5 replies to this topic

[jpc]

Hey, i'm very new to the whole mini scene and am looking for some advice. I am currently restoring a 86 mini mayfair with a standard 998 engine. i am a long way from finishing the restoration but would like to decde what to do to the engine to gain an extra bit of power so that i can be looking out for the parts i want. I like the idea of a 998 turbo but dont know much about them,i have looked at loads of fourms but am still confused as to what is actually involved. My aim is to end up with a reliable 90 -100bhp engine, Would alot of the stard parts be ok for this power like gearbox and pistons and distributor. i was tinkin of trying to source a standard 12g295 head, would this have to be skimmed for the right CR. I also would like to upgrade the cam, From looking at other fourms ii see that alot of people use a metro cam or the kent 500(i think), it this what i should be looking for.As for turbos i was going to go for a T2 turbo from a renault 5 or is there another turbo that would be better. I was thinking of getting the exhaust manifold made up from stainless steel so that the turbo could be located over the gearbox or somewhere as i dont want to go cutting the bulkhead .Now its from here on in that im seriously confused. What type of carb could be used and inlet manifold(cud this be made up in stainless). Minis are very scarce where i live so sourcing metro turbo bits could be a challenge. Also will the standard fuel lines do the job and as for fuel pressure regulator and fuel pump, can these be got from another turbo car at a scrapyard. I no that the turbo requires oil feed and return pipes but thats as much as i know and do i also need an oil cooler , Also i was thinking of fitting a intercooler but what type could be used as i cant see any place to put it, And where do these intercooler pipes actually go,I no i dont know much about it but would like to do a project like this and am willing to learn, any help will be apreciated just to get me on the right track.

[Cooperman]

With turbo-charging or supercharging the compression ratio needs to be lower, not raised. The pistons also need to be capable of coping with the application.
The distributor needs a very different advance curve to prevent 'detonation' which would quickly destroy the pistons.
For the cam, you certainly don't want one with too much valve timing overlap, as that would require very high revs and turbocharged engines don't need to rev so high. An MG Metro cam would probably be fine, although something like a Kent 255 might give the best power band.
You need to really 'read-up' on forced induction technology and the various calculations involved with it. You will find that the maximum boost pressure will influence the other considerations. Do your homework first. You might consider a supercharger on a 998 as that used to be a good solution when the Shorrock unit was correctly fitted (Google 'Shorrock Supercharging').

[Liam Mini 35]

To get the compression low enough you will have to either use dished pistons or have the chambers in the head enlarged. Your also going to need a turbo hif 44. Have a look on turbo-minis.com and turbominis.co.uk. Look at turbo-mini first a lot of info and its very easy to understand. Tuen go over to turbominis and become very confused. Lol, there is so much info abailable on both sites. You may also want to consider buying tuning the a-series by david vizard.

[Wil_h]

To get the compression low enough you will have to either use dished pistons or have the chambers in the head enlarged. Your also going to need a turbo hif 44. Have a look on turbo-minis.com and turbominis.co.uk. Look at turbo-mini first a lot of info and its very easy to understand. Tuen go over to turbominis and become very confused. Lol, there is so much info abailable on both sites. You may also want to consider buying tuning the a-series by david vizard.

If you use the 12G295 head with the standard 28cc chambers on flat-top pistons you get around 9.4: CR, this is perfect for your aimof 100bhp whch should be achievable on on around 10psi.

All the standard engine and gerabox stuff will be fine with the exception of the diff, a crosspin would be advisable.

I have found that the Minispared mega range of pistons are decent for turbo charging, but the 20773 and the later slipper pistons are fine as long as you are sensible with boost.

As said the dizzy needs to be in the bin, mapped ignition is the best solution, and the HIF44 is the easiest route, using a metro plenum.

Finally, the MG cam is perfect, but a standard cam would also work.

[jpc]

Thank for the quick replies.
I Have done alot of research into forced induction and have looked at other 998 turbo projects and i do grasp the basic idea but need a bit of help for certain bits as im struggling to find a simple explanation i can understand.
So the standard distributor should be ditched, is the megajolt kit the best way to go or is there a cheaper alternative as from goin by ebays prices its an epensive bit of kit.
Would you get away with using a standard diff or is ugrading a must?
I am still a bit lost with the oil feed and return to the turbo. is the return just going back to the sump? where would i get the feed from?
Also as for the intercooler, where is the best place to mount it, also does the intercooler pipeing connect it directly to the carb as im not too sure
And can the fuel pressure regulator and fuel pump be sourced from another car instead of a metro turbo.
Any ideas where i could source some of these parts, like the carb, inlet manifold fuel pump and regulator?

[samsfern]

oil feed to turbo is taken from where the oil pressure switch goes at the front of the block, via a t-piece, so you can still run a oil pressure gauge/switch. Oil drains back into the block via the fuel pump hole at the back of the block. As for intercooler, the best place to mount one is where it will get maximum air flow.