Adam's Homemade Plenum chamber thread

Eliot · Post by **Eliot** » Sat Mar 24, 2007 9:15 am

katanaman wrote: By the way has some posts been deleted edited out of here as the thread seems disjointed?

Indeed - i was thinking that. Remind me why you are making this plenum and have you any photo's sketches? -

adamnreeves · Post by **adamnreeves** » Sat Mar 24, 2007 6:09 pm

I am installing the RV8 into a westfield. For bonnet clearance I need to reduce the trumpet length and also the air intake has to be moved from the side of the chamber and moved to the end for clearance also.

As this is a new build I do not have an existiing plenum chamber. I see many going on ebay for prices of £150 and upwards and apparently westfield charge £500 to make the changes. Looked at the ACT performance solution and that looks an even more expensive option.

Knowing myself, I will probably go for downdraughts, IDF, whatever they are called so do not want to spend this sort of money only to upgrade in 6 or so months.

I have not done any GRP work and have been looking for an excuse to practise.

In terms of drawings, I do not have any yet, I was hoping to do these today but something turned up. All I have figured out at the moment is that I need to fabricate a flange to go around the plenum base to provide a better seal for the GRP chamber. I am looking to make the chamber so that internal width and length match the base. It will kind of look like a loaf of bread with the ends being 75mm in height and the top highet point will be 90mm. It will take 71/72mm throttle. If you know the shape of the ACT chamber it will not be too different from that, however I think mine is lower and the trumpets are only 10 and 25mm long. I could lower on the chamber but the throttle body will not fit in an aerodynamic fashion.

All this is also kind of educational, had I gone for a ready made one I would not learn what I am to learn about here. Who knows I might be able to sell a couple of thee once I have a mould? I might selll cheaply to someone that is prepared to foot the dyno bill to hone it a little!!

Comments?

Eliot wrote:
katanaman wrote: By the way has some posts been deleted edited out of here as the thread seems disjointed?
Indeed - i was thinking that. Remind me why you are making this plenum and have you any photo's sketches? -

ihatesissycars · Post by **ihatesissycars** » Sat Mar 24, 2007 6:17 pm

Act put a flange on the twin plenum they make.

Here's the metal flange that bolts to the trumpet base.

And theres a corresponding flange on the plenum top which screws to the trumpet base.

adamnreeves · Post by **adamnreeves** » Sat Mar 24, 2007 6:42 pm

Yep, thats what I intend on doing, I have looked at some pictures of the ACT version and can see why this is done so I am adapting on my design.

ihatesissycars wrote:Act put a flange on the twin plenum they make.

Here's the metal flange that bolts to the trumpet base.

And theres a corresponding flange on the plenum top which screws to the trumpet base.

Post by **Coops** » Sat Mar 24, 2007 8:19 pm

Eliot wrote:
katanaman wrote: By the way has some posts been deleted edited out of here as the thread seems disjointed?
Indeed - i was thinking that. Remind me why you are making this plenum and have you any photo's sketches? -

If they have been deleted then it was not by me

Post by **katanaman** » Sat Mar 24, 2007 10:44 pm

you will get a plenum top for a lot less than £150 as whole injection systems can go for that. Or dont you have anything yet?

adamnreeves · Post by **adamnreeves** » Sat Mar 24, 2007 10:47 pm

All I have is the intake manifold and trumpet base. Shortened flared trumpets already installed. But the cost of modifying the plenum top would cost more than my home made one and not be as efficient. (I hope)

katanaman wrote:you will get a plenum top for a lot less than £150 as whole injection systems can go for that. Or dont you have anything yet?

adamnreeves · Post by **adamnreeves** » Sat Mar 24, 2007 10:54 pm

Spent a long time thinking about these templates! But this is the closest thing I have to a diagram. First template is the rear end showing where the throttle intake will be, second and third templates are for the middle of the plenum section and fourth tempate is for the front.

Also see my trumpets in the foregroumd.

Higher res one here:
http://www.westfieldbuild.com/images/hi ... G_1798.JPG

pitsnow · Post by **pitsnow** » Sun Mar 25, 2007 10:53 am

adamnreeves wrote:Knowing myself, I will probably go for downdraughts, IDF, whatever they are called so do not want to spend this sort of money only to upgrade in 6 or so months.

Adam, I have a set of 44 IDF with manifolds and even a spare 44 IDF carburettor that will be for sale. The jetting will be very close as our engines are similar. I also have lots of main and air jets and emulsion tubes. Send me an e-mail if you are interested. We may be able to trade your plenum solution as I want to use a blower on my engine.

adamnreeves · Post by **adamnreeves** » Sun Mar 25, 2007 3:50 pm

Acutally didn't think too much about that statement, I am injected and dizzyless and will be using megasquirt.

pitsnow wrote:
adamnreeves wrote:Knowing myself, I will probably go for downdraughts, IDF, whatever they are called so do not want to spend this sort of money only to upgrade in 6 or so months.

Adam, I have a set of 44 IDF with manifolds and even a spare 44 IDF carburettor that will be for sale. The jetting will be very close as our engines are similar. I also have lots of main and air jets and emulsion tubes. Send me an e-mail if you are interested. We may be able to trade your plenum solution as I want to use a blower on my engine.

adamnreeves · Post by **adamnreeves** » Sun Mar 25, 2007 4:05 pm

Today I cut out my templates and started making the base flange template.

http://www.westfieldbuild.com/images/hi ... G_1800.JPG

ian.stewart · Post by **ian.stewart** » Sun Mar 25, 2007 5:13 pm

Are we prototyping a toaster???????????????????, ----------------------------------------------------------------------------------------------------------------------------------------------------- sorry Ill leave now

adamnreeves · Post by **adamnreeves** » Sun Mar 25, 2007 8:17 pm

ian.stewart wrote:Are we prototyping a toaster???????????????????, ----------------------------------------------------------------------------------------------------------------------------------------------------- sorry Ill leave now

ihatesissycars · Post by **ihatesissycars** » Sun Mar 25, 2007 8:18 pm

Is that not too tall?

Post by **katanaman** » Sun Mar 25, 2007 8:30 pm

ihatesissycars wrote:Is that not too tall?

I was thinking that too.

Does anybody know if there is such a thing as too large a plenum?