Looking for some advice.
Turbo Mini Forums

Hey guys, i've been reading through the forums trying to figure out what i need etc if i want to go Turbo with my mini. I'm sorry if this is the wrong area of the forum to post this.

I'm rebuilding a mini at the minute, and the body work is pretty much finished. I don't want to cut into the bulkhead if i don't have to. So the mirage manifold seems like the right choice here.

But here's the thing, i have a 1330 engine, thats recently been re-honed/skimmed, and a stage 3 head. Inside the engine is a SW-5 Cam, balanced crank and omega 7.5 pistons. It's getting rebuilt soon, so instead of just putting it back together, is there anything i would need to do/get done in order to prep it for a turbo?

Would this engine be okay for a turbo? I'm assuming i'd have to use a T2? Simply because of the size and fitting it under the engine bay?

What's the story with gearboxes? What's required to handle the output from a turbo'd 1330?

And finally, this is probably a very stupid question, but from reading posts on here and looking at the pictures, the carbs all have a box sitting behind them, doe's this replace the standard air filter?

Thanks very much for your time if you've read all of this, and thanks in advance if you have answers for any of my questions!

p.s. Mods, please move this to the right section if it's in the wrong place!

N. Ireland Mini Forum: http://www.mini-chat.co.uk

1) You want to get your compression ratio down for turbo use. i would suggest around 8.5:1 as this will; give you scope for the inevitable winding up of boost in the future. To get your compression ratio down you want either the chambers in your head enlarging, bigger dished pistons, or both. Talk to BENROSS for the head machining work. Someone more clued up on cams will advise on an SW-5.

2) the mirage manifold is designed for a T2 Turbo so yes you would be best using that.

3) Gearboxes....it is accepted on here that anything over around 100bananas (its really torque that kills them but) will need an uprated gearbox. I would suggest the minispares Clubman SC gearset. Also an uprated diff (cross pin?) and SC drop gears.

3) the thing behind the carb is the plenum chamber. your boost pipes that go from the turbo outlet connect there, idealy for any respectable amount of boost, via an intercooler. The air filter now moves to the inlet on the compressor side of the turbo, as this is now technically the start of your inlet "track"

Hope that helps.

Edited by James_H on 3rd Mar, 2009.

Top answers from James.

Take a wander through Turbo Phils site, it gives an excellent introduction into turbocharging minis.

www.turbo-mini.com

Thanks very much guys, i'm reading through that link right now. Easy day in work enh?

My engine seems to be fine, it's the gearbox that will need looking into, and i might need to double check the pistons i'm using, so i can get the right CR.

The only headache is positioning that turbo, the mirage system really does seem the best choice!

Is a T4 turbo a lot bigger than a T2? Because i have one available stupidly cheap and brand new!

N. Ireland Mini Forum: http://www.mini-chat.co.uk

There is no T4 turbo suitable for a 1330cc engine.

The helical box is infact capable of much more than Jame alludes to. The first weak points are the drop gears and the diff pin.

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

Fantastic!

So i'll stay away from that T4, T2 it is for definate!

Looks like i'll just built my engine as normal, checking the CR but the gearbox rebuild will need a few goodies!

I'll get the car up and running and gather all the bits and pieces for a turbo then! More research to do still with regards intercoolers, dump valves etc!

The 1330 should already be near 100BHP, it was dynoed at that before i stripped it for a rebuild, it fired a gear through the casing!

What sort of BHP could be expected a T2 turbo fitted?

N. Ireland Mini Forum: http://www.mini-chat.co.uk

With an efficient intercooler running at 12psi with a decent head, I'd say 140 to 150 more should be easily achievable.

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

perhaps i was thinking about 100 ft-lbs (maybe NM?!) torque then?

seem to have 100 somethings in my head for a gearbox limit...