M20B25 downdraft weber idf build ideas

[DoctorDrift]

Hello guys im in the process of planning an m20 with webers. i know you will all be thinking why bother turbo is better etc but this is what i want to do becauae i love carbs and cant go forced induction if i want to enter my local sprint and hillclimbs in roadgoing which i do so please dont suggest alternatives.

now my biggest potential issue is spark. will my standard dizzy work with the carbs? if not could i use an older dizzy set up for example an e21 m20 dizzy with vacuum advance?

i will also be having headwork and a stronger cam fitted. cant increase capacity because it will be against regs and .
i will have to go up a class otherwise.

any help/advice is appreciated, thanks

[freeflow]

Hi,theres no reason why you cant use your existing spark set up,the ECU is,nt clever enough to know there,s something wrong if the injector plugs are not connected and the ignition will run as normal.
The only downside i can see is you will be running on the standard ignition map,not one that is optimised for your engine set up.On this score i would ditch the whole motronic set up and use a spark only programable ecu,this way it can be mapped to the optimum for your engine and carbs , cam etc.
The spark ecu,s a re not expensive and we keep them in stock.

cheers Keith

[Speedtouch]

See these links:

http://www.e30zone.net/modules.php?name ... c&t=153473

http://forums.bimmerforums.com/forum/ar ... 90331.html

I have previosuly seen BMW E30s with Webers, using the old block-mounted distributor as fitted to pre-facelift chromie 320i and 323i models.

[DoctorDrift]

interesting link guys thanks. i think programmable spak is defo way to go like you say but just as a top gap it might be easy to use 320i dizzy.

in terms of manifolds anyon know of any downdraught ones out there. ive been searcging alot but no luck guessing custom might be the only way

[Speedtouch]

http://www.piercemanifolds.com/

[DoctorDrift]

thanks, i had previously searched that supplier before it seems they only have sidedraught manifolds though. im quite keen to have downdraughts so i can have huge trumpets out the bonn
et (ha ha joke!

to be honest if its not easy to get a downdraught tone then i will just go for the dcoes but just prefer how the downdraughts look in the bay.

in terms of headwork i have read that the stadard m20 heads are quite good but there is perhaps about 10% gain to be released with a good bit of headwork. who are the best people when it comes to m20 heads? i live in cornwall and know shillabear in launceaton has a good reputaion for fords has anyone used him before for bmw stuff.

thanks again in advance

[Speedtouch]

Someone's fitted IDFs, using an Alpina manifold:
http://forums.bimmerforums.com/forum/sh ... p?t=956480

http://www.rtsauto.com/fuel-injection-t ... le-bodies/