llusk

Looking for an Air Fuel meter for my 86 944T.

Looked at Widebands, Narrow and just and Air Fuel meter.
From what I have read the wideband is more of a programming tool and gives more accurate data, correct me if I am wrong.

I have 86 944 Turbo with autothority AFM, K27 turbo and LR boost enhancer. My concern is the car leaning out.
Recommendation on the type of meter needed etc.

Car seems to be running rich currently, have not pulled the plugs yet.

Car is used primarily for street with some autocross.

Paulyy

A narrow band doesn't tell you much. It basically acts like a rich or lean switch. If you have the NB gauge in the car, it will just flick side to side on part throttle, go red in deceleration and go green on acceleration.

A wide band gives you an accurate measure of air fuel ratio in the engine. Which is what you want if you want to see if your car is running rich or lean at any given condition.

I would be going for the wide band..

SamGrant951

WBs are so cheap these days - its the only way to go. I use AEM in the racecar. Zeitronix and PLX make some that are multi-function. My zeitronix displays boost, EGT, and AFR in one gauge.

llusk

What are the differences?
Prices range all over.
Don't think I need anything extreme, but don't want to bring it home in a bucket of parts.

Suggestions on brands etc

Suggestions on where to mount thats not very noticeable?

Thanks for the input and advice

67King

David, a wideband is a bit of a system - it includes the O2 sensor (aka EGO or HEGO - (heated) Exhaust Gas Oxygen), and the meter. A wideband reacts quickly, and gives a number. A narrow band refers usually to just the O2 sensor in the car. Our cars all have them. They merely "switch" around stoich. If you are rich, the output will be constant on one side, if lean, it will be constant on the other side.

What you are really looking for to make sure you aren't getting overly lean is just the A/F meter which will tie into your factory O2 sensor. As long as when you are in the boost, your meter reads green, you are good. If it reads red, that is bad.

Long term, going to something like Rogue's MAF, the wideband would be a great tool. But to just know you are safe, all you need is an inexpensive A/F meter. Something like this: http://www.summitracing.com/parts/sum-g2885/overview/

llusk

Thanks Harry

Is it not that important to know how rich or lean the car is running?
From what I have read about the A/F meters they all seem to be about the same?

Side not, hope to go with Josh's Rogue unit next year.

67King

It will give you a good idea for how rich or lean you are. But it won't be as precise, especially around stoich (not as much of a concern for you). You are just making sure that you aren't running lean, given the capability of the turbo.

You know, I should probably let you just borrow mine for a weekend.

Techno Duck

This is not really true.

Take this scenario;

You are on full boost aiming for around 11.8 : 1 AFR.
Narrowband AFR gauge shows rich... so you think your ok.
Wideband AFR shows you are actually running 14.0 :1 AFR meaning you are running incredibly lean.

Your engine will not last very long in the above scenario.

This shows as rich on your narrowband AFR but does not tell you the entire story. When a narrowband AFR says your running rich, this can mean 14.6 : 1 or 10.0 : 1 AFR. Both are 'rich' per the reading on the gauge, but both mean very different things to how your car is actually running.

The resolution of a narrowband gauge is just too low to be useful to tell you anything. The sensor ranges from 0-1v , wideband is from 0-5v.

Do you need a wideband for a mildly modded car? Not really.. If your concerned about your AFR, dyno the car with a sniffer in the tail pipe and have the shop print you out the sheet displaying the AFR. I can tell you with the Autothority chips its probably a bit lean in the higher end. They are very useful for troubleshooting though and good for peace of mind.

As far as brand, go with whatever gauge style you like. AEM, Innovate, Zeitronix are all popular just to name a few.

mclarenno9

+1

To put it into perspective....

llusk

So a regular a/f meter won't work?
The local shop will not let me dyno the car without a wideband etc on the car.

Thanks for the info!

944Ross

I'm using this AFM on a carb'd truck for tuning and general diagnosis. Lots of features, including hookup to a laptop for recording and trending, plus software. About $150 on eBay. I would add a bung for the WB and keep the factory O2 intact.

http://www.ebay.com/itm/Innovate-MTX...91d558&vxp=mtr

llusk

Thanks 944Ross