People get the idea because sometimes engines are so rich they see flames coming out the exhaust. If you do your homework and look at the flame propagation rate it burns faster than petrol. “One of the other myths is that it is often accepted is that methanol burns slower than petrol and you need more timing. “But it doesn’t take into account the oxygen in methanol or the cooling effect, the cooling increases the air density in the cylinder. “If you look at the calorific value, petrol is higher than methanol and that leads some people to say petrol is a better fuel,” he said. Gower said the ballpark figure is about 2.5 times more fuel than the same motor using petrol. To take advantage of the power increases methanol can offer, it does require a much higher volume fuel system. Methanol engines generally make more torque than a petrol engine and they also make more horsepower because of the cooling effect and the oxygen content.” The importance of volume in the fuel system “But it depends on the engine combination, it’s often much more than that on a heavily supercharged application. “As a general rule, methanol makes about 10% more power,” he said. Gower said the cooling effect also applies to a naturally aspirated motor. The benefits of methanol aren’t just in boosted applications. The guys in the states with the C-rotor PSI superchargers are running 60 psi or more.” “What drag racers do with alcohol engines is crazy, we run compression ratios in the 10-12:1 ratio area and we are running 50-60 pounds of boost. It will just detonate and destroy itself on petrol with high cylinder pressure. “There is the fact you can run so much cylinder pressure and get away with it. On the Hemi engine, the valves are close together and directly across from one another, so during valve overlap a slug of air moves through the chamber and out the exhaust, and it carries a lot of that fuel buildup with it. Because we run constant flow injection, fuel builds up behind the intake valve when it’s closed. “A secondary effect we get on these blown engines is that some of the excess fuel we use cools the combustion chamber and valves, which also suppresses detonation. “It also carries some oxygen which you don’t get with petrol or gasoline, but no where near as much as nitro. “Methanol has a strong cooling effect on the air coming into the engine, so if you can keep the intake temperatures down you can run a lot of compression and a lot of boost,” he said. He said there are several reasons racers favour alcohol (of the fuel variety) and we got him to explain what racers should think about in considering methanol as a fuel. Why is methanol the favoured middle ground when it comes to high performing motors, especially of the supercharged variety? Greg Gower is the crew chief on Craig Glassby’s formerly world record holding alcohol funny car.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |