m20 b25 on bike carbs

[adam-325i]

what else would i need for a itb setup. i know i need two sets of bike carbs and a suitible inlet manifold the only part im not sure on is. do i need to have an aftermarket ecu for spark or can it be done with out ? any advise is welcome

[handpaper]

The standard Motronic ECU will happily provide sparks for you, whether they'll be at the right times is another matter!
I'm actually doing something similar, with LPG through a mixer (think big single gas carb). I'll be shorting the throttle position switch in the WOT position as this map suits LPG advance needs.
You could do something like this, though I'd advise getting a proper remap done.
Motronic could probably even handle alpha-n (projected airflow by throttle position) with a suitably calibrated throttle pot!

[HairyScreech]

http://www.mtechautomotive.co.uk/engine-management/

Ring these guys and ask about the NODIZ spark unit, it has been designed to allow injected engines to run with carbs for some racing categories etc.

I'm not sure if they are in production yet but if you give them a ring and say simon with the e30 sent you there way then you might get some info.

Tbh though i would advise against using bike carbs unless you have a very specific reason for doing so.
The carbs will give less efficient/accurate fueling during transient throttle, worse fuel atomisation anywhere other than peak port air speed and no ability to cut fuel on overrun.
It is a quick way to loose fuel economy, lowspeed tractability and low speed torque for a modest gain at peak hp.