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Inside The Crowerglide Automatic Clutch
By
Andrew Wolf April 23, 2019If you’ve ever tinkered with a basic mini-bike or go-kart clutch before, chances are the design behind
Crower Racing Products’ namesake Crowerglide automatic clutch isn’t all that foreign to you. Similar to those relatively rudimentary clutches, the Crowerglide operates purely on engine RPM and load, and while the premise is similar to a traditional pedal-operated clutch, there are advantages in certain applications.
Automatic — or slipper — clutches are certainly nothing new, as they have been utilized in nitro and alcohol racing throughout drag racing history. And while alcohol and Pro Modified combinations have moved to pedal clutches or torque converters as a result of the advantages they provide those particular combinations, it’s nitro applications that adhere themselves well to something akin to the Crowerglide. This is largely due to the nature of a nitro engine that shines when it’s under load, but also a result of the manner in which a nitro car is launched.
“Nitro applications depend on every launch being the same, so the car will react the same, making it more tuneable. If you’re using a pedal clutch and on one pass and you load it a little harder then the next pass, it won’t do the same thing it did the last time. A Glide clutch, because it’s automatic, it takes driver error out of the picture,” Crower’s Roger Levine explains.
In essence, because the driver is merely stabbing the throttle to accelerate, there aren’t variations in how the driver swaps feet or how consistently they release the clutch pedal from one run to the next. For this reason, the Crowerglide and other automatic clutches are very common fare in nostalgia nitro Funny Cars, nostalgia Top Fuel dragsters, and NHRA A/Fuel dragsters.
[QUOTE]If you’re using a pedal clutch and on one pass you load it a little harder than the next pass, it won’t do the same thing it did the last time. A Glide clutch, because it’s automatic, it takes driver error out of the picture. – Roger Levine, Crower
That doesn’t mean, of course, they can’t be used in an alcohol combination.
“The alcohol cars are leaving at high-RPM now to gain the inertia and to move the car, and with a Crowerglide you can’t leave at as high of an RPM. Even if you had a pedal to block the arms, which you can do, it would still be pushing back pretty hard. You wouldn’t be able to leave at 7,000 RPM or so like some of these guys are doing,” he says.