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Mikuni Carbs


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#26 Peter UC

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Posted 22 September 2016 - 09:39 PM

That image above was bought from the same people, Vintage Performance, they're in New York, however I bought mine when the dollar was still parity so it would be a bit more expensive now.



#27 madtoranajzedded

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    Sir ask alot

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Posted 22 September 2016 - 10:05 PM

Wow just checked out v performance site.
Great little read on there dyno testing
Su vs mikunis

#28 _oldjohnno_

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Posted 23 September 2016 - 06:20 AM

I think it's worth keeping in mind that the VP comparisons with SU used Mikunis and SUs of the same nominal bore size. As I've said earlier the bore sizing of the HSR isn't really comparable and the side-by-side photos on the VP site show that clearly. A better comparison would use SU's with a comparable flow area to the HSRs, and while I don't doubt that the Mikunis would still come out on top I'm sure the difference would be much smaller. For example on a Holden 6 you'd compare 2" SUs against HSRs or FCRs of around 40 - 42mm.

 

The testing against DCOE Webers showed the Mikunis again having the advantage, even after increasing the carb (and choke) size of the Webers:

Over the winter of 2010/11 we did a comparison of our Quad 45mm Mikuni HSR carbs vs sidedraft Webers. After running the Mikunis on one of our 2.5 L B20 engines, we installed the 45 DCOE carbs that are usually on my racecar.  After finding the engine significantly down on power compared to dyno runs with the Mikunis, we stepped up to a pair of Weber 50 DCO race carbs, first with 42 mm chokes and then with 46 mm chokes. Even with the 46 mm chokes, the power output was lower than with the Mikunis, with higher brake specific fuel consumption, while loosing power at lower rpm. The result - the Mikunis were the clear winner.

 

Unfortunately it seems the Mikunis aren't permitted in most historic racing categories.


Edited by oldjohnno, 23 September 2016 - 06:21 AM.


#29 madtoranajzedded

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Posted 23 September 2016 - 06:50 PM

Was looking at your thread Peter back in 2011
did you get yor engines output to the 230hp figure you wanted..

Maz

Edited by madtoranajzedded, 23 September 2016 - 06:50 PM.


#30 Peter UC

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Posted 24 September 2016 - 12:58 PM

Not sure to be honest, I know when it got its initial tune it made 102rwkw at 5000RPM and it was still climbing sharply, but as the engine was still being run in it was revved higher. I should get back and make sure the tune is fine and find out how much power but I haven't got around to it.



#31 _oldjohnno_

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Posted 24 September 2016 - 06:25 PM

With a half-decent head and the 626 cam I think you could expect an honest 180 - 190hp at the flywheel. Mightn't sound all that much but the 626 gives a very fat midrange so you get strong acceleration and good fuel mileage too. I think they're a good street cam and the fact that it's pretty much all over by 6500 is probably a good thing for engine life.


Edited by oldjohnno, 24 September 2016 - 06:27 PM.


#32 jd lj

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Posted 25 September 2016 - 06:18 AM

I don't really see the need for a street car to be reving beyond 6500rpm, any more than that and your pretty much just flogging the guts out of it for the sake of it to satisfy your own ego.




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