[L78toLT1]

Originally Posted by L78toLT1

I seem to recall reading that the low end of the ring gap tolerance band is .009 i believe the upper end is .015. I would wager that most will fall around the midpoint. As soon as i go out to the shop, i will measure a couple of mine - as of yesterday, my motor is back in the car, sans heads. I am waiting on some custom gaskets rom Cometic bofore installing the heads. I went with the gpi piston rod combo mainly because you have to pull the motor on these cars to do a cam swap.

I checked a couple of my old rings and found the gap to be right at .012 on all of them. Of course, my block has been very lightly honed - my machinist said he did the lightest possible hone in order to maintain the .005 piston to cylinder clearance recommended by for my Diamond pistons. A .001 bore increase equates to .00314 increase in ring gap, so I was probably around .009 stock.

[JANNETTYRACING]

Originally Posted by toohighpsi

Pistons in the LTs are not weak, I've been to 800 wheel on stock LT1 bottom ends, but they won't handle mistakes well - the most common of which is lean/knock. You cannot count on a wideband to make sure you're not lean, with DI the fuel has to be injected within a certain window, if you're outside that window the fuel will still be burned and the O2 sensor will still show favorable ratio, but the actual combustion process will have occured without the fuel that the WBO2 displays. Rail pressure as well as injector pulsewidth are critical to keep an eye on, especially if you like to run at teh edge of the envelope.

Originally Posted by Dysan911

What Rail pressure do you think is considered safe? Like it should never drop below what numbers?

Commanded

Originally Posted by USAFS197

There’s always outliers in every situation. I, however, cannot think of a situation where I would be willing to boost my LT1 and not put aftermarket rings and pistons in place. Modifying engines is always risky and inherently comes with potential failures. However, if I can mitigate the chances of failure by a considerable margin, you bet your ass that I will put forth the effort to do so. I have always been of the mindset that I would rather over build and under perform, than vise versa. Granted, a bad tuner could undermine all of this.

Agreed because at the end of the day it will always be your decision.

Originally Posted by Dysan911

Wow this thread really inspires confidence!. :( I went into boosting my LT1 thinking here we have a lot of people doing it successfully and as long as you're reasonable with the power your making and have the fuel and a good tune you can get away easily without a problem but now it sounds like the LT1 is the worst motor ever to supercharge and it's not IF but When it's going to go.

I have several pulls to redline, many WOT runs, dyno pulls, etc. Does this mean my rings are obviously not .007 because it didn't fail yet or I'm just rolling the dice over and over?

There are more people doing it successfully than not, but it is always the case you only hear about the broken ones then the scare tactics come in to play.

Originally Posted by wnta1ss

No reliable way of knowing what your rings are unless you take the motor apart. In which case, you could obviously fix them or install forged pistons and new rings.

The reason that I am stressing this ring situation is, most of the posts on the board about supercharging the LT1 have been painting a pretty rosy picture. This gives something of a sense of overconfidence. I myself bought a supercharger with that incomplete information. Now that I know the risk when using the supercharger for my purpose (long runs) would have been very high, I gave it up. We need to make our individual choices, which are best done with more information.

Since Mr Jannetty is already tuning your car, then the things he discussed about reducing the heat in the rings via the tune are probably already in your tune? As far as extra steps to try reducing the heat, there would be adding water/methanol injection or straight methanol injection. Yet another would be to convert to E85. This last one for you, I think that you'd probably have to go back to a larger pulley (slow the blower down). Less boost would be because LT4 fuel parts are not very big, so I tend to doubt that they could handle E85 with the blower spinning this fast with the 3.7" pulley. You could ask JRE (your tuner) about these ideas if you want to try one of them. As previously mentioned, these types of measures could help reduce heat, but if there is a mechanical problem, they will not fix it.

There is enough fuel supply to support 750 RWHP on E-60 in the LT4 fuel system components.

I am not a fan of supplemental fuel supply through the intake track as distribution can be a problem, and has the potential for failure when you least expect it.

Always opt to put the fuel through the injectors in a DI engine and use good fuel it will always be cheaper than an engine.

Ted.

[laynlo15]

Dave I'm usually very careful in my wording so I don't over emphasis anything that could cause a misunderstanding of my knowledge. I'm not in the same time zone as JRE or toohighpsi on these motors.

[wnta1ss]

Originally Posted by JANNETTYRACING

There are more people doing it successfully than not, but it is always the case you only hear about the broken ones then the scare tactics come in to play.

Why would you call talking about a proven problem that exists in some of these LT1s "scare tactics"? Seems to me that the honest thing is to let our fellow Camaro drivers know about what they might or might not have to deal with if they slap a supercharger onto a stock LT1 motor. We should share the info we now have so they can make a more-informed decision.

[Drsagacity]

Originally Posted by wnta1ss

Why would you call talking about a proven problem that exists in some of these LT1s "scare tactics"? Seems to me that the honest thing is to let our fellow Camaro drivers know about what they might or might not have to deal with if they slap a supercharger onto a stock LT1 motor. We should share the info we now have so they can make a more-informed decision.

Probably because he knows how to.tune, so its a non-issue for him...at the same time if you go to someone else they might blow it up...just guessing.

[MR 45TH]

At the end of the day all of us that jump on the mod train take on that added amount of risk of things going wrong! Yes there are a lot of people having great success with boost and the LT1, and I agree it will always come down to the tune.
To the OP, sorry to see it go down that way for you. Hopefully you get up and running soon stronger than before

[wnta1ss]

Originally Posted by Drsagacity

Probably because he knows how to.tune, so its a non-issue for him...at the same time if you go to someone else they might blow it up...just guessing.

A good tune does not guarantee that you could use the car however you want without any chance of trouble. Obviously a good tune gives you a better chance of success, but if there's a mechanical issue in your engine like really tight rings, there's only so far that you could push it.

[KingLT1]

Originally Posted by wnta1ss

A good tune does not guarantee that you could use the car however you want without any chance of trouble. Obviously a good tune gives you a better chance of success, but if there's a mechanical issue in your engine like really tight rings, there's only so far that you could push it.

How many LT1's have you heard of failing on E85?

[JANNETTYRACING]

Originally Posted by wnta1ss

Why would you call talking about a proven problem that exists in some of these LT1s "scare tactics"? Seems to me that the honest thing is to let our fellow Camaro drivers know about what they might or might not have to deal with if they slap a supercharger onto a stock LT1 motor. We should share the info we now have so they can make a more-informed decision.

I do inform every one of my customers the risk involved in modifying any car regardless of year make model etc.

I have been adding superchargers to cars and trucks since 1990 knowing all the risk involved.

I would never recommend supercharging an engine that is incapable of handling it but we have been very successful at supercharging even the weakest of engines 4.6 2 valve mustang, 5.7 Chrysler Hemi, 2.2 liter cobalt just to name a few.

I mentioned in a earlier post about controlling combustion temps which is the primary cause of failure because it leads to ring expansion, piston overheating, uncontrollable detonation, bent valves or failure, melted plugs, etc.

You can have the same combustion temp at Idle or wide open throttle as an extreme example.

There are many ways to control it but primarily injection timing, AFR and Spark.

Then there is exhaust flow, and intercooling.

The ability for the cooling system to carry away that heat is one of the major limitations to making reliable power.

No one talks about it but, Cooling system technology evolution is why we can make so much power reliably.

I think from this you can put the pieces of the puzzle together.

Ted.

[Raptor Jesus]

Originally Posted by wnta1ss

A good tune does not guarantee that you could use the car however you want without any chance of trouble. Obviously a good tune gives you a better chance of success, but if there's a mechanical issue in your engine like really tight rings, there's only so far that you could push it.

Tight ring gaps are not a mechanical issue, it's a characteristic of the engine. It's something you account for and tune accordingly. We used to tune Honda 1.6 motors and 300whp was the absolute max before the ringlands would crack. Now it's known how to tune accordingly and people are pushing 500whp on stock internals. The tune is the weak point. If you tune it with no detonation then it will take a lot of cylinder pressure to crack a ringland normally.

[bpang1234]

Ted is my tuner now but I learned THE HARD WAY that the tune is the make it or break it factor in these applications. Not just a guy that is known for generally being a good tuner but someone who has in-depth experience with our platform.

The original tuner of my car had it too lean and I blew a ring on track. Ended up going with drop-in pistons, a bunch of reliability mods that Ted suggested and now I am much more confident in my build to not blow up on track.

[SGDM]

The stock LT1 engine is running 11.5 compression, if you add forced induction you must lower your compression to 10.3-10.5. I have talked to several people that have this piston problem and none of them have lowered their compression. I placed a .010 spacer between head and block after I did head work, "old school" cylinder compression change. I have not had any issues with my LT1 running a LT4 blower at 10# boost.

[JANNETTYRACING]

Just finished another JRE Super Street Brawler package on 93 octane.

https://www.facebook.com/jannettyrac...1693976464327/

[Raptor Jesus]

Originally Posted by SGDM

The stock LT1 engine is running 11.5 compression, if you add forced induction you must lower your compression to 10.3-10.5. I have talked to several people that have this piston problem and none of them have lowered their compression. I placed a .010 spacer between head and block after I did head work, "old school" cylinder compression change. I have not had any issues with my LT1 running a LT4 blower at 10# boost.

This is 100% untrue.