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MG Midget and Sprite Technical - Wideband AFR Controller

Anyone ever come across these?

http://ldperformance.co.uk/product/wideband-controller/

Seems a good bit cheaper than other controllers. Can't decide if that is a good thing or a bad thing!

Or anyone have a wideband afr kit they would be willing to loan/rent me? :-)

Cheers,
Malcolm
Malcolm Le Chevalier

What's it for? Didn't read all the technical stuff.

Clare
C Ravenwood

Go with AEM. And I find an analog gauge easier to read than a digital one.
Trevor Jessie

I wouldnt do that gauge... it looks way to special effects chessy sci fi...go with gauges that match your cars

I do have a wide band AFR set up... but its gauges only nothing else

Because we have duel carbs you you will need to have the sensors placed into the exhaust manifold ...i did mine on the 2 outside down pipes and ran 2 gauges one for the front carb and a 2nd gauge for the rear carb

Although you could a use some kind of toggle switch to move back and forth from front and rear carbs


Shold be a fun project.

Prop
Prop and the

AEM....I agree is a cutting edge company defiantly the way to go.

But im not sure id get them off ebay... id say most of those are going to be china fakes

You cant go wrong supporting the hometown pro. Esp with advice on setting up


Prop and the

Hi Malcolm,
Ive got the AEM one, works fine.
it has the digital readout as well as some different coloured lights around.

I welded in the bung that came with the kit at the point where the 4 of my exhaust headers joined together .

I compared the reading with another gauge with the sensor stuck in the end of the exhaust and got the same readings.

If i put my foot down i get to 10:1 in the extreme case, but normally on acceleration its about 12 or 13:1.
Cruising at about 70 in 5th gear gives me about 17:1.
Driving around normally at about 50 or so in 3rd/4th gear gets me around 14 or 15:1

This is with a weber 38DGAS...

The gauge comes with a black and a white face and you can easily change it by unscrewing the bezel.

Here it is on my centre console i made.
(i use the white face)


Andy Phillips (frankenfrog)

Alternatively just get the sensor and use a voltmeter to look at the output.

or you can build your own meter inexpensively, its basically a voltmeter linked to some LED's.

Just google DIY AFR meter and lots of examples...
Andy Phillips (frankenfrog)

I wish it was that simple! :-(

I have a narrow band installed wired to a volt meter blue tacked to the dash. A narrow band sensor is quite simple. It is a one wire sensor that outputs a voltage, 0.1 volts = lean, 0.8 volts = rich, with little else in between. I thought this would be useful for dialing things in, but in reality it's pretty useless.

A wideband sensor typically has five wires and outputs a current from something like -2mA to 2mA that varies linearly with lambda from ~6 - 20.

The controller serves two purposes: 1. to power the sensor (heater etc.) and 2. takes this current output and converts it to a voltage between 0 and 5 volts.

This output I could connect to the volt meter again to get wideband lambda readings.

I have looked at DIY. It's only a bunch of ICs and resistors soldered on a circuit board, but dunno if I can be bothered! Getting old you see ;-)

Cheers,
Malc.
Malcolm Le Chevalier

Malc

Thats the problem with narrow by the time you get a reading its Ten minutes later

On mine ... i dont have numbers its color coded lights on a dial...

Once your carbs are dialed in ... its rather useless gauge intil a flaw halpens ... but its fun to look at and watch to see how it performs with varying driving styles

Whats great on mine if the float needle sticks you know rifht off which cadb is suffering same with a bit of debri in the needle jet

And if you got a fuel problem devoloping i can see it on the dials

The number dials are more practical but the changing flashing lights are alot more cooler fun to watch bouncing around back and forth it gives me a better scence of how hard im hitting the gas peddle and when

Prop

Prop and the

Could someone answer Clare's question please as she stuck her head over the parapet and asked how these are used on spridgets (and I might know what you are on about too, eh Clare!)
Graeme Williams

Clare
Air (to) Fuel Ratio. Optimum combustion occurs at 14.7:1 air to fuel ratio. Modern cars have a sensor in the exhaust that, in conjunction with another sensor in the air inlet (Mass Airflow sensor) allow the engine ECU to precisely control the AFR. An AFR sensor produces a varying voltage dependent on the AFR so that a readout is possible.

In a classic car, you can measure exhaust emission and determine if the engine is running rich or lean and adjust the carburettor(s) accordingly. If you read about this stuff it rapidly becomes quite complicated. I welcome any corrections to my simple explanation.
W Bretherton

W...

Id say you got it...thats it in a nutshell

Just add... AFR are also for those that just want to tinker

Of course there also EGT (exhaust gas tempture) to add to the diagnostics and a vacume gauge maybe 2 or 4 on a switch to read the vacume at both carbs and the port vacume and reg engine vacume and dont for get both an amp and volt gauge ... did i mention a fuel pressure gauge ...oh maybe a fuel tempture gauage wojld be a bit much ...but if in rome yeah know

So there is that....i got a lot more work to do before i can take my last breath...haha
Prop and the

Sorry Clare, yes Will has it.

Lambda/AFR/o2 sensors allow you to measure the oxygen content of the exhaust gases. Excess oxygen going in = lean = unburt (excess) oxygen in the exhaust. And vica versa for rich.

Modern cars use them to control fuelling. We can use them to diagnose and set carb jettings more accurately. A wideband is preferable as it gives more accurate readings over a much wider range of air/fuel ratios.

The controller I am looking at does as explained above. It acts as a converter for the sensors output.

Malc.
Malcolm Le Chevalier

I attended a talk recently by a well known authority on engine tuning who strongly advocates setting up engines using exhaust gas analysis. He uses a portable device but warned that these items need regular recalibration and needed to be quality units if the results are to be relied upon.
I have come across these bits of kit on modern vehicles but hadn't realised they were being applied to the likes of spridgets. Presumable this is for data collection rather than any form of control. Are the results accurate enough and what sort of cost are we talking about?

Graeme Williams

data collection and refining on a carbed engine, as you have to change jets/needles to fiddle with AFR.

With an ECU, though, feedback loops and closed loop running allow the ECU to continuously aim for a set AFR - mapped normally. Wideband much better for this, as it tells you what the AFR is from the exhaust. Narrowband simply says "rich" or "lean" either side of stoic. (14.7 AFR). Narrowbands harder to use, because AFRs are often aimed at that are not 14.7 (e.g. 11 for acceleration, 15-16 for over-run lean conditions. Most ECUs will cut out AFR/Lambda feedback under hard acceleration conditions and allow it go go rich.

Amusingly, all this stuff is sorted by an SU with a spring, a damper and the right needle. Everything else is trying to copy that simple mechanical setup.
Rob Armstrong

It's basically a better use of equipment used to do boring stuff like measure emissions! :-)

Malcolm Le Chevalier

It wasnt to expensive

I had to get 2 kits one for front carb and 1 for the rear carb

The wide bands i got from amazone ... with the welding the bung into the exhaust header and wire and connections ect ect

It was about $125 per kit X 2 for everyrhing

Prop


Prop and the

In Bosch speak, an LSF is narrowband, LSU is wide band, and LSU ADV is the newest wideband, heats up quicker and has a bigger range than LSU.


Worth a look https://ldperformance.co.uk/product/wideband-controller/

do be careful thou, the LSU ADV is slightly less robust than the older models - simply put they need a better controlled warmup strategy to dry the lambda sensor our before cranking the heater on full.

Malc
Malc Gilliver

Thanks for that malc...

I wasnt aware of a new system


P.
Prop and the

This thread was discussed between 07/02/2017 and 11/02/2017

MG Midget and Sprite Technical index

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