Thread: #4 piston carnage..detonation

well i was curious to see the full extent of the damage to the #4 piston so i decided to pull it at 1am and take a look. Looks pretty decent to me, hahaha.... Hey at least the bearings were in awsome shape. no wear at all. This motor definetely had alot more life in it if that wouldnt had happened. oh well. 1 up to soko for a great condition motor. This was on 16psi boost on a jdm 9.5:1 motor and this is what happens when you run crappy pump gas at that level.

Here are the pics









and here you can see the awesome condition of the bearings.



well the new jdm from soko is ready to be put into the car. now just waiting on a couple little parts. should be an even sicker setup

Yeah i wouldn't suggest running 16PSI on a 9.5:1 motor even with 93. Too risky.

Nice carnage pics anyways I've never done a piston in that bad.

I can't see pics Damn work. What was your AFR at?

That kind of damage its due to running way too lean and retarded timing.... creating high cylinder temperature causing the piston to melt.....

Saw the pics now. That's crazy!

GOTTA be from running lean. Piston literally melting away! Did you not have an EGT gauge?

no egt guage. a/f according to the wideband was 11.5:1 Thats what im guessing is that it ran way too lean for too long. Not sure if it was was the cause being all the other pistons are fine. all other plugs were fine. Im sure most of you read my post on what happened. So it still confuses me. either that it was detonating soo many times in a row that it just eventually melted it. my open dp is soo loud i probably couldnt hear it happening. but it sounded smooth until it blew completely.

See my quote from what Pete, aka ClassicAddict said, in my signature...

true, it did feel soo good at that boost level. no traction till 80+mph and even in 4th gear it was jumping the tires loose. It pulled sooo much harder than 8psi. Definetly was a big increase. Its too bad i didnt get a chance to see what it would do on the track on slicks. but with this setup i know now and should be able to do it safely without destroying anything, haha, but the track will have to wait till the fall being its already starting to get warm and all my money went into a new motor and other small parts. So i will just make sure everything is running smoothly at both boost levels and then know i have no problem running it hard at high boost.

gonna go for the t25 record. So come fall just before the convention i will take it and run it down the strip full out on slicks and see what that nets me. Im gonna loose a couple more pounds off the car too even though its already light as hell. So we will see

16PSI on a T25 is producing a lot of heat. It may not have been so bad on a larger turbo.

yessir, you sure this was a t25??