Weber DCOE tuning swap shop - sticky?

[Zedyone_kenobi]

I was thinking that we here at Classic Z cars are a unique bunch that are willing to share knowledge at the slight hint of a question.

What I would like to propose is an online collaborative parts sharing for Weber DCOE?

Anybody who has triple webers on their cars, has a bunch of spare parts, jets, linkages, rod ends, emulsion tubes, etc. We are all trying to improve the tune of our cars, and for the vast majority of us, we settle on good enough, rather than perfect because the price of jets and air correctors are prohibitively expensive to buy in bulk. 6 of anything is about 40 bucks.

however, a padded envelope is not that expensive and a stamp is within all our means. What I propose is a listing of all the spare jet sets, air corrector sets, venturis, chokes, linkages, etc we may have that we would not mind loaning out to other Weber owning members.

The purpose of this is to let people try out different configurations on different engines at nothing more than the cost of an envelope so they can find what works and only have to BUY parts once.

This will also aid everybody out as people can report back before and after runs with their new set ups and collectively we will all see more cause and effect from a set of mains or idle jets.

I am about to place a large order to get my gal dialed in, but what I will not be using I will offer to anybody else to try in their DCOE's.

We can all save each other a bunch of money.

I will make a list of all the parts I have available for check out.

This whole thing will rely solely on the honor system. The payout is a larger data base of information on the effects of what parts do what. Since we are all running L series engines with L24, L26, or L28's we can really narrow down what is a good configuration and what is not.

We may find a special setup by accident that really sings.

[240260280z]

I'm in.

[LeonV]

I'll be going to Keith Franck's place pretty soon to tune the Z with his new idle jets and e-tubes. Luckily enough, he's local to me. I'll post up after doing so. Sounds like a pretty good idea though, although I currently don't have much of a jet selection to send out.

[240260280z]

I need three new 175 fuel bowl needle valves. Once I get them I can unload the three new 225's that are in the carbs and the three old 175's

I also need 12 air horn tabs.

I also have 3 extra long-flo filters

Edited August 7, 2012 by Blue

[Zedyone_kenobi]

I currently have Installed:

160 Air correctors

130 Mains

F11 Emulsion Tube

55F8 Idle Jets

170 air correctors I can loan

I have ordered:

180 Air corrector

140 Main jets

50F9 Idle Jet

55F9 idle jet

I have to go through all my spares to see what I have available.

[hls30.com]

I have a set of tripples on a canon Intake and either one or two spare complete carbs-and a canon intake in two parts (broken runner). I believe they are all DCOE 40s, but on the od parts I am actually not sure. I also have two pairs of the Down Flow Webers with manifolds. I have the Haynes Techbook Weber Carburetor Manual (also covers SUs)-and an original Mikuni book, and the Nissan Motorsports Schematic on the Mikunis, and SUs, early and late.

[Zedyone_kenobi]

I currently have Installed:

170 Air correctors

130 Main jet

F11 Emulsion Tube

55F9 Idle Jets

Updated Loanable tuning jets:

180 Air corrector

160 Air corrector

140 Main jets

130 Main jets

55F8 idle jet

50F9 idle jet

parts coming in:

120 Main jet

60F9 idle jet

[Lazeum]

Too bad I'm the other side of the ocean but we do that also here in Europe

I've tuned 3 different configurations of L28 always with 40DCOE.

I always found idle jets 50f9 or 55f9 working the best over xxf8 units for instance which are too lean for our L-engine.

F11 emulation tube always works good also.

My car was always healthy during accel with bleed jet (the one on the bottom of the fuel bowl) being clogged with solder.

The rest of the configuration depends on choke size, carb size.

with 32mm choke, N42 head, flat tops & Schneider stg2 cam:

Main: 135

Air: 200

idle: 55f9

=> good AFR but timing was low to avoid ping. setup was undercarbed after 5500tr/m (rich AFR at high rpm whatever the air jet was)

then with P79 milled/port/polished, Rebello street cam & flat tops, still 32mm chokes:

Main: 115

Air: 185

idle: 50f9

=> New setup is much more efficient, I had to restrict fuel a lot to get good performance (= good AFR). car is undercarbed for now after 5000rpm.

Stock setup with 35mm choke (too big!)

Main: 140

Air: 180

idle: 50f9

=> not very efficient, a lot of fuel required since vacuum is not so good during operation, idle is easy to tune.

Edited August 21, 2012 by Lazeum

[Zedyone_kenobi]

55F9 is a great idle jet for L28. It is so close for me. I could probably get away running with it all the time as it is only lean under VERY low load, steady state cruising in 3rd and 4th gear.

I am surprised that your mains are so rich! But every car is different. I am betting the bigger choke on your cars allow you to run more fuel in the mains as you are getting more air. My 30mm chokes are making my 130 mains very rich indeed. I may need to get some 32mm chokes.

[Lazeum]

The main on the stock setup has to be big since 35mm choke does not provide enough suction to pull enough gas out of carbs. So we have to open up jet size.

bigger jet does not always mean more fuel on different setups. The 115 on my current P79 setup is pulling more fuel than the 140 on stock setup for instance.

[Zedyone_kenobi]

OH I agree, The amount of variables that contribute to fuel delivery from the carbs to the engine is staggering. Head, exhaust, camshaft profile, carb chokes, ignition, Valve lash, etc. Its all contributes to how much vacuum the carb sees, and what is the strength of that vacuum. Such a wonderfully complex thing to tune, and when you think about how Webers are built, and how many ways you can tailor them to accommodate so many variables, the beauty of the design is amazing.

[240260280z]

Hmmmm for the idle jet, I have 55F11 and they seem rich on the 240z with cam. I get the car back in a couple of days and can investigate more. I probably do not have the balance between exposed progression holes and idle enrichment set correctly as I could drive around with no mains installed up to ~ 3000rpm... that must be rich indeed...maybe they were drilled.

Anyway, the books and the net say this for relative idle jet air orifice size:

Rich - F6 F12 F9 F8 F11 F13 F2 F4 F5 F7 Fl F3 - Lean.

Does anyone have a table of absolute hole sizes and number of holes for the air inlets for the above parts? I think it is time to raise the bar from symbols to real numbers. Assigning a cross sectional effective hole size to each symbol would be a first step.

Thanks!