Vx Taper throttle bodies...feedback required

[captain chaos]

Hi

I am planning an overhaul of my car and I've decided to consider removing the caterham inlet manifold from my current TB set up.

 

From my untrained eye, the CC manifold looks restrictive and they crack over a period of time which I've had happen to me recently. So I'm thinking there must be something better?

 

Are there any gains from a tapered set up 🤔 as there must be guys on here like Graham Ford, Paul Gibb and Marius to name a few ( there must be others ) who have considered this problem and have come up with there own solutions.

 

I don't want to re-invent the wheel and if there are only very marginal gains with alot of additional aggro then I'll stick to the current manifold and try to have it strengthened.

 

I've visited both QED's and SBD's sites to view whats on offer but I'd rather hear from people who have actually done the work before I start listening to sales talk.

 

PS Thanks to DaveK for popping down and installing a new throttle pot for me on friday which has not got my car up and running again...cheers Dave

 

Comments appreciated

[Alba 7]

I've put the SBD direct to head taper throttle bodies on my VX (as it was previously a carb'd engine from another car, this also involved adding an ECU, loom and other bits).

It fits tidily under the bonnet but to get a sufficiently sized air filter in place, it did require a cut out in the bonnet to me made. It clears the top chassis rail but there isn't a huge amount of room should you need to get to the throttle cable which comes from below the TBs (though this may be the same as the CC manifold set up).

 

I'm very happy with it and compared to the carb'd set up with a mechanical dizzy in the other car, it is a joy to drive. Cold starting can be a bit of a pain (it runs lumpily and may stall after running for a few seconds); Arnie did offer to adjust my map as this seemed to be a well known issue but I've grown to live with it so it can't be too much of a problem. I can't compare with the CC manifold injection set up but the power delivery, even from the stock map, is nicely linear. I had half expected the map to be a very safe compromise but this has not been the case. Most noticeable (at least for me when comparing it to the Carb'd set up) is that the torque curve is even wider and more usable with the DTH TBs. With my low gearing I can happily burble through a village in fourth (on a five speed box), hit the end of the 30mph speed limit and accelerate away without a stutter or need to change down - makes you darn lazy as you can almost spend the whole day in the same gear!

 

If you wanted any pictures, just let me know.

 

Nick.

[captain chaos]

Nick, thanks for your reply..

 

I'm already on jenvey TB's and can vouch for the improvement when swapping from carbs.

I think i will also be considering an airbox to add further improvements to the induction system along with any benefits in reducing the noise levels.

 

I'm now interested to see if someone who has made the same changes as me replies so I can see if it's worth it.

 

[ECR]

If you are considering fitting an airbox it might be worth checking that a standard one will fit whichever bodiies you decide on. Some are a lot easier to fit than others. The box manufacturer will advise....

[captain chaos]

DaveK was over on friday sorting my throttle pot issue (as predicted by yourself!) and he has recently sorted a customer with one which he thinks will fit my car..

AT A COST OF 450 quid

 

I'm going to spend the next couple of months doing some research before I start spending!

[Rob Morris]

Chaos......£450.........what do you mean *eek*

 

😬

 

[Andy A]

 

I have heard tapered are supposed to give better torque and throttle response. I guess you wouldnt find out until you do a rolling road comparison since there seem to be so many factors that affect each other.

I have the Jenvey / QED paired bodies. Along with all the other bits that have an influence the overall effect is very much all or nothing.

 

[captain chaos]

DaveK has intimated that, even though I have an all steel engine which could cope with more aggressive cams/revs/BHP, personally i'm keen to keep the revs down and increase the service life of each rebuild. I run her for about 7k between rebuilds and she gives me a solid 249 bhp.

I'm beginning to think it would be more productive to reduce weight rather than chase another 10 bhp by going over to tapers and put up with changing the inlet manifold each year or using the Swift method of de-stressing the TB's.

The airbox is definatley one to investigate if only for the noise benefits.

 

[ECR]

Don't forget that trackday noise testing is normaly a 2 stage process. A static test before you are allowed on track where I believe an air box will not influence the reading greatly, and then monitoring of noise as you drive past where the air box is useful. The point being that you need a good silencer system as well as an air box.

[DaveK]

ECR

 

Its all your fault , i only told Cpt Chaos about the Airbox you had designed and fitted by reverie 😬

 

Thanks for the tip though as i've sold one already.

 

Dave

[ECR]

[Paul Deslandes]

The Caterham manifold is restrictive but can be flowed to make the throttle bodies work extremely well. On 48mm Jenveys and a flowed head and manifold (with the right cams) we've had mine up to over 250bhp. Without the manifold being flowed it wouldn't have got anywhere near that figure according to the guy who did it - probably closer to 215 - 220. The consensus seems to be that throttle bodies on a decent manifold give as good as tapers so if you're looking at having yours strengthened see if you can get it flowed at the same time. You could try Simon Armstrong at Ultimate Performance near Northampton and is ex Ilmore. www.ultimatep.com

 

The only other problem seems to be the lack of strength and consequent cracking that you and others have experienced. so far I'm pleased to say that it hasn't happened to me yet.