Low Imp Injectors

General support questions and announcements for MS3. See also www.ms3efi.com for MS3 information

Moderators: jsmcortina, muythaibxr

Re: Low Imp Injectors

Postby JAM » Sat May 19, 2012 4:47 pm

thanks. Count me on the list, i will buy when they are ready. will there be a case for this board?

Can you comment on my opening time question above?
"The only thing you can buy at Jegs is the same thing everybody else has"
http://www.msruns.com/viewtopic.php?f=97&t=23284
JAM
Master MS/Extra'er
 
Posts: 583
Joined: Sun Jan 22, 2006 7:58 pm
Location: Cincinatti,OH

Re: Low Imp Injectors

Postby racingmini_mtl » Sat May 19, 2012 5:23 pm

Yes there will be a case.

And the problem is that it is difficult to generalize because not all low Z injectors react the same. However, the p&h drivers will give more consistent results under all conditions simply because of the current sensing and the fact that you have a lower hold current. With resistors, you have to choose a resistance value that is a compromise between opening the injector under most battery voltage conditions and that keep current low and closing time reasonably short.

Jean
jbperf.com Main site . . . . . . . . . . . . . . . . . . . . . . jbperf.com Forum
Image
racingmini_mtl
Super MS/Extra'er
 
Posts: 6531
Joined: Sun May 02, 2004 6:51 am
Location: Quebec, Canada

Re: Low Imp Injectors

Postby JAM » Sat May 19, 2012 7:43 pm

racingmini_mtl wrote:Yes there will be a case.

And the problem is that it is difficult to generalize because not all low Z injectors react the same. However, the p&h drivers will give more consistent results under all conditions simply because of the current sensing and the fact that you have a lower hold current. With resistors, you have to choose a resistance value that is a compromise between opening the injector under most battery voltage conditions and that keep current low and closing time reasonably short.

Jean

Thanks Jean, that is how I understood it. Thanks for the verification. For my application I believe it is the best method.
"The only thing you can buy at Jegs is the same thing everybody else has"
http://www.msruns.com/viewtopic.php?f=97&t=23284
JAM
Master MS/Extra'er
 
Posts: 583
Joined: Sun Jan 22, 2006 7:58 pm
Location: Cincinatti,OH

Re: Low Imp Injectors

Postby Fabio421 » Mon May 21, 2012 6:53 am

Thanks for your advice. First, let me say that electronics aren't my strong suite. I have a few more questions. When batch firing the injectors, is it necessary to use a resistor for each injector or can you use one resistor for each bank? If I were to use the P&H board from racingmini, how do I mount this? From what I can tell from reading the site, I would need two boards to run 8 injectors. Am I correct that these two boards will not fit inside the MS3x box? Would I have to build a seperate box for these? Is this available somewhere commercially?

Regarding someones earlier post that I should switch to high Z injectors. The car is a 1982 Porsche 928s that I have turbo charged. I plan on using high Z injectors later on in the build but I'd like to adapt to the stock fuel system first. The stock fuel injection on this car uses low Z and I have found and fitted some larger than stock low Z injectors. This car has Bosch L-Jet which uses low Z, barb style injectors. These are very rare birds. They use a small hose between the fuel rail and the injector. I've just finished machining some custom rails and hold downs that will utilize the high Z injectors but I have more to do. I still have to build and route all of the fuel hoses, regulators, dampners, hard lines, etc. I thought that it would be nice to go ahead and temporarily use the stock fuel system and adapt the MS3x to it to allow tuning. Later on, I would pull off the stock system because my plan is to use E85 ethanol and these 29LB injectors don't flow enough to support that. The L-Jet fuel system w/ MS3x controller will then be fitted to an older Porsche 928 that I have that currently has mechanical CIS fuel injection.

I appologize for all the noob questions. I'm just getting into this so I'm learning as I go. I appreciate all of your help.
Fabio421
MS/Extra Newbie
 
Posts: 3
Joined: Thu Sep 08, 2011 6:21 am

Re: Low Imp Injectors

Postby racingmini_mtl » Mon May 21, 2012 6:57 am

With an MS3/MS3X, the simplest solution for p&h drivers is to use the external box version. This is the one I have at this time: http://jbperf.com/p&h_board/v2_0.html#Buy. And you will need 2 of them since they only have 4 drivers per box.

Jean
jbperf.com Main site . . . . . . . . . . . . . . . . . . . . . . jbperf.com Forum
Image
racingmini_mtl
Super MS/Extra'er
 
Posts: 6531
Joined: Sun May 02, 2004 6:51 am
Location: Quebec, Canada

Re: Low Imp Injectors

Postby Peter Florance » Mon May 21, 2012 7:10 am

racingmini_mtl wrote:With an MS3/MS3X, the simplest solution for p&h drivers is to use the external box version. This is the one I have at this time: http://jbperf.com/p&h_board/v2_0.html#Buy. And you will need 2 of them since they only have 4 drivers per box.

Jean

Is that a straight interface to the MS3X injector output?
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Check your grounds: http://www.msextra.com/doc/general/grounding.html
User avatar
Peter Florance
Super MS/Extra'er
 
Posts: 3377
Joined: Fri Apr 02, 2004 8:40 pm
Location: Virginia Beach, VA

Re: Low Imp Injectors

Postby racingmini_mtl » Mon May 21, 2012 9:02 am

Peter Florance wrote:Is that a straight interface to the MS3X injector output?

Yes it is.

Jean
jbperf.com Main site . . . . . . . . . . . . . . . . . . . . . . jbperf.com Forum
Image
racingmini_mtl
Super MS/Extra'er
 
Posts: 6531
Joined: Sun May 02, 2004 6:51 am
Location: Quebec, Canada

Re: Low Imp Injectors

Postby billr » Mon May 21, 2012 8:33 pm

If you can machine fuel rails, you might consider doing what I did. I made a special finned heat-sink with a pocket on the back side in which my two V1.1 boards mount. That unit then is screwed on to the top MS cover and makes a fairly protected and compact package. It adds 1" to the height of the standard MS case, but I'm pretty sure I have much more fin than I need, the extra height could probably be reduced to 1/2". I joined the two V1.1 boards on the edges where each has a single-row header such that I connect from the MS3 with a single cable and double-row connector. No, of course I don't have any pictures handy, but I'll attach a .pdf of the heat-sink.

ms heatsink.pdf
billr
Super MS/Extra'er
 
Posts: 1910
Joined: Sun May 15, 2011 11:41 am

Re: Low Imp Injectors

Postby racingmini_mtl » Mon May 21, 2012 9:11 pm

If you ever take pictures, I'd be interested in seeing them.

Jean
jbperf.com Main site . . . . . . . . . . . . . . . . . . . . . . jbperf.com Forum
Image
racingmini_mtl
Super MS/Extra'er
 
Posts: 6531
Joined: Sun May 02, 2004 6:51 am
Location: Quebec, Canada

Re: Low Imp Injectors

Postby aarc240 » Tue May 22, 2012 12:01 am

Jean, thanks for replying re the consistency question (I'm catching this thread occasionally between visits to the orthopaedic surgeons).
My testing concurs, high heat or freezing cold has very little effect on Hitachi injectors as used on a Datsun Z car or the higher capacity after market equivalent when driven from the P&H boards.
I wouldn't expect this to change much with other injectors provided they are in the impedance range the P&H driver boards are designed for.
This is not the case with OEM Datsun injectors and resistors where the injectors run extremely hot in high heat testing.
As always, the environment in which they are used is a significant factor and in my case that is summer shade temperatures of 43 degrees Celsius, engine bay temp often 60 degrees higher. Winter is the opposite, sub zero mornings being common.

Re the question whether OEM's used lo-Z because they were cheaper, no that wasn't the case.
Initially, there wasn't a choice between hi-Z and lo-Z injectors, all were lo-Z. Improved manufacturing methods made the hi-Z feasible and reliable (the wire gauge used in in hi-Z injectors is remarkably thin).
If there is a choice between the two, hi-Z may be the better option but that's not always possible without undesirable modifications to an existing engine.
Again, for an OEM this is a cost cutting exercise - no resistors means less components and zero failure rate from them. The devices to drive the injectors are cheaper too
Art,
Datsun 260z 2/2 with 280z/MS3+/5spd for the road
Datsun 240z with 280z. nearing the road again
Nissan E24 Urvan with 260z/Megajolt/5spd parts hauler - sold
aarc240
Helpful MS/Extra'er
 
Posts: 120
Joined: Wed Jun 01, 2005 3:11 am
Location: Australia

Re: Low Imp Injectors

Postby JAM » Tue May 22, 2012 7:20 am

Here is another way to do it with the earlier version of the board with the standard case and a small additional cover. i used 9 pin DB connectors, 1 for each bank and a 3 pin for each board (it was batch fire mode)

Image
Image
Image
"The only thing you can buy at Jegs is the same thing everybody else has"
http://www.msruns.com/viewtopic.php?f=97&t=23284
JAM
Master MS/Extra'er
 
Posts: 583
Joined: Sun Jan 22, 2006 7:58 pm
Location: Cincinatti,OH

Re: Low Imp Injectors

Postby Peter Florance » Tue May 22, 2012 7:35 am

JAM wrote:Here is another way to do it with the earlier version of the board with the standard case and a small additional cover. i used 9 pin DB connectors, 1 for each bank and a 3 pin for each board (it was batch fire mode)

Nice work
BTW love the signature quote
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Check your grounds: http://www.msextra.com/doc/general/grounding.html
User avatar
Peter Florance
Super MS/Extra'er
 
Posts: 3377
Joined: Fri Apr 02, 2004 8:40 pm
Location: Virginia Beach, VA

Re: Low Imp Injectors

Postby billr » Tue May 22, 2012 8:44 am

I'm going to have my unit out soon to add wiring for a fuel-pressure sensor; I'll take some pictures then.
billr
Super MS/Extra'er
 
Posts: 1910
Joined: Sun May 15, 2011 11:41 am

Re: Low Imp Injectors

Postby billr » Tue May 29, 2012 6:16 pm

OK, here are some pix. I'm sure the heat-sinking is way too much, I could probably cut off the fins and have just a plate. I don't know if it really matters, but I like having the P&H boards pretty well shielded and isolated from the MS3 with the MS standard cover in between.
billr
Super MS/Extra'er
 
Posts: 1910
Joined: Sun May 15, 2011 11:41 am

Re: Low Imp Injectors

Postby billr » Tue May 29, 2012 6:17 pm

And, the last picture...
billr
Super MS/Extra'er
 
Posts: 1910
Joined: Sun May 15, 2011 11:41 am

Re: Low Imp Injectors

Postby racingmini_mtl » Tue May 29, 2012 6:30 pm

Bill,

That's a great setup. And while this is likely overkill for almost any condition, there's nothing wrong with it and just means that it's one aspect (heat) you will never have to worry about.

From what I can see, I imagine the small blue wire is to send 5V from one board to the other?

Jean
jbperf.com Main site . . . . . . . . . . . . . . . . . . . . . . jbperf.com Forum
Image
racingmini_mtl
Super MS/Extra'er
 
Posts: 6531
Joined: Sun May 02, 2004 6:51 am
Location: Quebec, Canada

Re: Low Imp Injectors

Postby billr » Tue May 29, 2012 7:40 pm

Yes, the blue wire connects +5 on each P&H board, the ground traces on each are jumpered together at several places, on their adjacent edges, on the far-side. Each +5 pin connects to the proto area +5 supply on the V3.0 mainboard, and each ground pin connects to the MS3 injector header; plenty of redundancy on both. I have dots marking the connector that plugs into the header on the two P&H boards, but even if it was reversed there would be no damage; only effect would be injectors wouldn't be in proper sequence
billr
Super MS/Extra'er
 
Posts: 1910
Joined: Sun May 15, 2011 11:41 am

Re: Low Imp Injectors

Postby bytesandbolts » Fri Nov 09, 2012 4:08 pm

Just come across this thread, have a couple questions of my in regards to running low impedance injectors with a MS3X Board.

According to the docs you are able to run the injectors using PWM from the two main injector pins from the MS3 board. However the docs also mention "Ensure your board and loom are wired for the injector flyback 12V return if using injector PWM". Would someone mind clarifying what this is for, as I'm a bit puzzled. Also not sure how the 12v return should be wired up, it appears to run from pin 6 on the DB37 from the images I have seen?

I only need to control a single injector and PWM seems like the best bet to get things running to me.

Dan
1974 Mk1 Escort 1.3 Turbo MS3X
bytesandbolts
MS/Extra Newbie
 
Posts: 23
Joined: Thu Oct 18, 2012 5:50 am
Location: London

Re: Low Imp Injectors

Postby Peter Florance » Mon Nov 12, 2012 2:19 pm

bytesandbolts wrote:Just come across this thread, have a couple questions of my in regards to running low impedance injectors with a MS3X Board.

According to the docs you are able to run the injectors using PWM from the two main injector pins from the MS3 board. However the docs also mention "Ensure your board and loom are wired for the injector flyback 12V return if using injector PWM". Would someone mind clarifying what this is for, as I'm a bit puzzled. Also not sure how the 12v return should be wired up, it appears to run from pin 6 on the DB37 from the images I have seen?

I only need to control a single injector and PWM seems like the best bet to get things running to me.

Dan

As long as your MegaSquirt Pin 28 is powered from same relay output as injector +12v, you should be fine. It will be important you follow MSExtra recommended grounding scheme.

http://www.msextra.com/doc/general/grounding.html

Image
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Check your grounds: http://www.msextra.com/doc/general/grounding.html
User avatar
Peter Florance
Super MS/Extra'er
 
Posts: 3377
Joined: Fri Apr 02, 2004 8:40 pm
Location: Virginia Beach, VA

Re: Low Imp Injectors

Postby bytesandbolts » Tue Nov 13, 2012 12:38 pm

Hi Peter,

Yes my grounding is already setup the same to the diagram you mentioned.
I sourced a 4ohm resister in the end to get my injector working, all set up correctly now.

Thanks again
1974 Mk1 Escort 1.3 Turbo MS3X
bytesandbolts
MS/Extra Newbie
 
Posts: 23
Joined: Thu Oct 18, 2012 5:50 am
Location: London

PreviousNext

Return to MS3 General Support

Who is online

Users browsing this forum: xrattiracer and 1 guest