Corvette LS3 Engine - Worthy Successor

The New-For-'08 LS3 Improves On Its Predecessor In Every Way. A Talk With One Of The Engine's Creators Reveals How.

Christopher R. Phillip May 1, 2008 0 Comment(s)
Vemp_0805_06_z Corvette_LS3_engine Valves 1/10

The LS3's hollow-stem intake valves (right) measure 2.16 inches in diameter. The LS2 used 2.00-inch, solid-stem units.

Vette: What challenges did you overcome to increase the horsepower of the LS3 while also improving engine life?

JR: The block was one of the challenges that we went after, and we had to resolve it using analysis tools. That was very successful. Another area was the rod-joint capability-the rod bolts. We had to improve that entire joint. We went after a redesign of the bolt-or rather, a change in the materials of the rod bolt-to a higher-grade bolt very similar to what we use on the LS7. That was an area [where] we actually ran many component tests to verify we were capable of running at high speeds and high loads for a prolonged amount of time-something that's very important to the people who take these engines and cars out on the track. It was a challenge to go after that!

Vemp_0805_08_z Corvette_LS3_engine Combustion_chamber 2/10

In addition to its larger intake valve, the LS3 head (right) also gets reshaped combustion chambers.

Vette: When you designed the LS3, was your horsepower target purposely weighed against the classic 427/430 L88 motor?

JR: No, we didn't purposely compare the horsepower of the LS3 to the plateau reached by the classic Chevy big-block motor. We looked at our competitors of today and where they are, and where our platform needed to be from a performance level. The Corvette is class leading, but we wanted to increase that lead.

Vette: Did computer technology at GM change sufficiently between the development of the LS2 and the development of the LS3 so that you were able to increase performance as a result?

JR: Our standards of what we look at and what we try to do have changed quite a bit. Our capability has become very good. Pretty much every month we have new techniques that improve our capability for analysis.

Vemp_0805_07_z Corvette_LS3_engine Engine_covers 3/10

While enhanced performance was the chief goal of the LS3 program, improvements in refinement were also targeted. For example, these new engine covers-complete with insulated inserts-help quell valvetrain noise.

Vette: Did you design the LS3 with future modifications in mind, so enthusiasts can easily add horsepower?

JR: There's always room for improvement, so enthusiasts can do things, whether it's [reducing] induction-system restriction or exhaust restrictions. As I mentioned, you can polish these cylinder heads or take them out to a porter and do some work on the intake ports and the exhaust ports and get toward an LS7 in performance. There are camshaft options out there, too, that can get you more performance. What we put together is a good balance. It gives you emissions capability, fuel efficiency, and much more performance [than the LS2]. It's a quieter application, too. We've added some features for refinement, but someone who wants to actually go out and increase the performance of the LS3 has a lot of capability to do that.

Vette: How do you feel about power adders on the LS3 to elevate its horsepower output to supercar status?

JR: We expect it. Many of our buyers do quite a lot of things to our vehicles and take them on tracks and enjoy their performance, and we get good feedback that way. There are many aftermarket performance parts out there, and we expect our customers to do things like that.

Vemp_0805_09_z Corvette_LS3_engine John_rydzewski 4/10

GM Powertrain's John Rydzewski poses with a cutaway version of the LS3.

Vette: How do you feel about the LS3 being carbureted for hard-core race use?

JR: Wow, this is the first time I've been asked that question. If it works, if someone wants to do it, I don't have a problem with it. It's a big change; you'd have to change the intake manifold and fuel system, [but] that certainly is a possibility. I'm sure there are people out there that will do something like that.

Vette: What do you see in the future of the LS3?

JR: We're looking at all kinds of technology. We definitely can't sit still, because the competitors aren't sitting still. We have to focus on many of the regulations out there, [including] emissions. Fuel efficiency is one of the most important things customers want right now, but we want to deliver the class-leading performance along the way, too.