Weber emulsion tubes

[1QuickS]

I would like some help classifying emulsion tubes by application. I have the following info and would appretiate review and input:
F3: Solex and S cams
F24: race cams
F26: mild cams (T or "Normal 2.0" cams)
F1: E cams (richer than F26 tubes)
F7: ?
F11: ?

Cheers,

1QuickS

[snbush67]

From:

Weber jetting chart

[ttweed]

Originally Posted by 1QuickS

F7: ?
F11: ?

The notes I have from when I still had a carb'ed car show the F7 as "for low RPM enrichment" and the F11 for "low RPM weakening" of the mixture. It all depends on their diameter and where the holes are in the tube.











HTH,
TT

[john walker's workshop]

good luck.

[Trackrash]

I noticed on the bottom chart there are TWO different F3 emulsions listed.
Why is that? Is one for triple webers?

[snbush67]

Found this;

https://wolfgangint.com/blog/emulsion-tubes-n5

F11. This is the most common tube that comes in IDF carbs. It’s large in diameter so there’s not a lot of room for fuel in the well. It has a lot of air holes in the side so a lot of air can be mixed with the fuel after the well is dry. As you stay in the throttle the fuel ratio will continue to get leaner as the RPMS go up and load is increased. This tube is a great tube for a daily driver and most applications.

F2. This is one of my favorite tubes for racing. It usually doesn’t come in anything and you have to order them. It is a little bit smaller in size then the F11 tube, so again not a lot of fuel in the well. Just a hair more then the F11. It has fewer air holes in the side so it mixes less air as the RPMs and load rises. As far as air fuel ratio goes you will see it flat line or just slightly rise. This tube works great for race cars.

F16. This tube is slightly bigger than the F11, so it has less fuel then the F11 in the well. It also has fewer air holes then the F2 so it will mix even less air as the RPMs and load rises. When you look at the fuel ratio it will actually get richer and richer as the RPMs and load goes up. I have yet to get these to work on a VW engine, even in an all out drag car. In theory they sound like the way to go, but in reality they get so rich the car just bogs. Now I have run four 48 IDAs on a hemi V8 and they worked great. Go figure.

F7. This tube usually comes in an IDA carb. They are smaller in surface area than the other tubes I have mentioned. What that means is you get a lot of fuel at the hit. I find it’s too much fuel for most of the stuff I do. Some guys can get them to work, I can't. As far as the holes go in the side, they have about the same as an F11, so they get leaner as the RPMs and load rises.

I hope I explained this well enough. It is a complex little device in a carb that makes a world of difference in how your car runs. The biggest thing here I see all the time is floats being out of whack. The float level in these carbs is so important. If you’re not sure, check it.

[1QuickS]

Wow, revisiting a 12 year old thread!

The link refers to E-tubes not used in triple throat Webers.

[snbush67]

Originally Posted by 1QuickS

Wow, revisiting a 12 year old thread!

The link refers to E-tubes not used in triple throat Webers.

The link came up when I was searching for F16 e tubes. This pelican thread also came up in the search.

I’m getting edumacated. Thanks Paul.