astra 1.4 8valve lpg turbo.
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Schrödinger's cat - so which one am I ???

ok doke , bit of a test sesh ,

http://youtu.be/2GKHdI89Xfo

http://youtu.be/tTq4NEFhbpU


up to 30 psi ok with he 2.7 ohms. up to 44 psi , ok with the 1.8 ohms . max rated pressure from the regulator is 38 psi.

also checked temp rise , in 2 mins ,the 2.7 ohm rose from 14c to 25c.
the 1.8 ohm rose from 14 to 55c .not really hot to the touch .

amps with the 2.7 ohm were 1.99 A
with the 1.8 ohm were 2.47 A
with no resistor 3.39 A

also a bit about temperatures..

http://www.hondata.com/techlowohminjectors.html

Edited by robert on 13th Nov, 2012.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

having read back through the thread ,all these q are anwered ,some of them by me ?lol, what memory !

i have now got myself all confused ., if the ms2 has a pk and hold function ,why do peole use jeans board ? ahh is it so they can use all 4 channels for fully seq ,and then the board allows a pk and hold .whereas with its pk and hold function enabled ,the ms2 can only fire 2 channels ,so batch or semi seq.

so if i am happy with batch ,why not just use the pk and hold thats already in the box ?(my 'robert your saying stupid stuff here 'alarm bell just went off ).



right, so having ignored the above meanderings ..


another question ,can i run my 25 w resistors in parallel to feed each pair of inj with 1.5 odd ohms ?
eg 12v >> 2 res in parallel>>2 injector feeds.


also , if there are 2 injectors to each driver circuit ,the amps would not be dictated by the resistor and single injector ,but by the combination of the resistor and inj in parallel with the other injector and resistor .

so not the 4.5ohms from one inj and res ,but in parallel a total of 2.25 ohms . which with a 14v gives
6.22 A and 87 watts . not sure how that divides up between the injectors and the resistors ,but would the 25w reistors be getting a bit toasty ?

having said that ,the chap in my link was running a single channel with 4 injectors and 1 ohms resistors on it (i think), so thats a single combo of 4 ohms in parallel with 3 others....and nothing over heated nor nuffin ,so looks like a fair bit of leeways meltdown wise . he did 10k km with that setup ,and no probs .

Edited by robert on 14th Nov, 2012.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

The peak and "hold" function on the standard MS2 uses PWM (pulse width modulation) to generate the hold current.

It does this by using two of the CPU output pins to provide the PWM (square wave) signals then adds them on top of the two injector drive CPU pins with a logic chip.

This means the parameters (how long the peak is, and the duty cycle of the PWM bit) have to be set up in the software. No big deal, the instructions are all in the MS2 manual.

For my first build I used it that way and it works fine.
That was non-staged siamese sequential that works with 2 channels, once I wanted staged siamese I had to have 4 channels.

The possible issue is PWM is very noisy electrically - didn't affect me but it does some people - or at least some people have noise issues and the PWM is easy to blame.....

So you can have two basic reasons for switching over to either of Jean's boards (he does a 4 channel high z one as well),

1 - with the MS-Extra code you have access to the PWM CPU pins as two more injector drives, ie you can now have 4 channel fully sequential (including staged siamese for the A series).

2 - no noise, less parts and a much neater solution (even if you only want 2 channels). The less parts really only applies if you build yourself, all the un-neccissary parts are already installed in your case from how you've described it.

There are a few other technical advantages as well but I don't want to start a book :)

Yes two 3ohm resistors in parallel is 1.5ohms and add the power ratings together.

EDIT - typo

Edited by Rod S on 14th Nov, 2012.

Schrödinger's cat - so which one am I ???

ahh cool thanks rod ,so i can connect my 4 resistors of 2.7 ohms , in paralel pairs instead of buying 4 more 1 ohms .and use them to feed the two pairs of injectors ?

i should add , i imagine one wants to make sure that the pair of injectors fed by the paralleled resistors ,both go to the same driver !

Edited by robert on 14th Nov, 2012.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

If I've understood you right, yes.

Parallel pairs of resistors (making 1.35 ohms and 50w max power dissipation for the pair) feeding two injectors in parallel, connected to one channel, then repeat for the other channel.

In that configuration, each individual resistor will be dissipating less than 15W at 14V if the injector was open continuously, which it won't be, so more like 12W at a typical duty cycle.

Depending on how you intend to fire the injectors - you can't have fully sequential like this but I "think" there are variations on the batch mode alternatives - you will need to decide which cylinders you are pairing.

Don't forget to configure the MS2 as per the HIGH z instructions (ie, to defeat its PWM mode of operation).

Edited by Rod S on 14th Nov, 2012.

Schrödinger's cat - so which one am I ???

how do the numbers work out rod , if i run 1 2.7 ohm resistor to two 3 ohm injectors ?

two inj in parallel ,is 1.5 ohms ...... plus the 2.7r= 4.2 ohms . as opposed to 4.35ohms, with the other idea .

so im working it at 30 watts on the r1 and 16.66w on the injectors ..is that anywhere near correct ?

if so that would get a little toasty .

Edited by robert on 14th Nov, 2012.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

In did the maths on the resistors and injectors doubled up



If you run a single 2.7 resistor to a pair of injectors then you are probably about right... (I'll check in a minute).

More to the point, if you do it that way, you drop the current through the individual injectors and maybe compromise them openning.

Schrödinger's cat - so which one am I ???

with the setup of 2 parallel resistors and two inj ,it makes 3.47 A dropping to 3.34A. looks like thats the way to go rod .
oops looking at your da vinci diagram rod ,it looks like i must have measured that incorrectly. ill have another go.

ah it sort of works if you know that i am using 12 v bench power supply ,and my paralleled resistors add up to 1.8 ohms for some strange reason ,maybe because the conections are not soldered just wires popped through the holes in the pegs .

Edited by robert on 14th Nov, 2012.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Schrödinger's cat - so which one am I ???

got my jectors mounted and pipes on .sorry about the poor focus.

Edited by robert on 15th Nov, 2012.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

at low impedance around 1 ohm or less standard multimeter's struggle to give accurate readings, a "4-wire" method is needed, and obvo you want to try test at 14v as rod used buddy, those two volts can tip a component over the edge as thats a ~10% increase in current. Cant help but notice the presence of a petrol fuel rail, surely your not thinking of going dual fuel :)

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

wash your mouth out denis ...dual fuel ,,pppshawww.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

jees you lot have lost me now

give em hell

little bit of progress ,all ecu wiring done ,and the pc talks to the ms .still to do the inj wiring in the bay .

god knows who decided to use a tiny row of pins and diddy plug on the ecu.needs to be about twice the size and proper click lock.bah .


very happy with progress so far ,just need to get circulation back in my knees .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Schrödinger's cat - so which one am I ???

i know rod , im just having a grizzle ,i think i may have used a slightly bigger wire for the plug than normal .but hey , it all fits in ,and thats what matters .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Schrödinger's cat - so which one am I ???

i did have to remove the retaining clamp lugs in the plastic chrome case ,and stick a big zip tie in there for restraint .so its not all plain sailing using 6 amp wire . :$

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Theo looking on with discontent, as is a cats prerogavtive :)

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

That pose reminded me of this:

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Schrödinger's cat - so which one am I ???

I just took an absolutely perfect picture of my cat, trying to sleep in the lounge in her favourite spot....

One eye half openned and a filthy look when I deployed the camera...

Auto-focus worked, auto-everything else worked, the camera made realistic artificial noises of shutter, film winding on etc, displayed a perfect picture, then displayed in the viewfinder "no card".....

Cat got up and walked away whilst I went looking for the SD card.

Schrödinger's cat - so which one am I ???