Weber Jetting Survey

[Snakebit]

I would like to start a survey of any one running Webers to list the following:

Engine cu. in.
Cam profile
Choke size
Emulsion tubes
Main jets
Idel jets
Air correctors
Pump jets
Exhaust jets

Based on the above information, a person could zero in on a starting point to set up their Webers

[quickjack]

This is a great idea, but shouldn't it be in the Weber area under engine building?
When I get mine set-up I'll post the details.
Jack

[Allan A]

This might be help.


http://www.jesterscobra.com/blog/bma...r-Tuning-Guide

[ENTDOC]

seems to me that fact #2 is wrong on his site.If you have to open the idle screw more than 1 turn would that not tell you the idle jet is too small? chuck

[G.R.]

I agree Chuck because if more than 1 turn you'd be progressing off the idle circuit? Right?
All the info I've gathered highlighted the fact that the idle screw/screws should never be more than 1 turn open.

[Scott S]

My coupe engine has these settings, Inglese assembled the Webers and I have found that so far this is a really nice running engine. The idle even cold is around 600, absolutly no stumbles or spitting. Sounds incredible.

Engine cu. in. 331
Cam profile Ford E-303
Choke size 37
Emulsion tubes F5
Main jets 155
Idel jets 60
Idle Jet Holder 1.10
Air correctors 190
Pump jets 50
Exhaust jets ?

The most important things I have learned about Webers is throw away the factory linkage and make every carb individually adjustable AND big cams kill webers.

[ENTDOC]

stroked 427SO-454 cu
cam-comp, 248 at .50 lift; seperation-110, gross lift-645

main jets-165
idle jets-60
idle jet holder-120
air corrector 205
E tube-F7
bypass-50
pump jet-50
choke-37
plan to go with a 55 bypass since it is rich

[Cal Metal]

Pump jet and exhaust jet are the same.

[Scott S]

Thanks Cal I was a bit confused with that.

Scott S

[Snakebit]

After playing around with different jets, idle jet holders, and emulsion tube combinations, here is what I settled on. I tried 120 holders with a 65 idle jets and f7 emulsion tubes I leaned out the idle jets using a 1.20 holder and 60 idle jets. I switched to f5 emulsion tubes to richen up the transition changed idle holder to 1.10 with 60 jets, tried 155 mains with 210 airs. It still ran rich and the plugs were black

Engine 302 stroked to 331cu in.
CompCams 282S cam .236/.236 @.050
40mm chokes
f16 emulsion tubes
165 main jets
120 airs
1.10 idle jet holders
65 f10 idle jets.
Pump 50
Bypass 35
idle screws 3/4 out

The plugs are a dark tan, runs smooth. Lots of experimenting and spark plug changing, but well worth the effort.

Just put the car on a Mustang chasis dyno. AFR with the above set up was too lean in the high end AFR was 22. Went to 175 main jets and the AFR came down to 12.8 to 13.0. Idle circuit was 12.5. The distributor was recurved with 18* mechanical advance with a total of 20* advance at 2900 rpm.Initial advance is 18* for a total of 36*. You have to tune Webers on a dyno or hook up a wide band AFR meter.

New set up:
40 chokes
f16 emulsion tubes
175 main jets
120 airs
1.00 idle holders
65f10 idle jets
35 bypass
idle screws 3/4 out

Still had a slight hesitation around 2800 rpm and if I punched it at 2000 there was a bog until the fuel caught up with the air being dumped in.

I contacted Jim Inglese and gave him all my specs. He set me up with F11 tubes, idle jet holders, airs, and main jets and didn't rape me for the parts. He was almost dead on. I had to lean out the idle jet holder from a 90 to 100 and increase the main jet from 160 to a 165. I also changed the pump jets to 00. The hesitation is gone and so is the bog at 2000 rpm. Final set up is:

40 chokes
f11 emulsion tubes
1.65 main jets
200 airs
1.00 idle jet holders
65f10 main jets
00 pump jets
idle screws 3/4 out
fuel pressure at 2.5 psi
Timing 20* advance with 18* in the distributor for a total of 38* all in at 2900 rpm.

I want to get back on the dyno just to double check the air fuel ratio.

[ack fia]

My setup on the new 347 is:
WEBERS
Choke 37mm
Idle fuel jet 65
Idle jet holder 120
Main fuel jet 150
Air Corrector 200
Emulsion Tube F7
Accel. Jet 50
Bypass jet 50
Screws set at 3/4 turn
CAM
Lift .577/.580
Duration @ .050 230 / 236
Lobe Separation 113

[Caprimaniac]

347 stroker (302)

48 IDF carbs. (PS!)

CompCams FS 308-R10, cam Lift .613, Lobe sep. 110 deg.
40mm (40,5mm) chokes
4,5 aux. venturis
f11 emulsion tubes
165 main jets
190 airs
65 idle jets.
Pump bypass 000 (closed)
50 pump jet
Idle screws 3/4 out

By 7/6- 2011 (edit) I run:
40mm (40,5mm) chokes
4,5 aux. venturis
f11 emulsion tubes
140 main jets
190 airs
50 idle jets.
Pump bypass 000 (closed)
50 pump jet
Idle screws 1/2- 2 out (some of the fuel orirfices partially blocked?)

As a remark: I did several AFR test- runs last year with 150 main jet and got a little ritch readings on medium to high RPM's. Hopefully it has dropped down to ÀF around 13.0, I haven't tested yet.


Rune

[Eljaro]

Choke 40
Main jet 150
Emultube F15
air jet 120
idle jet 65
holder 100
pump bypass 0
screw 1 - 1 1/4 out

I have checked and doublechecked the air corrector choice, and with the 200 the mixture goes very lean when you rev up to 6000 and stay there for a few seconds. Same with the 150 air jet. Finally I settled for the 120 air. I do not know if anybody has experienced this (using an A/F sensor of course), but this is definitely so and if you abuse the engine with a 200 air corrector you could end up damaging it.

[Rick Parker]

Those of you who are running roller cams will be able to run a smaller fuel jet than the same engine with a flat tappet cam because of the faster valve action and quicker pressure drop in the venturis. Keep that in mind when making comparisons.

[ack fia]

I was playing with an Air / Fuel Ratio meter on my 347 with Webers. I put the Oxygen Sensor about a foot from the header flange in the 3" collector of the ERA system. Testing resulted in a change to the idle jet from a 65 to a 60 and a pretty flat 14.6 fuel curve. It runs really good now. The car likes no filters and open pipes.
On the dyno you can see the accelerator pump contribution.
Pat

[*13*]

My setup on a 289 (294CI) is:
48IDA WEBERS
Choke 37mm
Idle fuel jet 65
Idle jet holder 120
Main fuel jet 150
Air Corrector 120
Emulsion Tube F7
Accel. Jet 50
Screws set at 3/4 turn
CAM
Lift .468/.462
Duration @ .050 229 / 236
Lobe Separation 112

Sorry for the late add on this. It's something I've been meaning to get to for some time. I just changed out my MAIN & IDLE jets & the car is running a lot better. I will likely need to change out the air correctors, but at least I've got her within range now. This thread has been helpful, thanks guys! Someone should post a database only, without commentary, spreadsheet? The commentary is also very helpful. Would just be nice to see all the numbers side by side. The one thing I would add & reiterate here is that matching the main Jets to the Venturi's should be the place you start with these carbs. If you look at all the numbers people have posted here you'll see that this is a fairly consistent value. The the main jetting vary a size up or down from this but for the most part they have a pretty tight range. Like a Holley 2 or 4 barrel, there is only some much fuel that can be sucked out with a specific venturi size & oversizing the jet beyond reason really isn't going to get you too far. Picking your idle jets is fairly easy from that point, just go back to the list here & make a guess based on what you see. You should be pretty close. Second thing I'd do is get them sync'd up. At this point you should be ready for fine tuning. Hope I'm not over stepping anything here. Just a lot of back & forth info when you read up on these carbs. It gets so confusing that you feel like you might need a 4 year degree in webers before you start. If you understand the principals of a carburetor I believe this multiple carbs is just the next step & Webers are just a carburetor. Use "carburetor common sense" & you should be able to handle it.

[desmo]

Ford FE 427 S/O stroked to 482ci.
I will try this setup (48 IDA) :

choke : 40
main jet : 160
air corrector : 180
E tube : F11
idle jet : 65
idle jet holder :120

What do you think ?

[Eljaro]

I do not know why many of you are still sticking with air correctors 180 and up. Believe me, if you floor the engine and rev it up to 6k and over, you will lean out. Checked it out many times with the A/F meter.
If this is for a short time nothing will happen, but if you constantly floor it like on a race, you will get less power and some overheating.
I have the 120 air jet . maybe a 150 would work well too but I haven't got one. 180 definitely was too large.

[desmo]

Hi Eljaro, thanks for your response. What is your final setup ? 40/160/120 (for a 482 ci S/O) ?

[Eljaro]

I am using the 40mm choke now. The main jet is variable between 140 and 165. It depends on the altitude, the humidity of the air and the ambient temperature.
O good setting in summer is not good for fall, spring or winter, so you have to find a compromise
I find that a 150 main is still too rich for my engine ( a KC 482) according to the A/F meter, but then the plugs look almost white. So I am not sure of that and believe that with 155-160 you are on the save side if only slightly rich.
The 120 air jet is probably a must, and you can see that here are many using it now.
The basic settings many years ago which you read in the books and Inglese and in VW engine forums suggestion are for small blocks and VW engines and can not apply for huge and probably unefficient BB's. My experiences have been confirmed by many other Weber enthusiasts which have ended up with similar settings.