Standard MPi pistons + Boost
Turbo Mini Forums

Basically, Im collecting parts to convert my Mini to turbo -

Its a Mpi, with 50k on the clock

Will the standard pistons be ok for a bit of boost? I plan on lowering the c/r with having the head machined for the time being, then when funds allow, I'll have a 'decent' engine built


Looking at running no more than 10psi through a Fiesta RS Garrett T2 turbo unit

Would it be advised to uprate the diff at this boost?

Thank you for replies

Radleigh

Lightweight racer coming soon.

Hi,
I'm planning on doing the same. I'm going for 10psi on a completely standard engine.
I will be fitting a 4 pin diff, not sure about final drive ratio, yet...
Cheers,
Gavin :)

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10psi would be a little high IMO

You'd be hoping for 120+bhp I assume with that boost...

and then your into st8 cut gears and drops.

Alex

AlexF

don't forget the intercooler.

I'll be running an intercooler don't worry 8)

Alex,It needs a 'box refurb anyway as you know

Lightweight racer coming soon.

The fiesta t2 will not fit onto any of the usual manifolds. it uses a 3 bolt pattern... just something to think about, I'd try and find a Renault 5 model to make life easier

wot about the fueling? didnt think you could get enough fuel for 90bananas on a n/a unless you use a suck through set up and megasquirt?

Lightweight racer coming soon.

std pistons will brake in the ring land, I've tried to boost na engines (9.4cr) to make cheap turbo (8 psi), but it's same story, each time broken ring lands, you have to change these for turbo ones

Wheres best to get the rings from?

Any ideas?

Lightweight racer coming soon.

not only the rings, it's the piston which brake between rings.
I would use + 40 megas turbo, or +20 omegas, perhaps std if you can find a good set of std turbo pîstons

so was u going to have a suck through or blow throu on your mpi? and how you sorting out the fuelling issues?

I'm wanting to bin the management and go for a SU Carb set up, like the Metro Turbo

I have been looking at the Polestar choice, looks ok!

Lightweight racer coming soon.

Keep the head standard and get yourself a set of decent second hand standard turbo pistons, have the dish machined out to increase the cc above the piston.

There is a topic around here some where regarding standard turbo pistons, tough as old boots they are.

I have a set ready to go into an engine. The unfortunate thing is standard rings are nearly impossibe to find. I bought some gapless Total Seal rings instead.

Edited by Sprocket on 11th Aug, 2007.

Yeah, Since reading that.. Im now thinking of doing the pistons.. If they have to come out to have the rings changed, Then I might aswell just do the pistons instead!

Lightweight racer coming soon.

rings are availables new ,
just had a set last week,
I'll look if I kept the box , for ref

Edited by fab on 12th Aug, 2007.

if you put a carb set up on a mpi car it will fail an mot! unless you can prove the age of the engine or car is pre catalyst emissions testable! unless your using it for track use only of course.

Hi,
That's a good point. Looks like you maybe forced to go electronic after all....
Cheers,
Gavin :)

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Oh.. I never thought of that :(

Lightweight racer coming soon.

emissions laws are very strict now! i struggled getting my mpi through and i tested it myself! oh the joys of being a mot tester.

There's no way of nailing a different number on the block either as the original number is etched into the block and no holes drilled, as well as the block being a different shape, not that i condone such things.

You would need to at least run Megajolt, so why not go the full hog and inject it as well. Carbs are history

My SPi passed the 'BET' test with 0.098%CO and 155ppm HC, i did tune it in the fast idle region for the 'Cat' test and probibly would have passed. That is WITHOUT a cat using VEMS

Edited by Sprocket on 12th Aug, 2007.

without a cat that is good, it even passed the bet test which is stricter than the cat test. 155ppm hc is quite high though probably because your cat is missing mine was about 25ppm hc but the emissions was really slow settling back down at idle, took til the last 3 seconds to come below 0.3% co

Yeh, passing cat tests with out a cat is a discussion on the VEMS forum, and it is clear that it can and does work if you tune it right, It all depends as well on the wear of your engine.

Lets not forget, as you say, the cat does more than reduce CO.

I thought the BET was less strict than the Cat test? but there you go BET with 3.5%Co and the cat test with 0.3%Co, HC limits escape me though

the bet test has a 0.2%co and the cat test is 0.3%co at fast idle the hc ppm is the same on both and at idle bet test is 0.3% co and on cat test its 0.5%co. 3.5% co is for cars between 1984 and 1992 bet tests and cat tests are for 1992 cars onward which is when it becomes very strict