A/F Dynojet vs W/B Commander...the question which is

[Mr Hemi Head]

correct?

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If you cannot see the Dynojet A/F don't worry it's not your eyes. 10:1 except for a spot at 3500 rpms.

The upper graph is the W/B commander wired into the VEC2.

The Viper pulls hard without hesitation or break up in any gear.

Why the drastic difference?

 

[Schulmann]

Mr Hemi Head !

THANK YOU FOR THIS REMARK ON THE AFR

Search my posts regarding this AFR matter.

I noticed this problem in June 2005 when I got my LC-1 from Innovate.
I have a WBO sensor on both side of my car.
Generally speaking the WBC always indicates an AFR above normal value under 14.7AFR and an AFR below normal value above 14.7AFR.

The AFR curve of a WBO sensor is not a straigh line.
I have the impression that the WBC algorithm read the Voltage as a straight curve. I think there is a bug in the WBC.

However if you have a cross section in your exhaust and one side of the engin is running richer than the AFR read at the tail pipe will be lower.

You could have gained 2-5% more HP if you had leaned out a little your AFR on this Dyno program.

 

[Mr Hemi Head]

The Corsa cat back does have a crossover.
Does the LC1 read higher than the WB Commander? The difference would then be greater, no?

I took temp readings with the Raytec, all cylinders were around 320deg.at about 3K rpms. The Dyno operator thought that was low because of the Jethot coating.

 

[ViperBing]

I had the same thing happen. The Dynojet dyno read below 10.1, yet my wideband commander is reading about 11.1.

My problem is that since I didn't take the readings from the same tailpipe as the WBC, I can't be 100% certain that one of them is in error.

 

[Schulmann]

I did a lot of testing:
- Same pipe different location
- Same pipe same location

There is always a différence no matter what.
I even changed the oxygen sensor so both have the same age.
Under 13AFR the différence is very important.

I even contacted the WBC support without result.

Send a mail to the WBC support
[email protected]

 

[Mr Hemi Head]

I spoke with Phil at Dynojet who is product manager for the Wideband Commander.

He explained:

1.The Dyno facility is using an old sensor. Because of the variety of engines tested(leaded fuels, juice, etc.) they recommend replacing the sensor yearly.

2.The filter in the Dynojet pump has not been serviced.

3.The Dyno sensor must be at the same location as the W/B Commander for the best accuracy.

During product testing they used a Viper GTS, to compare the two systems, .1 difference.(did not tell him I have a GTS until the end of the conversation)

Their latest Dyno software has provisions for logging the output of the Commander and overlay onto the dyno graph. The shop I used must not be aware of this.

They compared the Innovative system with theirs and found the readings to be the same. What else. LOL

New products are in development that will permit monitoring both sides. To be released early next year.

Finally.
If my GTS is that rich the car would be running poorly.
The performance is awesome.

 

[Schulmann]

Phil is the same person that I talked with.
This French guy is very sure of his product.
He told me exactly the same thing.
I think he wrote an internal not that he reads back to all customers complaining.

I am rather scared that there product is not accurate.
Running in lower 10AFR is not so bad until you hit 8 AFR.
You can't see/feel the difference between 10 and 11 AFR.
You need instruments for that.

 

[Mr Hemi Head]

I have been employed in the instrumentation field (medical)for the past 23 years. Our test equipment must be calibrated yearly using standards traceable to NIST.

Until there is a cal. lab who will certify W/B meters we have only the manufacturers claim that they are accurate.

 

[Schulmann]

Medical equipment is not the same as a tuning tool.

I believe that they have tested their staff a year ago when they released it. At that time it was running accurate. However since they have had several new firmware releases and likely they introduced a bug. The best exemple for this is the VEC2 firmware and cylinder #10. It took a couple of months before we got a fix, thanks to the feed back from several guys.

 

[Jack B]

A few insights:

1. Most dyno operators use extreme smoothing, therefore, up to 4000 rpm you are seeing an average value that is affected by the leaner condition prior to wot. When smoothing is applied while sensing, you loose the base data.

2. It is almost impossible to get a correct reading with the tail pipe sniffer.

3. The one year comment by the Dynojet engineer is absurd, I have had them change the sensor multiple times during a a long dyno session, if the facility changes it once a year, forget the accuracy.

4. To be consistent, have them place the sensor in the front oem O2 well.

5. When trying to compare two O2 systems, you have to offset the graphs if the physical locations (distance from collector) are different.

6. Innovate will calibrate your sensor with a series of base gases.

Mr Hemi:
It would be nice to also see throttle position on your log.

 

[Mr Hemi Head]

Jack

The TPS signal has been aquired and the graph will be attached soon.

The W/B Commander cannot be calibrated. They are relying on the sensor manfacturer(Bosch?)for this.
Free air cal is not necessary, if the meters accuracy is in question the sensor must be replaced...so said the Dynojet Rep.

As for verifying the A/F meters accuracy,I don't have much confidence when it's left to a manufacturer.

When Google searching this I found many conflicting reports and claims. "Dead on accurate" was commonly used but compared with what standard?

 

[Shelby3]

How can any AF system be any more accurate than the O2 sensor itself?

 

[davem]

Some of the replies from the Dynojet guy sound hokey, some sound correct.

The tailpipe O2 pump:
I had used the dynojet pump for 2 years before I chucked that piece of crap in the trash. In addition to the filter clogging instantly, the cheap hoses inside the pump come off and let air leak in around them, which give incorrect readings. I'm guessing that this is what you were up against. I've changed to a Land and sea type O2 pump which works much better.

The sensor:
I use a powertrain electronics afm 1000 sensor, which requires free air cal and has been rock solid for 5 years (It better, it cost $1600). I'm very careful to not let leaded fuel come near it. So without a cal I think your apt to get errors due to sensor aging. It's possible what the dynojet sensor was junk.

Bottom line is you don't know which sensor to trust. I'd take it to another dyno shop that has better equipment and see how they compare.

good luck,
Dave.

 

[Mr Hemi Head]

Dave are we expecting too much? There is a big spread between your $1600 afm 1000 and a $400 W/B Commander. Have you tried comparing your A/F monitor with similar meters? (Innovative,W/B Commander etc.)

 

[Mr Hemi Head]

Jack

The TPS signal has been aquired and the graph will be attached soon.(Blue)

and here you are. Sorry about the quality,don't own a scanner.Still in the stone age when it comes to computers.


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