Mercedesben

any problems with a stock head gasket running 18 psi?

David Floyd

As long as your A/f ratio is correct and the gasket is in good shape to start with, the type headgasket does not matter. IMHO

Bret 944

If by "stock" you mean "stock style" and not ORIGINAL headgasket (which would be 15-20 years old), then I'd say sure. WFHG is mostly a stock headgasket anyway.

toddk911

Pressure, with in reason, does not blow headgaskets; Heat does.

Which means, technically, knock doesn't either, it is the heat that is creating the knock.

So when you hear people say they blew the HG and were running a bunch of boost, it wasn't the boost, it was the fact that they were to lean and the cynclinder got to hot.

Porsche-O-Phile

Bingo. It seems to me the vast majority of the people that end up with a milkshake machine are the ones that take their knock & overboost protection out of the loop with manual controllers. They end up with lean spots in the RPM band (so I'm told) and whammo! There goes the H.G.

As such I'm retaining the stock circuitry in my 951 including the CV (and resulting ability for the KLR to access the wastegate if it detects knock - that's its function) and will opt for an electronic (non-manual) boost controller as the primary boost controller that can compensate for non-linear relationships between air/fuel mixture and engine RPM, which a manual controller cannot. Basically you end up with two things connected to the wastegate - the EBC (electronic boost controller) that should manage things quite nicely and the CV which will step in if there's an emergency and "blow" the wastegate open to relieve boost pressure.

Mercedesben

thanks
I have the original HG

DDP

toddk911

Yep. You should call Danno. But his 18psi chips are pretty much nailed down now.

Did it start by dialing back the fuel or adding fuel? If you added fuel it might be a bad or misfiring injector.

toddk911

Also, if you only adjusted the air/fuel for idle, it should not affect the entire band. I am not complely familiar with the Arc2 though.

'86 944 turbo

I've been running 18psi all summer long with the stock head gasket no problems to report yet. I guess if you have the ar/fuel in good shape you'll be fine.

ewainwright

I have 160k miles. I've been running 18 psi for two years with no head gasket issues ( Clutch, axles, CV joints, brake pads and tires are another issue - go figure) A/F ratios approx (13 - 13.5) 800K - 2.9K from 12.9 (3.2 K -5.5K) 6k to redline and up 11.9

hally

My original head gasket blew a year or so after going to 15-16psi.

rhesus

what kind of chips

Mark-87-951

Ive been using Huntley racing chips and LBE at 15psi for several years with no HG problems.

B951S

I run 20psi and sometimes 22psi with water injection, nice fuel ratio and 'sensible' timing on stock head gasket that was changed early in the cars life. The orignial owner changed to Autothority chips and blew the HG with way less boost than I run. Like many have before, keep the AFR good and run appropriate timing and you should be ok.