17 replies to this topic

[mab01uk]

Couple of interesting pdf articles below on the MPI Mini development story from Vehicle Engineering & Design magazine November 1996 and The Engineer magazine October 1996.

Attached Files

•  MiniMPI_eng.pdf   230.42K   199 downloads
•  Mini_stays_Mum.pdf   643.94K   167 downloads

[Dylan8660]

Brilliant, great job posting those up. Thanks.

[mab01uk]

Interesting to read Mike Theaker's (BMW/Rover Engine Development Engineer) account of the Mini MPI development story and how it was BMW's will and John Cooper's insistence that finally got the MPI into production in 1996, extending the Mini's life by 4 more years. Mike Theaker also later worked on powertrain development for the New MINI (R50).

Mike Theaker on the Development of the Twin Point Injection system for the Mini.
Link to PDF below:-
http://www.turbomini...ts/493117-1.pdf

 

(September 2000 Miniworld)

Edited by mab01uk, 23 September 2014 - 07:55 AM.

[jamesquintin]

I do love the reliability of my MPI... 

The only time it failed to start was when I've left the lights on and the battery was flat! Had it 12 years and done 88,000 miles...

[Ruckus]

It’s funny that they state “the existing singe-point fuel injection, which relied on petrol and air mixing in the inlet manifold, could not be controlled precisely enough.” But now we have the Specialist Components injection kit which takes a MPi back to that set up and works perfectly and can meet emission regs even with modified engine and heads. Make you wonder what Specialist Components know now that the whole of BMW/Rover didn’t at the time…

[Ruckus]

I do love the reliability of my MPI... 

The only time it failed to start was when I've left the lights on and the battery was flat! Had it 12 years and done 88,000 miles...

 

But when they go wrong, oh boy do they go wrong!

[cian]

The specialist compnants kit is fantastic, in the article they said the mpi inlet manifold was developed for torque but it looks as if it's just bodged together for ease of production, also it says the test cars where "rockets" as they had a3.2 diff and smaller wheels 

[Ruckus]

There a few MPI's that came on 12's with standard wheel arches, and I belive you could order the 3.14 final drive.
But most went for the sportpack I surpose.

[A-Cell]

It’s funny that they state “the existing singe-point fuel injection, which relied on petrol and air mixing in the inlet manifold, could not be controlled precisely enough.” But now we have the Specialist Components injection kit which takes a MPi back to that set up and works perfectly and can meet emission regs even with modified engine and heads. Make you wonder what Specialist Components know now that the whole of BMW/Rover didn’t at the time…

After market only has to meet static CO2 and HC limits at idle during MoT test.
Manufacturers have to homologate the vehicle and demonstrate compliance with EEC emissions regulations covering an actual driving cycle including fuel consumptions, CO2 emission over total driving cycle. As well as CO, HC, NOx emissions.
The SPi was unable to meet the (constantly) tighter limits.

[Ruckus]

After market only has to meet static CO2 and HC limits at idle during MoT test.
Manufacturers have to homologate the vehicle and demonstrate compliance with EEC emissions regulations covering an actual driving cycle including fuel consumptions, CO2 emission over total driving cycle. As well as CO, HC, NOx emissions.
The SPi was unable to meet the (constantly) tighter limits.

Right I see, that makes a lot more sense now.

Thanks for the explaintion :)

[A-Cell]

...and getting the Mini to meet the more severe crash requirements also required some ingenious engineering design and development by Rover engineers

[cian]

I would imaging to get the shorter final drive was a John Cooper garages job, I wonder how much money went into the mpis just to see those last few years of production

[Guess-Works.com]

It’s funny that they state “the existing singe-point fuel injection, which relied on petrol and air mixing in the inlet manifold, could not be controlled precisely enough.” But now we have the Specialist Components injection kit which takes a MPi back to that set up and works perfectly and can meet emission regs even with modified engine and heads. Make you wonder what Specialist Components know now that the whole of BMW/Rover didn’t at the time…

 

Not strictly true....

The fuel in the MPi and the Specialist components system is injected after the butterfly, where as the SPi injected the fuel before the butterfly and hence worked more like a carburettor.

I don't think there's was much revolutionary thinking with the Mini Mpi system, it was basically reusing parts and tech from other MG/Rover installations, like the Metro, Rover 25, MG TF etc

[Ruckus]

So the SPi is basically a electronic carb, where as the SC setup is a wet manifold injection system..?

[Dylan8660]

It’s funny that they state “the existing singe-point fuel injection, which relied on petrol and air mixing in the inlet manifold, could not be controlled precisely enough.” But now we have the Specialist Components injection kit which takes a MPi back to that set up and works perfectly and can meet emission regs even with modified engine and heads. Make you wonder what Specialist Components know now that the whole of BMW/Rover didn’t at the time…

It also has to do with the fuel atomisation, I'm not versed in spi's but they do run a lower pressure so I doubt that their injectors atomised the fuel as well as the mpi injectors. Even now there are improvements with atomisation I tried these: http://www.racetroni...=01D116x&eq==

 before my re-build and found them to work well, unfortunately my engine was too worn to properly assess them but it's nearly ready to try again.