sr20det w/gt2871r.....Is this boost ok??

[D1 guy]

I have an s14 notchback sr in my 97 240 and Im running nismo 555s that flow at 615cc w/z32 mafs, jwt ecu tune, walbro 255 pump, and a z32 fuel filter. My turbo is the big gt2871r. I also have 256/264 hks cams. Ok heres my question. I dont have a metal headgasket because I figured its better to blow the head gasket rather than blow up my engine. Ive been running 20psi and the car seems fine. My aem wideband shows around 13.6 at full throttle. feels like about 400hp. Is this ok or should I turn down the boost? What is recommended for the factory head gasket? Thanks very much and I did search, but couldnt find a direct answer.

[karmakaze]

I have an s14 notchback sr in my 97 240 and Im running nismo 555s that flow at 615cc w/z32 mafs, jwt ecu tune, walbro 255 pump, and a z32 fuel filter. My turbo is the big gt2871r. I also have 256/264 hks cams. Ok heres my question. I dont have a metal headgasket because I figured its better to blow the head gasket rather than blow up my engine. Ive been running 20psi and the car seems fine. My aem wideband shows around 13.6 at full throttle. feels like about 400hp. Is this ok or should I turn down the boost? What is recommended for the factory head gasket? Thanks very much and I did search, but couldnt find a direct answer.

13.6 is kind of high isn't it? isn't around 11.5 ideal?

as you know, my car is working on a pretty similar setup as yours (except i have a 1.5mm metal HG). however, all the research that i have done says that its not a good idea to go over 17psi on the stock gasket.

[Dori Dori]

I have an s14 notchback sr in my 97 240 and Im running nismo 555s that flow at 615cc w/z32 mafs, jwt ecu tune, walbro 255 pump, and a z32 fuel filter. My turbo is the big gt2871r. I also have 256/264 hks cams. Ok heres my question. I dont have a metal headgasket because I figured its better to blow the head gasket rather than blow up my engine. Ive been running 20psi and the car seems fine. My aem wideband shows around 13.6 at full throttle. feels like about 400hp. Is this ok or should I turn down the boost? What is recommended for the factory head gasket? Thanks very much and I did search, but couldnt find a direct answer.

If that gauge is accurate, you're running lean especially with so much boost. Also realize that you can still blow up your engine before your headgasket goes and blowing a headgasket can be the result/cause of more problems. First bit of advice, add more fuel (got a fpr?) and turn down the boost, then go ahead and order up a headgasket. 11.5~12:1 is safe for a street car although some people run closer to 12.5:1 but 13.6 is bad for a boosted car.

[D1 guy]

This thing may not be accurate then. When at idle, itll show like 14...sometimes 15 and when I let off the gas and depress the clutch at a redlight, itll sometimes even bounce to 16......That doesnt sound right does it? I just ran out and did a test run with my friend watching the gauge. At full boost @ 19.5 psi it showed 10.8. I guess thats better than 13....but what about the idling? As you can tell, I dont know much about afrs. Thanks very much. I need all the help I can get apparently

[574-240sx]

Thats a little lean for WOT. I would turn the boost down or add some fuel, maybe even both. Wouldn't be a bad idea to do some data logging with a wideband or at least an air/fuel read out at a dyno.

[Dori Dori]

^exactly. Get your self on a dyno and have a tuner take a look at the a/f map. Usually w/ an Enthalpy tune, people use either an adjustable fpr or an SAFC to "fine tune" the map. The dyno should tell you what you need to do.

[pampadori]

10.8 is okay. i don't think you are going to blow at 20psi. and you might be around 340whp, close to 400 crank.