Cam design limitations

Arco440 said

Hey bill i read what you posted about lob separation and duration is this for tuning at idle?
So you can optimize boost.if so wont a higher duration help you out in the higher rpm range and if so have you looked in to the rhoads lifter as they allow you variable duration for better idle and pump up around 3000 rpm.I know this is a slant 6 but i use rhoads lifters in my 440 and i have a long duration cam but i idle very well at 800 rpm.just asking if this might help save you a dollar.

http://www.rhoadslifters.com/Pages/PartNumber.html

I just checked web site they dont list /6 but i would call them any way.

Click to expand...

You could be right. I have NO experience with turbo cam design, and am just going by what I am told by a few successful turbo racers who make virtually 500 horsepower from a 225 slant 6. They are all running short (210 degree) duration cams. I get a lot of feedback from a group of Buick Grand National racers who I meet for breakfast at (YAWN) 8 a.m., every Saturday. Three or four of their cars run in the tens (231 cubic inches) and none of their cams have more than 215 degrees duration @ .050"-lift.

So, being the newbie, I kind of have to go with what works for these experienced racers.

The cam in the engine now, is a 210/210 (Bullet) grind, but I have a new Comp cam that is 210/220 that I want to try after I get a baseline with this one.

I'm afraid a "good" cam for a normally-aspirated engine would just blow significant amounts of boost out the exhaust valve during overlap.

But, we'll see; this is just an experiment...


Thanks a lot for your interest and input!!!