510 Race Engineering - Developing The LSA

[KCS]

One of the great things about working in a custom automotive shop like 510 Race Engineering is that you are privy to a lot of cool R&D on some of the newest platforms. Take the LSA for example. It is easily one of GM’s most potent small block V8 engines ever, but in the hands of talented and ambitious enthusiasts, it gets even nastier and shops like us are at the forefront of improving the original design to squeeze out every last bit of power.



The supercharged LSA isn’t the first production engine to employ the benefits of pressurizing the intake charge. The OEM’s have been doing it for years, with the Toyota Supras, Mitsubishi Eclipses and Evo’s, and of course the Ford Mustangs. One of the lessons learned from modifying these vehicles is to capitalize on the air compressor by increasing boost pressures and make it as efficient as possible at compressing the inlet charge with as little increase in heat as possible.

Superchargers are relatively simple devices. They are basically belt driven air compressors. Generally speaking, spin them faster and they make more boost, but you have to be careful not to over spin or create too much heat (more on that later). The LSA in stock trim produces roughly 9psi, which is a conservative amount of pressure for an OEM engine, but it can take more in the hunt for more power. To do so, we can use a larger pulley on the crankshaft, a smaller pulley on the blower, or a combination of both for a max of about 16psi. Going straight to 16psi on a stock engine is not something we would recommend, due to the laws of thermodynamics.

No matter what, whenever you pressurize a gas, it heats up. When it heats up, there is less mass of oxygen per volume of air, and consequently the engine cannot burn as much fuel and cannot make as much power. When the hot air goes into the combustion chamber, the engine becomes more prone to detonation and timing advance, and again, cannot make as much power. In this aspect, we focus our attention to improving the design and function of the intercooler. An air to water intercooler, like what is found on the LSA, pulls heat out of the intake air by circulating a chilled liquid through a tube and fin heat exchanger in the inlet path after the blower. Keeping that liquid as cold as possible drastically reduces the intake air temperatures. To achieve this, we looked at the reservoir where the liquid is stored and immediately thought, “this just isn’t big enough.” By custom fabricating our own reservoir, we are not only able to increase the fluid capacity of the intercooler system, but the reservoir itself is now able to store 20lbs of ice to chill the fluid even colder. The result is drastic drops in the IAT1 and IAT2 readings (intake air temperatures before and after the blower) and as much as a 30-40whp gain.



With the supercharger making more boost and the intercooler even more efficient, we turn our attention to improving the inlet path and cam combination. The LSA heads are already stout rigid pieces, but as always, there is room for improvement. We start with a proprietary valve job that we’ve nailed down after trying out several different combinations of angles and widths with our LS3 cylinder head program, and move into the ports to increase flow and reduce turbulent areas all while keeping material removal to a minimum to avoid killing the average airspeed throughout the port. The manifold for the supercharger is a different story as we found that we had to remove a lot of material, but suffered no loss in power anywhere. On the LSA manifolds (CTSV and ZL1), the injectors are placed in such a way that a huge restriction is created in front of the ports. Reshaping these key areas meant taking out a lot of material, but we were rewarded with huge gains in airflow on the Flowbench and power on our dyno.



When the LS3/L92 style heads first came out, they threw a lot of people for a loop when it came time to pick out a camshaft. These weren’t the little 2.00” valve, 200cc cathedral port heads we were used to seeing in the Corvettes and Camaros, these had huge 2.165” valves and 250+cc ports capable of flowing over 300cfm straight from GM. What this translates to is a cylinder head that is capable of filling the cylinders very quickly without a lot of duration. Too much overlap and the exhaust gas can find its way into the intake manifold and contaminate the fresh intake charge. Too late of an intake closing and the intake charge loses its inertia and the cylinder filling suffers. Either way, power is lost in a big way. On the other hand, there is still a blower cramming a ton of air into the cylinder, and it needs to get out effectively through a 1.59” diameter exhaust valve. With these two dynamics playing out in the LSA engine, we’ve come to prefer a specific cam profile that has an intake duration in the 220’s and an exhaust duration in the 240’s.

With all of these areas addressed, we are seeing as much as 750whp in our top level “Flame Thrower” package named for the tendency of the exhaust to spit out a fireball when the throttle is snapped shut. This package includes upgrades to increase boost pressure, intercooler efficiency, and custom porting of the induction system and exhaust, including a stainless header and exhaust system.



For more information on any of our various LSA upgrade packages, feel free to give myself or any other one of our staff members here a call.

[DaFlash]

"You... your good you. Naw naw your good"

[My Caroline]

Awesome! So, can you explain the ice bucket? I'm assuming it would only need to be filled with ice under race conditions?

[KCS]

Originally Posted by My Caroline

Awesome! So, can you explain the ice bucket? I'm assuming it would only need to be filled with ice under race conditions?

The ice tank works extremely well with ice, but the advantage isn't just when it has ice in it. It's a much larger capacity, so it takes more heat to raise the temperature of the coolant. The result is that coolant stays cooler longer than with a lower capacity system, even without ice. It's a completely custom unit built in house. With the CTSV's, we built an even bigger tank...

[ssgirl2010]

Can the ice kit be installed without going into the shop?

[KCS]

Originally Posted by ssgirl2010

Can the ice kit be installed without going into the shop?

We would prefer not to.

[Trob85]

How good would the flow rate be on the heads if you were just to go in and polish the heads for instance I'm building a forged 376 with the pistons I have 68 cc heads are right in my 9:2 compression range. Would doing that be able to flow 16-20 psi thru a centrifugal blower making 900-925 hp at the crank

[Matt@510]

Originally Posted by Trob85

How good would the flow rate be on the heads if you were just to go in and polish the heads for instance I'm building a forged 376 with the pistons I have 68 cc heads are right in my 9:2 compression range. Would doing that be able to flow 16-20 psi thru a centrifugal blower making 900-925 hp at the crank

what supercharger head unit are you using and cam specs?

doing a full port job on the heads would be better open them up to allow more airflow. we dont actually polish the runners any longer you want a slight bit of texture left in the runners. on the exhaust side and in the chamber yo can polish to remove hot spots and areas for carbon build up.

[Trob85]

I'm running a Procharger d1sc and the Lingenfelter gt9 cam I think the specs are 215/247 .629/.656 121cl

[Matt@510]

Originally Posted by Trob85

I'm running a Procharger d1sc and the Lingenfelter gt9 cam I think the specs are 215/247 .629/.656 121cl

with that combo your power goals are doable you will be pretty well maxing out the supercharger. the heads would certainly help you get higher hp numbers. the more power you can make without the supercharger then you make substantially more with the blower.

[Matt@510]

We just finished Jimmy's ZL1 Inferno 645hp package.