800hp Endurance LS3 Engine

[Bazman]

Starting to write my shopping list and prepare a budget for my LS3 twin turbo. Goals are it must endure and be reliable at a sustained 800hp even hot lapping on a hot summers day.

Research has found the OEM block will fail at that power level if sustained, and with ERL gone, there is no fix. So I've been directed to the newer improved BMP Warhawk block - likey the 4.125" bore 9.24" deck version for a 387 ci.

I can share my shopping list to date if anyone is interested, but I'm stuck on valves at the moment.

Delwest valves came up and looked amazing.... but they do not suit an LS

I was thinking titanium intakes and perhaps sodium filled iconel exhaust - but what do you guys think? Engine has to endure street, track days (road track), and extended closed road events. I'm basically trying to build an endurance engine that requires little maintenance, yet sustain repeated 800hp pulls all day (a few seconds a time but heat control becomes vital as the miles and speeds add up/vary. The drive home like a stocker.

Was thinking factory heads (cleaned up/port matched), OEM rockers with CHE trunion upgrade, 231/231 cam by Mike Jones, cut to length pushrods, JE Ultra coated pistons, Molnar rods, super finish/coated stock crank, cometic gaskets for a quench under 040, and oiling TBA - either Katech upgraded pump with baffled pan or dry sump and be done with it.... and oil squirters, along with oil coolers for engine, trans, and diff.

What valve brand makes valves that are precision made and have great metallurgy/endurance but are light?

[swampbuggy]

Bazman, you mentioned stock crankshaft. What is the manufacturing process and what is it made out of ? Mark H.

[Bazman]

They're a cast iron crank, but nobody I have ever heard of broke one unless something else went very wrong. They're strong enough for over 1000hp.

The only reason to change would be if I have to run a dry sump (need longer front snout).... if that is the case, then I'll be forced to... in which case for the same money I may as well drop in a 4 or 4.125 stroke and go for 427 - 441 cubes and drop the rpms. Maybe then I'd go for the 9.8 deck block to run longer rods - but budget getting out of hand at that point, I'd like to make the 387 work if possible.

[KnightEngines]

I would dry sump it, you're going to be in it for quite a few $$, you wanna protect that investment in an application that will tax the oiling system.
I wouldn't bother with Ti valves tho, rpm will be quite low, steel intakes & inconel exhausts will be more durable.
I would also use tool steel retainers rather than Ti.
800hp is not a lot for a turbocharged LS, you don't need to get exotic on parts, but the application will require stuff to ensure long term durability.

[MadBill]

Hollow stem steel intakes are a good compromise.
2X on the retainers. a good tool steel one is ~2 g. more than Ti and there's no worry about dampers or inner coils carving them up.

[GARY C]

Heat management for both engine and trans will be a priority.

[needforspeed66gt]

I have Darton sleeved LS9 endurance racing engines making over 1k HP that run for literally hours on end at high RPM in heavy desert trucks that are going on three and four seasons with no failures...so saying they can't live past 800 without ERL (LOL) working on them is a fallacy.

Secondly, BMP makes horrible products, their casting and machining is worse than some imported chinese stuff I've seen.

GM LSX block(iron) or Concept Performance LSR(aluminum) are the two to pick from for what you are talking about if you insist on an aftermarket block.

I'm editing this just to point out a couple other things wrong with your first post....the stock cast LS3 crank will not break at that power level, but in an endurance application it will act like a wet noodle and kill main bearings, at a minimum you should be looking at a Callies Compstar Center Counterweighted shaft.

For valves, the Delwest GM Ti intake valves and sodium filled exhaust valves or even the hollow stem LS3 valves will be perfect for that use, keeping the valve train light is paramount to longevity. Putting in heavy aftermarket exhaust valves is not the way to go. There's a lot more that can be said about this subject, but I think you need to reevaluate where you're getting your information from because as someone who does these motors every week, I can tell you that priorities are being mixed up as far as component selection.

[Bazman]

Thank you to everyone that has contributed. I appreciate it.

Conflicting information has been a part of going fast since it started, it's a great thing because there are often several roads to reach a common destination and part of the fun is deciding which road to take. I agree that once a path is chosen - it makes sense to have a compatible package - not a piece meal one. Thank you for pointing out I'm not on the right page yet.

Re BMP - I understood the quality control issues were rectified and were now pretty precise??? I do know there's a few been built here in NZ (down under) that worked out no issues. Bill told me there were no new blocks till next run in early new year so I think they're re-tooling.

Iron block too heavy, other one sounds interesting, will check that out.

LS9 block is stronger than the LS3 - and has piston squirters. That is probably the best way I should go if I can source one for a fair price. LS9's seem to cost more than aftermarket, hence I hadn't looked too hard. Given what I'd be spending it may be better to just buy a fresh LS9 with dry sump, sell off the blower, run the LS3 intake and turbos, cam it for more zest and keep it under 800hp. Save the blueprint/custom build for another day.

Cast crank. When it comes to food and motorsport I'm not a fan of noodles or crackers. Good to know lol

[steve316]

Bazman nice post; You are evidently a gear head & and a gentleman.

[32vape]

We have several customers that run LSA engines in 5th gen Camaro ZL1's that road race and open road race. 150-160 mph average speeds on closed highways for over an hour. Stock everything except cam, springs, trunions, pushrods, headers, and pulleys to drive the stock supercharger faster. These are all making over 700 at the rear tires. Nothing exotic by any means. Cooling and proper efi tuning to adjust for increased intake air temps, coolant and oil temps are the biggest part of keeping endurance applications happy.

[Bazman]

That's great endurance.

Cooling is a problem when there's 25mph hairpins and tight sections where you can't get air flow, followed by constant acceleration at full boost/deceleration between turns on twisty closed roads.... or hot lapping tight circuits. My car will hold a solid 1g + on the turns so going to look really close at the oiling next build to see if we can get away with just a better pump and an accumulator.

Concept Performance LSR block looks good Nate, though a built LS9 with coated pistons and squirters is very tempting despite less wall thickness