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Author Topic:   How much HP is a Roller Cam Worth?
Speed Racer X
Dirt Full Roller

Total posts: 61
posted December 08, 2002 08:22 PM
For discussion's sake let us assume that a given roller cam and a flat tappet cam have the same profile. How much more HP is the roller worth? I understand that that a roller can open and close the valves faster, thus filling the cylinders better, but is this when they get their increased power or is it from the reduced friction? Thanks!

outlawstock17
Dirt Forum Champ
Total posts: 620
posted December 08, 2002 09:18 PM
one of the reasons that you run a roller cam is so you can take advantage of the faster opening and closing rates available with a roller. depending on the engine, i'd guess that a roller cammed engine could make as much as 100HP or more than a flat tappet engine of similiar design. some of the gain would be in loss of friction and some would be in the more aggressive profile associated with the roller.

don't take this wrong. you're not going to get an extra 100HP out of your stock 305 z-28 by dropping a full boogie roller cam in it.

another thing you get out of a roller cam is a big ol' flat torque curve and that's where the big advantage is.

[This message has been edited by outlawstock17 (edited December 08, 2002).]

rico 08
Dirt Freak

Total posts: 372
posted December 10, 2002 01:09 PM
I read somewhere that from just friction loss alone a roller is worth 14-16 h.p. and probably more if you factor in the faster opening and closing ramps.

UDHarold
Dirt Newbie

Total posts: 2
posted December 23, 2002 10:38 PM
As I just posted on another thread, we ran a dyno test in the 80s(Turbo heads, no less!) on a 355 with my most popular solid, and my most popular roller, in it. Both cams are 288/296 at .020", 255/263 at .050", with the roller being about .075" higher in valve lift.
The roller was 30 ftlbs of torque and 60 BHP higher than the solid.......
As a thought, the solid lifted the valve over .0070"/* at the cam, and the roller was over .0094"/*.... At .200", the roller was 10 degrees fatter than the solid.
This was April 1980 technology.

UDHarold

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