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Changing over to bike TB's from DCOE's
steve allen - 17/12/05 at 09:11 AM

Sure someone will put me right on this subject, Due to poor running on 45 DCOE's I'm thinking of changing over to TB's, this seems now to be a regular thing, my concerns are i dont really know what i'm doing or what i need, can anyone advise, : What bike carbs would be best to run a Zetec, : what wiring would i need to get with the carbs,: Inlet manifold, i take it you just buy one fabricted to suit, (seen a few on Ebay etc) ECU - something like a Megasquirt - but how difficult are they to wire and programme. is this something that I could do myself!!!.
Just want a sweet running car that doesn't need setting up every couple of weeks.
Cheers Steve

Browser - 17/12/05 at 10:29 AM

Just a thought but, have you ever had the DCOEs set up on a rolling road run by someone who knows what they're doing? It can make the world of diffference. How old are the Webers though? If they were 'used' when you bough them, might be better to go the TB route. Have you thought about converting the DCOEs into TBs? Might be simpler as far as getting them to fit the cylinder head?

donut - 17/12/05 at 10:31 AM

What about normal bike carbs? Surrey Dave runs some on hic CVH and says they run sweetly! I'll be doing the same with my pinto at some stage. Alot cheaper than TB's.

steve allen - 17/12/05 at 01:02 PM

My DCOE's are from new and have been to three different rolling road centres, when set they are okay but progression has never been brilliant, not on the zetec anyway. just thought the TB's would be an easier and cheaper option, How would you covert DCOE to TB's as mentioned.

rayward - 17/12/05 at 06:40 PM

gsxr750/100 TB's are correct spacing and Bore for a zetec, you'll need a manifold, and probably best to run Megasquirt N Spark Extra..

Ray

James - 17/12/05 at 07:12 PM

Steve,

Are you talking about using Bike carbs or Bike injection throttle bodies? Or DIY'ing bike carbs into ITBs?


I'm planning to fit injection throttle bodies post SVA and using megasquirt. Bought a set of GSXR750 bodies for £75.
750's are overkill though at 42mm for a Pinto or Zetec.
You'd want 600s for your Zetec I'd have thought.

HTH,
James

stevebubs - 17/12/05 at 09:49 PM

quote:
Originally posted by steve allen
My DCOE's are from new and have been to three different rolling road centres, when set they are okay but progression has never been brilliant, not on the zetec anyway. just thought the TB's would be an easier and cheaper option, How would you covert DCOE to TB's as mentioned.


If progression isn't that good, are they changing the emulsion tubes?

Take a look at the follow sites:

http://www.furyworld.fsnet.co.uk/Crossflow.html
http://members.aol.com/dvandrews/

If you've 45s on a zetec then I think the top end will great, but you have a choice between top end and low-mid grunt. For the latter, you'll probably need either to change to smaller chokes or 40s

(or change to ITBs)

Browser - 18/12/05 at 09:06 AM

quote:
Originally posted by steve allen
How would you covert DCOE to TB's as mentioned.


The now-defunct Cars And Car Conversions magazine showed this with their engine guru Dave Walker doing a conversion on some old DCOE 40's. Basically he (for appearances sake) milled off the float chamber and stripped off all of the uneccessary hardware (accelleration pump, idle bypass screws etc), he then filled in all of the holes which originally went through the bodies (progression drillings etc) and painted them up. People who have followed his example since have actually sawn the carb bodies in half as the 'front' half isn't really required, you only need the butterflies.
Having said all of this, since you bought them new and since Weber 45's aren't as easy as they used to be to get hold of, you'd be better either:
(a) selling them and buying a throttle body kit.
(b) keeping them but getting mapped ignition. This may help fill in some of the 'holes' in the power delivery.
(c) selling them and buying some bike TBs and a mapped ignition/injection ECU.
Hope the above is some help