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| are split webers worth it? https://www.ausmini.com/forums/viewtopic.php?f=5&t=80397 |
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| Author: | EN40B [ Sun Feb 17, 2013 5:36 pm ] |
| Post subject: | are split webers worth it? |
I say yes - because I enjoy something different, I enjoy the extra horses and they look great! I've had some great discussions where the other party says "no" - because it's a waste of a weber, the hassle doesn't equate to benefit blah de blah anyone else out there running a split setup? thoughts on the extra power you gain? general thoughts? |
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| Author: | mini_mad_matt [ Sun Feb 17, 2013 5:54 pm ] |
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Haven't tried them personally but seeing as you can buy new weber carbs, it's not a waste of a weber, its just a waste of money (if you think it's a waste). Secondly, the hassle doesn't equate to the benefit? well that just depends on what you are doing. Hassle is really just time, and time is money. So really it's a matter of is the time and money worth it to you? If your car is a budget racecar, probably not, as there are probably more beneficial ways to spend your money. But if your car has the best of everything, then sure it's probably worth it. |
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| Author: | Smarty [ Sun Feb 17, 2013 6:36 pm ] |
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They are cheap http://www.minisport.com/mini-spare-par ... S2976.html and cool, go for it I say!! |
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| Author: | SuperCooper [ Sun Feb 17, 2013 8:33 pm ] |
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Wasn't the only point of split webers to do with an FIA ruling of not being allowed to use dual throat carburetors, so they used 2 chokes from separate carbs to get around it? Not sure it produces any more power, so unless you are building to some historic regulations its prob not worth it. |
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| Author: | Lillee [ Sun Feb 17, 2013 9:25 pm ] |
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If a single HIF44 or Dellorto/Weber 45 can make upwards of 120-150bhp, I don't see what the point of a split weber is other than what SuperCooper mentioned? |
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| Author: | drmini in aust [ Mon Feb 18, 2013 7:16 am ] |
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SuperCooper wrote: Wasn't the only point of split webers to do with an FIA ruling of not being allowed to use dual throat carburetors, so they used 2 chokes from separate carbs to get around it? Not sure it produces any more power, so unless you are building to some historic regulations its prob not worth it.
Yes the original use in 1968? was to get around the rules.. the twin SU manifold had to remain, so special tuning acquired (*cough cough*) a standard? pair of Webers which had special flanges to bolt onto it. Since then, Avonbar and others have made `straight shot' separate manifolds to bolt one and a half (ie a std + a butchered one) Webers on there for racing. Sorry I don't know anybody that runs one here, most in Nb or Nc use a long single manifold and single 45DCOE with good results (up to 162HP from a 5 port 1330). |
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| Author: | XC9000 [ Mon Feb 18, 2013 1:00 pm ] |
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[quote="Sorry I don't know anybody that runs one here, most in Nb or Nc use a long single manifold and single 45DCOE with good results (up to 162HP from a 5 port 1330).[/quote] CAMS for Nb (& I think same for Nc) state "Twin HS2 (1-1/4")"; then "Other period carburettors permitted (incl. Weber 45DCOE) subject to the integrity of the fireawall being maintained". My guess is you would be hard pushed to run the twin Weber set-up for Cooper S racing before December 1965. But I can advise that they are acceptable of a Groups C Cooper S, provided that it was set up that way when raced in the 1970s BUT that has to the actual car. That makes it very restrictive. Amal were run back in the 1960s. Phli Barnes ran 4# |
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| Author: | drmini in aust [ Mon Feb 18, 2013 1:35 pm ] |
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XC9000 wrote: Amal were run back in the 1960s. Phli Barnes ran 4#
I ran a pair of Amal Monobloc 1-3/16" (off a Triumph Bonneville) on my roady 1220 Mini in the `60s (it also had a 544 cam and a 940 head). The Amal's slide throttle linkage used to stick at idle, so you either stalled it on the line, or left the lights in a cloud of tyre smoke. 
Eventually I tired of this and fitted a pair of HS4s. Much more user friendly. But the Amals were so easy to tune. |
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| Author: | slide [ Mon Feb 18, 2013 6:04 pm ] |
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I thought I read once (in CCC magazine probably )that split Webers had the advantage of allowing a straighter run of the inlet manifold into the head, unlike a sinlge Weber manifold that tends to splay out a little the closer it gets to the head, and that this straighter inlet resulted in a small increse in torque. Does David Vizard express any views on this in his big book. Plenty of Sports Sedans ran split Webers in the '70s and '80s. |
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| Author: | XC9000 [ Mon Feb 18, 2013 7:09 pm ] |
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Another thing with the dual Webers is that the Nb & Nc historics has a defined firewall modification for the Weber air box allowing the single carburettor to fit in the 175mm high X 215mm wide and get some sort of manifold length; for what its worth. Dual Webers wont go in there. |
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| Author: | Bubbacluby [ Mon Feb 18, 2013 8:57 pm ] |
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just lengthen the engine steady, machine the remote gear extention, modify a twin 1 1/2 su manifold and bolt on twin DCOE's. No mods to firewall needed. |
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| Author: | GR [ Thu Feb 28, 2013 11:32 am ] |
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If these don't fit in your car, and cannot be used in Group N. Maybe you could try this setup... 
32 DCOF running 22mm chokes 
Graham Russell |
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| Author: | EN40B [ Thu Feb 28, 2013 11:43 am ] |
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nice set up - what advantage would having twin throttles running into one port have? |
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| Author: | 1071 S [ Thu Feb 28, 2013 6:09 pm ] |
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Bill Quine (Manx Racing) did this in reverse to make a 7 port head... Cheers, Ian |
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| Author: | drmini in aust [ Thu Feb 28, 2013 6:10 pm ] |
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Bill Quine's work- http://manxminiregister.com/manx-mini-a ... gallery=14 5 port head converted to 7 port- unlike a Pierce 7 port, you can [edit] easily get at the spark plugs with the carbs on! Not sure how good this setup was for HP- anybody know? [edit] check the thick bushes in the pushrod holes near the inlet ports...! 
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