Wideband

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twayne24365

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ok guys I’m finally going to install my wideband today, I know you can torture yourself to death tuning with these but I’m wondering where about my afr should be at idle, cruise, and wot.
It’s a .030 over 383
About 10.6:1 iron heads
.557 mopar cam
Street dominator intake
750 mighty demon
38* timing locked out
4 speed and 4.56 gears
 
Curious, No instructions with the wideband?
 
I don't think the wide bandwould come with instructions other than just the obvious 14.7 to 1 being best burn. I try to keep mine idling close to that 14.7 as I can and from every thing I've researched about 12.5 to 12.6 at Full Throttle and that's just about where I have mine. At least this could give you something to start with and work from.
 
Yes 14.7 was really the only thing mentioned and I thought that was a little vague, seems like it runs pretty good so I’m interested to see where it’s at
 
Yes 14.7 was really the only thing mentioned and I thought that was a little vague, seems like it runs pretty good so I’m interested to see where it’s at
I run a dual quad tunnel ram so it's essential for me to have some kind of idea of what's going on. And the best thing I can do is just too both of them exactly the same even though they're two different carburetors that may have different requirements in the end 14 7 at idle LOL 12 5 at Full Throttle.
 
try this

IMG_8994.JPG
 
I have played with mine quite a bit on different vehicles.On my current dart i was running around 15.2 while cruising, a nice 14.5 at idle and around 12.5 at wot. As users know these are averages because of the constant fluctuations.Car ran great and didn't overheat with good mileage.
I have since richened it up a bit at cruise to around 14.0 just to be safe.
A great tool !
 
cruise can be in the low 15's. 13.0-.2 at WOT, 14.5-15.0 part throttle and under 15.5 at cruise. The higher AFR at cruise will increase mileage at the expense of higher EGT's and NOx levels if it has to pass the smell test. if you can tune on the fly, that's the best way to do it as all motors are different. Best thing about a wideband is plugging it in and seeing your Carter at 12.0 at idle...no wonder it stinks! But with that cam, good luck...

Make sure you install that O2 sensor at an angle off the exhaust pipe, you dont want it sticking straight up into the pipe (on the bottom of the pipe) as it will rust out eventually.
 
The larger the cam is, the tougher it is to maintain a stoich idle A/F(14.7).
So don't get your hopes up with that cam. The locked timing sure isn't going to help.

So I wouldn't go nuts trying to hit the perfect Stoich ratio at idle. You'll probably find an A/F 13.5:1 makes your combo's idle and tip in a heap ton better while keeping idle vacuum off the PV. Give the motor what it wants, regardless of opinion polls.

With that said, a lean part throttle cruise is perfectly fine.
 
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4 Speed makes thing a lot easier, no converter drag down.

The chart above is for boosted applications.

As mentioned, use it as a tool to find what the engine likes. I have a 340 with the 528 cam and it won't idle at 14.7 or close. It liked best at 13.7ish range. Fool around with the idle and see what it likes. Highest vacuum reading is a good spot to start from. May want a smidge richer, lower vac number to help tip in and cover some acc pump lag.

Cruise anything higher than 14.5 is good.

WOT 12.0-13.0 is a typical range. Some engines are close to 12, others closer to 13. Another, let the engine tell you. You won't likely hurt the engine if it's in this range to start and begin fine tuning. Highest MPH at the track is the best confirmation for WOT AF numbers.
 
Keep in mind the 14.7 stoich number everyone throws out is based on running pure gasoline. If your fuel has any ethanol in it, stoich is not 14.7. For instance, for 10% EtOH, it is 14.1, and 13.8 for E15, etc.

What type of fuel do you have?
 
ok guys I’m finally going to install my wideband today, I know you can torture yourself to death tuning with these but I’m wondering where about my afr should be at idle, cruise, and wot.
It’s a .030 over 383
About 10.6:1 iron heads
.557 mopar cam
Street dominator intake
750 mighty demon
38* timing locked out
4 speed and 4.56 gears

Curious, No instructions with the wideband?

The instructions don’t really say a target number
Because there isn't one. Tune for performance. Use AFR to better understand the tuning change. Over time you will narrow the best AFRs for the specific setup (car and engine) under various conditions.

I'll repost this summary:
There really is no single answer. There are general trends that were well established by testing and then the details vary with specific application.

If you're just going for engine effiency (in terms of making good power for amount of fuel used) and not dealing with emissions requirements, then the general trend of AFR can be described as follows:

"The [relationship] is rich idle, lean cruise, leaner (leanest, actually) part-throttle acceleration and rich WOT. The leanest is at mid-load, half-throttle or" somewhat more. Cruising, especially at lower speeds, requires little throttle and puts relatively little load on the engine. Half throttle or mid-load would be going up hills or part throttle acceleration. "The thing to understand is most engines respond to being leaner...at part-throttle..."

In summary "at moderate to mid load, engines will run lean and like it, and burn much less gas while doing so. They must be rich at idle and very low load, lean in the middle, and rich at WOT." The load where richer is needed varies with engine, gearing and vehicle. It may be 60-70% as shown here, or as high as 90%. Load relates to manifold vacuum, and therefore vacuum is used to signal when enrichment is needed.
blob-jpg-jpg-jpg.jpg

F is Fuel/Air ratio for gasoline. Invert the numbers to convert to Air/Fuel ratio.
0.08 = 12.5 AFR
0.667 = 14.7 AFR
0.06 = 16.6 AFR
Constant power is any steady throttle condition.
Steady 15% might be something like driving 40 mph on a flat.
Steady 25% might be cruising 60 mph on flat or steady 40 mph up a long grade.
Steady 100 % might be something like towing or dragging max load up up a really steep long grade, foot to the floor, without losing or gaining speed.

The acceleration loop shows that maximum acceleration (full throttle) has about the the same fuel-air needs as constant 100 % power.

"This ... graph is from Walter B. Larew, Carburetors and Carburetion. At the time he wrote his book on carburetors he was a retired Brigadier General who taught Military Science at Cornell, among his other accomplishments. He published this carb book in 1967. He didn't specify an engine type for this graph but his information is in the context of engines in general. His sources were most likely military aviation research. The math in his book is from NACA TR-49 and similar publications.
This graph is representative of a richer part-throttle that may be necessary to tolerate with an engine that has radical valve timing and perhaps not so good A/F distribution at part-throttle."

quotes and graph from Tuner on Innovate Motorsports Forum and full text now reposted at RFS
 
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Keep in mind the 14.7 stoich number everyone throws out is based on running pure gasoline. If your fuel has any ethanol in it, stoich is not 14.7. For instance, of 10% EtOH, it is 14.1, and 13.8 for E15, etc.

True, but if you cant change the A/F that equals a Lambda of 1.0, then the "gas calibrated" gauge will ALWAYS assign an A/F of 14.69 to a Lambda reading of 1.0.

Methanol, E85, Nartural Gas,,ect will ALL register 14.7 as a stoich if using a "Gas" calibrated Wideband gauge.
 
The larger the cam is, the tougher it is to maintain a stoich idle A/F(14.7).
So don't get your hopes up with that cam. The locked timing sure isn't going to help.

So I wouldn't go nuts trying to hit the perfect Stoich ratio. You'll probably find an A/F 13.5:1 makes your combo's idle and tip in a heap ton better while keeping idle vacuum off the PV. Give the motor what it wants, regardless of opinion polls.

With that said, a lean part throttle cruise is perfectly fine.
I agree. Only point I'd like to make is that 14.7:1 was never the best for idling. Even the CAP equipped cars only targeted 14.2:1 AFR. Standard idling for effciency and power is generally somewhere between 12-14. Stoich is not the most efficient or least polluting, its simply chemically balanced.
 
The 38* locked timing may be a problem in two ways.
One - timing and fueling go hand in hand. I know, less of an issue here with a manual transmission, rpms will be up by the time you fully load the engine.
Two - The AFR reading is an interpraton of the wideband's reaction to the oxygen. Assumptions are made about the combustion process. When the fuel - air combusts differently than assumed, the oxygen left over is different. When this happens, you get false reading. I'm not saying it will happen, but beware it is more than possible. If readings don't make sense, this is probably why.
 
Lot of information! I run a 50/50 mix of cam 2 and 93.

I also welded the bung in at about 10-15* angle like the directions said and about 3” from the header collector
 
Ok.... so here’s what I got, car runs well...once up to temp idle is a bit jumpy lol, 13.4-14.8 range. At 2200-2500 rpm cruise it’s rich at 10.5, 3200 rpm cruise is up to about 11.2 and wide open throttle is in the 12.5-12.8 range.

The other thing it does is say from idle if you wack the throttle when rpms come down it flashes dead lean
 
when the engine comes down off a throttle blip, it will run lean as no fuel is being drawn.
 
Drive on a flat road and slowly increase your speed, start at 1500 and roll there, then go up to 1750, 2000 and so on. Observe the reading. There should be a point where the numbers drop.

You need to find the point on cruise where the main jets activate. Doing this will allow you to make adjustments to the correct circuit.

One thing that is a total clusterf*ck in most of the newer carbs is the 5 emulsion main wells. Causes a bunch of issues and is a monkey see, monkey do type thing with carb companies/builders. The old holley 3310 metering blocks were SOLID and had 2 emulsions!!! More isn't always better.

WOT looks pretty good to start with.
 
Ok.... so here’s what I got, car runs well...once up to temp idle is a bit jumpy lol, 13.4-14.8 range. At 2200-2500 rpm cruise it’s rich at 10.5, 3200 rpm cruise is up to about 11.2 and wide open throttle is in the 12.5-12.8 range.

You'll want to lean out the primaries and probably fatten up the secondaries to compensate again for WOT.
This will fix the overly rich condition at cruise.
 
This is where some find the Edelbrock carb is a good fit.Using their guide it is very easy to tune each circuit seperately.
Having said that i found it impossible to clean up the idle on larger cammed engines...they just seem to create too much uburnt fuel at lower rpms.
...maybe it's me?
 
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