The AUSubaru.com.au Forums

Howdy Guys,
To get my pump to boost to the level I want I will need a few more revs out of it than standard gearing allows.

I need to make / have made / buy a double serpentine belt pulley.
With a 1/3 differencial in the pulley circumference.

Its made for medium boost on a standard 1600cc MR2 motor anyone care to tell me what that would be in PSI?

Anyone know who I should contact about custom pulleys?

Cheers,
Matt

Why run the weenie 4ag blower, start with the 1gg.
That will give you 4-5psi with full compression that will hump.
Steve

Thanks Steve, I will do, thanks for the advice.

hey what do you guys mean by a 1gg blower? is it the toyota one that is slightly bigger than the MR2 one?

cheers,
Gus.

The bigger blower comes from a Toyota 1GGZE 2 litre motor. The smaller on is an SC12 (which supplies 1.2 litres of air per revolution) Bigger one is an SC14 which similarly supplies 1.4 litres per supercharger revolution.
Stock boost on the smaller 4AGZE is 8psi and the supercharger is driven at something like 1.25 : 1. Rumour has it that they are only really able to be driven up to 10,000 rpm or supercharger reliability suffers.

There's a nifty spreadsheet on http://www.sprintex.com.au for calculating boost levels of different superchargers on different size motors. Just click on the supercharger type, then select different types until you find one with the right capacity (ie either 1.2 or 1.4 litres for the two types) From memory, you'll just have to pick one thats close, as I don't think the site lists any that are exactly 1.2 or 1.4. It definitely doesn't list the Toyota ones by name. Its not exact anyway, just good for a rough idea of what level boost you can get and what pulley ratio you'll need to achieve it.

I'm currently supercharging a Datsun 1.8 litre motor, and I've gone for a supercharger off a Mini Cooper S. These use Eaton superchargers, which are much more modern and efficient than the old Toyota jobs. They will reportedly survive speeds of up to 17,000 rpm 8O

Dave,
cheers for that info, yeah we talk about them as sc12 and sc14's over here, i hadn't heard the engine code before.

did you get hold of the mini cooper s supercharger easily? i guess it would take someone writing one off and insurance company/wrecker getting hold of it then selling the parts?

yeah the eaton would be way better, i have got a sc12 blower but i am thinking i should look for something a bit better quality.

i have got a ej20 NA sitting around, could be a goer with mild boost.

cheers,
Gus.

I got my Eaton from the UK, off eBay.

Apparently there is a "John Cooper Works" performance kit that can be fitted to the new minis, which contains a new, upgraded supercharger amongst other things. These are fitted to your new Cooper S, and you get your car back with all the replaced bits in the boot, including the old supercharger 8O

Mine cost me $450, of which postage was $200, and its basically brand new. If you look on ebay.co.uk there are usually half a dozen of these superchargers for sale at any time - the trick is finding a seller who is willing to ship it overseas.

A lot of the Mercedes "Kompressor" motors had a similar Eaton M45 type supercharger fitted - I've seen a few of these for sale here in Australia.

I'm fitting it to a Datsun 1600 running an 1800 motor which I'll be fitting with efi. I don't actually own a Subaru , I'm just on here looking for a Subaru R160 LSD as these are a straight bolt in for a Datsun 1600.

Main reason I went for the Eaton is that my car will be doing car club duties - ie tar sprints, hillclimbs, etc and the Eaton seemed more suited to this. There's nothing really wrong with the Toyota blowers, just that I was starting to push their limits as I want to run 12 - 15 psi boost, plus the little Datsun motor revs to 8,000 rpm. The Toyota blower would probably do one or the other, just not this level of boost at these revs.