flak monkey
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| posted on 6/11/09 at 11:38 AM |
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Megasquirt and staged injection?
Any one know or done staged injection with megasquirt?
So running 8 injectors on a 4 cylinder engine. Smaller ones at idle then bring in another set of larger ones at higher revs and keep both sets
running.
I know Emerald ECU's can do it, but can the MS?
Sera
http://www.motosera.com
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coozer
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| posted on 6/11/09 at 11:55 AM |
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I asked Phil at efiextra the same as I have 8 injectors on my set up.
MS can control as they go up to a v8 engine but he reckoned it was a waste of time on a car engine and only really applicable to high revving bike
engines.
So, the second set on mine will be purely cosmetic for the time being and I'm relying on the original ST set to do all the fueling... for
now
1972 V8 Jago
1980 Z750
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r1_pete
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| posted on 6/11/09 at 12:03 PM |
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How about using a relay on one of the user outs to power the second set of injectors at a pre determined speed.
That way they can be run with the same trigger as the primaries, but will do nothing until the relay kicks in and powers them.
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flak monkey
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| posted on 6/11/09 at 12:09 PM |
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The main reason for asking is basically as I have 410cc/min (@37.5psi) injectors at the moment. Although I will probably be running at 44.5psi (3bar)
which increases the flow rate to 500cc/min.
I am thinking that this might lead to problems at idle although I run HR code as well.
So what I was thinking was running the smaller bike injectors at idle then bring the bigger ones in as the revs rise. 500cc/min alone should be enough
for 400bhp so I dont necessarily need to run both sets of injectors at the higher revs, so if necessary I could just switch between them
Sera
http://www.motosera.com
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r1_pete
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| posted on 6/11/09 at 12:12 PM |
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How about an adjustable regulator to limit pressure at idle? sensing the vacuum.
[Edited on 6/11/09 by r1_pete]
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tomgregory2000
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| posted on 6/11/09 at 12:15 PM |
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quote:
Originally posted by r1_pete
How about using a relay on one of the user outs to power the second set of injectors at a pre determined speed.
That way they can be run with the same trigger as the primaries, but will do nothing until the relay kicks in and powers them.
I dont think it is a simple as that as you need different flow rates at different engine loads, throttle angle, not just different rpm
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tomgregory2000
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| posted on 6/11/09 at 12:19 PM |
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quote:
Originally posted by flak monkey
The main reason for asking is basically as I have 410cc/min (@37.5psi) injectors at the moment. Although I will probably be running at 44.5psi (3bar)
which increases the flow rate to 500cc/min.
I am thinking that this might lead to problems at idle although I run HR code as well.
So what I was thinking was running the smaller bike injectors at idle then bring the bigger ones in as the revs rise. 500cc/min alone should be enough
for 400bhp so I dont necessarily need to run both sets of injectors at the higher revs, so if necessary I could just switch between them
The injectors on my nissan are 740cc and when i heard it running in the car pria to it removal it would idle fine even with those fitted
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flak monkey
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| posted on 6/11/09 at 12:23 PM |
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quote:
Originally posted by r1_pete
How about an adjustable regulator to limit pressure at idle? sensing the vacuum.
I have one of those, which is 1:1 ratio.
So every PSI of change in the vac reference port it changes the fuel pressure by that amount as well.
So at atmospheric the fuel pressure will be 44.5psi. With 1 bar of boost the fuel pressure will rise to 59.2psi (increasing the flow even more to
525cc/min). At idle (assuming 30kpa) the fuel pressure will be 35psi and the injector flow rate 410cc or there abouts
Sera
http://www.motosera.com
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brianthemagical
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| posted on 6/11/09 at 12:24 PM |
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Sme of the MS ECUs will do it. It should be under the heading 'staged injection'.
Wether r not it's needed is another matter.
What kind of engine specs are you running? Induction, N/A, size, max rpm, max power, that kind of thing.
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graememk
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| posted on 6/11/09 at 12:40 PM |
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have you tried using "Bing" ?
1:1 reg maintains the pressure across the injector so the flow stays the same.
i would suggest you build it first and solve the problems as and when you get them, you appear to be creating more problems before you have even
turned the key.
i can not see why you would suffer with bad idle with 400 injectors unless you have the incorect flywheel weight.
[Edited on 6/11/09 by graememk]
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flak monkey
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| posted on 6/11/09 at 12:59 PM |
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Thanks graeme, just keeping my options open 
Whatever the ratio is then, is changes the fuel pressure as i said above lol.
Sera
http://www.motosera.com
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turboben
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| posted on 6/11/09 at 01:05 PM |
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I tried the staged inj on ms for a while but the transition never seemed that smooth so I swapped to dual table.I ran the second set only on boost and
divided the ve table no.s between the two. All so I could use the stock 270cc units that I had! Now I've got some 525cc injectors a it runs fine
with just 4.
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djtom
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| posted on 6/11/09 at 01:48 PM |
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I've been running 440cc injectors on my MSnS v3 running the HiRes code - idle is rock solid, so I don't think you have to worry too much.
I was also thinking of doing the same as you and adding the bike injectors back in
when I run out of PW on the big ones though, as inevitable rises in boost will no doubt bring me there sooner or later!
Tom
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MikeRJ
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| posted on 6/11/09 at 03:40 PM |
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quote:
Originally posted by flak monkey
I have one of those, which is 1:1 ratio.
So every PSI of change in the vac reference port it changes the fuel pressure by that amount as well.
So at atmospheric the fuel pressure will be 44.5psi. With 1 bar of boost the fuel pressure will rise to 59.2psi (increasing the flow even more to
525cc/min).
It doesn't work like this if you are injecting into the pressurised part of the inlet (e.g. cylinder head ports). The flow of an injector is a
function of the pressure drop across the nozzle; a 1:1 regulator simply compensates for 1 bar of boost trying to push the fuel back up the injector by
increasing the fuel pressure by the same amount, so it gives you the same flow under all conditions. You need a rising rate regulator to get more
flow with increasing boost.
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