@ 5 lbs of boost is an intercooler needed?
10-23-2020, 11:58 PM
#21
Platinum Member
Platinum Member
If you use thick head gaskets to lower CR on an LS motor, you completely lose the quench turbulence that prevents detonation. You need to keep the squish clearance under .050" and use dished pistons.
You also need to come to grips with the difference between a 700hp LS set up to live in a street/strip environment vs performance marine duty. Marine usage demands full continuous output at higher speeds, with no load cycling.
A lightweight boat running wide open for shorter blasts can make do withdturbo'ed junkyard donors. You'll end up disappointed if you plan to push a serious performance hull hard 30 minutes at a time..
You also need to come to grips with the difference between a 700hp LS set up to live in a street/strip environment vs performance marine duty. Marine usage demands full continuous output at higher speeds, with no load cycling.
A lightweight boat running wide open for shorter blasts can make do withdturbo'ed junkyard donors. You'll end up disappointed if you plan to push a serious performance hull hard 30 minutes at a time..
The following 3 users liked this post by mcollinstn:
10-24-2020, 01:41 AM
#22
If you use thick head gaskets to lower CR on an LS motor, you completely lose the quench turbulence that prevents detonation. You need to keep the squish clearance under .050" and use dished pistons.
You also need to come to grips with the difference between a 700hp LS set up to live in a street/strip environment vs performance marine duty. Marine usage demands full continuous output at higher speeds, with no load cycling.
A lightweight boat running wide open for shorter blasts can make do withdturbo'ed junkyard donors. You'll end up disappointed if you plan to push a serious performance hull hard 30 minutes at a time..
You also need to come to grips with the difference between a 700hp LS set up to live in a street/strip environment vs performance marine duty. Marine usage demands full continuous output at higher speeds, with no load cycling.
A lightweight boat running wide open for shorter blasts can make do withdturbo'ed junkyard donors. You'll end up disappointed if you plan to push a serious performance hull hard 30 minutes at a time..
I’d like to try to run the stock motor and probably will for the first pair. See how they hold up and go from there.
Old school sbc engines are nowhere near as stout as an ls engine and they seem to last forever in boat of every shape and size.
Thanks for the heads up on keeping min .050 on the squish. I spoke with shafiroff racing about that today he didn’t give me a dimension just told me to change pistons Instead of putting a really thick head gasket in it.
Since the engine make 695hp @ 5.5 lb of boost, I would set it up to run 5 lbs, I think it should live a long healthy life at that level.
Last edited by iliveonanisland; 10-24-2020 at 06:55 PM.
10-24-2020, 07:01 PM
#24
hell it it doesn’t work I can always sell the parts on eBay and go with old school 406 engines.
10-27-2020, 12:21 AM
#25
Platinum Member
Platinum Member
Please point us to the website that shows a 695hp LS at 5.5 psi of boost. At 6,000 rpm, that works out to 610 lbf of torque. A 400 ci LS motor will struggle to deliver 380 lbf of torque above 5500 rpm. Working backwards, you need to boost the motor to 156% effective torque capacity. Disregarding dynamic losses in the induction system, you will need a minimum of 8.4 psi of boost AFTER cooling the incoming charge back to within 10% of ambient temperature in order to approach what you describe.
I'm not doubting your recipe. I just very much want to see it, and the accompanying data.
Please link us up.
M
I'm not doubting your recipe. I just very much want to see it, and the accompanying data.
Please link us up.
M
10-27-2020, 03:28 AM
#26
Please point us to the website that shows a 695hp LS at 5.5 psi of boost. At 6,000 rpm, that works out to 610 lbf of torque. A 400 ci LS motor will struggle to deliver 380 lbf of torque above 5500 rpm. Working backwards, you need to boost the motor to 156% effective torque capacity. Disregarding dynamic losses in the induction system, you will need a minimum of 8.4 psi of boost AFTER cooling the incoming charge back to within 10% of ambient temperature in order to approach what you describe.
I'm not doubting your recipe. I just very much want to see it, and the accompanying data.
Please link us up.
M
I'm not doubting your recipe. I just very much want to see it, and the accompanying data.
Please link us up.
M
What’s out there for Chevy LS based engines
there are two videos of the guys with the LS dyno runs 
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OPS VZLA (10-27-2020)
10-27-2020, 07:51 AM
#28
how many lbs of boost did they make? Thanks
10-27-2020, 08:14 AM
#29
Registered
10-27-2020, 08:20 AM
#30
