Screw/ roots camshaft?

How much of a difference is there between the two? I'm runing a bae5 with a screw now with the same cam it had when it was a roots motor... Is it worth geting a cam that is made for the screw?

 

Cam

Hi,

I can't speak from experience on the screw blower cam but I have heard a lot of the guys just run the 118 instead of the 116 centerline with the same specs, I can tell you my cam came out of a well known screw blown dragster and is a 116. It is the same specs as my roots blower cam with some slight tweaks in design.

I know its vague but I hope that helps a little.

Trev

 

cam shaft

yes it is worth it

of course assuming you have the best roots cam vs.best screw cam ...

 

7 time IHRA champion Mark Thomas told me 15 yeas ago, that they had been using a 118 spread cam and were thinking about trying 119ls. Of coarse thats roots blown 14/71hh as per IHRA I think on 100% ethanol with corn oil in the crankcase:because theyre hillbillys like that.

Marty Creech
let there be rock https://www.youtube.com/watch?v=H5OOnVGEip0

 

camshaft

There is a mega amount of difference. A screw blower is cramming a ton more air down in the cylinders and needs to get it out way faster. you will be killing parts if you use a roots cam.

 

There really isn't much difference they've been using R296/500-16 (336 duration 296@.050 .500 lobe lift 116 lobe separation) in alky funnycars and R-296/4778-2s-14 cam (328in 332ex 296/300@.050 .4778/.5099 lift, 114 separation angle) I might be off a little on that one, I'm looking at the '80s crane catalog ;;; in dragsters,with roots and screw blowers since the '80s. Before 14/71's and high helix's
Drama Queen: https://www.youtube.com/watch?v=ArWHfpwMs3g


Marty Creech

 

cam

If this is a door car there will be a difference in camshaft selection, An alky funny car cam will be to aggressive down low and will tear stuff up.

 

Cam

Thanks for all the info guys! I talked to mike janis an he is going to get me a cam set up for what I'm doing...