rubber carb mounts

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james butler
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rubber carb mounts

Post by james butler » Wed Mar 07, 2012 7:44 am

all those with weber 32/34 dmtl conversions.
im in the process of maufacturing an aluminium carb mount to replace the forever splitting rubber one, has anyone noticed that there is a large restriction in the weber baseplate where it sits on the rubber one? under the larger butterfly flap there is a 45 degree chamfer to get it to fit on the rubber carb mount.
as im making an entirely new base plate im going to delete the protruding alloy by machining it as i think (by looking at it) this would help the carb to manifold flow better, i will try take some pictures when i get chance to show you all what i mean, hopefully you will get the idea though.
what im wondering is will i get better power gains from the weber? i know with this carb im not really going to get any real power gains but looking at this restriction made me think this could be why its so limiting.


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Nate
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Re: rubber carb mounts

Post by Nate » Wed Mar 07, 2012 9:41 am

if i'm picturing it right, then yes it should smooth the flow from carb to manifold, and theoretically this should improve the power output. probably by a measurable amount, but probably not my a noticeable amount.

if you're going to that effort, might be worth shaving your hedgehog too


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james butler
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Re: rubber carb mounts

Post by james butler » Thu Mar 08, 2012 7:23 am

cool cool, yeah ile give it a go and let you know how i get on.
im also planning to put in a gti cam as well but ile do the carb first to see if theres any difference in performance.


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MacColl
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Re: rubber carb mounts

Post by MacColl » Thu Mar 08, 2012 7:31 pm

This is interesting :yup:

When I converted my 1.3 Mk2 Polo from Pierburg to Weber DMTR carb (very similar to the DMTL we use) it had this adapter plate with it's gasket block..
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The adapter plate had a limiting wedge in it that i cut out. I actually shaved my hedgehog at that time also. I suppose it's about having a smooth transition into the inlet manifold which was certainly achieved with this set up.

looking forward to see some pictures :good:



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james butler
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Re: rubber carb mounts

Post by james butler » Sat Mar 10, 2012 10:04 am

took the car out last night with the new mounting block, its definately made a differance it feels more responsive and has better top end at full throttle. however will need to retune the car again now i dont have them pesky air leaks. once the car had warmed up i even had to unscrew the throttle stop to lower the idle speed to the point the screw nearly fell out to achieve 850rpm.
the car itself runs much smoother, i think to be honest ive been messing around with other parts of the car to cure misfires and general poor running when all i think it actually was, was this bloomin rubber gasket all along. im going to retune ma car all over again.
cant wait to get that gti cam in next!!!!
pics will follow am trying to get them off my fone but its not playing ball atm. :ire:


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james butler
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Re: rubber carb mounts

Post by james butler » Mon Mar 12, 2012 10:21 pm

heres some pictures of the new carb mount i made. i laid the new one over the old one to show you the differnce in size and how it fits on the carb better.
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MacColl
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Re: rubber carb mounts

Post by MacColl » Tue Mar 13, 2012 12:36 am

I am well impressed :good: When are you doing a group buy? :hugegrin:

It must increase power. I watch Nascar racing where they put a limiting plate with smaller holes sandwiched in between the inlet and carb/or now injection. This reduces the top speed for superspeedways creating the mad pack racing.

Anyway I'd possibly have a bash at making one, I suppose it would really need to be alloy? did you use a post drill and milling machine or router of some sort?
I've only really got a post drill, grinder and a bunch of bastard files :chortle:



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james butler
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Re: rubber carb mounts

Post by james butler » Tue Mar 13, 2012 9:11 am

yeah made it using a milling machine to get the shape n size then a piller drill to drill the holes then files and sandpaper to shape it best as i could.
one thing tho it is made out of alloy so when you machine it out and sand it you really need a face mask! alloy dust is the worst apparently.
took about 8 hours to make but that was me fannying over the milling machine, as there are so many handles to accidentally turn the wrong way and scrap my work.


I dont mind project cars but I HATE SANDING!!!