head studs has had a few runs up to 40psi as well, have just changed the ECU package, and have put a set of 272 cams in, so I'll see if it stays fine when it's tuned again, hopefully get close to 400 4wheel kws

 

 

Using the car for both drag and track, we know the fix for the issue I had and it's working

Also what power and torque do you think you will make? This only became an issue when we got to around 500 engine hp

 

 

 

Even with 11:1 and the head decking, you're only running 10 psi of boost. I'd be surprised if it's all that much higher cylinder pressure than (say) my car running 9:1 (with unknown but significant head machining) and 24 psi of boost.

After coolant pushes in, what are you doing? Pulling the head and replacing the gasket? Are you replacing the studs at the same time?

--Ian

 

My ecr is up there with your motor but I’m willing to bet my dynamic compression is higher. Boost psi and hp are not the sole determining factor of head lift.

coolant pushes so new gasket and new studs with a hot retorque. Head and block were both straight machinist straight edge and feelers. Both are as they were when decked.

The hot retorque did yield almost A quarter turn! And yes my multiple tq wrenches are in spec.

 

 

Coolant pushing into overflow tank is a symptom more of overheating than head lifting. Think generating steam and rapid expansion in the cooling system.

 

 

This is the same motor you were running before strapping the hairdryer on it, right?

 

I find it hilarious that you're claiming you know what you're doing and you think a straight extension/adapter changes the torque on the fastener.