"Though it certainly used to, heat or bad air does not slow the blown cars down anymore. This started to go away when IHRA first allowed the high helix blower, and is completely gone now. The reason for this is the new work they are doing to the superchargers themselves. They have machined and refined the supercharger case to dramatically reduce the friction in the blower, causing much less turbulence and, as a result, cooler air. When they ran the roots style blower, they did slow down in the heat. But this is no longer the case. Just take a look at the Drag Race Central archives for proof.

Speaking of archives, let’s go back in time for a little while. When Pro Mod started, it was a nitrous class. Nitrous companies put up the money to get the class off the ground. Blown cars had no class. There were very few of them, and they were outlaw cars. Eventually they were allowed in, but they couldn’t keep up. Scotty Cannon and Jim Oddy eventually made them competitive. Ever since that point, when Oddy got his stuff running and Scotty switched over to a blower, they have been the faster cars. Still, they gave them the high helix blower. Instantly there were more blower cars and they were almost all competitive, running near the top of the field."

 

just think how fast they would be if they let the turbos run

 

if they sounded like a blower maybe they would be

 

Mine loves to "whistle while it works". LOL

 

In the world of blown alcohol racing, the screw blower has it ALL OVER the High Helix. It's gotten so out of whack, that there's different rules pertaining to blower overdrive between the 2. A 500 ci blown alcohol engine with a 125% over screw blower is a BAD ****!!!! But typically hard on parts. They're usually singing 10,500- 11,000 on the big end!

 

Those PSI twin screws look awfully mighty. Are there any other companies that make competition twin screws that you know of?

 

We're running a PSI currently, in Top Alcohol Dragster. Whipple also makes a competition blower, but it's not currently SFI certified. The Alcohol Funny Cars are currently mandated to run the 14-71 High Helix, only. Mainly because the 500ci motor with that kind of overdrive running those RPM's thru the traps is a really volitile combo. Believe me, in this class(Alcohol Dragster, and Funny Car), the weakest link is easily found! We've run the PSI this year to 5.34-270ish with a 456 ci motor.

 

If I ran my truck on alcohol, I probably would be happy with how cool my screw compressor runs, too.

 

They run so cool, that after the burnout, right before the driver lights the pre-stage light, you actually have to spray de-icer on the injector butterflies. There will actually be ice forming on the blower case!