Wide band lamda probes - pros of them?

I was chatting to vw_singh about these on Friday, but I'm still genuinely confused about where the benefits lie.

As a background, I installed a lambda probe and Lumentition A/F guage a few years ago in a previous car (2001, pre widespread availability of Innovate kits & similar).

Conversations at the time with Badger5 pointed to there being some uber-expensive lamda sensors about that tuners used, but that a normal mainstream one would have to suffice. I nipped down the scrapper and had a 4-wire one off a Mk4 Polo, which had a Bosch part no of 0 258 003 478/479. The alternative would have been to go to GSF.

In combination with one of these:



.... I continue to use the same probe today. I've got an engine mapped which seems to sit quite happily at the max-power LED. So as far as I can tell, I'm doing ok?

What will a wideband lamda give, over and above this? I realise they come with digital A/F guages, so precision perhaps is a little higher, but on a standalone ECU without full air temp mapping for all temps, surely it is 'best approximated' mapping already?

The only thing I did notice, looking at the Innovate kit vw_singh has, was that the lamda probe is again Bosch (Gurds, can you post up the part no?) but it had 5 wires, instead of 4.

What do the 5 wires do?

AFAIK, mine are +ve, -ve + 2 (white?) heater wires.

 

This may help. Think the LSU 4 is a pump sensor.

 

If it was a 4 wire unit it would be a puesdo wideband unit. We use a similar one of these on the dyno. Part number 0 258 104 005 expensive at 120quid a unit.

It is the interface box that calculates the lambda reading to the machine. But it is still a switching sensor.

The sensor on Innovate kits are a Bosch LSU-4 unit Pt# 0285007057, called by other names as pump sensor, planer or continuous. These 5 wire units are std equipment on lean burn VW engines such as the Polo 1.2 on so.

Cost per vehicle, existing control modules and software may cause manufactuor to stick with the conventional HEGO i.e. a 5 wire bosch unit = 70quid and a 2 step unit = 30quid.

NTK wideband found on Honda = 90

UHEGOs with interfaced to gauges or handheld devices such as the LM1/2 LC1 techedge and so on, are favoured by mappers as you can mount in vehicle and use for road mapping fuel control. You can easly correlate the 0-5v output of the sensor to Voltage meter to read lambda.

Unless your interface is programable to configure to a 5 wire planer sensor, there would be no benefit to switching to this sensor unless you have an interface to read the sensor voltage and convert to a lambda or AFR measurement.
Some sensors like the puesdo sensor are good at reading AFRs in low flow and are very good at reading mixtures in excess air. Some of these units were originally used in diesel vehicles.

Eg the sensor using on the Dyno Dynamics dyno was originally used in a Mann truck.

The Lumenition was a device used to really 'keep and eye' on the fueling after being mapped on a dyno. The interface between the sensor mimicked the natural behaviour on the continous sensor used in a techedge , plx or innovate device. It would be harder to use this device when live mapping.

 

If your engine is already properly mapped and set up then changing your lambda setup won't gain you anything. As Eddie says, the meter you have is fine for monitoring your engine's A/F condition.

Gurds

 

depends if you want to know actual afr's of if you have red or green led's and be none the wiser as to its actual number, vs simple rich/lean leds

 

UHEGO = Universal Heated Exhaust Gas Oxygen sensor, ie the one I have or the 5-wire one?

My point is that, if my 4-wire & Lumenition guage does the job, why are people shelling out on Innovate ones when there is no apparent benefit (yet)?

I am guessing this benenfits an in-car mapper, but on the RR, a wide band can just be inserted for the duration.

As far as I'm aware, the Lumenition guage is a simple device, only capable of running a 4-wire sensor, but I'll check.

 

Unless you are planning to make changes to your cal and therefore need to set to a specific AFR or check you are achieving a specific AFR, there will be no real benefit. The Lumenition device will provide you with an indication of the likelyhood that there is a problem causing you to either be running too rich or lean.

Although, noticing in your other thread that you now have a standalone, It will be worth investing in a wideband sensor and controller if you plan to do your own fueling changes.

 

So are we saying that there is a real mapping benefit from the wideband, ie its ability to give a digital readout to the mapper?

Thereafter, the AF guage is a monitoring device, the precise output of which (LEDs or digital) is neither here nor there?

 

5wire one is a UHEGO (0-5v) and the 4 wire one is a HEGO (0-1v).

There different reasons why ppl do this. Some because they think they have to, others for style, some because they are fine tuning their calibration. For road tuning I would rather know exactly what AFR my engine is running rather than a LED that says "rich". The AFR/EGT gauge in my car is also mounted in my line of sight along with a a digital EGT readout. Very helpful when you are trying to quickly glance at the rev counter and boost gauge to workout what percentage you may need to richen or lean out up to improve drivabilty. Also having an AFR meter as a permanent mount in the case on my vehicles that are used as test mules, means I do not have to tie up my portable gear everytime I need to update a fuel cal.
RR tuning is not the end of the calibration process. So it would be good to have a digital gauge in car if I am targeting other areas in the calibration while on road.

Yes it is but only for keep an eye on things already determined.

 

it is of extreme benefit to the mapper because he/she is able to precisely set your afr's. Even as a monitoring device it is more useful than the led's becasue of the added accuracy of being able to read an actual AFR. Ultimately it comes down to what you intend to do with the information you are getting.

In addition, some standalone Ecus (even Megasquirt) allow you to set up a target AFR table and then use the wideband as feedback then adjust the fueling to precisely achieve the target. With a narrowband sensor you only really have the possiblity to set a stoiciometric target so only really useful for part load fueling.

 

Or if your vehicle has to be fitted with a cataylst.

 

Ah, this is a good point.

I've tried to run my DTA EXP 48 on closed loop in the past, but I don't/didn't think it was clever (!) enough to do it, but it has the functionality.

Perhaps that comes down to the lamba sensor?

 

Thing is Chris what benefits do you think you will gain from running closed loop.

 

The end goal would be condition compensation.

I've tried to create a road map in the past, and get it to run at 14:1, and close-loop to that target, with no success.

If that worked, I'd take it further.

 

catalyst.. whats that???? Never seen one!!!

 

You Mr KNKsensor, should know better

 

DTA will require a lambda controller to understand the readings giving to it by the lambda.

Only really a benefit on later ecu's which have a lambda target map, makes for quick mapping indeed, and also compensates for day to day fuel pressure and atmospheric changes.

 

As in a 5-wire wide band, not the Mk4 Polo Bosch one I'm running? Or an entire Innovate unit?

 

only required for wide band (5 wire)

This is a typical controller DTA would recommend, not the best, but gets the job done nicely

http://www.innovatemotorsports.com/products/lc1.php

 

http://www.fordmuscle.com/archives/2007/06/WidebandShootout/index.php

and some discussion

http://www.rx7club.com/showthread.php?t=666682

pinch of salt and all that, but interesting comparison between the available suppliers, nb techedge not included

the innacuracies of them and the fact that noone can predict AFR for max power shows that the AFR probes should be used as reference only, for basic set-up. They can't replace a proper set up on a rolling road. Once this is done a wideband is only really beneficial for a) improving steady state fuel consumption in closed loop. b) diagnosing problems.

Mike