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Thread: First Time Inside My W11

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Posts: 11-20 of 23
2009-04-14 14:26:14
#11
Yeah, I took the spark plug out and it was soaked in oil, so I'm guessing it was lean Haha. Taking a break from the head for now, heading back out to finish it in a few minutes. I never shifted past 7000 rpms, even when i was racing

I wasn't over boosting either, it was peaking at 12lbs, BUT then again, the boost guage I had was junk too, so I dont know. So you think its a hole in the piston? I'm hoping its only a valve issue, but with my luck its most likely not
2009-04-14 14:30:51
#12
When I get off work I'm going to check compression in that cylinder and change my rev limiter to 7500.
2009-04-14 16:45:17
#13
Originally Posted by 92BoostedSER
Yeah, I took the spark plug out and it was soaked in oil, so I'm guessing it was lean Haha. Taking a break from the head for now, heading back out to finish it in a few minutes. I never shifted past 7000 rpms, even when i was racing

I wasn't over boosting either, it was peaking at 12lbs, BUT then again, the boost guage I had was junk too, so I dont know. So you think its a hole in the piston? I'm hoping its only a valve issue, but with my luck its most likely not


no you melted a piston, 12psi is up there and especially if your a/f is not good like in the mid to high 11:1 range should be around 11.7-8:1

Yeah if you take the breather off the valve cover i can guarantee your blowing air out there along with smoke and oil as well. Trust me i went through the same thing 2 times.
2009-04-14 17:07:36
#14
It was blowing smoke out of the breather really bad when it happened. It was also pouring outta the exhaust. Surprised I didn't cause a massive pile up on the highway on the way home.
2009-04-14 17:22:21
#15
yep, no other way around it, you melted the side of the piston, more than likely more towards the exhaust or left side of the cylinder. Thats where mine both happened. The tops of your pistons that would sit under the exhaust valves are probably gonna be white and showing signs of pitting which is detonation due to hot spots on the pistons caused by too much heat which is in turn caused by too much backpressure due to too much boost from the t25 or running too lean for too long. It doesnt take much. Trust me haha
2009-04-14 18:33:44
#16
Yeah, I didnt realize it until now, but the exhaust ports on the head are soaked with oil, and the other 3 are dry.

No way i'm going to replace the piston/rings. I'll just get a new motor and start from scratch. Lesson learned the hard way. Next motor ill run .05lbs of boost just to be on the safe side
2009-04-14 18:50:32
#17
Originally Posted by 92BoostedSER
Yeah, I didnt realize it until now, but the exhaust ports on the head are soaked with oil, and the other 3 are dry.

No way i'm going to replace the piston/rings. I'll just get a new motor and start from scratch. Lesson learned the hard way. Next motor ill run .05lbs of boost just to be on the safe side


I have built many of these SR20DET T25 motors making 270 WHP at 15-17 psi.


I am not sure what you have but......

SR20DET ( 370cc injs )
54 mm Bored stock MAF
S4 cams
Nisma FPR
Walbro Fuel Pump
3 inch DP
3 inch Exhaust
JWT - Calum ECU ( set for 4 bar FP = 59 psi and bored MAF )
Aluminum Flywheel
Clutch
Front Mount intercooler


These cars trap 110-113 MPH and run 12.5-12.8 on slicks.


I think you messed up somewhere with something small.
2009-04-14 20:01:43
#18
miko i have all those same mods and i put down 246whp @ 8psi
2009-04-14 20:03:20
#19
Originally Posted by 2dr_sentra
miko i have all those same mods and i put down 246whp @ 8psi


Well keep going up. The small turbos dont really make any more HP as you go up. The % increase is very small for every pound of boost up.
2009-04-14 20:08:15
#20
Originally Posted by Andreas
Well keep going up. The small turbos dont really make any more HP as you go up. The % increase is very small for every pound of boost up.


Next time i go to the dyno ill try 15psi and see what happens. I hope i gain 25whp+
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