VX Inlet Manifold

[GordonW]

I thought I might improve on the original caterham item the webers feed through with a Jenvey alternative but it ain't gonna fit. I think I will resort to getting the existing one flowed and matched to the head as far as possible, can anyone out there recommend someone with proven expertise in this area?

 

Edited to add: If you have or know anyone who has a standard caterham weber inlet manifold I need it so please get in touch!

 

Edited by - gordonw on 1 Apr 2010 08:26:10

[Paul Deslandes]

Gordon

 

I had my Vx head and CC Weber inlet manifold gas flowed by Simon at Ultimate Performance and the performance improvement was enormous with 48mm parallel Jenvey TBs. At the time he reckoned that the inlet manifold was limiting the max power to no more than about 220bhp. Since having it flowed we've seen in excess of 250 with more to come. The alternative is to go to either direct-to-head TBs or tapers, also made by Jenvey but with their own manifold casting.

 

I would strongly recommend that you give Simon a ring and discuss it with him.

 

Click here for Ultimate Performance.

 

Paul

 

 

[captain chaos]

Hi Gordon,

 

I can second what Paul said but Swindon told me the gains were due to benefits in the flowing both head and inlet manifold.

 

I have since seen further improvements going to Jenveys own casting which almost gives the direct to head effect but that meant a new bonnet to raise the hole cut out for the filter.

 

If you do get the inlet manifold flowed ask them to weld some webbing support near the bottom hole castings (see archive) They notoriously crack here after time (I think Roger Swift had 2 go on him and Alex Wong had similar issues). Mine went just before I did my rebuild.

[Paul Deslandes]

Sorry, I should have been more clear. I had both the head and manifold flowed at the same time but it was apparent from flow measurements that, no matter what was done to the head, or indeed to cams etc, the standard CC Weber manifold would quickly become the limiting factor, restricting max power to about 220bhp. Just doing the manifold on its own would be unlikely to yield much improvement but it soon becomes the bottle neck when everything else is modified.

 

 

[GordonW]

Many thanks guys. Paul with embarrasment at my goldfish like memory I realised just after my post that you had mentioned UP previousley, I gave them a quick call and Simon seems to be a very good bloke.

 

There has been some work done on the head by Paul Exon and the manifold (and gasket) is now being matched to the head, so fingers crossed for a good result.

 

Captain, thanks for the tip although I seem to recall the Roger ended up putting some of the 'soft' gaskets between throttle body and manifold a la original carb style as a way of reducing the effects of vibration. I'll be retaining these with the carbs.

 

 

[Paul Deslandes]

Good luck with the manifold. I know that Simon removed quite a lot of material from the throats of mine, a bit more than just matching to the head. He was careful not to take out too much to avoid breaking through or weakening the structure - so far so good as its been on the car for four years now with 48mm Jenveys and a sausage filter hanging on to it.

 

Don't worry Gordon, my memory's like a sieve these days too. Anno domini in my case I'm afraid ☹️

 

 

[ECR]

I have managed to crack 6+ inlet manifolds of both Caterham manufacture and of Swindon manufacture. I thought that I had the problem beaten when I started using Misab washers between the throttle bodies and the manifold to damp vibrations but even this set up cracked eventually. I am now using the Jenvey inlet manifold as described by the Cap'n and so far have had no problems .... It does require fairly major carving of the bonnet apperture to get it to fit as it is not cranked like the Caterham manifold but it does give a nice straight inlet tract