Thank you for reinforcing my point. I am not sure you were trying to, but thats pretty much what I was trying to say. Basically, if you want a tune, go to someone who is reputable. ASK them what afr they run. If they quote normal PI numbers, screw em, and RUN.

 

The biggest contributer to these failures seems to be KNOCK. Whether from running too rich and too much timing or lean with too much timing or running way too much pressure. Knock whether it is rich knock or lean knock or too much timing causing knock is no good especially at higher pressures.

 

A guy here in Houston. HHR SS auto on GMS1. Cyl #1. Hes rebuilding and going big turbo + trifecta.

For me, it confirms the fact that there is some as-yet undiscovered design flaw related to running high boost for extended periods of time.

 

...or my case, where it was 1 and 3...

Cylinder 1 had the cracked piston/ring and cylinder 3 had scoring that is as of now still unresolved.

 

may be everyone that has a broken piston drove there cars hard. They might of hit full boost everytime they took there car out. they might of raced it every weekend!

 

Nope. Thats not it. I have over 60 1/4 mile passes on my car just last summer alone, and its running perfectly fine. 100% of them were tuned passes too.

 

well thats good to know I because I wanted to go to the strip a lot this summer!

 

Subscribed

 

at time of piping shattering and piston 1 cracked it only had hahn cat back and bsr tune.I replased piping with hahn's, had codes for map and mas air flow sensors replased them and car still wasn't right so i detuned and took it in gm covered it, but never tightened down the head so about athousand miles later i got misfire codes on cylinder 1 take it back in they tighten it down but know it breaks up at about 4500 rpm on stock tune and nobody knows nothing.they say its from the piping and exhaust but i know better.I'm thinking i'll be buying an ecm? they said compresion is good , i got spark, and they just changed the fuel pump it's beyond everybody. I don't know what to do my wife is going to kill me.

 

Don't buy the ecu. Tell them to cover whatever is needed. Their fault for not tightening the head down. I would have them pull the head back off and inspect everything.

 

but atleast he tested it to 30 psi... he is seting the standerds and leting everyone know so rilly he is doing feld testing more than being sleazy.... when i worked at the dealership ide take waranty work all day over oil changes and junk we got... easy work and some serious hours

 

thats what i said. But they have an out with the piping and exhaust still on the car so i gotta buy stock piping and weld up the old exhaust so they cant give me any excuses. You guys think maybe the cold weather has something to do with it. It was a cold one when piston one cracked on me

 

had missfires in 1,3, and 4 for a very long time



1 2008 SS/TC with Drop-In K&N, catless clear image automotive dp
2 tune time performance tune (holding 21psi til redline).... look up widowedeight on youtube to see the car in action (most recent race = me vs. a supercharged 350z)
3 Had about 43k on my car when it decided to go blah i think cylinder 1 but i don't know yet...
4 Had about 17k when i got the car tuned
5 dunno a/f ratios

yes... i know i drive alot....., no i don't race often

 

INB4 someone makes fun of your tune

 

In before someone tells you this is for LNF's and not LSJ's.

 

he has an LNF

 

HA! I fail. I only bothered to read the first part of the sig, then put the miles together.

Damn you do drive alot!

 

lol true. I drive a lot and only have 21,000 miles on my 08 tc

 

Dang, I drive alot and only have 18k on it. And 160k on my DD, lol.

 

yup car (til the summer) is my dd, anyone know anyone in central PA that is a trifecta tuner, or anyone in central penn with hp tuners?

 

destroyed all 4 pistons and cracked the block

1) 2006 SC with Stage 2
2) GM stage 2
3) Factory Stage 2 tune
4) N/A

 

so did you have stage 2?

 

What part of lnf performance tech do you lsj guys not understand!?!?!?!?!?!?!?!?!?!?!?!!?

 

12k miles on mine been tuned sine it has only 1000 miles... lots of 1/4 mile runs, 100's of dyno pulls, and 1000s of jaunts down the highway...

Doesn't even blink an eye... keeps going A/Fs are in check at 12.8 AFR, pulls and holds 22psi (on the stock turbo) about 19-20 on the 2871 (which is off now till I get my clutch)...

But runs great everyday!

 

Hey gang, I'm not a big poster here more of an observer but I just wanted to chime in real quick. First of all, Im sorry to hear that you guys are having difficulty with ring landings, coming from the L67 (Supercharged GP etc) crowd we also knew the sting.

I don't think piston weakness is the issue here.

On the L67s, in the beginning, the only modifications people ever did were, plugs, slightly smaller 3.4 inch pulley, cat back exhaust, and an intake. The problem is some people had KR stock. So dropping the pulley size (going up a few lbs) some people would have 3-4-6 degrees worth of KR. Now remember the L67 was an 8.5:1 comp motor, with a supercharger with absolutely no intercooler, and a blower with the worst adiabatic effiency out there... Once you pullied you were in the high 30's to low 40s percentage wise for adiabatic effiency, which meant crazy hot outlet temps...

People were breaking ring landings left and right, everyone was afraid to pulley the motor, it was just a mess.

Those who did not have any knock weren't breaking pistons... (Curious) Fast FWD many years later, people were putting over double the amount of power through the motor using an intercooled turbo, with no knock, and no piston or motor grenading.

I tell you guys this because I honestly don't think stronger pistons are the order of the day for the average modder.

Here is what I believe the problem is:

LNF works off of charge stratophication. It can run leaner combustion A/Fs because of its homogenous and heat soaking direct fuel charge effects (which we all know). However what may be happening is injector hiccup, rail pressure fall off. All it would take is ONE injection cycle where the fuel wasn't equally distributed to cause a lean pocket in the combustion chamber. Combined with the very high outlet temps of an overworked turbo and a poor intercooler would spell disaster.

It would be like having no Direct injection and trying to run 25-28 or even 30 psi of boost on a port fuel vehicle with higher compression 9.4:1 on a crappy intercooler and a turbo that falls off the map with factory boost let alone increased pressure.

I'm not sure how to remedy the problem, I do feel though its being caused by lean pocketing on top of very high inlet temps. I do not feel the pistons are at fault.

I hope you guys get this stuff taken care of.