Custom Plenum

[Jman]

Whats the whole idea behind the Rajab plenum? Why does it look so small in comparison to others?

[carbz]

so I would be better off going for say 5-6L volume?

Do you say keep the taper for a looks thing or because of the theory behind having one?

I was planning on using studs on the hoses inside the plenum and using a nut on the underside of the runners accompanied by some threadlocker.

[GR8XR6]

Some good info HERE

[austcro]

Some good info HERE

Good article GR8XR6

Yes the taper is a fundamental design element. Without it the inertia of the air being forced into the plenum will naturally carry it towards the rearmost runner, the taper will counter this somewhat.

[carbz]

Thanks heaps for the info guys. I now feel confident enough to finalize the design. ill get some pix up once its done

[GR8XR6]

How come so many manufacturers of plenums have gone for the from the front and not from the top like the APS ONE HERE???

[discostig]

Clearance under bonnet? Air comes up from intercooler underneath too so it's a shorter path?

[Jman]

I'm pretty sure the idea behind the aps one is to deliver the same volume of air into each cylinder.

However the pipework on that plenum looks to be pretty average imo.

I'm a little iffy about front entry plenums on a long motor such as the Barra.

On something like a SR20, doubt there would much of a problem however a long motor like this would starve cyl 6 and feed cyl 1 heaps.

[carbz]

Design is now finished. only thing missing is map sensor mount. I will sort that out when I trial fit the plenum coz I couldnt be bothered pulling everything off to get to it.

All parts are in getting laser/water jet cut at the moment. should hopefully see them in a week or so depended on how busy they are.

I went with 5.5L capacity

[GR8XR6]

Will you be flow testing these? Also how come you decided against 2 large holes rather than 6 smaller ones?