emulsion tubes.

[67worshipper]

having read about emulsion tubes in a weber tech manual,they say F2,F7 and F11 are the main selection for vw motors.what effect does each emulsion tube size make? ive read the F2 and F11 for mixture weakening at lower rpm and slight acceleration,and F7s for enrichment.all three seem to do the same but different.can anyone shed any light and the differences each make.thanks in advance. happy easter to all

[Jim Ratto]

Hi, you might read this old post... it might help. I have a hard time "describing" how different diam. emulsion tubes "work".... it all has to do with reserve of fuel in jet well and "mixing" of air thru air duct in top of carb and fuel available in jet well...
Some of the "operation" diagrams in the Weber literature might help if you follow the path of fuel.

http://cal-look.no/lounge/index.php/topic,4609.0.html

good luck (PS my car always runs best with F2, not with F7 or F11).

[DKK Ted]

Hey Jim, What jetting do you have now with the F-2's your running?

[Jim Ratto]

Hey Jim, What jetting do you have now with the F-2's your running?

I think from memory....

60 idle
110 idle air holders
165 main
180 air (I think).... can't remember.

anyway- it works.

[67worshipper]

guys im running F11s with 150 mains 60f10 idles with 120 holders,180 aircorrectors.37mm vents and 3/4 to 1 full turn on the mixture.seems to run as good as it has ever and the plugs brownish with a touch of black.id like to try F2s but at sixty quid a set i dont want to waste money.are they worth it?

[Jim Ratto]

guys im running F11s with 150 mains 60f10 idles with 120 holders,180 aircorrectors.37mm vents and 3/4 to 1 full turn on the mixture.seems to run as good as it has ever and the plugs brownish with a touch of black.id like to try F2s but at sixty quid a set i dont want to waste money.are they worth it?

You will have more of an effect with idle jetting on a street car running IDAs than the emulsion tubes and/or mains... so my answer is no.
I happened to have access to the three I listed, and chose the F2 because car seems to accelerate best with them. Also the fuel curve was most consistent. But the most profound effect you can create is with idle jetting. Sounds odd, but it's true.

[67worshipper]

what idles would you suggest then jim? at least the idles will be cheaper to play with

[Jim Ratto]

what idles would you suggest then jim? at least the idles will be cheaper to play with

depends on engine, ignition, etc. It really is a thing where one cannot say "use____" and it will work.
My car runs on 60 idle jets,
this is a factor determined by cylinder cc, cam (I should say engine vacuum @ idle), ignition advance
basically:
bigger cylinder cc needs bigger idle jet
more vacuum @ idle (less cam overlap) needs smaller jet
more ignition advance needs more fuel

it isn't easy to prescribe idle jetting... like main jets. It really takes actually installing them and driving car to get it right.
Be prepared for some work to get it right. Keep notes of your changes and don't rush. You can get 48IDAs to run as good as any IDF, it just takes more patience. If you hear the way Sarge's, Schwimmer's or Rayburn's cars run on IDAs.... you'll be convinced.
be wary of going too large on idles, like guys have posted here.... "70 idle jets will make a 48IDA run on anything" but they will not run well. If you go too large on idles, the car will pull off idle, but in transition it will hunt and peck like a hungry chicken.... because the mains and idles will overlap one another and try to both do the same thing... at lower rpm's under light load the car will seem to falter... "hunt around" and you can be sure it is way too rich and you're cleaning oil with fuel... not good.

[67worshipper]

i might try some 50 or 55 idles then.im not feeling that bad in the fact that its running poor its not its 100% better than it ever was but theres always room for improvement in the transition from idle to main.

[lawrence]

I have done a bit of jet experimenting to figure out exactly what my 1914 likes. 50 idles and 60 idle holders work best. Many people on other forums said that an idle jet that small would never work whatever. The formulas and charts that the weber manuals provide to determine jetting are very close to what an engine needs. If your car does not smell like its running rich, does not "load up" while idling or the plugs look normal ie: tan color. I would not change the idle jet. If your car idles fine but seems like it is running lean at the top of the idle circuit, (surging at steady throttle position and popping in the carbs), I would try some smaller idle jet holders

[67worshipper]

hi lawrence.my car runs good but theres always a slight hiccup but only very slight on the transition.just wanted to see if i could get it spot on.its a driver after all.i cant find many size jet holders.is there not many? nobodys said anything about the holder size before

[Rob DVKK]

hi lawrence.my car runs good but theres always a slight hiccup but only very slight on the transition.just wanted to see if i could get it spot on.its a driver after all.i cant find many size jet holders.is there not many? nobodys said anything about the holder size before

I think the ones that come stock in the newer IDA's are 120's. Haven't tried it yet but some of the guys in the club have soldered their holders up and re drilled at 115

[67worshipper]

i think mine are 120s rob.does it make much change at 115?

[Rob DVKK]

i think mine are 120s rob.does it make much change at 115?

It all depends on the engine and what it likes. The guys that have stepped down in size have big vents (42's or 44's)  so the signal isn't as strong as with a 37. It helped with the off idle smoothness and transition on to the main.

Haven't made the change yet, but found that the drivability increased 10 fold after ditching my old 009 in favor of an MSD distributer

[lawrence]

hi lawrence.my car runs good but theres always a slight hiccup but only very slight on the transition.just wanted to see if i could get it spot on.its a driver after all.i cant find many size jet holders.is there not many? nobodys said anything about the holder size before

I chased my tail for quite some time until I understood what the idle jet holder did and why it is necessary to change it in some cases. This is a good place for weber parts. http://www.piercemanifolds.com/ Hopefully they ship overseas. Any weber distributors across the pond??

[Bruce]

....l.i cant find many size jet holders.is there not many?

The only ones that exist from Weber are 60, 100, and 120.
One time I tried the 100s.  They made the engine pig rich at 3700-3900 rpm on the freeway such that it would start to load up.  I concluded that the jump from a 120 to a 100 was a HUGE change.  A 115 is a good step.

[Arry]

i think mine are 120s rob.does it make much change at 115?

I'm using 115 idle air holders (with 37mm venturis) on my 1915. Me and my mechanic first tried size 100s, 120s and finally 115s, and they seem to work best (though we didn't notice a day-light difference between them).
Like Rob DVKK wrote, I'm sure an MSD ignition will help a lot.

[67worshipper]

i think mine are 120s rob.does it make much change at 115?

I'm using 115 idle air holders (with 37mm venturis) on my 1915. Me and my mechanic first tried size 100s, 120s and finally 115s, and they seem to work best (though we didn't notice a day-light difference between them).
Like Rob DVKK wrote, I'm sure an MSD ignition will help a lot.

im already running MSD dizzy.did you solder 120s the redrill or open out 100s arry?

[Arry]

i think mine are 120s rob.does it make much change at 115?

I'm using 115 idle air holders (with 37mm venturis) on my 1915. Me and my mechanic first tried size 100s, 120s and finally 115s, and they seem to work best (though we didn't notice a day-light difference between them).
Like Rob DVKK wrote, I'm sure an MSD ignition will help a lot.

im already running MSD dizzy.did you solder 120s the redrill or open out 100s arry?

We opened out 100s.
What springs-bushing combo are you using on the MSD?

[67worshipper]

i think mine are 120s rob.does it make much change at 115?

I'm using 115 idle air holders (with 37mm venturis) on my 1915. Me and my mechanic first tried size 100s, 120s and finally 115s, and they seem to work best (though we didn't notice a day-light difference between them).
Like Rob DVKK wrote, I'm sure an MSD ignition will help a lot.

im already running MSD dizzy.did you solder 120s the redrill or open out 100s arry?

We opened out 100s.
What springs-bushing combo are you using on the MSD?

now that i havent got a clue how many different combos are there?

[Jim Ratto]

one that works well in a hot VW motor. Fat bushng and light tension springs. The rest of the stuff you'll never use except maybe to make a mousetrap.
Or lock the advance out and go for it.