Stock head gasket limits.

[Inabj2]

Was a consensus ever reached on how much power a stock head gasket and bolts will take before the head lifts? Doing research around the years I see numbers posted from as low as 320 whp to no higher then 350 maybe 400 rwhp. But I suspect that this estimates were made with pump or lower grade race gas, where pre detonation is most likely the factor rather then boost alone. Assuming that pre detonation is not an issue as I use E85 what do you think the maximum power a stock long block sr20det can achieve before the head lifts? What is the most power anyone has reached using a completely unopened long block? (camshafts and oil pan allowed as these are easy bolt ons.)

[jr_ss]

You'll lift the head thus rendering your stock headgasket garbage. Plenty of people have taken the stock gasket w/ upgraded hardware into the deep 400s. If the motor is open, atleast throw a new OEM gasket and ARPs in and you should be good to go for awhile.

[Inabj2]

Motor is closed and running 20.6 psi of boost on E85, on a road tune, that was done for a previous built motor. This motor was supposed to be a temporary motor, however this has been my temporary motor for over 2 years.

I went to a dyno day recently and it turned out my car made 455 almost 456 rwhp and almost 350 lb-ft. Seeing how I been at this power level for some time, And how fuel richens up a bit after 7,000 rpm I think there is room for more power if fuel leans just a bit up top, and perhaps find if timing is ideal or if it can be advanced even more.

I wonder has anyone done 500 rwhp or over in stock headgasket and bolts? I know for sure of one car with over 450 in my personal experience this has turned out to be reliable. But I can't help but feel that I may be pushing my luck, if I go further.

[fliprayzin240sx]

I've seen people in Japan run fresh stock HG on ARP studs push to over 500 whp. From what I've been told by a particular builder, head will start lifting after 600hp. To keep the head from lifting, you run bigger head studs.

[Inabj2]

Well that is not very comforting, I am running a 15 year old head gasket and studs, and I want to retune it. I don't want to turn the boost up, but I want to advance timing some more (running only 25-27 degrees so far.) And lean it up to 12:1 ratio. And ok maybe 1 psi more couldn't hurt.

As it stands right now.http://i120.photobucket.com/albums/o180/Inabj2/Juans240sxdyno.jpg

[jr_ss]

Well that is not very comforting, I am running a 15 year old head gasket and studs, and I want to retune it.

What were you expecting? It's a relatively cheap upgrade and less chance of you lifting the head. If it were me, I'd do the preventative gasket studs, then get it retuned.

[Inabj2]

Bah, what is the unopened long block power record anyways? My friend that does the tuning is telling me just fix it if the headgasket pops.

[[email protected]]

your roughly where i would keep it. ive seen complete stock motors on C16 make 460 and with E85 running cooler it will help but your around the range where its a flip of the coin. I lifted my head with a [email protected] wit ARp's but now on a [email protected] and zero lift. it seen 35-40psi spikes too and all checked out. i wouldnt go any leaner and timing same thing. im on forged pistons and i have more timing but i wouldnt push the stockers any more then that