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general23cmp · 09-11-2010, 03:28 PM

We all know that the L99 has a slightly lower compression ratio than the LS3 and the bottom ends are made from the same materials (right on that?).

The LS3s are making more HP at the flywheel than the L99 due to camshaft, etc..

My question, given you can get enough fuel to the motor (injectors and pump), can the L99 have more boost applied safely than the LS3 as long as the power limits of the bottom end are not exceeded? If a powdered rod is going to break at 800 ft-lb at the flywheel (for example), then the LS3 might need only 8 psi to do that where the L99 might need 11psi. Providing you are safe on fuel and timing (tune), does the LS3 really have that big an advantage at the flywheel on power output maximum? I know there is some because of some of the extra valvetrain hardware in the L99.

If the above is reasonable, then the common comments that, for example, "7-8psi is about the limit for the stock bottom end" isn't too accurate. At 7.5psi, the LS3 on a twin turbo can make much more at the flywheel than the L99 at he same pressure. If they have the same bottom end (hopefully someone can confirm) then the L99 isn't really near its limit at 7-8psi as it would need more boost to hit the same flywheel HP.

Thanks for any comments.

09-11-2010, 03:28 PM	#1
general23cmp Drives: 2010 RS SS Join Date: Aug 2009 Location: Huntsville, AL Posts: 196	More boost "allowed" on L99? We all know that the L99 has a slightly lower compression ratio than the LS3 and the bottom ends are made from the same materials (right on that?). The LS3s are making more HP at the flywheel than the L99 due to camshaft, etc.. My question, given you can get enough fuel to the motor (injectors and pump), can the L99 have more boost applied safely than the LS3 as long as the power limits of the bottom end are not exceeded? If a powdered rod is going to break at 800 ft-lb at the flywheel (for example), then the LS3 might need only 8 psi to do that where the L99 might need 11psi. Providing you are safe on fuel and timing (tune), does the LS3 really have that big an advantage at the flywheel on power output maximum? I know there is some because of some of the extra valvetrain hardware in the L99. If the above is reasonable, then the common comments that, for example, "7-8psi is about the limit for the stock bottom end" isn't too accurate. At 7.5psi, the LS3 on a twin turbo can make much more at the flywheel than the L99 at he same pressure. If they have the same bottom end (hopefully someone can confirm) then the L99 isn't really near its limit at 7-8psi as it would need more boost to hit the same flywheel HP. Thanks for any comments.