Another twist on this for people to think about is that running a 44mm
Mikuni doesn't get you much if you are also running 34mm venturis in them.
The air velocity will be quite high through the venturi itself but will then
drop on the other side as the cross-section increases.
Running 34mm venturis in a 40mm carb will probably result in better airflow
characteristics and more consistent atomization of the fuel than running the
same size venturis in a larger carb.
Gordon Glasgow
Renton, WA
www.gordon-glasgow.org
> -----Original Message-----
> From: owner-datsun-roadsters@autox.team.net
> [mailto:owner-datsun-roadsters@autox.team.net]On Behalf Of Marcus A.
> Pryor
> Sent: Wednesday, June 07, 2006 10:15 AM
> To: datsun-roadsters@autox.team.net
> Subject: Re: Carburetion.
>
>
> I chose the 40mm carbs for the following reason. It involves what happens
> with a large overlap cam. It is critical to keep the velocity of the air
> stack up to avoid reversion as the exhaust valve opens. Smaller venturis
> help.
>
> It's not that the 40s are really THAT small. They will take up to 36 mm
> venturis, which probably equates to something like 350 CFM each. That is
> about 700 CFM for a 2 liter engine!
>
> Marcus A. Pryor
> For a new age of reason
>
> > Eric,
> > Delete this before you start thinking!
> >
> > Marcus,
> > I'm trying to tye together the thread about big cams to the fact that
> > you are using smallish (40mm) carbs on your U20. Most people would
> > expect bigger carbs with a bigger cam.
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