less torque but flatter peak power.

RonA

RonA

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Feb 26, 2008
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Zach.
The 188/220 tests are very impressive, but a bit unnerving. Is there a way to design one that will have similar spool up to a 181 but hold peak power to a higher rpm? I realize heads, turbo's, and timing come into the equation but it would be nice to see peak power hold for an additional 300 to 500 rpm and keep to torque below 2000.
Thanks.
 
Yep, that would be the 200-220. It spools slightly quicker than the 181-210 but not by much. Where the 181-210 starts to fall off at 3500-3800 and the 188-220 starts to drop off at 4200, the 200-220 will hold out to 4500-4700 depending on the head and charger.

Another thing you could do, is to get a 188-220 and retard it 5 degrees, That will bleed off some compression at the lower rpms and gain it back on the top end. You could do it with the 188-220-108lsa, but I would not do that with the 106LSA. I also think I have a few 110LSA's cut for testing that would work well for that purpose. In that instance, you could retard it 6-8 degrees max and still not close the exhaust too far after TDC. More or less every degree you retard the intake, you take away from the bottom end and add it to the top end due to the ram air effect at higher rpm.



Zach
 
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Torque limitation table is the one your looking for. Limiting the fuel with a mechanical in the same fashion I think would be more difficult, need the opposite action of a torque spring.
 
How deep do the valve reliefs need to be for the 200/220?
 
.080" You can get away with slightly less but to cover most piston protrusion and valve depth situations, we recommend a liberal .080". I have had a few people put one in with no flycuts, but they were virgin blocks.

Zach
 
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