How to tune with a wideband
05-27-2002, 10:51 PM
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How to tune with a wideband
Why use a wideband?
Full throttle tuning only tunes 1/5th to 1/6th of the available map area. Part throttle where you spend most of your driving time and is the most common area for complaints. (poor fuel economy, roughness, stumbling) Few dynos are capable holding a constant load for part throttle tuning. They do not accurately represent real world conditions like underhood airflow at speed and RAM air effects. Typically your car will run leaner off the dyno than on by about 3/10ths of a point.
FJO www.fjoinc.com has a plotted the response of a stock O2 sensor vs their wideband:
This tells you how inaccurate the stock sensor is for anything other than 14.7:1 air fuel ratio.
This picture is representative of measured airfuel ratios and the precentage changes you need to make.
The article http://www.hondata.com/techwidebandtuning.html gives you all the details.
Doug
[Modified by Hondata, 7:04 AM 5/28/2002]
Full throttle tuning only tunes 1/5th to 1/6th of the available map area. Part throttle where you spend most of your driving time and is the most common area for complaints. (poor fuel economy, roughness, stumbling) Few dynos are capable holding a constant load for part throttle tuning. They do not accurately represent real world conditions like underhood airflow at speed and RAM air effects. Typically your car will run leaner off the dyno than on by about 3/10ths of a point.
FJO www.fjoinc.com has a plotted the response of a stock O2 sensor vs their wideband:
This tells you how inaccurate the stock sensor is for anything other than 14.7:1 air fuel ratio.
This picture is representative of measured airfuel ratios and the precentage changes you need to make.
The article http://www.hondata.com/techwidebandtuning.html gives you all the details.
Doug
[Modified by Hondata, 7:04 AM 5/28/2002]
05-28-2002, 07:30 AM
#4
Re: How to tune with a wideband (Hondata)
Doug,
I'm glad you have been pushing wideband street tuning. I now have significant experience wideband tuning on the street. I did another GSR this weekend and it was a fiasco (wrong ecu conversion harness; spent 5hrs rewiring it from A to B version; had a silly short from a sharp solder spike; developed a few more grey hairs; fixed it; had a succesful tuning session the next day)
anyway, i'm jealous because his car drives better than mine without that silly hesitation that many of us are complaining about. Actually, to drive it you would think it was a factory turbo from idle to redline! Whats wonderful yet somewhat dissappointing to me is that I went back and compared his maps to my maps and you can almost overlap them. This shows the reproduceabilty of street wideband tuning which you will never get with wideband tuning on a Dyno. Hondata's basemaps confirm that. They are all over the place! I think a revamped set of basemaps are in order. I know you are working on them and they are needed badly. I would be happy to help out, at least for Integra GSR's.
Torin
edit:
I will also add this wideband tuning tip:
Careful about adding or subtracting fuel based on the reading shown in your display above. If you are lean along a specific range of rpms across a few MAP values, add fuel at least one rpm range before it. That is what is really affecting the lean reading in that area.
If you don't do it that way, you land up with large peaks and valleys from overcompensating. the final fuel maps really should look nearly flat and they should nearly parallel each other, rising gradually, tapering off at finally at higher rpms.
I don't recommend the brake/throttle procedure Doug suggests on his website article. It gives false rich readings from overthrottling on a pseudo load. Careful gentle throttle acceleration in each gear is more accurate and then extrapolate your curves to fill in the missing fuel cells. If you brake/throttle to fill in cells lower in an rpm range to fill in a MAP value (because you wont ever be able to fill it in with "normal driving" you will then falsely affect the higher rpms, compensate falsely, spend endless hours trying to adjust it out).
[Modified by GruvyTune, 11:41 AM 5/28/2002]
I'm glad you have been pushing wideband street tuning. I now have significant experience wideband tuning on the street. I did another GSR this weekend and it was a fiasco (wrong ecu conversion harness; spent 5hrs rewiring it from A to B version; had a silly short from a sharp solder spike; developed a few more grey hairs; fixed it; had a succesful tuning session the next day)
anyway, i'm jealous because his car drives better than mine without that silly hesitation that many of us are complaining about. Actually, to drive it you would think it was a factory turbo from idle to redline! Whats wonderful yet somewhat dissappointing to me is that I went back and compared his maps to my maps and you can almost overlap them. This shows the reproduceabilty of street wideband tuning which you will never get with wideband tuning on a Dyno. Hondata's basemaps confirm that. They are all over the place! I think a revamped set of basemaps are in order. I know you are working on them and they are needed badly. I would be happy to help out, at least for Integra GSR's.
Torin
edit:
I will also add this wideband tuning tip:
Careful about adding or subtracting fuel based on the reading shown in your display above. If you are lean along a specific range of rpms across a few MAP values, add fuel at least one rpm range before it. That is what is really affecting the lean reading in that area.
If you don't do it that way, you land up with large peaks and valleys from overcompensating. the final fuel maps really should look nearly flat and they should nearly parallel each other, rising gradually, tapering off at finally at higher rpms.
I don't recommend the brake/throttle procedure Doug suggests on his website article. It gives false rich readings from overthrottling on a pseudo load. Careful gentle throttle acceleration in each gear is more accurate and then extrapolate your curves to fill in the missing fuel cells. If you brake/throttle to fill in cells lower in an rpm range to fill in a MAP value (because you wont ever be able to fill it in with "normal driving" you will then falsely affect the higher rpms, compensate falsely, spend endless hours trying to adjust it out).
[Modified by GruvyTune, 11:41 AM 5/28/2002]
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