Side Draft Mikuni's

[manoa matt]

Anybody ever tried a set up like this: http://cgi.ebay.com/ebaymotors/ws/eBayI ... 0239379522

If a manifold could be modified so the carbs are closer to the engine then the brake booster may not have to be moved. Add a couple of phenolic gaskets to limit heat transfer.

Aybody have experience with other mikuni style carbs? They make a model very similar to weber 40 DCOE's

[Daniel]

I never tryd those have used Mikunis Delortos and webers but never that type if they are like motor cycle
carbs changing the needle setting for jetting would be nice but tuning 4 carbs vs 2 seems like a lot of work
plus mods to make them fit .
You would need to make a adapter for those carbs to fit a side draft manifold as well .


Daniel

[manoa matt]

They are pretty much like motorcycle carbs. The linkage on those carbs is already setup, just modify the cable end. There are several other Mikuni carb variations I've been looking at that might also work.

My question is this: In the IAP catalog the dual 40 DCOE's for the Alfa have a simple adapter plate where the carbs are very close to the intake ports of the head, about 3/4". The fiat manifold for 40 DCOE"S have longer intake runners, about 2-3 inches.

How short can side draft intake runners be, before the air and fuel don't have enough runner length to mix and atomize? What would happen if 40 DCOE's were fitted to a Fiat with an adapter plate similar to the adapter plate pictured on Page 13 of the IAP catalog?

[Daniel]

hi Matt

I think the real Q is what options do you have ? even if you wanted a short or long intake who makes a short or
longer manifold these cars died off in the after market automotive industry years ago if you can make a manifold
then you've got room to experiment . The Short Manifold your talking about is the Alfa Manifold for there FI its
stock i believe as for a short Manifold you could try finding a 131 Manifold that was in Europe very limited production
of 131s came with side drafts i am sure it will be close to impossible to find .

Here is the basics of manifold runner lengths from all the engine builder books i have read, a longer manifold would
produce more of a mid power band to a point shorter would be for high RPM but what lengths ? i have no ideal .
My Friend owns a Abarth Simca 1300 TC the Manifold on that is almost a foot long with DCOEs on it but it is straight
tubes no tapering or funneling to increase the Velocity as the intake travels down the runners . I'm sure they
experimented with this manifold to end up with that design for a almost race sports car that is what Abarth builds on
the most part higher performance / (race cars) .

Atomize isnt based on length of runners on a manifold its more of a mixture process from your Carb or FI and
your trying to keep the fuel from falling out of Atomized state . There are many ways to promote Atomize by the
finish of the runners swirl finished intake valves etc etc .

Daniel

[miragesmack]

I have a set of unused Mikuni downdraft from eons ago, made for a hot BMW 2002. They are 45's, so they may be a bit much for a Spider. I might dig them up and have a look see. They are sitting in the attic. They don't make this set anymore, and I see a lot of Bimmer folks drooling for a set, just to be different I suppose. I'm interested in what you find out though.

[Jim DeShon]

Not sure which carbs. you are talking about, automotive style or CV's like a motorcycle . I have had a lot of time with Mik's on motorcycles. I find them easy to tune. It has crossed my mind to use motorcycle carbs on a Fiat before but, I've never actually tried it. Jets and needles are easy to come by. At about 500cc engine displacement per cylinder you would have to go to some much larger jets than on a motorcycle but, I think it's do-able. ...J.D.

[Tappy]

it shure would be a cool "motor-mod"

[BluePaulie]

Look up the V-performance site and click on the Mikuni article.

This site is dedicated to P1800 Volvo's, but the information is excellant. I'm asking this fellow if he can modify a set of downdrafts for my 1800.

Paul

[manoa matt]

If you search the Guy Croft site, there was a member about a year ago that fitted motorcycle carbs to a Fiat TC with excellent results.

2008? Talk about an old thread.