Air Fuel Ratio Gauges - Recommendations

[Jabeo]

Okay people, with full exhaust and better turbo coming soon I'll be looking at getting a wideband o2 sensor and gauge. What's everyone's recommendations on brands and models that have served them well?

I Have been thinking of a digital aem x series, as the response seems mostly positive from everyone but i just dont want something that will shit itself after 3 months as i want to look after my car

[Benckj]

I have an Innovate MXL and although it works ok it’s one of the least dependable due to sensor failures. I’ve had one failure over the last 5 years but bought a Bosch 4.9 replacement from Alliexpress for around $35. It works very well and probably comes from same factory as the ‘genuine’ ones as Bosch has a factory in China.

From my previous research the AEM’s and Point 14.7 were the most dependable. They all tend to use the same Bosch sensors but it’s how the heat and ‘control’ it is the key. It also makes a big difference on how and where sensor & controller are installed. This is why you can get various results when searching reviews.

Much of your choice will depend on what you intend to use WB for. Mine is wired into the EMS so I can auto tune while driving on road. It’s not the sort of gauge you can watch and really interpret on the fly. Some will have their own logging system built in which will help but is only part of the picture.

Hope that this helps.

[Jabeo]

Much of your choice will depend on what you intend to use WB for. Mine is wired into the EMS so I can auto tune while driving on road. It’s not the sort of gauge you can watch and really interpret on the fly. Some will have their own logging system built in which will help but is only part of the picture.

Hope that this helps.

Yeah that helps a bit actually, my main intention for it is to just sort of monitor the afrs while im driving just so i know whats going on. with the turbo and exhuast and some more boost im sure things will be subject to changing so it would give me some piece of mind i guess.mine would be mounted just around the sump area on the down pipe like most MR2s cause i have a berk going on as well. I think im leaning towards the aem a bit more as it is pretty readily available and is a proven unit with fast response time as well. ive heard some people sometimes set small power delays on startup for their sensors so they arent shocked with the sudden temp change in the exhaust, to prolong the life of the sensors too

[Benckj]

The ideal placement for sensor is approx 400mm from turbo at position 9 or 3 o’clock. This tends to be on the lower section of DP before it enters B pipe.

All sensors must run at around 650C so require a heating element to get them up to temps. Having it too close or far to turbo will shorten its life hence the position is important. The controller sets the temp and is generally the biggest factor with sensitivity and longevity. One other factor is the ground placement including any voltage spikes, noise & interference.

Saying all that the Bosch sensors have come along way in the past 10years. They are now multi-fuel compatible and more robust. They are used on OEM vehicles and can last 100k although I’d only expect to get from 10-20k out of one in our cars. There are trade-offs between the 4.2 & 4.9 sensors so best to study up on those.

[Mr-Paulio]

I find this subject very confusing as there is so many differing opinions. My research hasn't helped. Most manufactures seem to state 18"-24" from the turbo. Of course this is a huge distance on our cars and probably to close to the end of the exhaust. Most feedback I see is that this distance gives inconsistent readings. And people prefer 3"-5" from the turbo. I ended up just asking my tuner and he said 100mm. So thats what I will probably do. The other intresting comment I saw a lot is that the wideband sensors are not designed to be left installed. Just for tuning then should be removed? Unless you want to buy sensors all the time? I don't imagine this helps you any?? (Sorry) But just adding in my confusing 2cents from my research!!

[Benckj]

Like any performance mods there is always conflicting information on the net. Need to do your own research and find the best fit for your own set of circumstances. Technology does change and often recommendations by others do not keep pace with the advances.

[Mr-Paulio]

Like any performance mods there is always conflicting information on the net. Need to do your own research and find the best fit for your own set of circumstances. Technology does change and often recommendations by others do not keep pace with the advances.

This is very true. At the end of the day my tuner will use it the most, and its most important for him. Which is why I will probably just go with what he said. And not sure I will run one permanently anyway. Food for thought though Jabeo?

[mknz]

If you do run one permanently you might be able to setup engine protection

[Benckj]

Good to have your own instrument for tuning & protection, if possible. I used mine on the dyno but had Tuner install his in the tailpipe so we could check and correlate data. Would have been nice to have both recorded and plotted but this wasn’t possible and all we managed was a few spot readings.

The best use of the WB O2 is road auto tuning. The dyno cannot completely simulate real conditions while driving. Depending on your EMS an AFR table can be compiled and with O2 input the auto tune adjusts the VE table to achieve best fit matrix. Lots of computations here but the more you drive the better it gets. I even used mine on the track and managed to reduce lap times as auto tune adjusted values. Do remember it generally only adjusts VE and not IGN which tends to make more power. If the Tuner can get the IGN matrix sorted then auto tune can do the rest.

[tw2]

Wideband should be about at the bottom of the downpipe/early midpipe. It should be slightly angled down so moisture can't accumulate which adds to failure rates. Load holding dyno's are by far the best way of tuning, you will be able to tune load/rpm cells that you can but rarely will encounter while road tuning. You can also tune the knock thresholds and use a flex fuel sensor too so you can run anything you like.

Personally I wouldn't bother with a wideband unless you are getting an aftermarket ecu. Unless you can change it, knowing the AFR won't help much. The AFM compensates ok to a degree unlike MAP where VE changes upset everything across the open loop board. Generally they run really rich anyway.