All these jets!!(Weber Re-Jetting)

[opelenvy]

I had got the jet kit from Racetep a year or so back and installed. For one reason or another I am switching to a different Weber 32/36 that is used. The jets are kind of reversed from what I have on my car, so now I am wondering if I put mine in wrong, or this carb is wrong.
Mine (other)
Main Pri. 150 (140)
Main Sec. 180 (135)
Air correcting Pri. 165 (150)
Air correcting Sec. 160 (160)
Idle Pri. 60 (55)
Idle Sec. 55 (50)

I'm thinking that the primary has the smaller jet with the secondary having the larger for that "pedal stomp"
Am I right?
And to make sure I'm not totally nuts, the 32 is the primary and the 36 is the secondary, right?

Oh, I have the Jacobs Pro Street, as well as the other stuff in my Sig.

[opelbits]

If you look on the outside of the carb, on the venturi area but ouside, there are some cast in numbers, probably a circle with a 28 or 27 in it. Or you can turn the carb upside down and look at the throttle plates. One is bigger than the other.

I'd say put it on and see how it feels. My feeling is that it may have that extra 'ooomph' for the pedal stomp, but 180 seems high. Or maybe it would bog before getting that 'ooomph'.

Or maybe I've had too many homemade Christmas cookies (orange!) and homemade toffee and I'm delirious with no idea what I'm talking about.......

[tekenaar]

Originally posted by opelenvy
. . . so now I am wondering if I put mine in wrong, or this carb is wrong.

Mine (other)
Main Pri. 150 (140)
Main Sec. 180 (135)
Air correcting Pri. 165 (150)
Air correcting Sec. 160 (160)
Idle Pri. 60 (55)
Idle Sec. 55 (50)

With the jets you have available in both carbs, stick with the richer idles and here's what I'd go with for mains and airs in your engine:

Primary (32): Main 135; Air 150
Secondary (36): Main 150; Air 165

You could go to a slightly richer mixture by using the 140 main and 150 air in the primary and the 150 main and 160 air in the secondary.

I'm a little surprised that they sent you a 180 main to run with a 160 air for your secondary, as it is generally accepted Weber tuning practice that "airs" be at least the same size or larger than their "mains", at least from what I've heard and read about it. If you want to go with the 180 main in the secondary, definitely use the largest air (165) you have with it.

[opelenvy]

Thanks Otto, I will try your sugestion. It will be a little while before I can test it out as I am waiting on a couple things to complete this project. Painted the Sprint yesterday, intake is done, carb will soon be done. I got shorter studs for the carb to use with nylock nuts. Got new intake/exhaust gasket and exhaust flange gasket. Waiting on studs for the exhaust manifold.

Another question. What exactly does the secondary idle circuit do? Is that for when you are idling at over 3/4 throttle?

[tekenaar]

Originally posted by opelenvy
. . .

Another question. What exactly does the secondary idle circuit do? Is that for when you are idling at over 3/4 throttle?

The idle jet is actually dual purpose and should more acurately be called an "idle/transition" jet, as it also controls the throttle transition phase mixture. Transition is when your throttle plate begins to open just "off idle" and before the main jet circuits kick in. You can understand why it's needed on each barrel of the carburetor as otherwise you'd get a huge bog when the throttle plate just begins to open.

If you open the throttle plate on your carb and look up the barrel from the bottom, you'll see a series of small holes, immediately above the throttle plate when it's closed, that serve as the fuel mixture source during transition. Hope that's clear.

[Gary]

George,
While you're at it, look into changing the emulsion tubes to size F-66. It gets rid of that little hesitation when you first hit the throttle. (RallyBob pointed that out when he jetted my 38 DGAS. and it made a noticeable difference)

[72Rallye]

One thing to watch out for is if the power valve in the bottom of the float bowl is still active. I believe the racetep recommendations apply to a disabled power valve. Mix these settings with a working power valve and the mixture is bound to be overly rich.
Thomas

[tekenaar]

Originally posted by Gary
George,
While you're at it, look into changing the emulsion tubes to size F-66. It gets rid of that little hesitation when you first hit the throttle. (RallyBob pointed that out when he jetted my 38 DGAS. and it made a noticeable difference)

We're talking about two entirely different carbs here and I don't believe the parts are interchangable between your synchronous carb (38DGAS, 40DFA) and his progressive carb (32/36DGxV). So, while tip is true for both E-tubes in your synchronous carb, I could be wrong, but I don't think it's true for his progressive carb.

[baz]

otto's right the emulsion tubes will be diff on a 32/36 as they need to do diff jobs than a Dgas
none of this trouble with a didta just wont run right

[opelenvy]

Originally posted by 72Rallye
One thing to watch out for is if the power valve in the bottom of the float bowl is still active. I believe the racetep recommendations apply to a disabled power valve. Mix these settings with a working power valve and the mixture is bound to be overly rich.
Thomas

This one is new to me. Anything w/ a cool name like "Power Valve" has to be good for something. No really, can you explain what disabling it get you and how you do it.
TIA

[72Rallye]

I am getting on thin ice here, but this is what I remember. The power valve is Weber's attempt to make the carb more economical. Using it, the carb can be jetted lean for good gas mileage at partial load. Under full load the power valve opens and enrichens the mixture for maximum power and low combustion temperature. Apparently, this works better than just tweaking the main and air corrector jets. The valve is actuated by a diaphragm connected to the vacuum upstream of the throttle. It is the spring-loaded rod sticking into the float bowl.
Why would you disable it? I can only guess. Maybe it gets too complicated for the home mechanic to optimize for yet another parameter. Or the power comes on too abruptly once the valve opens. Anyone more knowledgeable knows the answer?
I believe racetep mentions epoxying the passage to disable it. I'd rather solder the valve shut to avoid gas compatibility problems.
Thomas

[baz]

i think its another emision thingymabob to let the carb lean out and enrich to get the lowest CO2 readings as thomas says it is a vac opperated diaphram and the only reason i can think of to disable it would be for a set mixture ratio so you have only the jets to set instead of having to deal with a cab that leans out or gets rich all on its own (not good for high performance tuning)



then again where is my head

[Gary]

Yup, you guys are right on the e-tubes for the 32/36.....

http://www.opelgt.com/forums/showthr...emulsion+tubes

Love that search feature!!!

[cees]

I had to remove my carburettor to put a new gasket between the carbi and the intake manifold. This was a good opportunity to review the various jet sizes. This is what my Weber has -

Main Pri. 140
Main Sec. 140
Air correcting Pri. 170
Air correcting Sec. 160
Idle Pri. 50
Idle Sec. 50

The car seems to run okay, but I am not sure if these jet sizes are standards or if previous owners have been playing around with them? I hope this might be of help to you.

Regards from Australia

[tekenaar]

Originally posted by opelbits
If you look on the outside of the carb, on the venturi area but ouside, there are some cast in numbers, probably a circle with a 28 or 27 in it. Or you can turn the carb upside down and look at the throttle plates. One is bigger than the other.

. . .

Just went and looked at a brand new Weber 32/36DGEV that I had removed from my '69 Kadett to return it to stock, so here's the poop! The primary has a 26 cast in a circle while the secondary has a 27, and these are the choke (main venturi) sizes in mm. The 32/36 that is used to identify carburetor type is the size of the throttle bores in mm. This is the same nomenclature used in ALL Webers to identify bore size, regardless of type (identified by alpha characters).

[opelenvy]

OK, I finally got around to putting everything back together after a long wait. Now have Sprint, matched intake and I jetted according to what Otto said, "Primary (32): Main 135; Air 150
Secondary (36): Main 150; Air 165"

Started right up! Yeah! It seems to be running rich, especially on the secondary. On the primary I am getting a hesitation/sputter before it takes off, but when it does take off, it takes off nicely.
When I kick in the secondary it hesitantly goes (sputters). I can hear the throaty sound of the secondary and see some nice smoke out the rear view mirror.
It does run better over all than it did before, but something is really not right. I haven't earned my badge in "Tuning" yet.
I adjusted the air/fuel mixture screw (out is richer/in is leaner?) to where it sounded/felt right. Help.

[airbob01]

George,
Go to www.webercarbs.com. They have some good tech pages on Webber carb tuning. HTH

[tekenaar]

Originally posted by opelenvy
OK, I finally got around to putting everything back together after a long wait. Now have Sprint, matched intake and I jetting according to what Otto said, "Primary (32): Main 135; Air 150
Secondary (36): Main 150; Air 165"

Started right up! Yeah! It seems to be running rich, especially on the secondary. On the primary I am getting a hesitation/sputter before it takes off, but when it does take off, it takes off nicely.
When I kick in the secondary it hesitantly goes (sputters). I can hear the throaty sound of the secondary and see some nice smoke out the rear view mirror.
It does run better over all than it did before, but something is really not right. I haven't earned my badge in "Tuning" yet.
I adjusted the air/fuel mixture screw (out is richer/in is leaner?) to where it sounded/felt right. Help.

First things, first. You ARE doing all these changes in the "other" carb, not the original one, right? Did you remember to make the "enrichment tube/power valve" block off mod in the secondary of that carb, like instructed with your "racetep" kit for the first carb?

This could be your "running rich" problem, as it would sense vacuum drop in carb throat and cause power valve to dump extra fuel in response. In effect, blocking the power valve circuit to disable this requires overall enrichment of the main jets to compensate. So with the generally "richer overall" racetep setup and the "power valve" circuit still enabled, you're running REALLY rich.

Do that before anything else and if still not quite right, try what's below.

Leave the primary main jet alone, change the primary air jet to 160 (more air in primary "E" tube per volume of gas = leaner). Change secondary main to 140 and leave secondary air jet as is (less gas in secondary "E" tube per volume of air = leaner). You've now leaned out both primary and secondary AV (auxiliary venturi) mixtures slightly.

You can also adjust your primary and/or secondary idle/transition mixtures slightly leaner by going to a lower number "idle" jet. You've just learned an important and cardinal rule of carb tuning . . . trial and error.

[opelenvy]

Originally posted by tekenaar
First things, first. You ARE doing all these changes in the "other" carb, not the original one, right? Did you remember to make the "enrichment tube/power valve" block off mod in the secondary of that carb, like instructed with your "racetep" kit for the first carb?

Umm, no I didn't. I don't ever remember doing that to the first carb. But it was a used carb as well and may have already had it done so I just skipped right along. No I have to dig up my instruction from Racetep to find out this mod. Is this the one that had something to do with pulling a tube and blocking a hole with JB weld?
Thanks Otto. I think this is my problem.

[tekenaar]

Originally posted by opelenvy
Umm, no I didn't.

. . .

Is this the one that had something to do with pulling a tube and blocking a hole with JB weld?
Thanks Otto. I think this is my problem.

THAT would be it!

BTW, just so you don't think it's anything too unusual, it took me slightly over two months to fine-tune the DellOrto DHLA40 SSD setup on my "Hooters' Staff Car's" 1.9. Like I said . . . TRIAL AND ERROR!