Hi Gents,

I'm getting ready to mod my Nikki for Max flow on my Full BP 12A. I can read alot about it in here and i'm thinking I can do all of it. Currently my idle is a bit high (1700-ish) Maybe i can get it lower after mod ? Anyway I wanna get the car MOT approved before this.

Well the question lies in the title.

Has anyone thought about countersinking the butterfly bolts into the actual butterfly plates? This would get rid of those big bulky bolt heads for flow, but i guess the failure rate also raises ?

Stupid idea or go with it ? On other carbs (Weber, Dells) The bolts are countersunk into the shaft, but never seen it in the actual plate. MAybe for a reason... Hm.

 

I used some stainless torx fasteners that had a lower profile head than the factory screws for my nikki.

 

On my 1st FD throttle body mod I did the countersunk flat head screws in all throttle plates.

There are a couple things-
You have to make the holes in the throttle plate a bit oversize or else the taper portion on the screw heads will try to locate the throttle plate and you cant adjust plates for perfect fit in the bore.
The upper half of the split shaft gets pretty thin around the counter sunk holes. I ran this way for 14 years and never had an issue even with the throttle plates slamming shut (no dadhpot) on 26 psi boost.

The primary plate on FD is single throttle plate and the secondary plates are dual plates. I half shafted the single primary plate as well and had to oversize the primary plate counterinking and count on the locktite locating the primary plate once dry. Otherwise I couldnt line up the plate perfectly with the bore.

On my 2nd FD throttle body mod I simply used button head screws for the half shafted primary plate and the counter sunk flat head screws just for the split shaft 2ndary plates.

Locktite all the fasteners.

 

if you look at the nikki from the bottom, and just open the throttle you can see that its kind of amazing any air flows through the carb at all
smaller screws are a great first step, usually just a smaller head with a shorter length is good enough.

step 2 is to cut down the throttle shaft, but you need to be careful about keeping it strong enough not to bend. the FD is machined flat on both sides, you might try something like that

the FD throttle body is funny, its actually built a lot like the carb, its just missing the float bowl, and its mechanical secondary...

 

This is the end result. Looks like a massive improvement, let’s see if this will be notable on my Bridgeport together with an open exhaust and maybe DLIDFIS also, if I can figure that out.






Stock

 

when you can get some air through the carb, you will notice the difference!