Zetec inlet plenum

[gaz05]

I've tried a few standard manifolds and all seem to foul the steering column so in true tightwad style I've decided to make one. Last manifold I bought was brand new from a 2.0L engine and it has most of the bits I need to stick on a fabbed manifold. The injectors and rail will fit well and the throttle body has all the gubbins needed.

I'm doing this because I want to use standard ECU as I just couldn't be bothered to run around getting stuff mapped etc. There's also the cost element of after market Ecus etc to think about.

I haven't got the gear to do Ali so yesterday I got enough 1.5mm steel plate to do this and the fuel tank.

First consideration was the pipes from flange to manifold. I know they should really have a bellmouth or rolled shape where they go into the plenum but it's too much chew to make them. I've decided to slightly flare the ends so there will be a degree of smoothness for the air to flow. That meant making a small former to pean them over.


The plate was formed around a 40mm bit of solid bar and then welded. Once the weld was file flat at the end I put the former in the vice and slowly peaned them to the shape shown



The intention is to have a shaped plenum which is tapered. smaller at the front and getting larger to the other end which will have the throttle body on. It also means I can shape it to clear the alternator which on my engine is on the inlet side.

I'm not an expert the subject of plenums so anyone who wishes to offer advice is perfectly welcome

[gaz05]

I,ve also been experimenting with a boss to take the injectors. Slightly tapered at the top to accept the injectors.

[Coozer]

Would have just been easier to route the steering arm round the plenum??

[gaz05]

It would have been Steve but because I've got the motor so far back every manifold I've tried on doesn't leave space for a coupling.

There is a manifold out there that only sticks out 180mm from the head but I've had a problem getting hold of one. This is the original Mondeo one.


If this doesn't come out looking decent then I'll have to look at some other method

[Coozer]

Oops, just realised you showed me it before

Old age eh? What??

[gaz05]

You've got a few years before you catch up with me, young un

[David_17]

An EFI cast alloy one from an escort or fiesta rs1800 would fit. (don't know if the bonnet would go on though as it goes up and over instead of down like the rest)

[gaz05]

I've recently sold one of those David. It was Huuuuuuge. Would have been way above the bonnet line even without the throttle body.

[gaz05]

Anyway, been doing a little research here.
http://horsepowercalculators.net/int...anifold-design
Seems the best method is to bring the pipes into the plenum and stop them above the floor of the plenum. They should also be rounded at the ends to help breathing so I spent a bit time peaning them a bit more by hand.



The dimensions I'm using are probably not ideal but apart from neccesity I'm doing this just to see if I can.

I'm also going to incorporate the idle control valve and that's going to be complicated because the valve lets air into the plenum by bypassing the butterfly and taking it from an opening on the outside of the venturi.

[flyerncle]

Well done for the effort Gaz,you could use exhaust tube and save yourself a lot of work possibly.

Nice work.