Solex air flow

a little searching

A (very) little forum searching yielded these #'s from RallyBob:

"A Solex flows 190 cfm, a 32/36 Weber flows 270 cfm, and the 38 DGAS flows 330 cfm."

Re: early Solex cfm?

oldopelguy said:

A (very) little forum searching yielded these #'s from RallyBob:

"A Solex flows 190 cfm, a 32/36 Weber flows 270 cfm, and the 38 DGAS flows 330 cfm."

Click to expand...

Thought I read somewhere that the '68-'70 Solex (HC engine) flowed 220cfm?

Bob???

Re: a little searching

oldopelguy said:

A (very) little forum searching yielded these #'s from RallyBob:

"A Solex flows 190 cfm, a 32/36 Weber flows 270 cfm, and the 38 DGAS flows 330 cfm."

Click to expand...

So, kinda makes me wonder what a 40DFAV flows . . . you know, the other synchronous carb that fits our stock manifold?!

The flow numbers I mentioned for the 32/36 and 38 DGAS were published numbers from a book...can't recall the title offhand. The Solex was from my own flow bench, but that was the bare carb on an adapter, no intake manifold. The manifold would alter the numbers drastically, which is probably why the BMW numbers differ.

Bob

tekenaar said:

So, kinda makes me wonder what a 40DFAV flows . . . you know, the other synchronous carb that fits our stock manifold?!

Click to expand...

I was told by my old Weber supplier (Interco parts in NY) that the 40 barely flowed better than the 38, the reason being the venturis were almost the same size. I suspect that on a sub-130 hp engine you'd never notice the difference, since at that power level you can't truly utilize all the airflow a DGAS has anyway, so a DFAV is a moot point. Probably all you'd see is better throttle tip-in response, and a hair more top end speed.

But if the engine's cam, headwork and compression can support it, the bigger carb would make a difference. Like when I used to bore out 38 DGAS venturi's to 31 mm (from 27mm). This mod is too much for a normal street engine, but on a tweaked engine it makes a big difference in the mid-to-top rpm range. Works well with high compression especially,and allowed me to see 155 hp (flywheel) from a 2.0 litre streetable engine.

Bob

All the articles I read (and a frew with tests they had done) was that the 2.0L BMW 2002, had a noticeable difference between the 38DGAS and the 40DFAV.

I guess I will never know though, since i never owned a 38DGAS to compare it too.. Would be interesting to run the two seperately on the dyno at Carlilse. If someone had a gasket kit and 38DGAS to spare..

Charles