Seeing as the stock tune knocks like crazy between 2K and 4500 at WOT, I can see there being completely bone stock cars with cracked ring lands especially if you are flooring it everywhere.

 

The pistons and rings fail in these motors... Why put a shitty internal in when you have a block etc that is much stronger... Keep you thoughts to you self if this is what comes out.. not to be an *******

 

I floor it everywhere.

 

ummmm. Blow me?

You know, the intelligence level of some on these forums is almost nill. If you are going to take a stand on something as strong as saying the internals on the LNF are ****, at least have more to back up your argument then, "wait and see." We have a whole 3 failures on this, which is somehow the most popular board for the SS, and that is indicative of some widespread failure of GM's engineers? Some of you children that want to act like big time car tuners and engine builders really do need to take a back seat to the people in the industry that KNOW what they are doing.

Term, with the stock tune, are you saying with 87 octane it knocks like crazy? What are the knock sensors doing, if they are not trying to help prevent the knock?

 

No, with 93 it knocks like crazy. Lol.

 

X2

 

Quote:
Originally Posted by Cefaln452
The pistons and rings fail in these motors... Why put a shitty internal in when you have a block etc that is much stronger... Keep you thoughts to you self if this is what comes out.. not to be an *******

You know, the intelligence level of some on these forums is almost nill. If you are going to take a stand on something as strong as saying the internals on the LNF are ****, at least have more to back up your argument then, "wait and see." We have a whole 3 failures on this, which is somehow the most popular board for the SS, and that is indicative of some widespread failure of GM's engineers? Some of you children that want to act like big time car tuners and engine builders really do need to take a back seat to the people in the industry that KNOW what they are doing.


Did I ever say anything about them?... Its known in the lsj's and lnf's that this is a problem

 

I lived in West Texas for most of my life. 93 is everywhere. As far as I know, 93 is everywhere in Texas.

So do I, but I'm not tuned. We'll see if I crack a ring. With my luck, I'll get denied warranty coverage on an untuned car.

 

With my car, there was several combinations of what was done wrong, way beyond the tune.

My car didn't have proper crankcase ventillation, which i'm sure mostly attributed to the problem.

 

The rings aren't failing. The ring lands do, which are part of the piston. I think you should study more about the challenges of producing a high boost engine that meets today's emission standards and operating environment requirements before you say things like that. Forged pistons in production vehicles are inappropriate for many reasons. Hypereutectics are actually a good compromise for production vehicles. Unfortunately, it means that you run some risk of destroying ring lands if it knocks too much.

Warren

 

I have had personal experiences, of the ring lands, and the rings and the pistons.... and have seen others so I think it is you that needs to read some more. But if it cant be done why do it? i see where your coming from tho

 

This.

Saying that the internals are shitty is a naive statement (agreeing with you Warren). Its simply the lack of a good tune. People don't realize that the ECU in these cars is actually quite finicky. The car looks to the MAF and MAP sensors to create a mass of the air coming in. This is taken, and applied to the desired air fuel ratio so the car will run right. Things like weather changes, intakes that are untuned for, catless downpipes that are untuned for, and some other things play a major role in skewing the 'big picture' that the ecu sees.

For instance, when it gets colder, the air is more dense, therefore more fuel is needed. The car will correct for this, yes, but if you have an untuned intake, the MAF readings will be skewed. So, its taking a certain, skewed MAF reading, applying it to a correct MAP reading, adding such amount of fuel, and realizing it didn't add enough. The engine will compensate by making a fuel trim. But, the fuel trim comes after about 100 miles. Enough changes in the weather and/or tune, and the car is racking up mileage without the correct fuel trim.

The weather affects running more boost quite a bit, especially cold weather. When you spool the turbo up to 20+ lbs, the car has to play catch up. Even though it can fully catch up in a matter of seconds to this change, it could be too late. Usually, once knock starts, the car cannot quench it quickly, and it continues until the car pulls quite a bit of timing.

Its a small effect, really. But over time I could see this adding up to being a problem. It could also be caused from improper crankcase ventilation, the bypass valve being vented atmospherically, or even a faulty MAF sensor. Though, most of those will trip a check engine light.

This is how I understand it, do not take it as neither biblical truth, nor fact. I hope I explained it correctly. Its a very complex system, and I did my best to explain it simply.

Ummm, I think using a blanket statement to say the internals are shitty is wrong. The compromise for emissions HAS to be there (thank the govt). Its not that the pistons are weak, its that they aren't made for much more over stock power. A stock engine should last a very long time on all stock parts, stock tune, everything just how it landed out of the factory. But, some problems do occur on stock setups. Expecting a stock setup to handle more hp than stock is really taking a chance, and is a foolish concept.

 

Personally, I think maybe mine already had manufacturing faults in it and as with going more towards the edge of the envelope in anything, it tends to bring out whatever faults there are.

This problem seems like a very small percentage of the overall community (even taking into account that there are people that probably didn't chime in), so I wouldn't be worried that your car is going to suddenly tank one day. There are many more people that have had no issues.

This was basically for letting people know to keep an eye on things, what to look for if things start acting wierd, and for the associated eye candy.

Thanks for all the constructive input. I was actually very surprised by how quickly this thread exploded.

 

It will knock like crazy in the midrange on 93 octane. 87 octane would be engine suicide IMHO. The knock sensors work but they have to pick up on the knock in order to retard timing, and it has been my experience that even when the engine is seeing knock the commanded and actual advance stays the same for a while. It seems to take the ECM a while to actually retard the timing once the sensors see the knock.

 

I wouldn't call what the motor would do on 87 'knock', lol. More like BOOM.

 

I've actually had to run 85 in this car before out on Colorado (highest they had at the station!). I didn't rod on it at all heading back east to Iowa, but eventually I got to where I-76 joins to I-80 and had to merge around a semi. That **** gas coupled with about 4k feet lower elevation = MASSIVE audible knock. I got back out of it QUICK and limped into a BP station to get at least 91.

That was with the car totally stock still.

Was happy I didn't need a broom to pickup the pieces.

 

Well, in the higher elevation I think 88 octane is their premium fuel.

 

The ECM will pull up to 12* of timing maximum in the event of major knock (that severity of knock would probably take metal right off the head of the piston) and it would eventually kill the motor to run the stock tune with 87 octane at WOT for any length of time. 14.0 A/F in the midrange and approx 278 psi absolute pressure in the cylinders after compressing the mxture fully ( 9.3 CR (15.2psi + 14.7 psi = 29.9) = 278.1 psi absolute pressure

 

Hehe... ouch. I meant the motor goes boom, more like a boom boom clunk clink clank tink tink tink screeeeeeech.

 

I know but it might take it for a little while for it to actually go boom. Knock that severe would be clearly audible though and would be very damaging over time. I dont care for the stock tune at all because it is not safe at all IMHO. It knocks on the good 93 octane here in Florida I can only imagine what it would do on the lovely 91 octane they have in California that acts like 89 octane.

 

LOL uhhh no , I am at 6000 FT Canon City Co , 91 octane everywhere you go ..

 

In my part of the world, 91 octane is as good as it gets. I know they are basically useless unless added in very large ammounts, but its too bad that a good octane booster isn't really available in ammounts worth buying. and we can't use anything with MMT in it anyhow because of our platinum spark plug tips correct?? and there's no way I would be messing around with toluene in a trial and error attempt at finding a good mixture!

 

I know it's off-topic, but since we're on the octane subject, has anybody thought about using E85 in a meth-like storage and application? Like basically keep a separate tank of it and spray it when needed for the octane tuning benefits.

 

wouldn't you need an additional fuel rail/injectors for that? I think the direct injection of the LNF would change how that would work. There have been a few threads discussing e85 on the site, although I can't think of anyone discussing spraying it like meth......

 

Yeah, there's been talk before about using a piggyback system with it's own fuel rail and injector setup... basically port injection in addition to the direct injection. That all changed once the fuel tables got unlocked though...

I just randomly wondered today why nobody used E85 for the octane (and possibly cooling) properties only without actually running off of it. It would also avoid having to revamp your fuel system if it isn't compatible with it that way.