Individual Throttle body casting (Cosworth?)- must stop buying!

this is going in a polo?

 

But they're 8v throttle bodies, aren't they?? 16v inlet spacing is totally different (consistent 88mm, IIRC). There are plenty of bike bodies that are a good match for the 16v inlet spacing already, without having to butcher these ones, and go through the aggro of building up all the mechanism.

 

Yes they are Mike. 9a block, 8 valve head, low compression for methanol injection

Or I just wasn't thinking right and should have typed AGG, sorry

It is yes, and yes I am daft as a brush.

 

If you're using standard pistons on a 9A block and PB type head, that'll give you about 16:1 CR. Are you sure?

 

any progress on these yet?

 

I reckon the plates out of the solex carbs we both have are a good starting point as there is no point in butchering a set of more valuable webers.
Then it is a case of matching the cutouts in the solex spindles to a new blank rod at the correct centres in the new longer shaft.
Generally these slots will be ever so slightly longer than required allowing the plates to be seated perfectly in the bores when the retaining screws are tightened. Important in this case due the the lack of balance adjust-ability between cylinders. Something the f3 folk were not unduly concerned with. Air bleeds could be incorporated somewhere if absolutely needed.

 

Got this done today.

Stripped out butterflies from the donor Solex carbs



Fitted Solex carb throttle shaft and butterfly to Cosworth manifold



They fit very well so all that needs doing now is drawing up the detail from the Solex throttle shaft where the butterfly mounts, and creating a long shaft with the butterfly mountings set to the correct bore centres.

 

what material are you going to use for the shaft Dan?

 

The 020 clutch release rod is the perfect fit as MikeH suggested, and as Gav has just suggested when he picked them up a minute ago, this keeps it "scene".

Now get those Solex carbs stripped down to get the butterflies out.

 

these look dam interesting. anyone know if theres others to be had?

 

Hope you're only destroying Solex 'doppelgasser' and not 'dreifachrgasser' carbs? And, if so, they had better not be from a TTS!

Interesting. How will you cut the slots in the shaft? Is the push rod steel easily machined?

 

from what i can gather, there were only two or three available.

 

no idea where they are from.

what puts me off the pushrod, is it will be hard as feck!

 

I've heard that it's better (and easier) to machine flats into the shaft, to a sort of 'D' cross section to mount the throttle plates. By leaving the centreline of the shaft alone it turns out stiffer than a slot through the middle?

 

The 020 clutch pushrod is only hardened at the ends where the blueing is visible. The slots are not in these areas.
It is really not hard to get a slot machined at a decent machine shop. They work with lots of fancy metals and have the relevant tools to cope.
Gav should have the detail drawn up anytime now.

Where did all the other castings go then? Apparently there was a box of them as someone mentioned. I got in touch but they had all gone. Only 2 have turned up on here.

 

'Induction/Flame Hardenable' steel! In the order of 0.5 to 0.6 % Carbon, and low in alloying elements

 

when i found them there were inly 3 available, there may have been more, like you say only two turned up on here and i havent seen anyhting on club audi or any other audi forums, that i frequent from time to time.

 

I plan to do the D section along almost the entire length of the shaft, which will help with balancing the idle out too.

 

safe to say me and danny want one each. eyes peeled please chaps.

 

Still haven't been able to find a machine shop that will make up one of these for sensible money, as the slots for the Solex plates I want to use are only 1.6mm wide, so they need to be wire erroded



Thats the drawing I'm using to quote at the moment, still don't have a sample so it may be rubbish. This is using a 020 clutch push rod.

Anyone else progressing faster than me?