MPI Mini\'s Tuning Possibilities
Turbo Mini Forums

Hi All

Some of you my remember me other's will not :)

I am just looking at getting back into mini ownership after 6 years away from the fold and I am currently looking at getting another MPI mini.

When I left the scene, they were hard to tune the standard injection setup was unresponsive and the 90bhp where pushing it in the power claims department. I have had a search an cannot find anything to indicate any improvements have been made with the Rove ecu etc.

However I have noticed the Twin Cam heads from a BMW motor bike etc and someone has managed to fit these on an MPI block (Sprocket I think). It looks like a lot of work, and quite technical (the most I have managed to get my hands dirty is converting a mini from drums to disc's).

Is this sort of conversion do'able by someone with little knowledge or is it one best left to the experts?

welcome back dude :)

does seem like quite an involved conversion to DIY but you can buy most of the stuff in kit form now.

Yeah I have seen the kits, looking though all the threads, and it look quite difficult for a first conversion. Just looks like the only decent upgrade for an MPI without throwing most of the car away.

How did you ever get your clubby finished as I didnt see it in the show us yours thread.?

Edited by Stig on 4th Feb, 2011.

I wouldn't say its that complicated (but then again I'm still at the parts gathering stage!), especially if you buy a complete kit from the likes of specialist components then all you need to do is bolt it together.

If you are happy to build a normal mini engine then I'd not worry about doing a 16v.

The mpi isn't really different that any a-series, the only changes that really mater is the fuelling,

You still need to overbore, cam, head flow it.... to sort some bhp from it, even if the 90bhp kit made some writing,
no A-series could sort this sort of bhp with just a cyl head change and a high lift rocker set.

Then make a 1360, a good camsaft (I used a 274i with very good effect, the torque curve is very nice, and at 4000 rpm it does blast you to 5500 then slightly less to 6000), a nice head on this and would like to put this on the roller.
About fueling, I used a 52mm trottle before reverting to the 48mm one (town driving), the 52 is only usefull keeping the engine reving all the day, it does ennoy the 4000 first rpms,
I cleaned injectors, increased fuel pressure before to take it back to 3 bars (was a lot too rich at idle/part throttle, and at certain points on te curve that cloosed loop couldn't correct.

So I used a wb02 lambda, with which I corrected a bit the signal to ecu, it does work nicely, then I know I can work on injectors and rail pressure with a boost one.Then ... msq siames code and...booooooooooooooost

fab

Why not go for a seven port head mod like the SC billet head. Nothing more complex than changing the head gasket and a bit of wiring.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

hi, welcome back. when i was first looking at tuning my mpi a few years ago people said that they were unresponsive/not worth tuning, plus the only mods were really the bolt on stage 3 type mods that were discussed or mentioned at the time.

im with fab on this one though. mpi minis can be tuned and made really nice to drive. i had mine overbored to 1360, ported/polished/double sprung head, with the 1.5 roller rockers. i increased he compression ratio to nearly 11:1, changed the cam for a sw5i.
the inlet manifold is ported, i have a 52mm throttle body modified from a lotus elise, increased the fuel pressure. the exhaust system is sorted on it.

probably the best upgade i made was to build a 1275 gt close ratio gearkit into an a+ gearbox, usual mods such as centre pick up, changed the final drive for a 3:2.

the car flys for a mini. there is power in pretty much every gear at any revs. it is very torqey. its not a patch on most of the cars on here power wise. it will never be an all out racer. however for a nice smooth mini with lots of torque it works really well. a standard mpi car is not a patch on it. apart from a couple of electrical niggles it has been very reliable also.

dan

@Nick looks realy good chap. You and Kean have made nice job of that

@Fab thsnk for the info I am more concered about getting a tuned mpi past the more stringent (spelling) emmisions test, hence the through of a injected 16v lump with a mappable ecu might be the only way to go?

@Ben, I will have a google, never really though of a 7 port.

@Welshdan.

I take it you have ditched the standard ecu for something else. Do you have a build thread?

hi, im running the standard mems. with the fuel pressure increased. people say you cant really run a tuned mpi engine with the standard mems, however i have done 20k on it so far. if you were nearer i would have taken you for a spin in it so you could make up you own mind. as i said its not particularly quick by todys motoring standards, but works very well as a setup in a classic mini. it probably could do with a modified ecu to be honnest though. the emissions are something else on it though...

Thanks, Dan I have spent you a pm

When I had an MPI for the ex. I looked into MPI tuning and was considering well modded heads, lcb, cam, 52mm tb, 1.5 rockers etc etc.

Someone had already fitted a great massive playmini exhaust mucked around with the TB and the airbox and it was running rough as a bears snatch. I put it all back to standard then forgot all about tuning it. (not to mention she took it when we split)

However if I were going to tune an MPI I would go for:-

Mild head with 35.7mmx29mm valves (up the CR slightly)
Std Manifold
Maniflow downpipes and maniflow twin box exhaust (retain the cat)
Alloy TB (as the plastic ones are prone to warping)
K&N filter in standard airbox
Superchips ICON (ignition advance modifier thingy)
3.2 FD

I reckon this with a bit of roller time to get the ignition setup and perhaps slightly up the fuel pressure if required would make a decent motor to drive.

The C/R helical box that welshdan has would probably make it feel more sporty too.

If something is worth doing, it's worth doing half of.

sounds a good proposed setup. i took a chance on a second hand ICON superchip but the thing was broken.

with the setup on my car it runs really smooth and is a joy to drive everyday.

John, Dan

Your thoughts are apreciated. The reason I ask was I thought about buying back my old MPI Cooper however, the orignal reason I sold it was due to the lack of power constrained by the ecu and the emmisions test.

I dont want to be in the same boat again. I was looking for about 120 nanna's in which the twin cam fits the bill on a aftermarket ecu which should have not issues with the dreaded MOT.

However the more I read this isnt really possible any other way than the 16 valve route (which is more expensive than other means to get the same power). I suppose after 4 years away I hope someone would have cracked the MPI and got it sorted .

Looks like if I want power on an MPI twin cam is the only way. However I could have quite a bit of change in buying an older model and using more traditional tuning / forced induction.

Hmm moree food for thought

Stig, you could always buy my M45 set up of me? Its on the forsale board at the mo!

Hi Andy

I just had a look unfortunatly the timeing is a little out as I could not afford the car and the kit.

Looks like another option long term though.

Thank you

Twin cam isn't the only way - 7 port with a good fuel injection setup should make good power. Have a look at the Specialist Components 7 port setup.

If injection is what you want, then have a look through the EFI section on here.

We are planning an injected NA 1380 5 Port that should make around 120hp. A pair of Jenveys or Mikunis and an MS2 running the TM developed code will do the business.

Save yourself a few grand and learn something in the process.

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."

have browesed the EFi part of this forum several times. the people in that area certainly seem to know what they are doing!