Lifting the Rover MPi ECU Limitations
Turbo Mini Forums

An open ended question I know and I do not seem to be able to finish something before starting something else.

I have two of Jean's Microsquirts getting prepped to go on these two engines:

http://www.tmsmini.com/cooper/images/2014_..._01-2014-01.jpg

http://www.tmsmini.com/cooper/images/2014_..._01-2014-02.jpg

I seem to get in my own way of moving forward on this as my wife and I bought this a few months ago:

http://www.tmsmini.com/cooper/traveller/Lu...2014/index.html

And it has required some attention.

now I bought another MPi engine.

My question is this…Mpi engine upgrades have always been limited by the ECU, with that limitation removed how far could I go with an engine for a road car?

I am having the engine built by 7 Enterprises and we are discussing the specifications. I will stick Rover hardware for now, but I have a cam that can be reground as needed. I also have a 52 mm throttle body I intend to use. One of the heads was reworked by Minisport and has larger valves, supposedly the Stage 3 version. The transmission will have a 3.1 FD, although the new Traveller has a 3.44 and I am not finding it too bad on the freeway for short periods.

Jean suggested maybe looking into having the inlet extrude honed, but that is a bit pricy.
Jean also mentioned paying attention to overlap and its impact on the injection window.

Any suggestion on how far to go, cam spec etc? I am not looking for outright power but a happy medium of increased power over standard MPi with the reliability of EFI.

Terry

The MPi inlet manifold is, in my opinion, the best factory manifold produced for the Mini. It has a decent plenum and runners as long as you can get in the space without incorporating bends. It appears that by the 90s Rover had started to understand the importance of inlet tract design.

I would just clean it up and use it as it is.

The only other way to make more power, as you already have the head and assuming that you use an LCB would be to fit a decent cam.

I would use the Kent MD274 or equivalent. Very good for torque.

I'm not sure that overlap is a particular issue on the injection front. We briefly ran a 1293 with the MS3 with a fairly lumpy cam and didn't notice any fueling issues. So I think that you could go higher spec with the cam if you wanted more usable revs.

Edited by Paul S on 10th May, 2014.

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."

I'm running the MPi engine on megasquirt, monitoring the inner and outer AFRs. It's the standard engine with a few tweaks:
35.6mm inlet valves
29mm exhaust valves
ported and flowed head
9.4:1 CR
Economy drop gears
Metro HLE gearset (still 3.1 FD)

It drives lovely, gearing is perfect for the road. However, with this setup i've been unable to inject enough fuel to rev past 4000rpm (with acceptable AFRs, obviously i could rev it if i really wanted). I expect 4000 is near peak torque so the fuel demand is at its peak.
I can't see that rover would be able to get much more fuel in than I am (they probably managed slightly more accurate injection timing). So i've got the bits to make up my own inlet manifold so I can use two injectors per port and get the required fuel (and in preparation for the turbo).
So just something the bear in mind that you may not be able to safely use all the potential power on the standard injectors.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

Dan, do you really need to go to 2 injectors? Have you tried to simply install bigger injectors in the MPi manifold?

http://www.jbperf.com/

yeah, i expect that'd work but I wanted to make the runners longer to benefit from the pulse tuning and make a better fit for the turbo below. And just for the fun/ challenge really.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

Dan, I'm sure that there is a fuel delivery problem. I've responded in your build thread.

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."

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

Just mill out the existing bosses and weld in a dual boss suitable for two pencil injectors side by side on each port. Then a single billet fuel rail will suffice.

Looking for a spare manifold to butcher.

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."

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

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."

I appreciate the responses so far. This is as much of an educational project for me as any thing else.

Switching to a larger injector is something I could do, but getting the manifold modified would be expensive.

I have a spare manifold I would donate to the project, but I am a little far away.
Terry

You could easily get away with single 80lb injectors on an N/A motor. Enough fuel for 100hp plus.

I'm just thinking of using two injectors per port on a budget, low boost 998 turbo motor, enough fuel for 120hp and staging the secondaries in on boost.

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."

After discussion, 274 cam on order and the builders are going to locate a reworked MPi head in the UK as it will be cheaper than rebuilding the existing head. Most likely the forged 1.5 rockers.
Thanks for the discussion. Now I should get back to work on the existing engines...

Fuel pump fixed it! Paul you're a fantastic man!
Discussed in my MS testing thread.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo