DIY_EFI Digest V4 #570

[Ade + Lamb Chop]

At 15:00 09/10/99 -0400, DIY_EFI Digest wrote:
>Subject: RE: How completcated does Efi HAVE to be? Not that complicated!
>Bosch LE/LE2 based systems have been taking EFi trigger signals from the
>ignition for years..

That is good to know.

>Don't lose sight of the big problem with mini's - siamesed ports! For those
>not so familiar, the head has two inlet ports which each split in two to
>feed two inlet valves; Cyls 1&2 are fed by one inlet tract and cyls 3&4 fed
>from the second. Throw the firing order into the equation, and you will
>appreciate the problem of mixture distribution, specially from a throttle
>body injection arrangement. for this reason, Mini's run with uneven mixture
>across the cylinders even with carbs that feed fuel into the airstream
>continuously. Consider what happens when you inject pulses of fuel into the
>airflow way back at the throttle body, synchronous with the engine cycle.
>This is why I believe some (if not all) TBi sytems inject 'asynchronously'
>(randomly?). Certainly Vauxhall/Opel Multec TBI systems inject 5 pulses per
>cycle to try and spread out the uneven distribution so that each cylinder
>gets a fighting chance of seeing reasonable mixture on average.

Carbs manage it acceptably I was thinking of just streaming fuel in the
same way carbs do. After all Tbi is just a carb with an injector controled
by a processor rather than 'machincal means'

>Don't let this put you off - Rover obviously achieve reasonable results;
>indeed if you 're not using the 'A' series engine, and you've got an 8-port
>head, then please bung this message in the bin...

SU carbs have been doing it for 40 years!!! 8 port!! Don't be silly!!
<shiver> :-)

Mind you there are the Arden heads 8 port X flow/8 Valve and KAD 16V alloy
heads But if I had that sort of money I would need to ask you lot would I!!!

Thanx,

Ade