[laynlo15]

My engine builder opened mine up an additional 5 thousands if I remember correctly

[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.

[Dysan911]

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.

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

[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.

[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?

[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.

[wnta1ss]

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?

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.

[DaveC113]

That is not a piston failure, it's a tuning failure imo, or just what we get with modern engines and not a ton of experience with DI depending on your perspective.

Those rings got blown out by MASSIVE overpressure in the cylinder due to "super knock".

[laynlo15]

Its all about Fueling and Tuning, don't loose confidence just go slowly towards your goal, don't get greedy as I did.

[DaveC113]

Originally Posted by laynlo15

Its all about Fueling and Tuning, don't loose confidence just go slowly towards your goal, don't get greedy as I did.

I agree, but without understanding exactly what's happening you don't have a direction to go and can obviously run into major issues.

As a Magnuson employee I'm not sure it's in your best interest to share exactly what you know, but it would be a lot more helpful than telling people to "Just do it right!"


IMO... unless you love working on cars just buy a ZL1. There are many advantages besides a warranty, the car's traction and stability control systems are actually tuned for the amount of power it makes, something you'll never get modifying a SS. And resale value...

[DenverTaco07]

I'm running 9 psi, 620 to wheels, but that's adjusted to the 6000 feet i'm at. The tuner i used has tons of LT1 experience and i do know he pulled some timing.

I've considered drop in pistons, not sure about rods but would probably do them too, but i figure it would be 5 to 6 grand.

Is it necessary to pull the motor or can they do it on a lift?

I also have a lack of trust issue, i'd love to have one of the member shops here on the forum do it, but they are all out of state.

[KingLT1]

Timing isn't necessarily the issue. Rail pressure and Injector MS is CRITCAL!! You can still burn a piston up with low timing if the Injector MS gets above 6.5-6.7 and the Rail pressure drops. These engines love timing, but they don't like to be starved of fuel...and maintaining proper injection timing is critical.

[Drsagacity]

Originally Posted by DaveC113

I agree, but without understanding exactly what's happening you don't have a direction to go and can obviously run into major issues.

As a Magnuson employee I'm not sure it's in your best interest to share exactly what you know, but it would be a lot more helpful than telling people to "Just do it right!"


IMO... unless you love working on cars just buy a ZL1. There are many advantages besides a warranty, the car's traction and stability control systems are actually tuned for the amount of power it makes, something you'll never get modifying a SS. And resale value...

I thought about trading for a ZL1, but after driving it and seeing how much slower it was, I changed my mind. Still, nice car and if I were starting from scratch again, I would use the ZL1 as the base. . .but at the end, they are all the same because with the Z, you already have the forged rods/pistons, but you have a crappy little cam...so you are getting in the motor anyway and getting a better piston rod forged combo that what comes with the Z only costs $2k. My $.02.

[Drsagacity]

Originally Posted by DaveC113

I agree, but without understanding exactly what's happening you don't have a direction to go and can obviously run into major issues.

As a Magnuson employee I'm not sure it's in your best interest to share exactly what you know, but it would be a lot more helpful than telling people to "Just do it right!"


IMO... unless you love working on cars just buy a ZL1. There are many advantages besides a warranty, the car's traction and stability control systems are actually tuned for the amount of power it makes, something you'll never get modifying a SS. And resale value...

There is no doubt that when done right you can take the stock internals up to 700whp safely by getting everything in the JRE Super Street Brawler package. Personally, I added drop in pistons at the same time and am about to make the same decision again on my LT1 Vette. For me, it's just peace of mind. . .plus the flexibility to run into the 700's if you feel like it.

In fairness, I have decided to dial my Camaro back down to the original Super Street Brawler Package - 8psi @ 715whp until I get different tires. Then I will re-evaluate my setup and consider adding more boost. As I see it, a street car with 800bhp is pretty sick.