LS3 v L99?

19z28camaro02 · 05-01-2009, 10:13 PM

Whats the difference? Is one better? I'm good with the LT1 engine, and SBCs for the most part. Know a little about the LS1. Don't really understand any of the other ones though, the newer stuff goes over my head? Anyone want to give a break down?

SSPORT10 · 05-01-2009, 11:52 PM

Quote:

Originally Posted by 19z28camaro02

Whats the difference? Is one better? I'm good with the LT1 engine, and SBCs for the most part. Know a little about the LS1. Don't really understand any of the other ones though, the newer stuff goes over my head? Anyone want to give a break down?

They are basically the same engine, sort of. The LS3 is the exact same engine that is in the C6 Vette, just a different exhaust in the SS, hence the 4HP less. The L99 is the LS3 but they did some modifications to it in order to include AFM (Active Fuel Management) and VVT. I believe that the cylinder walls in the block were made thicker so it could handle AFM, which the LS3 has issues with AFM. The LS3 puts out 426HP/420 lbs of torque while the L99puts out 400HP/410 lbs of torque. With the taller gearing of the A6 transmission and the L99 the car basically is even in terms of 0-60 times and 1/4 mile times as the LS3 and the M6 transmission. The L99 is about 1 or 2 mpg better in fuel efficiency then the LS3. So in other words even though the L99 puts out 26HP less and 10 lbs of torque less than the LS3, both engines are essentially equal.

JakeRobb · 05-02-2009, 12:26 AM

The cylinder walls are the same. The only differences are the inclusion of AFM and VVT in the L99, along with a less aggressive camshaft (which is necessary because the special lifters needed for AFM can't handle the LS3's aggressive lobe profiles) and a corresponding tune. I'm not sure, but I suspect that the L99's engine computer is different. Specifically, it should include the ability to control the AFM and VVT systems. It's possible that the LS3's computer is the same, with those capabilities disabled.

I haven't seen an L99 dyno graph yet, but VVT should broaden the power band on the L99 compared to the LS3.

Hoss 2000 Z-28 · 05-14-2009, 11:54 AM

The 2 gents above nailed it.

The L99 does make less hp and torque than the LS3 but I think the aftermarket is going to be very kind to the L99. Comp Cams already has a Phase Limiter Kit that enhances the variable valve timing technology of the L99 that is supposed to make huge peak gains without sacrificing low end.

http://www.camaroz28.com/forums/showthread.php?t=674859

There are going to be some DIRTY L99's out there!