Michael Galimi
November 1, 2008
Our test vehicle was simple-built short-block, TEA-ported Two-Valve heads, AFM F-42 cams, a Fox Lake P-51 intake, and a ProCharger P1SC blower.

Call It the modern-day Gasser Wars. When it comes to high boost and big timing curves, there are only two fuel choices that will keep your Mustang alive-high-octane race fuel, or a mix of pump gas and methanol injection. Of the two, race gas has been around for years, while the meth mix is much newer and all the rage. Both, however, have pros and cons when it comes to cost, making power, and running safely.

With these things in mind, we put each through its paces on a supercharged Two-Valve combination. As different as meth/pump gas and race fuel are to each other, the outcome was strikingly similar on the chassis dyno. It's your wallet that gets affected differently for each.

We employed Dez Racing's shop car for this test-those who checked out the September issue of MM&FF are familiar with this Two-Valve terror. A quick overview for those who don't remember this ride is in order, though. The '01 GT sports a built short-block (stock displacement), TEA-ported Two-Valve heads, a Fox Lake P-51 intake manifold, Anderson Ford Motorsport F-42 camshafts, and a ProCharger P1SC (11 psi) blower, amongst other parts and pieces. It's a solid combination that runs mid-11s on pump gas. Of course, we wanted more, and we decided to turn up the timing. We wanted to crank up the boost, too, but the P1SC head unit was nearing its capabilities. Ultimately, we decided that adding timing was the best course of action.

We wanted to see what was better for our street car: race fuel or adding methanol injection. Cutting right to the chase, both techniques made nearly identical power. It makes sense because we started off with 16 degrees of ignition timing on pump gas, and then bumped it up to 23 degrees and 26 degrees on both meth and race fuel. For race fuel, we used VP C16 (117 octane), and to inject the meth, we added a Snow Performance methanol injection system. Think about it: We kept the airflow the same since the blower was fixed at 11 psi of boost. The timing curves were identical, so the car should make similar power. The only differences were with the air/fuel ratios. The air/fuel ratio on the dyno meter read 11.8:1 with meth pumping through the system, while the racing fuel runs showed a reading of 11.5:1.

"The difference between the two air/fuel ratios is because the meth injection cools in the intake charge. You're not pulling out as much heat when running solely on race gas. I added some more fuel to cool down the cylinders [when running on race fuel-Ed.]," says Mike Dezotell of Dez Racing. The output was nearly identical, with the Snow Performance-enhanced runs making 470.22 rwhp and the C16 stuff helping the engine make 469.92 rwhp.

Torque saw a reversal of roles as the C16 had one more lb-ft with 455.70 rwtq, while the Snow kit showed off a best of 454.97. The results were so close, we called it a draw. Our baseline pump gas runs were 437 rwhp and 420 rwtq. It was down from our previous runs in the 450 range, but we wanted to conduct same day comparisons. Our original dyno runs were made in the cool, early spring air; this time around it was hot and muggy. Same day testing and adding timing netted us 32-33 more rear-wheel horsepower.

We made several observations while the car sat and cooled down between dyno pulls. First was Dez's comments about meth injection. "It's a performance enabler," he proclaimed. Adding meth, or race fuel, won't add power; it just lets you push the parts you have to the limits. We were definitely at the limit with this Two-Valve combination. Dez went from 23 degrees up to 26 degrees, and the output remained identical in both meth and race-gas trim. That meant we were out of airflow. The engine needed a D1SC with more boost or better flowing induction. Considering we had killer TEA heads on there, a Fox Lake intake, and a healthy set of cams, we figured more boost would have made even greater gains over straight-up pump gas.