Race Engine Forum UK

Hello Guy.
My question to your is-
I have a few Beta Volumex engines kicking around and for one project I want to use the head with twin carbs making use of the larger inlet valves. From your book I have found that the inlet ports are 36mm all the way down. Is there scope to alter this so I can create a venturi in the port? What method should I use?

Thanks in advance

Mark

There is no benefit to having a venturi port as such, parallel is better, if it is of the right size. They flow OK if the convergence isn't too acute but a parallel port flows better.
No, I would not reshape that port in terms of its general diameter, just tidy up the finish and radius the short-side region - but be aware it's so big that you will doubtless (if there is such a thing) need a healthy CR and powerful inlet cam etc etc to get good bottom-end torque.

GC

The manifold bolt pattern is different to other non VX heads too. Finding a manifold maybe difficult or expensive.

Steve, hi

you're right of course, but in fact the Vx head has extra threaded holes for the Vx inboard manifold and still retains the normally aspirated ones too. So you can bolt a sidedraft manifold a la 131 type straight to it. It is necessary to plug the lower 3 Vx holes because they go straight into the cooling passage.

GC

Thank you Guy.
What CR and cams would you suggest? I want to use beta 1585 pistons, are these suitable? I am also planing to use 45dhla s carbs that were originally from a 2.2 lotus esprit . I would like to set up the engine for a fast road spec mated to a VX box.

Thanks again

Mark