High RPM LS1.
10-15-2015, 10:04 AM
#1
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High RPM LS1. So, I got a question about how hard we can twist a fairly well built LS1. It's got JE pistons, Eagle rods, and AFR heads with a stock crank. Block is studded top and bottom. Cam is a LG G5X3. I'm running twin GT-35's in a jet boat on E85. Last night it bolted to 7,200 rpm, banged the crap out of the rev limiter and blew a head gasket. Got a couple of option.
1 - Raise my rev limiter and let er rip.
2 - Put a short stroke 4.8 crank in, raise the rev limiter and let er rip.
3 - Get a bigger impeller to slow the motor down, leave the rev limiter where it's at, and let er rip.
E85 is cool, the exhaust smells like moonshine.
1 - Raise my rev limiter and let er rip.
2 - Put a short stroke 4.8 crank in, raise the rev limiter and let er rip.
3 - Get a bigger impeller to slow the motor down, leave the rev limiter where it's at, and let er rip.
E85 is cool, the exhaust smells like moonshine.
Last edited by Blazeracer; 10-15-2015 at 10:29 AM.
10-15-2015, 01:07 PM
#3
I am not a boat guy, but I hang around with some and I think they would tell you to change your impellor. Depending on the cylinder heads you have, I think you would want to keep the RPMs down in the 6000s just for engine efficiency. As for the safe RPM, it is the connecting rods and oiling system that will determing that. So, the question becomes who well does your oiling system hold on to oil pressure over 6500 and how much do your trust those Eagle connecting rods.
On the valve train, some might disagree, but in my opinion anything that will spend regular duty above 7000 RPM is solid roller territory. The hydraulic will work up there, but it is no longer optimal and has the potential for problems.
On the valve train, some might disagree, but in my opinion anything that will spend regular duty above 7000 RPM is solid roller territory. The hydraulic will work up there, but it is no longer optimal and has the potential for problems.
10-15-2015, 04:29 PM
#4
Yup, swap the impeller. That motor will do well with the extra load (builds boost faster).
As far as safely raising the rev limit, all kinds of fun stuff. Once you look into all the little bits and pieces, the LS1 is not the best block to use.
Dry sump motor with complete dry sump system, solid roller or link bars, and distributor. Depending how high you really want to rev it, might be worthwhile to have main girdles to keep the block and crank from wobbling to death.
As far as safely raising the rev limit, all kinds of fun stuff. Once you look into all the little bits and pieces, the LS1 is not the best block to use.
Dry sump motor with complete dry sump system, solid roller or link bars, and distributor. Depending how high you really want to rev it, might be worthwhile to have main girdles to keep the block and crank from wobbling to death.
10-15-2015, 05:34 PM
#5
Yup, swap the impeller. That motor will do well with the extra load (builds boost faster).
As far as safely raising the rev limit, all kinds of fun stuff. Once you look into all the little bits and pieces, the LS1 is not the best block to use.
Dry sump motor with complete dry sump system, solid roller or link bars, and distributor. Depending how high you really want to rev it, might be worthwhile to have main girdles to keep the block and crank from wobbling to death.
As far as safely raising the rev limit, all kinds of fun stuff. Once you look into all the little bits and pieces, the LS1 is not the best block to use.
Dry sump motor with complete dry sump system, solid roller or link bars, and distributor. Depending how high you really want to rev it, might be worthwhile to have main girdles to keep the block and crank from wobbling to death.
I agree with the others about a bigger prop. A Accusump would be nice insurance.
10-16-2015, 12:19 PM
#6
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Damn, this used to be a nitrous motor. Ran a 220 shot in it all the time. Boost did it in. This blocks junk. Cam is hyd, so yeah, gonna put a bigger impeller in it. Also gonna bore my iron 5.3 to a 5.7 and put all my internals in it. See if that'll hold up to boat abuse.
The whole right side of the block is done.
The whole right side of the block is done.