my engine is currently supercharged with an m45, considering turboing it aswell.
my charger is over the exhaust mani so theoretically it could be done with a bit of welding and pipework.
would it be best to have the charger feed the turbo or the other way round?
Cheers

The better question would be what are you aiming for?

I think the normal method would be to use the turbo to pre-charge the supercharger but be prepared to deal with getting rid of a lot of heat or your efficiency will be horrendous. Personally I think I'd probably just stick another pulley on the SC or increase it's size, adding a turbo just adds complexity, weight and risk, but it sure would be fun to try.

The Graham Bell book (Forced Induction Performance Tuning) mentions this a bit.

Turbo - cooler - supercharger - cooler - intake.

The wikipedia page is informative http://en.wikipedia.org/wiki/Twincharger

I'd worry about how to control it all!

What engine?

I have an MP62 charger on a 1.8 MX5 engine.

That will spin on a 1:1 ratio and give around 250 - 270 bhp which is right on the limit of what the standard engine will take.

If you forge the engine you can use an M90 to get to 300bhp.

Spinning the charger any faster give heat problems even with an intercooler or chargecooler.

A Turbo on a forged engine will give more than 350bhp which is where the gearbox etc start to become suspect.

The way twin charged diesels work is that the two chargers are in parallel not in series. There is a flap valve which the turbo by passes the super when the boost pressure is higher and an electric clutch disengages the super to take the load off the engine.

It may be a bit complcated but its the most efficient system.

i know it wouldn't be simple but it would gimme a nice wee task and a big smile if it worked! thanks for the links and the info so far

would the charger not be restrictive if after the turbo if placed in series?

you need to read the build thread on here called twin charged kitten.

cant remember who it is but he tried all sorts of things and has photos. he was using a saab lump i think and IIRC decided to cut the lot out and slap a massive turbo on. this created massive lag but great traction control!