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 Intake / Carb and Fuel Delivery Tech
 Wide Band Carb Tuning
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GtoGuy32
Cochise

USA
839 Posts

Posted - 14 May 2017 :  10:18:28 PM  Show Profile  Reply with Quote
I am considering getting a wide band to help dial in my carburetor.

Is it worth it and has anyone found it to really help get the carb adjustments better than measuring MPH in the 1/4 mile and/or reading plugs?

Thanks

Dave

cortcomp
Coyote

USA
5269 Posts

Posted - 14 May 2017 :  10:20:54 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I used it, and it was great. That, combined with cluff showing me how to tune APT (screw) and WOT (with needles) made it a snap. I was very rich WOT (10:1) and around town (about 12:1). I adjusted that car to about 12:1 WOT and 14.5:1 around town.

Reading plugs i feel can be off depending on fuel type, additives, ethanol, etc.

On the 1/4 mile, I wouldn't be consistent enough to be sure that an adjustment was the reason i went faster or slower or me.
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Bentwings
Tribal Scout

USA
28 Posts

Posted - 15 May 2017 :  08:11:11 AM  Show Profile  Reply with Quote
I've had one on my Willys for ten years. It's really the most accurate way to adjust carbs or EFI. I combine it with the vac/boost gage. The newer ones have data recording so you can see where you are at all speeds and loads.
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GtoGuy32
Cochise

USA
839 Posts

Posted - 15 May 2017 :  11:22:04 PM  Show Profile  Reply with Quote
Good feedback guys. I might pull the trigger on one. I may not keep it in the car all the time, just use it to get the carb dialed in.
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cortcomp
Coyote

USA
5269 Posts

Posted - 16 May 2017 :  09:36:36 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I thought the same, but i still got the black faced one so it would blend in with the interior. After it was installed, i just left it in the car when i sold it, it didn't look too out of place, and it was one more thing to look at in the cockpit to know things were smooth.
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DanM
Buffalo

67 Posts

Posted - 26 May 2017 :  2:17:08 PM  Show Profile  Reply with Quote
I am in love with my AFR (air fuel ratio) gauge. I use the white face to match my oil and water gauges. Unfortunately the O2 sensor died.

I have found it to be indispensable for tuning my carb. My idle has been finicky for several months. I would adjust it by "1/2 hour increments" at a time. It either stalls in cold wet weather or revs too high in warm dry weather. and everything in between.

So I got a new O2 sensor.

My idle mix has been too lean, ~16:1. If the engine RPM dropped the AFR would go leaner, lower RPM, leaner, lower RPM, stall. So last night with my new O2 sensor I got a great idea. Why don't I plug one of the two idle-air orifices on each side of the carb? That will surely richen my mix by forcing the idle circuit to draw more fuel. My valve body orifices were 0.038" diameter (based on previous measurements I made at previous rebuild.) I happened to have some 0.032" lead solder laying around. So I made a small thumbtack shaped piece of solder and dropped that into each of the orifices and smashed it into place with my finger. I figured the lead solder would mold itself to the carb body and if all else fails, the engine would chew it up like gum and spit it out with no risk of damage.

Man did that do the trick! It now idles exactly at 15.4. I can finally adjust my mixture using my idle mix screws which used to be useless. Instead of having to go by instinct or by vacuum gauge I can turn the screw and watch the AFR gauge. Amazing how it would run less smoothly if it got leaner than 15.5 etc.

At cruise I'm at 15.2. I'd rather be at 15.4 for maximum mpg but hey, 15.2 aint bad and it flutters anyway. Unfortunately at part throttle when my power piston engages (or disengages depending on your perspective) it goes pig rich to 10.1.

Currently 0.077" jets and 0.044" rods. By doing some simple math (pi*radius1squared - pi*radius2squared) I estimate I can switch to 0.072" jets and 0.039" rods to maintain my great cruise AFR but lean out my part throttle closer to the ideal 12.6. I will try that this afternoon or tomorrow.

I don't expect to get it right the first try. But I should be able to get very close by my second try. Then it's back to the dyno to recover that 25 HP I am missing because I'm running too rich.

All made possible via AFR gauge. Worth every penny.

71 LeMans Sport Convertible with 310,000 miles driven year round since 1994.
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DanM
Buffalo

67 Posts

Posted - 26 May 2017 :  2:17:57 PM  Show Profile  Reply with Quote
...I expect the AFR to change with the seasons. I'll be watching that AFR gauge for years to come.
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GtoGuy32
Cochise

USA
839 Posts

Posted - 26 May 2017 :  10:15:00 PM  Show Profile  Reply with Quote
I purchased an Innovate ML-2. The gauge wont stay in the car, but I can hook it up periodically to check how the car tune is doing.

My carb is definitely suffering from idle circuit / transition circuit issues. I hope to get those sorted out soon.

I am also considering a carb body with Annular Boosters.
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Dweld02
Tribal Scout

8 Posts

Posted - 14 Jun 2017 :  11:32:03 PM  Show Profile  Reply with Quote
I didn't thought these carb tuners are giving so good differences.
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Blued and Painted
Chief PONTIAC

USA
3370 Posts

Posted - 15 Jun 2017 :  12:42:44 AM  Show Profile  Reply with Quote
There are not a huge amount of carburetor turners out there.
Seems to be more Laptop fuel injection turners around town. Many of thease guys are good, but are hesitant to suggest any adjustments for a carb.



Bull Nose Formula, 461, TH400/ 3.08 8.5 / R44TS.
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DanM
Buffalo

67 Posts

Posted - 26 Jun 2017 :  09:56:52 AM  Show Profile  Reply with Quote
It's been a few months and with it enough variation in the weather that I've noticed some trends.

After changing primary jets and rods a couple times I'm currently at 72/37. Yes that sounds super rich but I have a 0.120 diameter air bleed hole in my air horn on the primaries. This totally leans out my mixture. I was running around 16 - 17 AFR. One day I came up with an idea. I got a coffee stir from Dunkin Donuts, the kind that has the cross shaped cross-section (four ribs not two). I sliced off a little from each of the four ribs so that it fit snugly into the holes and then cut about a 3/4" long piece. I stuck one into each air bleed. this restricted the air bleed enough to richen my mixture to exactly where I wanted it: 15.4 AFR at cruise.

But, when the weather is super hot it goes rich to about 14.2. When the weather is much cooler it goes lean to about 15.8. Overall I'm very happy with my cruise AFR.

Of course the part throttle AFR moved in the same direction. I got the primaries to be almost exactly 12.6 when the power piston engages (pops up, low vacuum) which is right where I want it. The AFR varies the same as cruise does depending on temperature.

The secondaries are so much easier to adjust. I have two hangers, one has the hole in the middle. The other has two holes: high and low. So I can select which hanger I need to tune the secondaries AFR from about 11 to about 13 under WOT.

71 LeMans Sport Convertible with 310,000 miles driven year round since 1994.
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DanM
Buffalo

67 Posts

Posted - 26 Jun 2017 :  10:00:12 AM  Show Profile  Reply with Quote
Idle and off idle are finicky.

My idle is lean and my off idle is rich. WTH ?

My idle air bypass holes were also too large so I plugged one on each of the idle circuits with a piece of solder smashed into place. This put my idle closer to 15.4 and now my adjustment screw actually does something. However the AFR varies quite a bit depending on the weather and the idle rpm (13 - 17.)

Even with the idle at 15-16 my off idle is rich, around 13-14. That's not so bad I guess but I would rather it be in the mid 15s so my fuel economy would improve.

Finally, I get about 12.4 mph during a week's worth of commuting in half stop and go, and half highway cruise speeds. If I do just open highway driving I get as much as 14 mpg. I cruise at 75 - 80 so my fuel economy suffers as a result.

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Blued and Painted
Chief PONTIAC

USA
3370 Posts

Posted - 26 Jun 2017 :  12:46:52 PM  Show Profile  Reply with Quote
carbs don't atomize fuel nearly as well as an injector under pressure. Large fuel droplets and wet intake walls limit efficiency and fuel ratio to only an average.
An injector and ecu can adjust in a fraction of the time.
Being perfect stokometreic efficiency is 14.6, more lean can lead to hi combustion temps and detonation, and will not improve power or mileage. More likely the opposite.


Bull Nose Formula, 461, TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 26 Jun 2017 12:53:38 PM
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