Weber Jetting Survey

[*13*]

Will do guys, thanks! Should have it updated this eve. Hyde

[*13*]

Updates have been made. Let me know if any of you want to make changes or add your info to the list. Thanks, Hyde

[Caprimaniac]

Great work, Hyde.

A useful reference list for all of us.
Personally I'd like some more data for the IDF setup.... I fell kind of lonely; I'm the only IDF-er on your list.
RS

[Gaz64]

Originally Posted by Caprimaniac

Great work, Hyde.

A useful reference list for all of us.
Personally I'd like some more data for the IDF setup.... I fell kind of lonely; I'm the only IDF-er on your list.
RS

Yes, good work Hyde.

Don't feel lonely Rune, I'm an IDF-er and a DCOE-er.

[*13*]

Maybe you can be the inspiration for those who want to be a little quirky

[Gaz64]

Originally Posted by *13*

Maybe you can be the inspiration for those who want to be a little quirky

Hi Hyde,

My inspiration would be to have an IR manifold (one choke per cylinder) that has a rotating barrel or slide throttle to pair up opposing runners so then each cylinder can breath through 2 chokes at high rpm.

I could then have a 32mm choke for low speed and twin 32mm chokes for high speed per cylinder instead of my single 38mm per cylinder.

I'll do it one day.

[*13*]

You'll need to post a build thread on that one so we can watch it all happen! Sounds like fun

[*13*]

John, just a note. My bell crank is not centered to the carbs. Changing to the bell crank has made a ton of difference. It'll never be perfect, though. Not noticeable when driving. If one has a choice of manifolds, this is a good question to ask. I know some have a centered mounting point.

[jhirasak]

*13*,

When I changed my linkage arrangement from a single cross bar to a bell crank arrangement, I had to fabricate a mount that allowed me to place the bell crank povot in the center between both banks of carbs. This mount is attached to the manifold flange attachment bolts on both sides of the engine with longer bolts to compensate for the additional thickness of the mount. Perhaps you could fabricate a similar mounting plate and place your bell crank where you desire.

The use of a bell crank with carbs that are mounted with the fuel bowl inlets pointed in the opposite directions significantly improved the ease of tuning and drivability of my car. I would highly recommend this linkage arrangement for anyone who still has a single cross link setup and is having a problem tuning their 48 IDA Weber setup.

If anyone has a 48 IDA manifold setup that has all of the fuel bowl inlets pointing in the same direction, the single cross bar linkage is more appropriate for use.

John

[*13*]

The bracket sounds like a good idea. The outward fuel inlet manifolds are much more plentiful these days. There are a few of the others still around, though.

[zimmy]

Check with Jim Inglese. jiminglese@att.net

[65arboc]

We're looking for a discusion here on others experience with webers.

[65arboc]

Yesterday I spent some time ballancing my 48 IDA's as I was having some poping out of the driver side pipe. Part of the linkage between the left and right carbs had loosened up since I had not tightened one lock nut securely. Then I reset best idle on all carbs. I then took it on a 30 mile trip to see a friend and it ran so good I couldn't belive the difference. Having the carbs ballanced front to back and side to side is the real secret to getting your setup running great. I run 90 octane gas btw.

Jim in Pa.

Paul, if you have any questions please let me know and I will try to answer them based on my experience, but I am not an expert by any means. I have only this summers' driving time to relate to you.

[1795]

Whenever I am approached at the track by people who are interested in Webers, but have heard horror stories about how difficult it is to get them set right, I tell them that it is not that difficult, they are easy to adjust, and the most crucial piece is to have a strong and stable linkage. Linkages that are loose, or not well stabilized or use components that can be stretched are a recipe for disaster.

I had to add some further bracing to the support that comes up from the back of the head that connects the throttle arm to the arm that then connects to the linkage going down between the carbs as it would twist a little under hard acceleration and the car would not run right. Since stabilizing that support, no problems.

Jim

[65arboc]

Originally Posted by 1795

Whenever I am approached at the track by people who are interested in Webers, but have heard horror stories about how difficult it is to get them set right, I tell them that it is not that difficult, they are easy to adjust, and the most crucial piece is to have a strong and stable linkage. Linkages that are loose, or not well stabilized or use components that can be stretched are a recipe for disaster.

I had to add some further bracing to the support that comes up from the back of the head that connects the throttle arm to the arm that then connects to the linkage going down between the carbs as it would twist a little under hard acceleration and the car would not run right. Since stabilizing that support, no problems.

Jim

Hi Jim,

Very good information. This is what I would like to see here, others experience with their Webers to help new owners get their setup sorted out.

Thanks Jim for your input.

Jim in Pa

[svassh]

Not an expert myself but will share some notes that I have gathered from various internet sources and emails/calls with Jim Inglese. I am running a Redline manifold on a 347 with Weber 44 IDF carbs.

Weber 44 IDF Setup
Main jets – 145
Idle jets - .65
Emulsion Tubes – F11
Air Corrector – 175
Floats – 11mm open without ball valve being depressed

My timing is all in early before 3K RPM at 38 degrees BTDC and roughly 20 degrees initial.

1. With motor off, Disconnect linkage between carb left and right side
2. Back idle speed screws out till not touching, then turn in ½ turn on each bank
3. Set idle mixture screws to ¾ or 7/8 turn out from seated
4. Start motor
5. Synch carbs on each side using only adjustment screw on linkage between carb banks
6. Reconnect linkage between carb banks
7. Adjust linkage between banks till left and right side banks are in synch then lock down linkage
8. To set best lean mixture, for each cylinder
a. Turn idle mixture screw out 1/8 turn
i. If idle speed increases stop, if not repeat 8a till idle speed increases then stop
ii. If idle speed decreases or does not increase, turn idle mixture screw in 1/8 turn till idle decreases then back off 1/8 turn
b. Repeat for each cylinder
9. Check each spark plug condition after driving for lean or rich, adjust each cylinder as needed. 1/8 turn in on idle mixture screw if rich, 1/8 turn out if lean.
10. If you have a flat spot during transition from idle to main circuit, back each idle mixture screw out 1/8 turn.

I can tell you I spent weeks messing with different idle jets only to discover what a significant impact timing has on these setups. I have since gone to a locked out MSD Distributor at 40 degrees and control the timing curve with an MSD 6AL2 Programmable ignition box. Too much or not enough timing will cause a stumble thru the transition phase that you will swear is an idle jet problem. My car is very docile and predictable at low RPMs and all thru the transition curve to 3K RPM with light throttle and will climb thru the RPMS quickly with heavy throttle. I have found with my setup I do need to run slightly rich or I will get lean pops in the sidepipes under light acceleration and deceleration.

Some web links for helpful reference:
http://www.redlineweber.com/html/Tec...t_controls.htm
https://www.racetep.com/manufacturer...ber-carbs.html
https://www.gt40s.com/threads/weber-...youtube.32276/
http://www.timsroadster.com/html/tuning_webers.html
Ignition Timing and Webers
https://jiminglese.com/common-questions
https://jiminglese.com/weber-tech
https://www.gt40s.com/threads/weber-help-please.41056/

[65arboc]

Here are my final specs and the engine is running great like never before. Just a little rich at 1000 rpm idle.

Engine is a 289 bored .030 over
Heads are iron stock but with upgraded valve seats.
Manifold is from Redline Weber
Mild Grind Cam from Comps
Carbs are 48IDA
Choke are 37mm
Idle jet holder-120
Idle Jet-F-10-65
Air Corrector Jet-195
Main Emulsion Tube-F-7
Main Jet-180
Pump Exhaust Valve is Non Ported

Hope this helps someone else.

Jim in Pa

[priobe]

Hello All
It’s been a while since I’ve posted. I came across this website and checked it against my settings. It’s not perfect but you will never find a perfect recipe for any setup. It will be a fine tune trial and error.

I hope it helps put some one in the ballpark to get started

https://www.carbparts.eu/calc

Sorry if this was mentioned already.

[65arboc]

Thanks Priobe,

I had just about givin up on anyone posting about their jetting recently. I really like the calculator however with my 48 IDA setup on my 289 V8, the answers don't even come close to my settings. Is there another calculator somewhere for 48 IDA carbs on a V8? Seems like not many are interested in this subject on here.

Thanks,

Jim

[PDUB]

Yes, interesting, but 48IDA/IDF would be helpful.