plastic bits on VHPD throttle butterflies

[garyo]

The bottom half of my KV6 throttle bodies have plastic wedges on them - why? at full throttle they seem to be the same thickness as the spindle, so there's probably not much to be gained by removing them. If they were carbs then I can see some sense in blocking the bottom part of the port while the top half opens, so that the idle jets would get more signal... but with injectors?

[V7 SLR]

DVA had a theory when looking at my old KV6 throttle boddies that the wedges may have been because throttle fed 3 cylinders. 2 on one side and 1 on the other. It was surmised that the wedges may balance the requirements of 1 cyl vs the other 2.

 

Only a guess but it seemed a good one.

 

Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours

 

[garyo]

cheers nige, and so did he remove them for you - or recommend you should? They seem redundant in this application

[Bob Corb]

The wedges are to improve throttle progression. When you crack the throttle open it only allows airflow over one side, then as you open further the other side opens too. It just makes things more controllable whilst pootling in traffic. I'm going to have a chat with the local Weber agent to see if they can be replaced with std plates - just to experiment. If I do change them I'll gas flow the bore of the body to remove the steps before and after the blade (not nice) and shave the spindle down a bit. That should boost power to the same level as the later type..

 

BC

[V7 SLR]

I didn't remove mine as I was selling them. Didn't want to risk damaging them. Dave did fettle the manifold/TB interface and remove those steps though.

 

Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours

 

[D Jones]

Thread resurrection

does anyone have images of this work?

I need to adjust/remove the plastic part to avoid it being eaten by the engine

[simon_h]

Why do you need to remove them? Have they become loose?

As the throttles are on the big side anyway they aren't in the way and you will make the progression worse and it will jump in on tip in.

If you just want to do it because then carry on of course but I wouldn't bother.

[D Jones]

Simon,

Oily, has advised to remove them, I remember seeing an article on this, removal of the plastic piece is simple and now done, the hole now needs to be soldered up and then filed flat. 

I remember seeing images and advice on this but. Cannot now find them

[oilyhands]

As Bob says they are partial hemisphere that softens initial throttle response. The issue with them is that they are plastic and attached by plastic ‘riveting’, they have a nasty habit of breaking off and being ingested by the engine; this is never a good thing.. The TBs  are a production item from the Rover KV6 and arguably do not need the wedges in place in a Caterham, if it were me I would remove them and solder the holes meanwhile taking the opportunity to radius the sharp leading edges of the throttle plates.

Oily