My 998 turbo spec.. all opions/comments/advice etc welcome
Turbo Mini Forums

I thought i would post up my proposed 998 turbo spec just to make sure that is the right way to go before diving right in. and to gain abit of advice. as for what boost and CR to run i don't know. I would like a powerful, well built motor but as its for road use, a balance between reliability, MPG and power, hence why going the turbo route in the first place. 120-140 BHP would be nice.

right here goes.

Turbo:
R5 T2 on a matty manifold (hopefully get in on the next batch)
standard metro turbo HIF 44, plenum (modded for IC and DV) MG metro inlet, maniflow 2 inch exhaust system.
I have a turbo dizzy for it as well.

Head:

12G295 unskimmed casting i have, will prob get it ported with new bronze valve guides and poss new valves but the current ones look fine.

maybe unleaded conversion but what are peoples views on this?? worth it??

Block:

either a A+ or A block (I have both) bored to +60

I have a set of brand new AE pistons @ +60 i think.

has "AE 20950 +1.54 FUF" stamped on it, are these ok to use for turbo application?

set of A series con rods, ARP bolts.

A series crank, has been hardened and wedged.

(both above came from 998 cooper rally engine.)

kent 266 camshaft

full engine rebuild, all new bearings and appropriate machining work.

Clutch:

cooper backplate, turbo clutch plate, standard flywheel, has been lightened with the back plate. orange spring (will this be ok??)

the crank, rods and fly have all been balanced together but im going to polish up the rods and crank so i assume this will need re balancing at the end of it all??

Gearbox:

remote 12G1128 casting, full rebuild with comp layshaft.
stright cut Tran-x clubman set.
3.1 Final drive
4 pin minispares diff

at the moment i only have helical drops but i may go SC for these as well to be on the safe side.

anything ive forgotton??

Edited by retro-racer on 15th Dec, 2010.

You might consider switching your exhaust valves to bigger ones 27,3 or 29 mm ones

Maybe you can convert to megajolt instead of Metro turbo dizzy, saves room for the IC and you can have your ignition spot on.

As you are after a lot of power, you'll need a lot of boost but I know nothing about pistons so I won't tell bullshits on that subject.

Rusty by nature

Very similar to my latest build:

http://www.turbominis.co.uk/forums/index.p...tid=383285&fr=0

Cam may be a bit radical.

The P20950 are a well regarded piston. Just don't put the circlips in, use buttons instead.

You will need the bigger valves in the head. I would suggest 33/29. Go unleaded if you plan on a lot of use.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

regarding the valves i dont really want to have them too big so that i need to pocket the block/that kind of thing.
wahts the biggest you can go without doing block mods?

I'd say to make 140bhp you'd be better with a 1275.

I know I have a 998 with more than this, but it's not the kind of engine for pootling around town in and it's not the kind of engine that'll last for ever either.

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

www.twin-turbo.co.uk

well im really going 998 as i have so many 998 bits already, don't have any 1275 bits to start with, i may still go ahead with this and just down grade my bhp figure expectation, i just guaged it by looking at other peoples 998 threads. anyone got a more accurate bhp figure i can aim for? with a 998 turbo and being a road car not a track car.

100 to 120.

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

www.twin-turbo.co.uk