AFR Gauge and jets

[VWDruid]

so you have a air fuel gauge what carbs are you running at what altitude and engine size are you runing.

I'm running a solex mex 34 pict 3 1600cc ocean level in a bus
Main Jet x125
Air Correction Jet 60Z
Pilot Jet 57.5
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70 Westy, 2027cc "dual DRLA 40 m130 i55 wjdoc a165 p33 v30 "w100 straight cut 040 polished heads 1.25 rockers 1.5 A1sidewinder supertrapp muffler trans 091 coil SUM-850500 CDI universal svda Pertronix
http://www.storyofstuff.com/
It's not the straight cut gears It's the T.A.R.D.I.S. engine.
wanted Chameleon Circuit

[Lionhart94010]

FYI,

The configuration I am running as of 3-31-08 with my 1600DP engine with Engle 100 cam is:

New Brozol Carburator
Venturi 26mm
Main Jet x125
Air Correction Jet 60Z (had to find)
Pilot Jet (AKA Idle Jet) 70 (drilled out a 65 jet to 70, now idles on its own when cold)
Pilot Jet air bleed 147.5
Auxiliary fuel jet 42.5
Auxiliary air jet 90
Power fuel jet 100/100 ( I am assuming that it is a 100/100 but would prefer a 95/95)
Pump Inject Qty. (Have not measured but max possible Brozol can do, My AF meter indicates I could use more but due to the way the Brozol is built it can not go to full + because it interferes with throttle returning to full closed )

I think the main reason my engine needs a larger idle jet are the Engle 100 Cam and that CA gas has the alcohol additive that changes the volatility of the fuel…

With this combo My AF is approximately-

At cold idle between 9:1 to 10:1 Air/Fuel; choke on & 1,200-1,500rpm
Around 13:1 Air/Fuel at Hot idle 850-900rpm
Around 12.8:1-13.3:1 at around 1,000-2,000rpm when accelerating from idle
Around 13.2:1: -14.1:1 at around 1,000-2,500rpm when cruising
Around 13.2-13.4:1 at around 2,500-4,000rpm when cruising
Around 11.8:1-12.5:1 at Wide Open throttle under full load
(Apr 07, 2008 Data)

From additional reading, off throttle, higher numbers(15-17) are acceptable and running the engine a little leaner(than the above) can make it more responsive…

(from VW Manual With Out Guesswork)
Factory Jetting for a Type 2 Bus with T2 Solex 34 PICT 3

Venturi 26mm
Main Jet x125 (bug 127.5-130 bus jet is smaller because ACJ below is less)
Air Correction Jet 60Z (bug 75-80Z)
Pilot Jet 57.5 (bug 55 except AE bug motor =60)
Pilot Jet air bleed 147.5 (all same)
Auxiliary fuel jet 42.5 ( AE bug motor and 181 where 47.5)
Auxiliary air jet 90 (all same)
Power fuel jet 95/95 (bug 100/100)
Pump Inject Qty. 1.45-1.75 cm3/stroke (bug 1.3-1.6 except AE motor = Same)
_________________
Current VWs 71 T2 Westy SO-72/6(Miami), 71 Crew Cab, 72 KG GT;0) 12 JSW TDI
Other owned VW’s 59, 68 1500s, 69 & 71 Bug’s; 72 & 73 S-Bug’s; 67 Westy, 67 Deluxe, Other 71 DC
VW technical information sights
thesamba - www.ratwell.com - www.shoptalkforums.com/ - www.vw-resource.com - http://www.type2.com/
http://bobhooversblog.blogspot.com/ - www.aircooled.net/gnrlsite/resource/articles.htm

[Lionhart94010]

PS

To me your engine would run way better with a larger idle jet, one way you can tell if you need a bigger idle jet is; if your engine runs better if you open up your fuel mixture screw more than 2 1/4 to 2 1/2 turns, if it does, then you probably need a bigger idle jet…

Ho to:
Install a larger idle jet then adjust AF and idle speed, test-drive check AF at various RPM and seat of the pans feel… keep trying bigger idle jets until the engine starts to run worse the go back to the previous idle jet…

FYI, changing the idle jet will change your AF at idle, mid rpm and top end rpm, if you look at a cutout view of a 34-pic 3 I think you can see that the idle jet(circuit) is connected to all three fuel circuits…
_________________
Current VWs 71 T2 Westy SO-72/6(Miami), 71 Crew Cab, 72 KG GT;0) 12 JSW TDI
Other owned VW’s 59, 68 1500s, 69 & 71 Bug’s; 72 & 73 S-Bug’s; 67 Westy, 67 Deluxe, Other 71 DC
VW technical information sights
thesamba - www.ratwell.com - www.shoptalkforums.com/ - www.vw-resource.com - http://www.type2.com/
http://bobhooversblog.blogspot.com/ - www.aircooled.net/gnrlsite/resource/articles.htm

[VWDruid]

your totally right I was buzzed and doing it from memory
that's the stock setup for a bus.
my old carb had 127.5 main 80 air 55 pilot.
my new setup from memory 130 main 100/120 air 65 pilot
it ideals fine but when im driving over 2000rpm it go's extremely lean on me, I'm going to try a 135 first then a 132.5 if it's to rich
_________________
70 Westy, 2027cc "dual DRLA 40 m130 i55 wjdoc a165 p33 v30 "w100 straight cut 040 polished heads 1.25 rockers 1.5 A1sidewinder supertrapp muffler trans 091 coil SUM-850500 CDI universal svda Pertronix
http://www.storyofstuff.com/
It's not the straight cut gears It's the T.A.R.D.I.S. engine.
wanted Chameleon Circuit

[Lionhart94010]

Your Air Correction Jet needs to get smaller if you want to richen up your AF, it is counter intuitive, but the bigger Air Correction Jet you use the leaner AF becomes at higher RPM, it also messes up the Main Jet and the idle circuits...

The way to think of the Air Correction Jets in the 34-pic 3 is; the bigger the hole in the ACJ and the faster the air come into the carburetor, as RPM increase, the more the air slow down(counter acts) the fuel coming up from your main jet = leans it out...

So, for Air Correction Jets in 34-pic 3, bigger = leaner and smaller = richer ;0)

i.e. if you are running a 100 or 120 ACJ your bus is going to run lean and over heat under load at higher RPM... use a 60 ACJ if you can find one :0)

PS many 34-pic 3 ACJ have been drill out by previous owners because they did not understand that bigger is leaner, all Main and ACJ should be measured if doing any work on any VW Solex carbs, 80% of the jets I have checked are bigger than what was stamped on them :0(
_________________
Current VWs 71 T2 Westy SO-72/6(Miami), 71 Crew Cab, 72 KG GT;0) 12 JSW TDI
Other owned VW’s 59, 68 1500s, 69 & 71 Bug’s; 72 & 73 S-Bug’s; 67 Westy, 67 Deluxe, Other 71 DC
VW technical information sights
thesamba - www.ratwell.com - www.shoptalkforums.com/ - www.vw-resource.com - http://www.type2.com/
http://bobhooversblog.blogspot.com/ - www.aircooled.net/gnrlsite/resource/articles.htm

[VWDruid]

you know I think it was 60 or 75, I did the research and had notes before i ordered them from Kef, he said was the best match for what i had going on, less he let one slip by.

I have a german solex that Im cleaning up and installing tho see if its the carb.

I'll try the 135 main if its 60 or 75 air on the cleaned out carb see how that works.
_________________
70 Westy, 2027cc "dual DRLA 40 m130 i55 wjdoc a165 p33 v30 "w100 straight cut 040 polished heads 1.25 rockers 1.5 A1sidewinder supertrapp muffler trans 091 coil SUM-850500 CDI universal svda Pertronix
http://www.storyofstuff.com/
It's not the straight cut gears It's the T.A.R.D.I.S. engine.
wanted Chameleon Circuit

[kafer113]

Lionhart94010, could you tell me where the fuel mixture screw is on a 34 pict3? I'd like to test it out like you suggest. My bus may be leaning out due to too small pilot jet. It has a 55 stamped on it, but I haven't found a gauge to measure it yet. I can actually cool down if I lower the rpms. I took the cover off of the main jet. I can't read it. It was loose. It should just unscrew and slide out when I tilt the carb, right?

[VWDruid]

http://www.vw-resource.com/carb_41.html

#9?

the main will drop out if you tilt it.
_________________
70 Westy, 2027cc "dual DRLA 40 m130 i55 wjdoc a165 p33 v30 "w100 straight cut 040 polished heads 1.25 rockers 1.5 A1sidewinder supertrapp muffler trans 091 coil SUM-850500 CDI universal svda Pertronix
http://www.storyofstuff.com/
It's not the straight cut gears It's the T.A.R.D.I.S. engine.
wanted Chameleon Circuit

[Lionhart94010]

RE: where the fuel mixture screw is on a 34 pict3 using http://www.vw-resource.com/carb_41.html provided by VWDruid,

FYI, Your Idle fuel mixture screw is #18

Your ACJ is #9

if you want to change the ACJ, it is # 9 and should help cool your engine if it is running lean above 2500 RPM, see if you can find a 60 :0)

My engine needs a 70 idle to run well with the 60 ACJ, possibly a 75 ACJ and a smaller idle may work but it is impossible to tell with out an AF meter...

What Rob and Dave say it true “The idle and timing are interrelated and must be set at the same time. See the Timing Procedure below”
http://www.vw-resource.com/tune-up.html#idle

It is hard to adjust the AF of a mistimed engine (also it is a very good idea to verify the accuracy of the TDC mark on your pulley( may have come from a different engine), you can buy a spark plug holes TDC stop from Summit racing for 12mm(HP Heads) & 14mm(stock Heads) around $8-15)

Crane Cams 99412-1
Summit SUM-900189
COMP Cams 4795
_________________
Current VWs 71 T2 Westy SO-72/6(Miami), 71 Crew Cab, 72 KG GT;0) 12 JSW TDI
Other owned VW’s 59, 68 1500s, 69 & 71 Bug’s; 72 & 73 S-Bug’s; 67 Westy, 67 Deluxe, Other 71 DC
VW technical information sights
thesamba - www.ratwell.com - www.shoptalkforums.com/ - www.vw-resource.com - http://www.type2.com/
http://bobhooversblog.blogspot.com/ - www.aircooled.net/gnrlsite/resource/articles.htm

[kafer113]

Ah, the volume control is the mixture. Gotcha. I pulled the carb out but I didn't check the ACJ because I didn't have a replacement gasket and I didn't want to mess it up. I couldn't see the number stamped enough to tell what it was. The carb is a Bocar with 127 main jet and a 55 idle jet. Seems to me this was set up for a beetle not a bus. The cutoff is mexican and the choke says 74 on it. Man, I'm going to have a real hard time finding an ACJ. I'm running a Brazilian 009 all in at 32 degrees at roughly 3500rpm. Not ideal, but will be my backup dizzy once I get a proper vacuum advance one. I have a degree pulley to make it easy on that front. It starts and idles like a dream. Its cold natured against a load when its cold but after about 30 seconds its golden. The big air bypass screw is 1 turn out from the bottom.