Aluminium for plenum chamber???

[chodjinn]

Righto, I'm going to fabricate a new plenum (with help!!) and I'd like to know what would be a suitable 1). thickness and 2). grade of aluminium to use. Been looking on fleabay and there's loads of different types.

The adapter for the trumpet base will probably be 2-3mm aluminium. Plenum will be a simple box with a throttle body on the front, possibly tapered down at the rear but nothing fancy.

Any suggestions would be great! cheers

[katanaman]

would think 2mm would be more than enough (depending on shape) but for the adapter plate I would use thicker say 10mm. You cant afford for this to warp in any way and 2-3mm is just too thin to stop this in my opinion.

[chodjinn]

ok cool. The adapter plate that i have at the moment is steel and 2-3mm so i guess a thicker alu one would be needed. The plan was to have an adapter that bolts to the current trumpet base ins the same way as the ACT one i have, then make a plenum to bolt to that. Should the skirt of the plenum be thick as well?

[Eliot]

2mm seems too thin to me. Even the OEM cast lid is thicker than that.
1/8th plate (~3mm) plate would be better. NS4 grade or similar.

Are you boosting it?
My big water intercooler expanded quite a bit when pressurised - I was quite suprised.

[CastleMGBV8]

Olly,

What about a couple of hotwire plenums cut and joined in the middle, saves a lot of hassle and you then have a feed from both sidesand bolts onto a standard trumpet base which if required you could have bored out for larger trumpets.

There was a nice polished one on e-bay last week, don't know if its gone yet.

Kevin.

[chodjinn]

Well, apart from the fact it looks absolutely gash IMO, I'd have problems with the plumbing and the turbos due to how far out the plenums would go. I originally was going to use just a standard plenum, but they extend almost to the far side of the rocker cover, which is where my turbos are! Same reason I'm having to bin the ACT carbon set up, which is by far the sexiest I've seen, but it just won't work easily. Shame as well!

And besides, i couldn't make it work with and intercooler (or two) given how compact the engine bay is, their ain't much room! I've just bought myself a nice new intercooler and throttle body and already got the plenum design in my head. Just need to buy alu now and get cutting/welding lol.

[topcatcustom]

I'm for modifying a std one- shape is already perfect, nie and thick, you could put a spacer in if need be to get a bit more hight (or cut the trumpets down) and throttle bodies can be added wherever you like! I'm doing one (when I get the other throttle body through) with twin BMW 58mm bodies next (or maybe a triple for fun

[chodjinn]

Well to make a standard one work, I'd need to chop the throttle part off and mount it on the front like the Westfield ones, then weld up the side, it would just look nasty, and I'd still need to get the throttle opened out anyway. Or I could bin the stadard throttle, weld on a new one, but then I'd have a cast plenum with a billet throttle botched on the front. Can't have any more height on the plenum, it already sticks out of the bonnet by 2". I'm already getting sick of this thing, the amount of times I've had to change things and it's no closer to being driven. I've owned it for 4yrs as well and sunk a fortune into it and all i want to do is get it on the road lol. Maybe i should sell up and just buy a cossy it would be far simpler and probably faster!

[chodjinn]

like this but with the throttle at a shallower angle;



nice eh?

[topcatcustom]

I like the fuel rails

[chodjinn]

lol so do I, but a second hand fuel rail just cost me about £15 so I'm not gonna argue!