[Kaludar]

I see a lot of talk of supercharging these engines, and it’s something I’m considering doing myself down the line. How equipped is the LT1 to handle boost without going forged internals? Is the engine in the Zl1 literally the exact same engine that I have in my SS with a supercharger on it or is this not the case?

[TJay74]

The LT1 the SS uses is not the same as the LT4 the ZL1 uses. Same displacement, heads, and some other minor parts but thats it. The LT4 has forged pistons from the factory and a stronger rod. The crank is the same from what my shop said when I asked.

The LT1 can handle up to around 700rwhp reliably, but there have been cases before that and after that where the ring gaps have caused issues.

[KingLT1]

LT4 and LT1 are not really close at all. LT4 is lower compression, forged pistons, different heads, different cam. LT4 can handle 1000whp on stock internals. The general consensus is a SBE LT1 can handle around 700whp on the SBE with proper fuel supply....Some have been higher...fueling and proper tuning is key to longevity. These engines will blow up at 600whp if the fueling is not on point.

[Kaludar]

Originally Posted by TJay74

The LT1 the SS uses is not the same as the LT4 the ZL1 uses. Same displacement, heads, and some other minor parts but thats it. The LT4 has forged pistons from the factory and a stronger rod. The crank is the same from what my shop said when I asked.

The LT1 can handle up to around 700rwhp reliably, but there have been cases before that and after that where the ring gaps have caused issues.

What is peak boost on your current tune, how long have you been running boost?

Also out of curiosity what tires are you running? Can the stock f1s even hook with 650whp?

[laynlo15]

I finally had a couple ring lands break after about 80 runs at above 14 lbs of boost. I was making around 700 rwhp. Broke #1 and 8 between the 1st and 2nd ring. I ran it like that for about 25 runs I'd guess. Still went 10.13@139.50 broken and that was at 16 lbs of boost on race fuel and meth/water. If it hadn't pushed the rear seal out at the Camaro fest I could have probably made it till the end of the season. So my new motor is more like the LT4, stout for sure and should make over 800 rwhp on 14 lbs of boost.

[oldman]

I think it is in part due to the tight ring gap, a road race is going to put a lot more heat load on the piston vs my 1000 plus full throttle romps at about 10 seconds at a time.

[wnta1ss]

Originally Posted by oldman

I think it is in part due to the tight ring gap, a road race is going to put a lot more heat load on the piston vs my 1000 plus full throttle romps at about 10 seconds at a time.

He's getting at the big problem here, which is ring gaps in factory engines. The guy from Procharger has told us that he's seen top ring gaps in factory LT1s as tight as .009" ! That is ridiculously tight for a 4.065" bore like this. What this means is, in such an engine, enough heat buildup causes the ring to butt up against itself, and the ring land breaks. Often people have been getting away with modest amounts of boost for short runs, like not more than a 1/4 mile. Turning the boost up or running it WOT longer seems to increase the chance of breakage. Heat buildup increasing from more time under boost or more stress. There is of course the pot luck factor of whether your engine was built with ridiculously tight ring gaps, or just tight. So there are variables in play, and blanket statements made about xxx hp is safe are not really true, because they ignore the questions of factory build quality, and how hard the engine will be run. So your desired use, and how much boost you want to run, will influence how much of a roll of the dice it would be to slap a supercharger onto your stock motor. I ran one on mine briefly, but limited myself to just a 1/4 mile run, because of the incorrect ring gaps that have been found in stock LT1 engines.

[Walt88]

One thing I've always been curious is if you can estimate ring gap doing a compression test. Like if its 170 psi it means the top gap is about 17 thou, or if its 150 psi that means its 22 thou, but I have no idea if that would actually work. If a few people who are going to crack open their motors feel like doin a compression test beforehand and then comparing the ring gaps....

[MP3BOOSTED]

Doesn't sound like it holds very well, i'm going to go the e85 meth route.

buy a Alky control meth injection kit, LT4 injectors, LT4 fuel pump, and low side fuel line pump kit.

[KingLT1]

Originally Posted by wnta1ss

He's getting at the big problem here, which is ring gaps in factory engines. The guy from Procharger has told us that he's seen top ring gaps in factory LT1s as tight as .009" ! That is ridiculously tight for a 4.065" bore like this. What this means is, in such an engine, enough heat buildup causes the ring to butt up against itself, and the ring land breaks. Often people have been getting away with modest amounts of boost for short runs, like not more than a 1/4 mile. Turning the boost up or running it WOT longer seems to increase the chance of breakage. Heat buildup increasing from more time under boost or more stress. There is of course the pot luck factor of whether your engine was built with ridiculously tight ring gaps, or just tight. So there are variables in play, and blanket statements made about xxx hp is safe are not really true, because they ignore the questions of factory build quality, and how hard the engine will be run. So your desired use, and how much boost you want to run, will influence how much of a roll of the dice it would be to slap a supercharger onto your stock motor. I ran one on mine briefly, but limited myself to just a 1/4 mile run, because of the incorrect ring gaps that have been found in stock LT1 engines.

Octane plays a factor here as well. Hence why the LT4 is lower compression.

Which is why I plan to run e85 and less boost. Part of the issue is due to the compression combined with not enough octane. 93 isn't enough octane to allow a LT1 NA engine to target MBT. E85 will keep those pistons and rings nice and cool.

It is obvious this engine loves E85. It gains 25-30whp on a NA engine and 60-70whp on a boosted engine over 93. LS engines were lucky to gain 6-8whp on E85 and that was because they could hit MBT on regular 93.

Moral of the story...I wouldn't run 93 unless you have Meth injection to supplement octane. That is where a lot of folks have run into issues along with improper tuning and not enough fuel supply.

[Kaludar]

Originally Posted by KingLT1

Octane plays a factor here as well. Hence why the LT4 is lower compression.

Which is why I plan to run e85 and less boost. Part of the issue is due to the compression combined with not enough octane. 93 isn't enough octane to allow a LT1 NA engine to target MBT. E85 will keep those pistons and rings nice and cool.

It is obvious this engine loves E85. It gains 25-30whp on a NA engine and 60-70whp on a boosted engine over 93. LS engines were lucky to gain 6-8whp on E85 and that was because they could hit MBT on regular 93.

Moral of the story...I wouldn't run 93 unless you have Meth injection to supplement octane. That is where a lot of folks have run into issues along with improper tuning and not enough fuel supply.

So if I only have access to 92 and no e85 options I’m pretty much boned?

Portland sucks, supposed to be the “green friendly” capital and no e85.

[KingLT1]

Originally Posted by Kaludar

So if I only have access to 92 and no e85 options I’m pretty much boned?

Portland sucks, supposed to be the “green friendly” capital and no e85.

Sorry for not being clear. I was speaking in reference to turning up the power over what most base kits make. 550whp blower kit is fine on 91-93 octane. You can always add a Alky/meth kit or race fuel to supplement for octane if you decide to make more power down the road. It's actually easier to make power this way. LT4 fuel system and Alky/meth kit is a popular setup.

[Need4Camaro]

Originally Posted by Kaludar

So if I only have access to 92 and no e85 options I’m pretty much boned?

Portland sucks, supposed to be the “green friendly” capital and no e85.

Plenty of trees and full service gas stations

[cmitchell17]

I saw something the other day that said the LT4 block had different oil passages? Anyone ever heard of this? I was thinking LT1 and LT4 used the same block, I guess not, but they still may use the same casting, but maybe if they changed some stuff they use a higher strength casting?