9 replies to this topic

[MiniBonkerz]

Ok im loving the power my mpi produces as standard beats most cars off the lights upto about 20mph however what mods can i do to make this little beast go even quicker im happy with the top speed its never going to break the sound barrier but its quick enough so how do i get more low down grunt any info, tips, tricks, or advise will be hugely appriciated as i dont know a hell of alot about engines would like to mention i would still like to keep it reliable

Edited by MiniBonkerz, 08 December 2009 - 11:03 AM.

[Guess-Works.com]

First of all, have you modified the stop on the throttle body ?

[MiniBonkerz]

No only bits i have done it has a s/s rc40 please explain

[l_jonez]

same as most engines, start off with air filter and exhaust followed by a better head then a cam. after that its things like rebores etc etc. the problem with the mpi is its expensive to tune and is limited by the ecu.

i got a k&n filter and single box rc40 on my mpi, it made a noticable diffrance

[MiniBonkerz]

I have a k&n i took it off as i felt i lost acceleration having it fitted sounded great tho

[Guess-Works.com]

On the std mpi throttle body there's a stop which restricts the opening of the throttle to 'fully open', if you take the air filter off and look at where the thrttle cable is attached, move that as if pressing the throttle, you will see the stop.. and where the butterfly stops. Quick mod.... more air = more fuel = more grunt..

[MiniBonkerz]

like it will have a look later once at work a quick question about the k&n if i fitted it again what bolts hold the throttle body bracket in are they stars? or normal hex? cant remember

[evansisgreat]

like it will have a look later once at work a quick question about the k&n if i fitted it again what bolts hold the throttle body bracket in are they stars? or normal hex? cant remember

I think this is the bit guessworks means. The bit the end of the dremel is sitting on. I think it can also be removed totally.

Also remember the final drive on mpi's is crazy low. The next time you get your box rebuilt (because out mpi one are made from sponge) you could change that, obviously yhr trade off would be top speed and higher revs on the motorway.

Attached Files

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Edited by evansisgreat, 08 December 2009 - 11:47 AM.

[Cooperman]

As always with the A-series engine, the limiting factor is the head. Get a good gas-flowed head, if possible with slightly larger inlet valves, and you will really notice the difference. Plus, of course, a lower final drive ratio when the engine is off the box, but that's a much bigger job.

[mykweb]

The Mpi is very restricted by nature by a few things.

Firstly and the most expensive restriction is the ECU. The original Rover Mems will only go to about 90ish BHP. The onboard memory is ROM and can't be modified or adjusted.

Secondly is the cost involved in modifying an MPi mini.

Rough costs are

Stage 3 head - Starting from £400 plus exchange. This will give you bigger inlet and outlet valves as well as double valve springs, better gas flow.
1.5 Roller Tip Rockers - starting from £150, This will improve the opening and closing of the valves offering a faster responce to the engine.
Cam Shaft - Starting from £140 - the two main choices are Swiftune SW5i or Kent (not sure of model) This will offer a slightly higher rev range.
Lightend Flywheel - around £90 upwards - Lighting the flywheel will cause the crank to rotate smoother
Final Drive - Not going to put a price on this as it requires full engine out and gearbox strip, Will improve the acceleration.
S/S Exhaust and LCB - £90 upwards - will improve gas flow and back pressure.
Induction Kit - £35 upwards - will improve airflow
Burlen 52 mm Throttle - £150 - same as above but will also improve throttle responce

All the prices are without labour, unless you are doing this yourself it can be an expensive job. I spent the best part off £1000 on my mpi engine over the summer.

I am running a 1295 Mpi Block, with Swiftune SW5i, Duplex Timing gear, EBC waterpump, Standard Final Drive, Central Oil Pickup, Avonbar 1.5 Rockers.

I have just fitted a Stage 3 head and this has improved the acceleration greatly, but its still limited by the ECU. Not only does the ECU limit the top BHP it also restricts your Rpm and it will back off the Revs well before the real red line of the engine.

Emerald and Diamond do programmable ECU's for the MPi, starting costs are around £600 for the kit and then you need a few hours on the Rolling road. Costs can easily rocket to £900+

The Mpi engine could have been better if the ECU was not locked, but then again the Mpi can struggle to meet emmisions on mildly tunned engines. I have seen an MPi fail on emissions just for having an Induction kit and Exhaust change.

Some people say the 90BHp will struggle throu the MOT. My engine now meets that spec, I am a few months away from the MOT but I am going to get the car tested well before the date incase I need to swap over the head etc.

Also the 90 BHp JC kit never makes this figure. You are lucky to get 84-86 on a good Dyno.

If you have the money.....do it, if you don't..... use your mini for what it's intended for.... Embarassing other Euro Box's.

Get the handling sorted on the car, Improved dampers, negative camber front and rear, uprated tie bars, Bigger Brakes.

Hope that helps

Mike