normally aspirated pistons
Turbo Mini Forums

right i'l start at the beggining i've bought is what i thought was a full complete standard turbo power plant. turns out the block is a normally aspirated engine with turbo etc. the question is is how long before i melt my pistons and is there owt that i can do to prevent it? i'm gonna be using a calibra intercooler and 1.5 forged rockers other than that standard setup.

i've tried the search tool to no joy any help would be great

cheers

depends what pistons, some are better than others, the blocks are the same

if you have to ask "how long before i melt my pistons" they you probably shouldn't be messing with it

Yes i moved to the darkside

Instagram @jdm_brett

tbh the condition of the engine is pretty good. what i ment was if i dont do something about standard 6cc (or whatever it is) dish would this be enough to cope with just strapping a turbo on or would i have enlarge the chambers? what the min. size that would cope? i get most of it, its just that i should ave been more careful in the 1st place and that has caused me more work that i dont quite get

its the overall compression ration vs boost you need to be worried about, plus spark advance get the combo wrong hello dett good by engine 4spi boost and a goo intercooler and you 'may' be safe i realy dont know too many variables

Yes i moved to the darkside

Instagram @jdm_brett

that still helps though, cheers

all depends on how messed with the engine is, how much boost is used, and how well set up the fueling and ignition are.

A normally aspirated 9.4:1CR A series engine used a 7cc piston with a deck hight of roughy 0.040", while the Turbo 9.4:1CR A series engine used a 12cc piston and almost zero deck hight.

If its standard compression ratio, you will be limited as to what boost you run. if you try and push the boundaries of boost with a standard 9.4:1CR, you then might damage your engine, but it will unlikely be the fault of which ever pistons are in there, other than maybe if they are KING pistons.

KING pistons i doubt. how would i go about lowering the deck height then? if i was to lower the deck height and and run aprox 4 or 5 psi of boost would this be enough?

Get the chambers in your head opened out, does the same job as opening the piston dish out, but doesn't involve stripping the whole engine down.

PM Benross, he's near to Wakefield and is very good with heads.

I've got a set of turbo pistons if you fancy ya chances on doing a rebuild?

i get what your on about now you've said it again sprocket. i know you need lower compression to run a turbo than a n/a engine. i'm just tryin to weigh up all my options before i start. i've just had conflicting info before i joined on ere.

from what i can gather mr. benross is a very busy man cos my mate has being waitin 3months before he could fit him in.

cheers for all your advice its been very helpful

I think I can put it more simply.

Calculate the CR. if it is 9.4:1 or less run standard metro boost (7psi). If it is higher than 9.4:1, find a way to lower the CR.

The standard pistons will cope with 7psi boost assuming that ignition advance and fuelling o=is ok.

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

Benross is a great bloke, drop him a pm, I'm only waiting 2-3 weeks for my head back :)

Audi s4 b5 - 470bhp & 486ft lbs

On 30th Apr, 2012 Brett said:
yeah stick the bit in and give it a wobble