First Engine Build
Turbo Mini Forums

Hi, I have been browsing these forums for a while now collecting info on the turbo conversion, and I am now at the stage where i need to decide what engine spec to go for.

I have a standard metro turbo lump, which I am fully rebuilding before it goes in my mini, I was hoping for a BHP of around 100-110, Whats the best way of achieving this, obviously the cheaper the better. It is a daily driver so I dont want to be shreading any parts, and I want the compression ratio quite high. BTW I will be running a std T3.

Any help would be greatly appreiciated.

Thanks, Kav

Just turn the boost up a bit .... that is cheapest.

I'm looking at doing somethign similar for my girlfriends engine and to me the best bet is to change the cam (MG Metro / Kent 500 can normally be found for nearly free as lots of people pull them for something hotter in NA engines).

A bit of blending work on the manifold parts and you should be well in on the 110BHP plus, all so far for nearly free!

Every day is a school day ...........

How fast and how expensive ...... the same question...

For that sort of BHP, all you will need is a tad more boost and an intercooler.

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

Hi,
A standard rebuild with an intercooler and 10 psi should see that much, plus a bit more. You may want to go for a straight cut transmission and mapped iginition system though ...
Cheers

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My Mini build diary

Thanks for the quick replies, so what kinda boost can the standard compression ratio take? or will fitting an intercooler do the trick for the sort of power im after. Also straight cut gears were mentioned, I'd like to avoid this route if possible, as it aint so cheap, what kinda gearbox mods could i get away with? centre main strap, centre oil pickup be ok?

Cheers,

Kav

well i know a bloke with a standerd metro turbo lump in his mini running 10psi with out an intercooler!

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985

A well rebuilt box can handle around 140bhp spec (it's the torque that kills them, especially in first).
I normally put a switch, connected to the standard boost solinoid, into the selector housing so that when in first I can only get actuator boost (normally run an Escort RS Turbo actuator on a T3 .... around 7psi)

I don't like straight cut boxes in daily drivers, the noise soon gets to be a real pain. By the time you NEED an SC box you will not be on a budget build IMHO!!

Again an RST can provide a reasonable intercooler for upto about 12psi (10psi is where your going to want to be!)

No point in fitting a centre main strap if the engine isn't going to rev highly. That said it is cheap insurance.

Every day is a school day ...........

How fast and how expensive ...... the same question...

Hmm how long will that hold out though? If im shelling out for a rebuild I want something reliable, and driveable, hmmm t3 driveable?, anywho cheers for the posts, got some options to take, like the sound of the almost free upgrades though...

I did well over 20k miles with the engine in that spec with only a rebuilt standard box (well done) and a 4 pin diff.

I didn't mention how essentail that bit is .... ooopppsss.

Every day is a school day ...........

How fast and how expensive ...... the same question...

Yer 4 pin diff was gonna go in, i've heard minisports should be avoided for the diff... think I might go for summet like that, hows this sound

Std metty turbo block and pistons
standard turbo head, possibly with the chambers enlargered to lower compression slightly.
standard rocker gear
4 pin diff
10 psi boost
rs intercooler
standard oil cooler or maybe a smaller 6 row
centre main strap, worth it?
centre oil pickup, worth it?

Centre main strap is worth doing for the little it costs. Centre oil pick up is a MUST. Oil cooler probably unneccesary, fit a gauge first.

Hi Kav, Thanks to the huge help from members of this forum I managed to build a similiar sort of engine (my first Turbo) which gave the power figures you are after, and built with reliabilty in mind have a look at http://www.turbominis.co.uk/forums/index.php?p=vt&tid=139114

Hope this helps a little with your decisions and good luck with it. Cheers
Deano

Hi thanks for the support roadrocket, your setup sounds like the kind of thing i'm looking for, you mentioned you increased head capacity to 29cc, what compression ratio does this give you, also what size valves are those?

What is it like to drive off boost? cos I've been toying with the idea of a t2, also what psi were you running to achieve 110bhp? as there were some differant gauge readings,

Cheers,

Kav

Hi mate not accurate on the comp ratio mate Im affraid but I believe its near 8.8:1

Off boost the car drives like a dream, still very torquey before the boost comes on and getting about 35ish MPG when cruising Motorways etc. You can see from the torque curve at very low RPM (1500) the torque is over 90lb/ft!! probably down to the smaller 45mm intercooler pipes.

110BHP was achieved on the standard actuator I believe it was only 4psi. Visiting another rolling road soon so I will clarify the BHP when at 8psi.

The Cylinder head is as follows (taken from Minispares site) but the chambers have been reground as recommended by BENROSS who I am sure can do this for you.

The head has Cooper S valve sizes as follows:

MSE3 - PRE 1992 unleaded Stage 2 (Road Rocket) large-bore head
Part No Applications: MSE3, C-AEG544, C-AEG106, TAM2069, C-AJJ4037, C-AEA526, ADU4905
Inlet Valves 35.6mm(1.401") dia. Tuftrided EN214N s/steel P/No. C-AEG544
Exhaust Valves 29.5mm(1.161") dia. Tuftrided EN214N s/steel P/No. C-AEG106
Exhaust seats Latest type Beryllium-based for lead-free fuel P/No. TAM2069
Valve Guides Magnesium bronze P/No. C-AJJ4037
Valve Springs Nominal 180lb. Max actually valve lift 0.500" P/No. C-AEA526

Hope this helps mate.

Cheers

Deano

Edited by Roadrocket on 27th Feb, 2007.

Thanks that helps alot, the only thing confusing me now is wether to mod my std turbo head or not, if your getting that kinda power at 4psi, then without the modded head and just the n/a cam with 8ish psi I might be able to hit the same kinda figure, but then again I suppose u lose some driveablity off boost...

cheers,
Kav

Oh BTW the only reason iIm leaning away from differant valves is that the std has the sodium filled exh. one's are these worth working around, or do they make little or no differance, also did you get the 3 angle valve seats done?

Cheers,

Kav

Best thing to do is do a search in Turbominis Forum regarding the sodium filled exhaust valves. I originally asked the same question before I replaced our Turbohead for the N/A stage 3 head. I believe the MS3 head did come with 3 angle valve seats.

IMHO, no need to lower the CR if you want 100-110BHP, as its a bit of give and take...take more out of the head give more boost... Lol

I ran my mini for 2 years about 10,000 miles at about 10PSI, ran spot on with an intercooler no probs.

Main things needed.

Decent intercooler
2 core rad
Decent clutch plate (Orange is a good compromise good clamping force and you don't end up with a left leg like popeye!).
And as Roger says if you can get hold of a cheap or free cam even better!:)

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1/4mile in 13.2sec @ 111 terminal on 15psi

thanks for the reply, what kind of power were you getting, obviously not needed to seriously mod my head would cut down on costs, so atm ive decided on minispares cross pin diff, rs intercooler, 2 core radiator, bleed valve, dump valve (any reccommended for this kinda spec?

Cheers, Kav