Supercharged Morris Minor
Turbo Mini Forums

Hi guys,

I am about to supercharge my 1098cc morris minor.

I am using a bmw eaton m45 from the cooper s . standard CR on the engine is 8.5:1 .

I am using the standard pulley on the charger, and same size crank pulley from the cooper s to retain the psi output of 11.6.

how much do i need to lower the compression ratio for reliabilty and performance and whats the best cost effective method of lowering the CR. i dont really want to fork out for new pistons, or porting etc,

Im not looking for massive hp gains, just more driveability.

Any help much appreciated!

paul ,
i d keep with the 8.5 to 1 you have allready, as long as your sure thats what it is ?

if you put the charger on the engine with the same gearing as it had on the cooper ,you will get more boost than the cooper had cos the engine is smaller by about a 3rd ,so it will swallow less air per rev ,but the charger will be trying to supply the air for a 1600cc engine to get to 11.6 ,so your boost would be well up there ,this also depends on the airflow of the head and so on.
so you may need to look at the blower gearing once its going ..
with the 8.5 to 1 cr , id guess around 10 psi boost would be ok on normal fuel ,although with a good intercooler and water injection it could run a lot higher .

hope that helps
regards robert

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Thanks for the quick reply,

really helpful, hadn't considered those points.

Im sure ill be back for some more help sooner or later!

sounds a good project

Please keep us (well me any way) informed on how it comes along

love minors, didnt someone on here mention an m42 as another option for smaller engines?

good luck!

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

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Pics when you can.
Minors are the dogs.
Me grandads first car.

Back once again like a renegade master

minors are great cars but the brakes are worse than original mini drums so hope you are changing them to.

keep us all posted

always looking for them bigger bunches of bannanas