Suck Through Set-up
Turbo Mini Forums

Right I've been given a challenge of making up a suck through turbo set-up using a weber carb. I'm aware and understand how to connect up the Manifolds, the fuel regulator etc, but the problem is the dump valve (where it should be positioned and connected) and bleed valve as I won't be able to use an ECU. Could any of you guys shed any light on this please?

It's only being done as a bit of fun to learn from, the engine isn't in a car. Once I've fully worked out what goes where, I'll give it a try at making it up.

Suck thru is easy to set up, but not great in practice. You can't intercool, which limits potential, and finding turbos that are ok with suck-thru is also a challenge.
A 'valve' would ideally be fitted that bypassed the throttle, and was actuated by vacuum between the buterfly and turbo. This would not make a 'dumpvalve' sound at all...

Bleed valve is connected between the turbo 'signal' pipe (be it on the compressor housing or manifold) and the actuator.

Just thought.... you'll also need to ensure your actuator is ok running with blow-thru.... petrol vapours might not do the diaphram inside any good!

just use the webber in blow through...

Alex

AlexF

The thing is I have thought about using the weber on a blow through set-up but rumour has it the weber won't take the pressure and the seals will blow. I personally can't see how that would happen though as the air flow is completely sealed (solid metal tunnels with 1 fuel jet and 1 butterfly each side) from the fuel .
The blow through type would be much easier to put together though.

you need to modify the carb a fair amount but its possible

or you could use a Delorto turbo from an espirt

alex

AlexF

Dump valve first: you don?t need one with suck thru since there is no carb between the engine and compressor. These are normally applied only to blow thru and can?t see any point in draw thru. If you place it anywhere in the system it will dump air/fuel mixture and that is not such a clever idea... Remember, it is air/fuel mixture that enters the turbo, not air like in blowthru.

With draw thru you will not need any tricks to the carb, jetting like in n/a setup. Actual jets do differ though. Depending on the age of Weber there are latest spec ones like DCOE 151 and DCOE152 that are supposed to be factory ready for blow thru. Dellorto DHLA45M as fitted to Esprit is another option.

Having said that (and done the Dellorto option), you will hardly gain anything by swapping the SU HIF to Weber or Dellorto, only extra cost and fabrication.

Jukka

Ok Dave.....Here's one for you.....

My components are gradually coming together.

Faced with a suck through turbo, how would you set up a standard carb and ignition, as close as possible before a good rolling road sesh? I have my own ideas but they are probably miles out.

I can't find any references anywhere.......

Elaborate.......cheers stu. (still off the road)

Bugger off, I'm getting there.

You coud go the Tickford route of using a Webber in a blow-through. They put a sealed box around the whole carb and pressurised this. This means that the inside and outside of the carb are pressurised at the same pressure, so no need to seal it.

Clever hu?

Wil

Fastest 998 mini in the world? 13.05 1/4 mile 106mph