Just read the thread 'cheap motor', there seems to be a bit of worry about engine looms and carbs.

Is there any reason why you cannot use a car sourced injection system complete to feed a bike engine (I one put a 1 1/4" SU on a CD200 for a mate who couldn't find a replacement Helheim!!). Could you also use 4 coils instead of the CDI thingy if you could sort out the advance/retard dilema if it was not sorted by the car sourced ECU?

I know you would have to make you own manifolds, but that has never been a problem for most of us.

Just a thought, but it would solve a lot of car/bike compatability problems (and costly bike stuff)

when i read that thread my thoughts went to my old pal who works for a transatlantic shipping company!

too much effort for me to be arsed though, but someone will get rich.

as for making injectors etc, beyond me but sounds like a good plan if you can! mayaswell get rob lane on the diy chips whilst you're at it!

car mfrs spend yonks on getting efi maps just right. mixture depends on revs, engine speed, vacuum, air volume, air temp, engine temp. probably more.

it just seems way too simple to throw an efi form any old engine onto any old engine.

same for doing your own from scratch.

I have no doubt the engine would run 'in a fashion' but wether it would run as good as std carbs for that engine, I severely doubt!

given access to a rolling road and diagnostics stuff, you would have a better chance....


ford efi from sierras and the like is a simple single channel system. even my V6 only has two injection outputs - 3 cyls get a squirt at the same time. So from that point of view its not complex. does bike efi have a simple scheme or do all injectors just have their own control line......would be a bit over fuelled if not!



atb

steve


[Edited on 28/12/03 by stephen_gusterson]

I think with all the cylinders having there own coils inside each plug cap the easiest way is to use the ECU that comes with the bike.
To set it up with another ignition would cost as much as byeing all the original parts, err... I think!

Steve

Guys,

Remeber that at 12,000 RPM (not uncommon on a BEC) you've only got 10 ms to get the fuel in the engine. Also, most car EFI ECU's couldn't cope with engine speeds over 10K RPM (and to still have some adjustability, the injection time at 12K rpm would have to be 8 to 9 milliseconds--> FAST injectors), so even if you could remap it you would lack the timing precision (just think about the ignition!) to get things running right. You'd need some pretty low resistance ignition coils too!

To sum it all up, i think it would be simpler and cheaper to pay a little more for a complete engine. if you can't afford to do it properly, don't do it at all.....

You can buy a set of used carbs for under £100 so it could still be a cheap engine option. The wasted spark system used on road bikes would be the simplest way to go about the ignition, two coils with two outputs each.

yours, Pete