First results from MPi...
Turbo Mini Forums

So, I've got data.
Annoyingly, The first blast up the road saw the single tooth I'd JB-welded to the crank pulley as my TDC reference dissapear at 5000rpm in 2nd.

Luckilly - I'd already recorded data for startup to idle. Several idle / revving scenarios (in neutral) and then did he quick blast up the road.

As for the results - Well - suffice to say they MPi uses little of the true potential duty of the MJY100460 injector.

It does move the injection event WRT rpm as well - but it also has a few actual injection sequences between idle and higher revs... It also appears to move the event depending on (either - or both) TPS and/or MAP. The use of longer duration cams is also a reason why if you try these in an MPi, you fail emissions...

This will actually take a long time to explain... I can't just upload a file in excel either - There is around 400,000 lines of data - way more than you can use in excel. If anyone has FAMOS - then it'll be of use - I don' imagine many folks do however!

For the short term - I'll do a few 'print screens'. I'll probably make a PDF or similar along the lines of a more detailed report.

I am actually tempted to put another sensor on the crank, and repeat the tests, also bringing MAP and TPS into the data stream. That said - I don't think we'll be replicating the MPI injection event. I'd like to say it's aimed at emmisions only, but even that is debatable given manufacturing tolerances in cam timings...

interesting bit of development work there dave

nice work

Hi,
That's interesting Dave, it seems the MPi system is a lot more complicated than first thought!
Cheers,
Gavin :)

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My Mini build diary

I always suggested that the MPi ECU was clever box of tricks, people are quick to put it down.

Anyways, Dave, why not speak to Johnk about one of Specialist Components trigger kits. It can come in handy if you want to run a lightweight flywheel on standard MPi ECU, just replicate the tooth pattern, I know it works on the SPi

Id be interested at looking at this info, I'll need to look into getting the software to read it though.

Top man!!

Any chance you could do some research on an SPi low ohm injector to find out its true peak and hold data?? similar to what you did on the MPi injectors. Id supply any hardware. Bosch are not playing ball with the info. Anyways thats another story and another subject.

Sprox

Just a thought on the shift in injection event, are you also measuring on the data the throttle response, obviously on acceleration there is extra fuel added to compensate wall film and fuel transport delays, so what you should see is a spike in the PW of the injector at these points, but the rate of throttle needs acounting for

Just a thought

Dave,

Can you send me the data? I'd be interested in looking at it.

Are you saying that the timing changes or that the injection pattern changes or both? What I mean by pattern is: does it go from squirt,squirt,wait,wait to squirt,wait,squirt,wait? Also do you mean that the timing changes with respect to the beginning of the pulse or the end of the pulse or both?

I suspected that there was a need to change things as RPM/load changes which is why I have an advance table in my code and why I have provided the possibility to time the injection with respect to the beginning, end, or middle of the pulse.

I look forward to have more details on this.

Jean

http://www.jbperf.com/