VX - Swindon Inlet Manifold

[ian balson]

Anyone out there using a Swindon Inlet Manifold, on a Carb setup. I'm interested to know if you had make any bonnet mods.

 

The guys at Swindon reckon the standard Caterham manifold could cost you up to 7hp on there 215hp kit.

 

Just doing a bit of long term planning

 

Rgds

Ian

 

ian_balson@yahoo.co.uk

[Peter Carmichael]

Arnie is vocal in condemning the Caterham inlet manifold. He will be a long shortly.

[Foxy Smith]

The Swindon manifold is supposed to be much better but the Caterham version can be improved. The Swindon version I believe has much straighter tracts, that being the case I would imagine that some bonnet mods would be required.

 

[EFA]

Foxy's correct.

 

The Caterham exhaust and inlet manifold's, plus some wrong factory jetting meant my 235 spec engine gave only 196bhp on a dyno when tested in that configuration!

 

Fat Arn

Visit the K2 RUM site

See the Lotus Seven Club 4 Counties Area Website here

 

[Paul McKenzie]

Foxy,

How do you improve the Caterham version?

Paul

[Foxy Smith]

Paul,

 

I was aware from speaking to Arnie prior to purchasing my car that the Swindon modded engines were badly let down by the use of the Caterham inlet manifold and also to a degree the exhaust system used. That being the case, when I took the Webbers off for a re-build I was not too surprised to find a badly finished(unfinished) interior to the casting. Casting flash had been left in large ridges parallel to the flow and also across the flow at both head and carburettor ends of the inlet tracts. An hours judicious work with a die grinder with alloy cutting burrs has made a big difference to power and interestingly has deepened the pitch of the induction roar.

 

The interesting thing about this is that this car was built by an ex tech editor of Low Flying, a guy called Don Cheshire. When built he felt the car was not as powerful as advertised by Caterham i.e. 218bhp and a lot of work and time on rolling roads were spent by various people investigating this. The whole saga was documented in Low Flying. I believe that the car did eventually make 220bhp but I think that this was achieved by use of a JPE exhaust which unfortunately was not on the car when I bought it this year. I wonder if a large part of the problem had been this poor manifold casting.

 

Turning my attention recently to the exhaust a huge improvement has been made by fitting a low loss silencer from Raceco and increasing main pipe size to 2.5". This has given a big increase in torque. I think it's probably time to get the car back on a rolling road and see where it's got to.

 

Alan.

[Paul McKenzie]

Thanks, Alan.

Looks like a nice little project for free power.

Paul

[Swiss_Tony]

I got a new manifold from Caterham earlier this year and it came with Swindon packaging etc

Is this normally the case?

Is the Swindon manifold a different set up?

 

James

 

[ian balson]

Thanks chaps,

 

I was planning to service my 45's this winter, so a close look at the manifold may be in order.

 

How does the Techcraft silencer compare to the Raceco re flow?

 

Ian

 

ian_balson@yahoo.co.uk

[Foxy Smith]

James,

 

The Swindon manifold that Arnie and I referred to is the one that Swindon uses on their dyno and in applications other than the Caterham. The reason it can't be used in the Caterham I believe is because it has much straighter inlet tracts and so will not clear the chassis rail that sits beneath the carbs.

 

I wonder if the manifold you have is a Caterham one that Swindon have talked to with a die grinder as I did mine?

 

Alan

[ian balson]

So, are we saying that the manifold sold with the Swindon kits won't fit a 7 due to the carbs fouling the chassis tubes?

 

Is the best option to clean up the existing Caterham offering?

 

Cheers

Ian

 

ian_balson@yahoo.co.uk

[Foxy Smith]

Yep, to the best of my knowledge that is the case. Hopefully Arnie will confirm that is true.

 

Alan

[EFA]

Yep I think thats right....

 

 

 

Fat Arn

Visit the K2 RUM site

See the Lotus Seven Club 4 Counties Area Website here

 

[NickD]

The Caterham inlet manifold is slanted front to back to offset the nose down Caterham engine installation. The Swindon one is level. I think Roger Swift has fitted both types to his car but I dont know if any bonnet mods were required. The principal performance problem with the Caterham manifold is that the inlet tracts are far too large and poorly shaped at the carb end (even for the original VX race 48DCOEs). Just about the only value in polishing the Caterham manifold is in port matching it to the head, as the other end of the tract is still too big.