Figure 3. A modified Chevy...
Figure 3. A modified Chevy 350 engine on gasoline.
If your rules allow, do some work on the heads. Put in some large valves and spend a day with a die grinder. But be sure to wear good goggles, as a trip to the emergency room to pull a sliver of steel out of your eye costs about as much as a good set of rods. Also get someone to teach you where to grind, and make some gauges to be sure you don't strike water.
On the software, I select Wedge/Fully Ported, Large Valves, 2.02-inch intakes, and 1.6-inch exhaust. Wow! That should pull us to the front-520 hp with 435 lb-ft of torque. See Figure 3. At this point, I am a bit suspicious. My porting jobs never work that well. Maybe professionals know a lot of tricks that I don't. Don't expect this much improvement unless you spend a lot of bucks on the porting job.
Now, let's make this engine a 351 Ford. The extra cubic inch and the blue oval really don't make a difference. The software doesn't seem to be biased either way. Now I go back to the Chevy 350. Under the induction section, there is a fuel-type choice. I select methanol and achieve 550 hp. That is about a 5.8 percent power increase. Sleepy Gomez, technical editor for Stock Car Racing, says that methanol likes high compression. Let's see what the software says. I change the compression ratio to 14. Horsepower is 595 on gas and 625 on methanol. That is a 5 percent increase. Changing the compression ratio to 8, I get 465 and 495, an increase of 6.4 percent. It appears the software averages around a 5.7 percent increase from gas to methanol with little change by varying compression. The software disagrees with Sleepy, but I tend to believe Sleepy more than the software. However, I don't think compression will affect the percentage of improvement much.
Figure 4. DynoSim data on...
Figure 4. DynoSim data on a Lewis 383 methanol engine. The software predicts the horsepower to be higher than measured. Also, the torque and horsepower curves are shifted up the rpm range as compared to actual measured data.
Methanol has a high-octane rating and will withstand high-compression ratios. I have seen an 8 percent increase with methanol using compression ratios from 10 to 13. I also note that this data shows dramatic horsepower improvement with compression-about 20 hp per point of compression. I haven't experienced that much. My rule of thumb is 10 hp for every point of compression, but perhaps I haven't learned all the tricks here, either. I do know that high-compression ratios are an invitation for disaster. Detonation can destroy a high-dollar engine, and a blown head gasket can ruin a good block and head.
At this point, I do not like the graphical display. It is set up for 1,000 hp and 15,000 rpm. That is out of our league. I had to read some more of the instructions, but I found that if you right-click the mouse on the graph, it gives you some choices. Low range goes to 5,000 rpm, mid-range goes to 11,000 rpm, high range goes to 15,000 rpm, and auto range also goes to 15,000 rpm. I would like to see 7,000-8,000 max, but I haven't been able to do that as of yet. On the vertical scale, the auto range does a nice job of expanding the graph.
I have some dyno data on my latest and greatest race engine that I will use to compare with the software prediction. It is a 383 Chevy small-block with ported heads, high-compression pistons, a roller cam, and a 950-cfm methanol carburetor. The software predicts 605 hp, flat between 6,500 and 7,500 rpm. Torque is 525 at 5,000 rpm but appears narrowband. The data is shown in Figure 4 (see page 74). The actual measured data on my engine shows 550 lb-ft of torque with a broad peak centered around 4,200 rpm. The horsepower is also broad, exceeding 550 hp from 5,500 to 6,500 rpm. The peak is 568 hp.