single barrel weber 40 IDF ( part 2 )

[QRP]

This is just a experiment I've been wanting to do for some time and all the parts I needed were at hand and just laying around the garage doing nothing so on a full garage tweaker mode I put it all together.

didn't take much to block off the left side with allen plugs & jb weld.
made an adapter plate to fit the stock 34 pict mani and I'm in business.

to my surprise the single barrel worked better than expected, throttle response is decent for now and at cruising speed ( 2000-3000 rpm )
its far better than the 30/31 pict I had on it.

with a solid day of jet testing I'm sure it can be improved.

jetting now is 55 idle / 145 main / 160 air / F7 e-tube / 70 pump jet

the carb does have a vacuum port on it so I may order an SVDA for it if I can't tune out the slight off idle bog.

I know I could just order a new 34 pict and run that but where is the fun in doing that.
I have a large selection of e-tubes & jet sizes that I've accumulate over the years so this should be fun
trying something different is what its all about.

[modok]

NICE
if you can get the emulsion tube and acc pump right, I am sure that it will be superior to a solex in every respect.

[Bugsy61]

Nice work. Don't forget to plug or disable the accel pump shot for the "dead" side of the carb. I've been thinking of doing this with a Holley four barrel and turbo setup, on smaller sized engines. Would be nice to have a vacuum secondary barrel.

[oprn]

Cool idea!

Bugsy61, there is a chap converting the Weber DCOE carb to progressive with a vacuum operated secondary for turbo Corvairs. Someone here (I keep forgetting who) got one from him for his VW. It could be done with the Weber down draught carbs too I'm sure.

I pirated this off his thread.

[QRP]

[Alstrup]

It is, or the fuel will slosh out of that hole when cornering.

The idea is not new. Has been used in at least 25 years in the Citroen 2CV races among other places. but i have not ever seen it on a type 1, - until now.

[QRP]

put some miles on today, only had to clean out the main jet once. LOL
tried a smaller pump jet ( 55 ) and it didn't like that at all so went back to the 70.
also went up a little on the main 145 to a 150 and that felt better.

[QRP]

finally figured out how to post video

https://vimeo.com/345555941

[modok]

I've suspected the reverse throttle plate may have better wet flow, meaning, less fuel wetting the walls below the carb, which could be a real reason why the temp would be warmer. Especially the acc pump and main, at part throttle, more DIRECT path right down to the T junction. While the normal throttle plate angle would throw fuel at the outside of the turn.

You could block off the fuel less destructively by soldering closed the main jet.

I tried a similar progressive opening concept years ago, worked good WOT but funny at part throttle, I suspect the dead riser messed with the fuel distribution somehow.
Also the carb is possibly too big to be used that way.

Going up to a 38 or 39mm riser size should help power even more.
A dellorto DRLA would also work....maybe even better, the floatbowl layout is ideal for it and they have, as you know, much larger and more forgiving transfer ports and a higher pressure acc pump.

[oprn]

Could dirty jets have anything to do with no air cleaner?

[QRP]

[mark tucker]

thats the kinda stuff I used to do.there are somany better ways to do things than the oe stuff in most cases. you can get yours better doing what your doing but.... a IR system will out perform and out MPG it every time when tuned right.but I do like what your doing, your thinking, your doing, your using your head and parts available..I used to swap anular booster venturies from ford carbs to my carter BBD carbs and many other carb mods. to lotsa stuff. keep your brain thinken!!! a properly made header type intake will improve it still farther... the possiabilitys are almost endless.especialy if you expearament with Junk parts!! GOT A IDF WITH ISSUES ON ONE SIDE..like striped main jet well......YOU HAVE THE FIX FOR THAT!!!keepo up the great work.and shoe some of the morons how to do stuff.

[Frank Bassman]

Very very very cool. Now you've got roller bearing throttle shafts and a world of adjustability. How do you feel the engine is breathing? Must be a nice improvement.

Empi made a 40 mm kadron center mount kit, and people apparently couldn't get them to run right. I suspect they were all running small jets for the app. I bet you could make it work. I know one person who experimented with similar and his name is our very own Alstrup.

-Frank

[modok]

Which way the float bowl is oriented does matter, to minimize hills and g-forces tipping the fuel level.
The throttle plate direction also maters, one way will work better than another and it might not be a lot but it's a very easy way to improve performance with no real drawbacks.

There are thousands of different carburetors in the world, IMO not much excuse of using the wrong type just because it's cheap or common, yet that's EXACTLY what the aftermarket companies do, they don't seem to give a crap if it works better or worse.

[QRP]

thanks for the props guys. it keeps me going.
gonna try and get some in car video later on when traffic and the weather cool down.
its a warm one today in the S.F.V.
so far I have been surprised at how well this setup is working.
I put off ordering the SVDA because the 019 is doing just fine.
make me wish I would've put a decent cam in this motor.

I may just try it with a 44mm on a 2276 I've got just for shits and giggles.

Modk
I didn't do anything to the cab that can't be removed and back to both sides working, only JB weld on the carb is to plug the auxiliary Venturie inlet. an easy fix back to normall.

I'll be back later with actual driving footage

[QRP]

[modok]

[nextgen]

Nice work, out of the box thinking, love it.

The dead side, acts as an umbrella for the distributor. Ha.

Serious, you made it work, that is how you can tell a good mechanic, get it going with what ever you have laying around.

Unlike modem car mechanic's ( if you can call the that ) that, plug in the computer and remove the printed circuit board.
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[QRP]

I finally got a test run video up.
had to shorten it to under 2 min for it to upload but its something.
I will apologize ahead of time for the shakey cam and bad sound quality, this is from my phone on a cheap 99 cent store mount.

https://vimeo.com/345953869

[chrisflstf]

Did Weber ever make any single throat carbs? Like a single 40mm?

Great idea you are trying