Racing Computer Programs - Racing By Computer

ProRacing Sim, LLC is a computer software company that specializes in simulation software for the racing industry. Their featured products are the DynoSim Advanced Engine Simulation, the FastLap Sim racetrack simulation, DragSim Drag Strip Vehicle Simulation, Full Throttle Reaction Time Trainer, and the Briggs Raptor Engine Simulation software programs.

Of special interest to the readers of this magazine are the DynoSim and the FastLap Sim programs. I installed copies of these programs on my personal computer and proceeded to build my very own race motor and test it. What I noticed right away (and I have some experience with racing oriented software) is that a lot of work went into making it user friendly.

I lean toward the chassis side of racing life, but that's not to say I don't get excited about engines and power. At an early age (during the mid-'60s), I read every Hot Rod magazine I could get my hands on and developed quite a wide range of engine knowledge. Let's be honest about it, the process of making horsepower is still mostly the same. We have merely refined it with advanced parts, processes, materials, and by using remarkable new tools such as these programs.

I called up my friend Wally, with Wally's Precision Machine, who has built many of the engine types I am interested in. He helped me select the components for the motor so that it would closely resemble "within the rules" NASCAR Late Model engines raced on the East Coast in and around the Carolinas, Virginia, and Maryland.

I began by installing the DynoSim software and selecting an engine. I chose the generic Chevy small-block 350ci engine and then selected a 4.03-inch bore and a 3.48-inch stroke (which makes this a 355ci engine); a compression ratio of 10.8:1; a 350-cfm, two-barrel carburetor; and a dual-plane, max-flow intake manifold (to simulate a common aftermarket intake manifold). I then installed stock port heads using 1.94-inch intake and 1.65-inch exhaust valves. With the small carburetor, we find that these valves work better than the larger 2.02-inch intake valves. The cam used created 0.550-inch lift at the valve on the intake and 0.520-inch at the exhaust valve.

Once all of the numbers were in, the engine came up to 376 hp at 5,500 rpm with 438 ft-lb of torque at 3,500 rpm. Wally had said to expect between 360 and 370 hp, so this is at the high end of the range of top NASCAR LM engines. We can also play with numerous values for the cam profile and duration, intake flow numbers for our personal intake and heads if that information is known, as well as custom bore and stroke numbers to see if we can generate more horsepower or torque while staying within the cubic inch and compression ratio rules.

I tried a little experimentation at this point in the process. While working with a team years ago in a Limited Late Model class, we were running an engine exactly like the one I built here. At practice one afternoon before qualifying, the crew decided to bolt on a 735-cfm carb and went out and outran most of the Late Model cars. The pits were buzzing and, after practice, they replaced the large carburetor with the legal 350 carb. I always wondered how much horsepower they gained from that big carb. By just typing in the 735-cfm number, the graph told me I now had 439 hp at 5,500 rpm. That extra 63 hp really helped perk up that motor for us back then. For now, I put the 350 back on.

Now that I had my engine built and ready to go, the next step was to use the track-testing software to see how fast I could go.