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Turbo Mini Forums

Hi

I'm not new to minis but i am to turbos, currently re building a '87 mini that i intent to fit with a mettie turbo engine (currently stripped on my bench), the bodywork on the car is a few month off been finished but i've already started on the engine, so hope you guys don't mind answering any stupid question i might have.

In fact i've got one that you maybe able to help with, i've checked my bores and in the most worn area they are about 4 thou worn, i was going to have a rebore of +20 thou, but i realise that this will increase CR (not good?), if i had the head skimmed and the block skimmed this will also raise CR. So my question is (at last i hear you say) what pistons should i be using, i assume dished but by how big a cc.

Sorry for the long post, and please be gentle with me.

Cheers

hello and welcome!!

A rebore does indeed up your CR, but only by 18cc (1275 to 1293) which is not going to make a huge difference. Skimming the head only needs doing if it is warped... the same with the block but it is farless likly to need skimming.

If you are worried about it, or want to run more than 8-9 psi of boost then your going to need to drop the CR anyway! The easiest way to do this is grind metal out of the combustion chambers.

As for pistons, I would stick with std metro turbo ones as they are cheap and strong :)

Alex

AlexF

Might add cheap and strong yes but if your going for something running very high boost then a set of omaga dished pistons will be required as there is only a certain about of material that can be removed from the combustion chambers. And therefore you will need the extra dish of the pistons to get hte compression ratio down.

Also to help prevent dentination your probably best looking to plum in an intercooler to help (also you get power gains when running more than 10psi of boost)

Cheers for the advice guys, my plan was to rebuild the engines internal with the thought of running high boost in the future. So the plan was to spend the money on the internals at the beginning and as i get more confident with the turbo set-up increase boost, add intercooler and other mods in the future, the car is going to be a fair weather/weekend racer, so it doesn't need to be 'nice' to drive day to day. What sort of cam would people recommend??

Cheers again

phase 2 turbo cam from avonbar/MED or a mild cam such as an sw5 (not tried that one). These should be reasonable for what you are after. Do not go for the phase 3 cam as this is for the drag strip or race use only