forced induction in a mark two

[justin]

if it helps anyone i have been looking at forced induction for some time

i first looked at turbos and decided that the standard metro unit will not fit without serious mods so that went out the window. I did manage to aquire a janspeed Metro turbo setup which would have fitted but it was a bit beyond repair so i gave that idea up even though it would have worked and sold it on on e-bay.
Next i became convinced that the eaton supercharger was the way forward so i spent three years collecting parts to do this to my mark two but there are a number of problems to overcome, the biggest is where you put the carb and there are 3 options. 1st you can put it where the mini boys do down the front of the engine but i discounted that as the hif44 is too tall and would require cutting the front of the car and the bonnet 2nd you can put it behind the supercharger with a 180 degree bend but this has to be fabricated and is still quite tight (this is what i did in the end) third option was to put it on a straight pipe or use the webber manifold that vmax scart supplies and use a pedal box to they can sit where the master cylinders go, i liked this option but the cost was high £500 for the pedal box and £150 for the webber manifold.
Whatever you do the supercharger will allways foul the bonnet so you have to introduce a bonnet bulge and a substantial one at that to clear it.
again people think that supercharger means huge power, it does not! the amount of money you have to spend to get the engine to produce much above 120bhp is enormous, anyone who thinks they can just bolt on a supercharger with the steel sandwich plate to get the right compression is kidding themselves, you might get 20bhp increase this way if you are very lucky and you will still run the risk of killing the engine to get a reliable high output costs a lot of money with many necessary mods and a propper 8:1 compression ratio you need forged dished pistons, big chamber head and remember a standard 1275 might get 12psi boost which will bring it close to detonation with standard pulleys but a sorted engine up to 1380 will need pulley experimentation as the standard ones run at about 6 psi on a sorted ported engine. this means you really have to go megga jolt to get the ignition right and stop detonation too of not intercooling, where do you stop?
i spent 3 years pawing over articles trawling the internet and working out what i needed to do and in the end i have decided to give up on this route and go the Vtec route which believe it or not is far easier to set up, ok you have to cut the lights off but so what you can run the engine standard for at least 180+ bhp mile after mile. the supercharged mini engine is not easy to set up properly and suffers from reliability unless you spend fortunes.

[Hans Efde]

I agree completely having driven a Gold with a MED turbosprint engine for 5 years now. The previous owner had already done quite a few good things solving many problems. To name a few:
- fantastic engine, slightly hotter cam shaft, 1,5 rockers, leadfree valve seats
- new Garret T3 turbo
- lowered compression
- manual adjustable waste gate, I run it now at 15psi without problems
- turbo ignition by Aldon, stiffer springs on the centrifugal weights for a slower advance
- dump valve, this blows of excessive air during gear shift, the turbo keeps happily spinning at 120000rpm, no more turbo lags when on song
- hydraulic clutch with race diafraghm, no more clutch slipping
- straight cut drop gears, the weakest gears now strongest possible
- extra strong diff pin
- home ground SU needle to give extra fuel for the extra oxygen

But there were problems when I bought it
- low oil pressure due to oil getting really hot
- heat under the bonnet
- useless Montego (2ltr!) intercooler
- standard open air carter ventilation
- 9% CO to get a decent acceleration
- very noticeable torque steer

So I did the following:
- Oil cooler with thermostat, oil now a stable 75degr.
- KN filter in the nose, nice and cool
- Small Ford 1.6 intercooler (but not yet installed)
- adjusted timing to 15degr BTDC at idle, solved the acceleration problem
- now at a normal 1,5% CO
- removed Montego intercooler
- big air hoses to cool turbo and bring fresh air to the KN filter, it's now cool under the bonnet!
- played with several SU needles, still not a good one
- 3.15 diff instead of the 3.44, still very fast, but a few less revs on the high way

Generally the car now works, but there are niggles:
- excessive fuel consumption, also during relaxed cruising
- axial play on the crankshaft due to the race diapraghm being too strong
- already too much play on the drop gears
- very noisy, acceptable for short trips but very fatigueing for long trips
- still torque steer

In the end it's too much hassle for say just 130BHP. The fuel consumption is completely unacceptable. I am thinking of selling it if I have found a modern replacement and if it could be financially even (more or less). I have planned a visit to the Toyota dealer to take measurements of the first Yaris type. I think the 1.3 or 1.5 Tsport might be interesting. Also here not a quick project due to other commitments.