lost for words
Turbo Mini Forums

i am lost for words now i was under the impression i could put all the metro turbo parts such as the head turbo and car onto a N/A 1275 block now my mini mechanic has told me the pistons will not last

Yes i moved to the darkside

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depends on what you do to the head and how much boost you run

Get benross to modify the head and keep the boost to 8-10 psi dont forget to uprate the oil pump

What you are saying is the your mechanic say that the standard N/A pistons will not last with boost.

Well the N/A 998 pistons are fine up to lots of boost (all things being otherwise spot on (CR, fueling, ignition ets)). It's not often done to use standard 1275 pistons for forced induction. But they shouldn't just melt. Just don't expect them to take 20psi.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

I'm going to build my supercharged engine on standard pistons. I'll be putting 12psi through them, with a CR of about 8:1.

I know full well that they won't last long. When they go I will rebuild with omegas or something. I'm only doing it that way because I don't have the budget for new pistons and a rebore at the moment and if I do absolutely everything up front, then the car will never see the road.

Is your bottom end rebuilt or are you just throwing your turbo bits onto a used bottom end?

I'm running 7-10 psi on an engine built in 1970., thats been for nearly two year now, all stock except the 12G295 head (To give me 8.7:1 CR) with correct ignition (via MJ) and correct fuelling.

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

I have run with standard MG Midget pistons for two years, using up to 20 psi on one occasion and the pistons have stood up OK. It all depends on how much advance you use, how rich you run it to keep it out of detonation and how long you hold it on full boost. Having said that the pistons have survived 8 runs on a hill climb and a visit to Santa Pod, so they must be reasonable.(did not have a big enough toy allowance to spend £400 on a set of Accralites)

as wil has said having the car set up spot on is half the battle, you can have the best gear in the world but if its not bolted together properly and set up properly it will break

hello again yeah its a completely standard N/A carb block, 30,000 miles from a metro i got a cylinder head from minispeed, i bought the turbo one and the chambers dont seem any different in size,

i will measure them and try and work out my CR

i didnt no i need a uprated oil pump is it a straight swap?

if i run about 6-7 psi of boost with the correct cr it should be fine then right?

Ultimately it depends how you are going to use it.

If its a road car with the occasisional use of boost, then it will probably give you many thousands miles of service.

If you put it on a circuit and run high revs and boost for a sustained period, then it will not last long.

It's all down to your right foot.

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Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."