plenum throttle options?

Seight-V8 · Post by **Seight-V8** » Sat May 23, 2009 5:04 pm

hiya all,

finally got my inlet manifold/trumpet base back from porting to 45mm by V8D.

Got it all assembled...and the next problem is the bonnet wont fit, as the 4.6 flat top plenum is too high.

Recon about 10mm to high....

So next option could be more outlay and maybe a ACT westfield plenum.

But anyone know the throttle options, as i am planning to run the GEMS efi.

Had orginally cut my 4.6 plenum up, to move the throttle to the plenum rear, but it just wont fit under the bonnet.

Could maybe use the throttle part, welded to a plate to connect to act plenum.

Anyone using a act plenum with GEMS...(dont hold up much hope here, but gotta try).

cheers

scott

CastleMGBV8 · Post by **CastleMGBV8** » Sun May 24, 2009 8:16 am

Scott,

You may have got this sorted but as I will have the same problem with bonnet clearance on the MGB I asked and was told that you can use the 3.9 plenum with the curved top on the gems trumpet base, you can pick one up for approx £35.00

Kevin.

Seight-V8 · Post by **Seight-V8** » Sun May 24, 2009 7:16 pm

Yes,

think i have a spare 3.9 plenum in my shed...could cut & shut the plenum from the 3.9 with the throttle plate part from the 4.6 plenum.

And solve my problem...

As i am planning still maybe to run gems... i need the 4.6 plenum throttle plate, as the stepper motor & throttle switch are a different arrangement.

thanks for the idea (think my brains in holiday mode).

cheers

scott

14500rpm · Post by **14500rpm** » Sun May 24, 2009 11:08 pm

You should be able to loose that much off the bottom of the trumpet base, maybe remove some from the top too. I had mine slimmed down by a local machine shop to clear the bonnet of my MX-5.

stevieturbo · Post by **stevieturbo** » Mon May 25, 2009 12:40 am

I had my old trumpet base machined too to reduce height.

You may be able to lose a bit off the manifold too....

Or drop the engine a tad ?

Eliot · Post by **Eliot** » Mon May 25, 2009 7:38 pm

You can loose some of the manifold and some of the trumpet base.

The lid doesn't have parralel sides, so you may get sealing issues if you cut too much from it.

Or maybe easier to make the lid of the GEMs plenum slightly rounded rather than graft the throttle onto a hotwire lid.

Dont rule out raising the bonnet a few MM on some thick rubbers either.

There are some photo's of the factory conversion if you are doing a cut and shut here:
http://mez.co.uk/westfield/