Need help with engine decision!
Turbo Mini Forums

Right, mini build has gone into full swing with the shell being welded as I'm on holiday.
But that brings me as to what to do with my powerplant as I could do with getting it running as soon as I am able to.
The parts I have in my possession are a 73.5mm bored block, n/a mg metro cam, a crank, ultralight pre verto flywheel, a series rods, an a box and transfer case with a metro hle gearset (needs stripping and rebuilding anyway) Soon to have a std 12G940 head too. Then I have an Spi tank with mpi pump, turbo hif44 and inlet, t3 and manifolds, 2" exhaust system, montego plenum which I will use with a Pitot tube, a cossie 4wd intercooler, i have a megajolt ecu but no other parts for it yet.
Now the original plan was to build this up for 170bhp, full straight cut box and drops, 4 pin diff, omega pistons, a decent head, but those are the parts I'm still left to buy, along with the associated gauges (mainly wideband and boost) and what's left of the megajolt setup. If I do this it's going to take me quite a while of saving and the car will probably be sitting without an engine for ages. Don't really want to stick a 998 in there because that would be a step backwards in power. If you were me, what would you do?

Build a 998 and bolt on the turbo bits . Cheap as chips to build so you can save up for the other bits then swap the lumps over.

Rick

I would say do it right first time, it will be cheaper in the long run

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

How about selling the block, finding a 'good value' block and pistons and building up the bottom end with the other bits you have now and run it n/a and convert to turbo as and when?

As for the box, drops etc, this can come at a later date. At least this way you can get it on the road

In fact, do a bit of home chamber work yourself and go straight to turbo. Either find the cash to get the extra megajolt bits or run a dizzy to start?

That was going to be the plan with the head maybe, find an old free or cheap head to practice on, and then port and resize the chambers on my own head, get manganese bronze valve guides fitted and bigger better valves. Reckon I could get away with running a standard box and drops at say 100ish hp? Until I get a better box of course. What would people say as far as pistons go? Should I just go straight for omega's?

well I've just taken the SC box and drops out of mine and I'm looking at perhaps 140? clearly it will all come down to how well it is all built and the condition of it all.

Remember Robert is still running helical drops with 'a lot' of power.

Has anybody used the short height pistons?
I can't seem to find any sensibly priced pistons for my application.
Obviously because I am having a 1380 I need to get as much volume from the engine block as possible and then enlarge the head chambers for the CR i want. So with a 170hp goal in mind, would 11cc normal height cast pistons work? Or would 11cc short height cast pistons be better? I think the turbo bikes do it that way but I can't find out what pistons most use apart from the 18cc accralites.

didn't use nick use standard pistons for 200bhp and didn't have any dramas.

Understand where the questions are coming from now

I will report back soon mate

Haha cheers Mark :)

http://minispares.com/product/Classic/Engi.../73.5.aspx|Back to search

After Mark coming back to me with what he ran, what are peoples thoughts on these? May be able to get an extra 2cc out of them safely i reckon. That's if people think they're up to the task?

.. Stick with the omegas. I really couldn't fault them.

The 11cc cast Omegas from MED are £312, can't see anything about postage cost though, anyone know if there is one and how much?