[Fot] Weber vs Mikuni

[JAMES GRAY]

The Mikuni HSR's are great carbs, pretty much set it and forget it unless you change altitude a bunch.

Then it's just the main jet. I used them for 3 seasons until I developed a head that out flowed the stock intake manifold.

I did all sorts of welding and reshaping to the intake and just didn't get what I wanted out of it so I went to a pair of DCOE's on Cannon manifolds. I first tried the TWM manifold from Pierce and after some attempted fittings I declared it a piece of junk and went with the Cannon intake. ( Thanks Tony for that bit of advice )

Long story short, Mikuni HSR carbs are great but the manifolds will only flow some much.

jim g

> On October 18, 2018 at 12:49 AM "van.mulders.marcel--- via Fot" <fot at autox.team.net> wrote:
> 
>     -"...hitting a wall at that point..." : is it possible this is rather pointing to the camshaft than to the SU's? If it are the carburettors, maybe the power would decrease more gradually above 6500 rpm.
>     -In general one choke per cylinder is better, and 2 Webers 40 DCOE isn't overkill I think
>     - what about trying HS6 SU's on your actual manifold?
>     At what maximum rpm is your engine still reliable?
>     Marcel
> 
> 
>     ---------------------------------------------
>     Van: "fot" <fot at autox.team.net>
>     Aan: "fot" <fot at autox.team.net>
>     Verzonden: Woensdag 17 oktober 2018 15:49:45
>     Onderwerp: [Fot] Weber vs Mikuni
> 
>     I'm looking into switching out my twin HS4s on the 1296 race engine to either Weber or Mukinis. I know this has been done for years and I'd like to get close the best set up out of the gate.
> 
>     I don't think the SUs are up to the task of moving enough air with the new ported head and Stahl header. I've worked on the SUs and gotten them to finally deliver a good AFR , 12.6, at 6500 RPM under load but I seem to hit a wall (figuratively) at that point. I suspect that the openings just aren't big enough to deliver the mass of air required. (spreadsheet or other flow calculator link appreciated)
>     Biggest gate I suspect is the intake valve, 1 3/8" head (~35mm) HS4 is ~38mm at best.
> 
>     Recommendations? I've seen all these setups at the track, each with pluses, minuses and overkill cause it looks cool.
> 
>     One weber DCOE 40 or 2? what jets, tubes etc for a starting point? Best manifold?
> 
>     2 or 4 Mikuni 40? jet size?
> 
>     thanks
>     mike
> 
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