mpi head mods and 1.7 rockers on mpi
Turbo Mini Forums

sorry, not a turbo question but

will 1.7 ratio roller rockers be any good for an otherwise standard mpi cooper? or do they give too much lift?

also, porting, polishing, reseating the valves, decoking and maybe having a chunk skimmed off a mpi head - will this give a decent power hike or will it interfear with the injection system?

many thanks

a well ported head will add a good 10 to 15 % to the power
this will be times by somewhat by fitting another cam and other mods remapping etc after the blot on bits have been fitted

1.7 ratio rockers are no good in my book, a cam change would be better
and 1.5s with the right cam

id prefer the cam change, reality is that i dont have time at the moment. afraid its just bolt on parts for now.

whats the4 difference between an mpi head and other a/a+ heads?

are they interchangable to use on an mpi? thanks

why would you not use the 1.7s? surely they would be better than 1.5s performance wise with a standard cam?ta

The standard ECU is pretty useless when it comes to changing cam profiles from what i've read. Thats why the upgrade kits for the injection Minis usually have high lift rockers instead of a cam change, so you get increased breathing through higher lift but without changing the cam characteristics.
Some sensible head work will also yield benefits, though in the end the limiting factor is the ECU.

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i know it wont make that much power, a nice 75 bhp and nice bit of tourqe would be nice. final drive change would be ideal, as i said i really dont have time for this at the moment. so its just the bolt on parts and head work for now. would skimming the head and raising the cr be benificial to the performance as well as porting and polishing?

What's the compression ratio now ?

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standard whatever that is.

anyone know of anybody using 1.7 rockers on their mpi? seems that 1.5s are of choice.

raising the cr ratio to around 10.5:1 max and Some sensible head work as phil said

what is the difference between a mpi head and other a series heads? had a quick look, all i can see is the alternator bracket. can a non mpi head be drilled and tapped for mpi use? thanks