LNF Premature Death - Tune Issue

[morecircles]

My 2010 LNF has bad rings based on a leakdown test done recently. I got 30% leakage, and my brand new k04 was puking up oil into the charge pipes. It has a cold air intake, zzp intercooler, zzp downpipe, and an HP tune by a local tuner.

Peak boost is somewhere around 22 - 24 psi, as this was meant to be a conservative daily driver tune. Reliability was of utmost importance to me, and I communicated this to my tuner. With the engine giving out at 180k km, I am not pleased. I was HP tuned since about 120k km.

Most of those kms are from driving to work on highways. Oil changes every 10,000km using Pennzoil Platinum.

The car has been tracked on a road course, but not frequently. Once or twice a year since 2015. I am a spirited driver, but I try to take care of the motor with my driving habits. I will allow the engine oil to come to temp before hitting full boost, and I never go WOT under 3k rpm. I also do not "race in Mexico".

Moving forward, I will be dropping in an LHU from a wrecked Buick Regal. At this point, I am not sure if the tune was the culprit behind the early death of my LNF. Would any tuners on here be willing to review my tune, and provide me with a second opinion?

Thanks.

[ECaulk]

There are multiple people on here who will look at the tune, most of them will not post comments on the tune from respect for the original tuner, some will PM you. Others will tell you to learn on here and look at the tune. Initial not seeing the tune ever comment would be to check the PE table and see if they're running a really rich PE (i.e. 0.80).

At the age of the engine and the life it's lived, having 30% leak down isn't unexpected. Racing a car on a road coarse isn't exactly driving the car easy and certainly takes away expected life.

[cobaltssoverbooster]

if you post a file here i will gladly look through it and put out "my thoughts". anything that can be directly related to a failure has to be handled between you and your tuner. Don't expect the posts in here to be admissible material in court if you take it that far. Opinions about something that hasn't been personally inspected and reviewed in person isn't solid information. I should start by mentioning that you do need to understand an ecotec engine operating at 22-24 psi your 75 k miles of boosted driving is a fair lifespan considering what the engine does have to put up with at full tilt. i always told my customers the engine should be torn down for inspection and a refresh at 60-70k miles because this seems to be the distance in which clearances open up and start causing some issues.
some other things you should understand:
1) the KO4 is considered an maintenance expense. this turbocharger was designed to operate at 15-18 psi for its max efficiency. with the intercooler the range opens up to serve as great use up to 20 psi. yes it is possible to keep boosting higher and get roughly 24 psi before having iat issues but unfortunately you decrease the turbocharger lifespan to roughly 35-40k miles (64k km) with boost exceeding 21-22 psi. at this pressure level the shaft speed becomes and issue and the journal bearing witnesses excessive shaft side load in boost higher than just mentioned deteriorating the the turbocharger. If you want to do road racing thats fine i would suggest switching to a gt2876r or a ZFR6258 to keep your spool range. if you want to push the power some then try a ZFR6758. these turbochargers are both engineered to operate at high pressure ratios and will not experience the same shaft failure as the KO4 does.
side note...when i replaced my original KO4 it cost me $1500 to get all the replacement lines and bs to install the turbocharger. if the ZFR was around i would have choose it, its a great price and drops right in with a little fitting and finesse.

2) pistons take a beating. If you wish to run boost in the high pressure ratio zones then it would be wise to open the factory ones up to .019" on the top and .023-.024" on the seconds and throw them back in. This does two things for you:
A) expanding the gap to the race spec for the bore size is going to prevent the rings from heating up and touching. This is cause #1 in most cases i see. the rings heat up so bad at 24 psi that they eventually stress cycle the piston above the upper ring land and the piston head. This zone is called the "top land". Although its not usually an instant failure type of event the claims i keep seeing from users lets me know the factory specs are just barely shallow enough to take the cylinder temperature caused by these high pressure ratio tunes.
B) expanding the ring land also bleeds a little bit more cylinder pressure off. although it only drops the compression test by a bit its not going to affect overall performance. in fact the looser gap reduce ring tension which decreases rotational friction by enough to just about null the effect of ring bleed. (these effects are on the effect of .3 of a hp so a good fart into the intake mid pull can cause more effect that ring gap change when running boost)
Spec. Comparison)
Stock GM Manual
Top compression ring end gap 0.20 - 0.40 mm (0.0078 - 0.015 in) Second compression ring end gap 0.35 - 0.55 mm (0.0137 - 0.0216 in)
Race Spec. per Carrillo/Pankl for forged turbocharged pistons
Top compression ring end gap 0.0483 mm (0.019 in) Second compression ring end gap 0.584 - 0.609 mm (0.023 - 0.024 in)

Ignition has a big play in the overall lifespan. factory pistons do not enjoy much more advance than about 14* all in on the top end and somewhere between 9-11* on the initial tip in around 3k rpm. cobalt's and hhr's can sometimes take more but kappa chassis are a solid stop around there. two things you can do to help you out big time:
A) If you re-gap the rings then you should also look at the cylinder head and pistons looking for sharp edges. i use air powered porting tools but if you notice anything sharp protruding in the cylinder or on the piston then you need to knock the edge off by touching it up with something equivalent to a 120 grit sanding roll. It doesn't need to be hit hard; think of it as a deburing process. These are the type of imperfections i correct. This is to also include the sharp edge left over by the machine shop decking service around the entire perimeter or the head chamber. chamber_burrs.jpg
B) If your engine has a floating clutch make sure you do the conversion to the non-floating flywheel. This bastard makes so much noise that i have had to turn the knock sensors off and use knock ears to determine real detonation by ear.

if you decide to open it up then all of these steps will help you with the new engine and help you keep it from experiencing a similar failure in the future.

[morecircles]

Thanks for the tips ECaulk. I looked at the PE Lambdas and they are 0.86 in the top end, which seems to be right.

Thanks for the comprehensive post, CSSOB. I am not looking to sue my tuner. Waste of time, and I probably would not win. My tuner is well regarded around these parts, and he was recommended by John Powell so I am not necessarily blaming him for my motor's issues. What I want to make sure is that the tune was not the root cause (people make mistakes) so I do not destroy the new engine too.

Unfortunately I do not have the means to open up the motor to re-gap the rings. This probably means I should run an even more conservative tune (20 - 22psi?).

I will PM you my tune. I appreciate your help. Thanks again.

[cobaltssoverbooster]

I don't exceed 22 psi when I hear the words autox, circuit race, and k04

[Area47]

Thanks for the tips ECaulk. I looked at the PE Lambdas and they are 0.86 in the top end, which seems to be right.

Thanks for the comprehensive post, CSSOB. I am not looking to sue my tuner. Waste of time, and I probably would not win. My tuner is well regarded around these parts, and he was recommended by John Powell so I am not necessarily blaming him for my motor's issues. What I want to make sure is that the tune was not the root cause (people make mistakes) so I do not destroy the new engine too.

Unfortunately I do not have the means to open up the motor to re-gap the rings. This probably means I should run an even more conservative tune (20 - 22psi?).

I will PM you my tune. I appreciate your help. Thanks again.

SSKev comes to mind now since you referenced a friend of mine.

[morecircles]

Sure. I was intentionally not naming names. Again, I'm not pointing fingers here. Just want to make sure my tune will not blow up a new motor because I'm not made of money.

[Area47]

Sure. I was intentionally not naming names. Again, I'm not pointing fingers here. Just want to make sure my tune will not blow up a new motor because I'm not made of money.

You're more than welcome to PM me if you like. I have been working with john for the better part of a decade now.

[morecircles]

PM'd. Thanks.

Come to think of it, I wonder if my new turbo did my motor in. I did not retune after replacing my old K04. We had a brief look at the boost and it didn't seem like it was over boosting but we did not look at it too closely.

[cobaltssoverbooster]

i went through the file. i can tell that the tuner for the most part choose to stay on the safe side.
after summing up the things i don't agree with and can agree with i would have to say no i do not think your engine has suffered a failure due to tune file quality.
granted there is room for improvement in a few areas but if i had to factor in limited time, maybe "customer waiting" type situation, then i would say its a fair file.
it is likely a factor of time that killed your engine and pressure ratio that killed your new KO4. there isn't anything that directly stands out as bad.

[Area47]

as ccsob stated, its a safe tune. Nothing stands out that would cause damage by any means. there is a few things i do that are different, but thats just me.

[morecircles]

Thanks guys. Good to hear that I can continue to trust my tuner.

Frustrating how there are guys with similar set ups that have 250k on the clock. I guess they are not pushing the car as hard as me.

New motor will get a 20 psi tune. Hopefully that's nice and conservative enough for a reliable motor.