LS3 TO L99 Horsepower Question?
 

I recently purchased a 2010 2SS/RS L99 Camaro with the 6L80 6 speed automatic transmission with only 10,855 mi. on the clock.

The LS3 manual transmission Camaro has 426 brake horsepower @ 5900 rpm, with 420 lb. ft. of torque @ 4600 rpm.

The L99 Camaro only has 400 brake horsepower @ 5900 rpm with 410 lb. of torque @ 4300 rpm.

Could someone please tell me why the HORSEPOWER is not the same for both the LS3 & the L99 Camaro. The information in the Camaro brochure, lists that they both have the EXACT SAME 6.2 liter (376) cu. in. engine. I am confused!

Also the REDLINE Max RPM for the LS3 is listed @ 6600, & the REDLINE Max RPM for the L99 is listed @ 6200. The top speed for BOTH cars also is listed 155 mph. Again, I am confused!

Thank You So Much in advance for the information.

All The Best,

Orange 2010 Camaro

Automatics have less power?

Yes they are both 6.2 L but the L99 uses AFM where it cuts off cylinders to supposedly save fuel while the LS3 does not. So they are quite a bit different right there. I think the L99 is based off of a sportute engine too not sure on that though.

Cam

I believe they have a more stout cam that that produces more power, but gets worse gas mileage. The L99 has weaker components with the lifters which are different due to being for AFM or Active fuel management. Chevy did this to make the camaro more fuel efficient to avoid the gas guzzler tax. Why the did this for one and not the other I am not sure, but there are a ton of articles on it and there are more informed individuals than me on this forum that I am sure will chim in, but that is the meat and potatoes.

One good thing about the L99 is the variable valve timing make a really nice torque by retarding and advancing the cam and if you put a VVT cam you have a beast on your hands.

The L99 has a different valve train (VVT) and lower compression ratio than the LS3. That is probably where the difference in power is coming from.

:headbang:

What they said.
Also, top is speed is not 155mph. It is electronically limited to 155. That can be tuned out.

They also have different gear ratios in the rear; L99 has 3.26 & LS3 3.45's.

I've long ago converted mine from an L99 to LS3. I think it would be odd to have VVT with 650HP in a Camaro with all the mods I've had done.

My head hurts from this discussion-I am SO *not* mechanically inclined. lol!!

The L99 is just an LS3 with VVT and AFM (and the corresponding changes that go with VVT and AFM).

They added the 1-4 skip shift to manual Camaros to bring the "normal driving conditions" fuel economy up and avoid the gas guzzler tax. The Chevy SS has the same LS3 engine in it but doesn't have the skip shift and has $1300 in gas guzzler tax on it.

They reduced the horsepower on the L99 so the LS3 could keep up

The L99 has a lower peak horsepower but the VVT yields a flatter torque curve, so it has the same or better horsepower in real world driving, that is, in the 1500 to 4000 rpm range.