mantaboy89 Posted January 20, 2013 Share Posted January 20, 2013 Has anyone used su carbs on a cih engine, about to start rebuilding a 2.2 for my manta, just wondering what fuel system to go for. Megasquirt, twin 45s? But as i have two su carbs sitting around i was wondering how they would perform on a cih motor. anyone got any info or tried this before. Any help would be much appreciated. Thanks Josh Quote Link to comment Share on other sites More sharing options...
rutts Posted January 20, 2013 Share Posted January 20, 2013 i have seen a manifold with twin 2inch su carbs gaz watson had it and sold it on ebay about 5 years ago, never saw them run an engine though but should be up for the job. Quote Link to comment Share on other sites More sharing options...
Shuviteer Posted January 20, 2013 Share Posted January 20, 2013 Had a set on an engine in a Chevette,,bloke I bought it off had made up an inlet manifold, worked a treat. Quote Link to comment Share on other sites More sharing options...
mantaboy89 Posted January 20, 2013 Author Share Posted January 20, 2013 Any idea what power it was putting out? Quote Link to comment Share on other sites More sharing options...
Retro Power Posted January 21, 2013 Share Posted January 21, 2013 would have thought they'd be a good option on a road rally engine, nowt wrong with SU's Quote Link to comment Share on other sites More sharing options...
mantadoc Posted January 22, 2013 Share Posted January 22, 2013 SU carbs properly set up give the best performance and fuel economy of any carb, historically only bettered by injection. Also they have don't have the issues of fixed choke carbs where you snap the throttle open wide, air speed drops and you get a flat spot, that is why fixed choke carbs generally have an accelerator pump, to squirt in neet fuel as your foot goes down to try and cover the flat spot, and SU do not. Quote Link to comment Share on other sites More sharing options...
mantaboy89 Posted January 22, 2013 Author Share Posted January 22, 2013 the su's I have are from a 3.5 rover. Is there much work needed to get these to run nice on a cam'd 2.2 cih? Quote Link to comment Share on other sites More sharing options...
lamchop77 Posted January 22, 2013 Share Posted January 22, 2013 They will be 2 1/4 or 2 1/2 won't they. I work on the fact that 2 of those ran a 3.5 therefore you will be able to jet down to run on a 2.2. I think they have to be mounted fairly level so you might have a few probs with the intake to get clearance above the exhaust. Think the float chambers are on the base of the carb (if they are the HIF 44 style of carb anyway!!) Chris Quote Link to comment Share on other sites More sharing options...
mantadoc Posted January 22, 2013 Share Posted January 22, 2013 A singlw 1 1/4 used to power 1000cc / 38 BHP of mini. A single 1 3/4 used to do a 1275 / 93B BHP Metro Sounds like 2 of 1 1/2 woul be a good balance of size to CC and BHP but as variale choke you don't have the issues of going too big like you do with fixed choke carbs. If I remember rightly the late 1 3/4 was a lot more complex than the tradiotional simple older ones so I would not go there. I think the 1275 cooper engines thathere passed through my hands, a couple had the twin 1 1/2 but probably a lot cheaper to get separately than that specific sought after setup but seeing one will show you how they were linked and balanced (rods not cables) but of course there are lots of ways to do it. Quote Link to comment Share on other sites More sharing options...
tony g Posted January 22, 2013 Share Posted January 22, 2013 They will be 2 1/4 or 2 1/2 won't they. I work on the fact that 2 of those ran a 3.5 therefore you will be able to jet down to run on a 2.2. I think they have to be mounted fairly level so you might have a few probs with the intake to get clearance above the exhaust. Think the float chambers are on the base of the carb (if they are the HIF 44 style of carb anyway!!) Chris I think because they were on a Rover v8 they would be angled (facing each other) so the float height would be ok if mounted at the same angle. Re jetting and different needles would be needed i reckon, but as a starting point they wont be too bad. Tony Quote Link to comment Share on other sites More sharing options...
mantadoc Posted January 22, 2013 Share Posted January 22, 2013 The casting in the side body usually allows the float chamber to be swivelled to sit correctly on the older ones Quote Link to comment Share on other sites More sharing options...
rutthenut Posted February 26, 2013 Share Posted February 26, 2013 I think I may have a pair of manifolds to fit SU carbs onto the CIH engine, somewhere in my bitsa box in the garage. Think they came from EARS, a very long time ago, when I had a Cav Coupe 1.9. Never fitted those though, as I then got a GT/E instead. If interested, I will try hunting to see if I do still have them. Quote Link to comment Share on other sites More sharing options...
mantaboy89 Posted March 3, 2013 Author Share Posted March 3, 2013 Yeh mate very interested. Pm sent Quote Link to comment Share on other sites More sharing options...
rutthenut Posted March 8, 2013 Share Posted March 8, 2013 Still to look for these - will let you know when I get a chance to hunt through the boxes of bits in the garage Quote Link to comment Share on other sites More sharing options...
rutthenut Posted March 17, 2013 Share Posted March 17, 2013 (edited) As per pm, I have found the SU manifolds, which were from PMC (Peter Maiden Cars) when I had a 1.9 engined Cav Coupe, or Manta coupe. Not sure which, it matters not. I never got to run the car with them anyway. Will upload some pictures so you can see what they are like. See http://www.flickr.com/photos/rutthenut/8565182925/ and http://www.flickr.com/photos/rutthenut/8566306462/ and also http://www.flickr.com/photos/rutthenut/8566342050 which includes an old SU carb and some odd brackets too In the same box of bits, I also found that I have another manifold to go with a sidedraught Weber DCOE (or Dellorto DHLA). Better still, this even has a Weber carb attached to it. That was a brand new carb, though many years ago. Also unused. Think that was my failed build of a Manta rally car. Will post photos of that manifold + carb to see if that is of interest. Edited March 17, 2013 by rutthenut Quote Link to comment Share on other sites More sharing options...
rutthenut Posted March 17, 2013 Share Posted March 17, 2013 In the same box of bits, I also found that I have another manifold to go with a sidedraught Weber DCOE (or Dellorto DHLA). Better still, this even has a Weber carb attached to it. That was a brand new carb, though many years ago. Also unused. Think that was my failed build of a Manta rally car. Will post photos of that manifold + carb to see if that is of interest. Also found a downdraught carb from the past, guessing/recollecting it is a Weber 28/36 DCD, if of any interest to Manta owners, See http://forums.mantaclub.org/topic/33082-manta-cih-weber-twin-choke-downdraught-carb/ Quote Link to comment Share on other sites More sharing options...
mantaboy89 Posted March 18, 2013 Author Share Posted March 18, 2013 Hi mate. Pm sent regarding su carb manifold and linkages. Cheers Quote Link to comment Share on other sites More sharing options...
rutthenut Posted March 19, 2013 Share Posted March 19, 2013 SU manifolds/brackets now on the way to mantaboy89 - be interested to see how well you find the setup to work. Quote Link to comment Share on other sites More sharing options...
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