9 replies to this topic

[shaddy]

I'm looking into making a plenum chamber for a super charged engine which will be running injection. I was thinking of a round alloy tube with a domed end, and at the other a tapered end for fitment of the throttle body.

My question is how big does the chamber need to be I have read a few things on the internet some say 1.3 times the engine capacity others say 1.5, and from what I have read the size can have different effects on how the engine performs in terms of throttle response and on overall power. also does the volume of the inlet manifold count as part of the chamber.

[dave1293gt]

I know a few people with kit cars that used a chopped up alloy fire extinguesher. The hardest part is getting bell mouths of the right size welded in place. Ideally mount the inlet tracts, flat plate with bellmouths fitted then cut the F/e to enable it to be welded to the flat plate. As for volume sizes affraid i have no idea.

[mini93]

There's quite a bit on google if you manage to search the correct terms, iv seen articles Which say tapered away from the throttle bodie end is the way to go... That principle I'd assume works more on non siamessed engines though with a port per cylinder. The idea being to get the pressures across each bellmouth the same, regular cylindrical tubes were shown to drop pressurer at the end of the plenum

[dave1293gt]

http://www.google.co...LLsPn8QOiqcXIAw

If that link has worked they are made locally to me by a good friend. They use jenvy individual tb's and inlets the rest is custom apart from the internal bellmouths that are also brought in. Not cheap tho as there is a lot of man hours in them. Plus they are proven to work.

Not sure if the same principles will work on the aseries due to sharing the inlet ports. Pretty sure this will have some reflection on plenum volume.

Edited by dave1293gt, 01 February 2012 - 11:32 AM.

[Ethel]

There might be some software available to help.

My guess is fairly long tracts after the chamber would help with a siamese head. Wonder if it'd help to put the inlet/throttle between the ports if there's only 2?

[shaddy]

I have also thought about putting the inlet to the chamber in the centre, I think this I a good idea and should provide even distribution maybe even use an air horn on this intake to improve the flow.

For the inlet manifold I was thinking about making something like that used on a Weber about 7" long with the injector as close as I can to the port.

[Wil_h]

Not too sure what you're planning here. As it's injection I presume that it will be blow through, right?

Also I presume that it will be a 5-port head, right?

If you are planning on using port injection, then you really need to carefully think about your injector positions as well as your plenum design. You will also need to run the siamese code on the Ms2 or MS3. This is a useful link to look at if this is your plan http://www.turbomini...tid=129557&fr=0 There is lots more info on turbominis about port injection and siamese code.

If you are planning a wet manifold setup (like the specialist components kit) then the injectors are positioned before the the split in the manifold, so there is no need for a plenum as the manifols does this job.

If you are planning a 7 or 8-port setup then you will need a plenum.

Edited by Wil_h, 01 February 2012 - 02:37 PM.

[shaddy]

Yes I am planning a blow through setup. On a five port head

Injector positions I was thinking one per port. so i would need a plenum chamber and an intercooler. I will be using a camems ecu which i know can run Siamese codes.

never crossed my mind about running a wet manifold injection system like the SC version i thought that wouldn't be as efficient

[Wil_h]

The Canams does not run siamese code as far as I am aware. It runs a semi-siamese that is esentially a refined wet manifold system (as I understand it). If you are planning on running siamese injection with ingectors in the ports you'll need 4 (one for each valve) otherwise you can't run the siamese code. as I said, go on turbo minis and read the threads. It's not so complicated to be impossible, but there are some important things to consider, such as using a specific type and size of injector, their positioning, cam sensors etc.

If you are using the canams, then you can just use a wet manifold setup and run the canams bodge to make it run 'better'. I personally use a single TB with two 440cc injectors on a wet manifold. I run MS1 firing the injectors 4-times per cycle alternativly.

I have no plenum, just the IC piped straight into the TB. It works fine. Your Canames should be a slight improvement over this. the siamese setup is superior, but for me it wasn't worth all the extra effort.

When I wanted the ideal setup, I binned the5-port head and fitted a 7-port, gets rid of the shared port problems in a stroke.

[shaddy]

my mistake it is only semi siamese but this would still work as i meant one injector per inlet not port, i have also started to look at the post on turbomini forum some intersesting reading on there