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staged injection on megasquirt
richyb - 30/3/09 at 01:08 PM

Thinking of setting this up in my bike throttle bod conversion. has anyone done this with 2 sets of injectors (standard zetec fuel rail and bike set up) on megasuirt. if so is it easy to set up, and how are the 2nd set of injectors connected on the ecu ?

struggling to find wiring/set up info on MSquirt site. thanks

BenTyreman - 30/3/09 at 01:12 PM

Megasquirt only has 2 banks of injectors. You would have to use one bank for the head injectors and one bank for the throat injectors.

Unless you have a very small set of head injectors (unlikely if they are standard Zetec ones), you will suffer from poor tunability at idle and low throttle openings.

cd.thomson - 30/3/09 at 01:47 PM

Hi Ben,

who made that airbox for your ecotech? Im after something similar for my XE, the pipercross ram air is very expensive!

MkIndy7 - 30/3/09 at 02:49 PM

quote:
Originally posted by BenTyreman
Unless you have a very small set of head injectors (unlikely if they are standard Zetec ones), you will suffer from poor tunability at idle and low throttle openings.


You can have megasquirt running on the standard head injectors (which are already appropriately sized) at low rev's, vacume or TPS and then switch over to the TB injectors or run them as well at the higher switch point you chose.

As said there's only 2 injector drivers on MS so you have to have them firing simultaneously.
Unless they've updated it don't use the swiching over calculations for the fuel from the Megasquirt manual they are wrong, use the values from the Megatunix software or manual, can't remember wich.

flak monkey - 30/3/09 at 03:22 PM

I looked into this for my duratec and rapidly decided it was too complicated and just bought some bigger injectors to fit into the head from the states and will blank off the throttle body holes. A complete set worked out at around £100.

David

clairetoo - 30/3/09 at 04:17 PM

I've been wondering about this for a while - using the normal injectors for low throttle / around town driving , and and then for higher speed stuff having a second set mounted up stream of the butterflies (F1 style...)
Something like this.....


[img][/img]

BenTyreman - 30/3/09 at 06:53 PM

quote:
Originally posted by cd.thomson
Hi Ben,

who made that airbox for your ecotech? Im after something similar for my XE, the pipercross ram air is very expensive!


I made a cardboard template and folded it up out of some spare aluminium. It's sealed using PU flex and it connects to the throttle bodies and air filter with fibreglass trumpets.

It should be about twice the size but I can't fit anything bigger.

quote:
Originally posted by MkIndy7
You can have megasquirt running on the standard head injectors (which are already appropriately sized) at low rev's, vacume or TPS and then switch over to the TB injectors or run them as well at the higher switch point you chose.

As said there's only 2 injector drivers on MS so you have to have them firing simultaneously.
Unless they've updated it don't use the swiching over calculations for the fuel from the Megasquirt manual they are wrong, use the values from the Megatunix software or manual, can't remember wich.


The original injectors are designed to be used sequentially. If you run them on a single bank then you need to run 4 squirts simultaneous to get equal fuelling on all cylinders. You will probably end up with a pulse width somewhere around 1.3 ms.

1.0 ms is opening time, so you will suffer from large opening time errors, large AFR changes with each VE cell change and problems with injectors varying between cylinders.

Ideally you would fit smaller injectors at the head to get good low throttle opening characteristics, then large injectors down the throat to provide enough for the total HP of the engine. Or look into the sequencer board to provide sequential firing.