# Blown Head Gasket



## 142BHP (Jul 21, 2004)

Yesterday while mapping the fuel and timing maps on my standalone management system everything sort of gone South. While running the car on the Dyno @ about 4500 rpm just as the T3/T04E was clocking full boost ( 12 psi) the car popped a head gasket so bad that the water was pouring out cylinder number 4 exhaust port. Oh by the ways it's a SR20 motor

I am planning to go for a cometa metal head gasket , will this improve my reliability and will I be able to run more boost. The head has been welded up to give me a CR of 8.5 to 1 and I have been able to reach 15 psi without any problems on normal pump gas. I plan to run the car on 10 psi for daily driving and crank her up to 15 psi for race days.

Your help will be greatly appreciated 

Thanks

Rudie


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## thestunts200sx (Jul 11, 2005)

www.outlawengineering.com

And read/view the dyno chart.


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## velardejose (Sep 9, 2004)

Hi
What was the A/F ratio before failure?
Peace


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## 142BHP (Jul 21, 2004)

According to the tuner she was running @ about 4.6 CO which if I work it back is about 12.7 AFR if I am not mistaken. I spoke to another trusted tuner and he reckons that the timing could have been a problem since I am running 550 cc injectors and the fueling should have been sorted with the management set up correctly. I think some detonation could have eaten away at the gasket since it blew on the ring around the chamber leading into the water jacket on cylinder No4 on the exhaust side. He said he had the timing running at about 21 degrees which sounds fast to me under boost but the management works on a MAP sensor that retards timing under boost by a set ammount. I went out this afternoon to buy a cometic metal gasket and the guys at the shop reckons that I should torque the gasket to 110 Newtons , but that sounds very high to me.... Any advice on similar gaskets for torqueing strength.

Now he wants to turn my boost down to about 7 psi but that is pointless in my oppinion and we are only fixing the problem and not the cause by doing that. I set this car up to run at least 10 psi for daily driving and I dont think that should be problem at all for the SR20 lump. If I am only running 7 psi how on earth can I run 15 psi for race days on 93 or 102.6 if need be.


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## velardejose (Sep 9, 2004)

I dont know about sr engines, but I am sure the big guys here who have/had turbo sr20 engines can help you
Peace


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## wes (Apr 30, 2002)

That is lean for a turvo setup on pump gas. You should be mid-high 11's. Peopl have pushed BONE STOCK sr20's to over 400 WHP. The only internal mod done was cams. SOmething else is the issue here, not the motor or stock head gasket.


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## 142BHP (Jul 21, 2004)

Ok the new head gasket has been sorted and i started the car last night and everything seems ok , lucky for me nothing was bent or broken out of shape with the water pissing into cylinder number 4. I think that i will take my car to another tuner out of town that has experience in setting the SR20 since they are one of the few who run SR20 race motors. The guys over here are crazy over the 2.0L EGI Mazda motor and all the tuners want to replace my SR20. No chance of that happening, I like to be different and not run what every second Tom is running.

I will change the ratio to run slightly richer under boost and rather pay the gas bill than the repair bill 

Cheers


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