Air/Fuel Meter and O2 Sensor, Keep that car in tune! Options

[Justinp71]

Well it seems that a good way to make sure your car is using the proper amount of fuel is to add a Air/Fuel meter, especially since few of these cars have modern computers. So I am looking at what options are available.

It looks like one option is to buy a kit from pelican:

http://www.pelicanparts.com/cgi-bin/ksearc...r=PEL-SW85-2437

Option 2: Use an 80-83 911 o2 sensor and add an aftermarket gauge...(Which I guess is similiar). I would like to use this sensor, b/c there is a chance I may use an 81 CIS system later on.

So... does anyone have any recomendations and/or suggestions?

[biosurfer1]

could try making your own:

http://www.scirocco.org/tech/misc/afgauge/af.html

http://www.redline.lt/magazine/spec-featur...e/article/17/1/

Here is a place that has a DIY kit:

http://www.autospeed.com/A_0217/cms/article.html

[Demick]

Unless it's wide band, it's basically useless for our cars. A narrow band o2 sensor is really almost like a switch, only telling you if it is lean or rich. And my experience with the 914 motor, is it always needs to run rich. Any leaner than 13.5:1 and it will cough and spit and run like crap. Stoich is 14.7:1, so on a narrow band o2 sensor, it will always just register as 'rich'.

A wideband sensor will tell you the actual mixture no matter how lean or rich. It's the only way to go.

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

[Justinp71]

I looked up the info for the K&N A/F meters that pelican sells:

http://www.knfilters.com/airfuelmonitors.htm

You can tell that your right, it has 4 positions for 14.7 and only 3 that are lower then that...

Well then does anyone know of a solution less than $300 for a wide band sensor and a gauge?

[ConeDodger]

Justin,

I am doing the Innovate LM something or other wideband sensor and guage. I haven't installed it yet but it is an easy install. If your interested in seeing it go in or helping let me know...

[iamchappy]

I have the LC-1 with the onboard gauge, the innovate systems seem to out perform the others.

[McMark]

It's a common misconception that an oxygen sensor (of any sort) can tell you if your car is running correctly. It's common, because you see these add on kits EVERYWHERE now, and they all say "Make your car run PERFECT!" But the reality is that there are actually very few times that a stoichiometric mixture is what you want. At idle you should be lean (without overheating) to save on gas, at WOT you want a slightly rich mixture, on over-run you want a leaner mixture, etc.

I recommend them, and they are a great tool. Just don't expect (as I did back in the day) to be able to install one, turn a few screws, drive a few miles, and have a sweet, smooth running car. An O2 sensor is another source of information. The more sources of info you have (EGT, CHT, etc) the better you can tune, BUT the more sources of info you have the more confusing it is and the more experience you need to make heads or tails of all that info.

[MartyYeoman]

"on over-run you want a leaner mixture"

Please explain "over-run"? (IMG:style_emoticons/default/pray.gif)

[Gint]

Over-run is when you left off of the gas...

[toon1]

There is a a company called" JAW", out if Canada. They make a DIY WB 02 sensor controller that has a gauge that is the size of a penny.

You can use a Innovate WB sensor with it. The whole kit will run about $150. This will give you a WB AFR reading in a small package.

The Innovate controller is a little on the big side.

Overrun is what is refered to as the times you let your foot off the gas and are coasting to a stop or going down hill.

The RPM's will be up and the TB closed. A rich mixture will cause backfiring out the tail pipe.

ON an MS system there is a setting for this called" decel fuel cut %" . I run about 80% fuel cut on decel.

BTW, a WB 02 sensor is a valuable tool for the stock injection. even though there is not much in the way of adjustments for the stock system, there are enough to be able to adjust AFR. Just my.02.

[Joe Owensby]

I saw 2 different ones that look reasonably affordable on CBperformance.
http://cbperformance.com/cataloglist.asp?S...h=oxygen+sensor

Has anyone tried these, and are they any good?

Cost doesn't look too bad. JoeO

[toon1]

I saw 2 different ones that look reasonably affordable on CBperformance.
http://cbperformance.com/cataloglist.asp?S...h=oxygen+sensor

Has anyone tried these, and are they any good?

Cost doesn't look too bad. JoeO

You'd be better off with an Innovate or a JAW.

Innovate has ton's of support

The JAW does the same and is more cost effective.


Both are cheaper than the CB perf. item's

[Borderline]

I have the Innovate LC-1 and have mixed emotions. When it is working, it is nice. Other times it is just screwy! Got to the Innovate forum and see some of the fun the guys are having: Innovate Forum

The system is very sensitive to ground methods and they actually recommend different methods in different manuals! Go to the site to get the latest info. I would be curious to hear about someone with the CB Performance unit.

[orange914]

Please explain "over-run"? (IMG:style_emoticons/default/pray.gif)

"on over-run you want a leaner mixture"

get a 1975 or 76 2.0 ecu it has the lean out decel for both emmisions and m.p.g.

[jesiv]

I have been looking at doing this as well. You might want to check this out.

http://www.plxdevices.com/products/dm200/


james

[TimT]

Unless it's wide band, it's basically useless for our cars.

Werd....

We have a few of these in the shop that we have been using recently...

NGK wideband

We also have widebands by FJO, MoTec, Tech Edge and PLX,In all we probably have 10 widebands, some we broke, some broke, some we dont seem to use anymore.. and we buy new ones when we see something that piques our interest.. right now this NGK is doing alot of time when we dyno cars and it seems to give good repeatable readings.


You can get it for about $250 from ballenger motorsports.

[LvSteveH]

I really like the LM1. It has a data recorder that allows you to track the AFR and the correlating RPM. It will log up to 44 minutes if memory serves. Then you can download it to your PC to analyze it.

It is also possible to hook up a throttle position sensor to have awesome data, but you can also get good results by doing a voice recording of the session making notes of full throttle, part throttle, decel, etc. By playing it back when viewing the log it's easy to add notes to the log and identify areas that need adjustment.

[brant]

We've been running an LC-1, with an XD-16 for about 3 years constant now
we leave it in and turned on for every single run, every single day

our tracks vary in altitude from 5,000 to 900 foot and we rejet for each different one.

it's interesting data actually and can pick up on things you would otherwise miss
3 weeks ago we went to texas for a 3 day weekend.
my Innovate told me something was wrong at full throttle as it started spiking lean intermittently

turns out I sucked an intake gasket slightly

you couldn't feel it by seat of the pants.
but you could see it on the guage.

I added the rare and often unused auxillary enrichment circuits to my IDS carbs this year and completely had to re-think my jetting. I could of never done this without the innovate. the car feels absolutely the same but I'm now able to keep my AFR from 12.5 tp 13.5 (1 full point) where I was only able to run from 12.5 to 14.5 (2 points) previously.

the LC-1 shows a double curve now that the car gradually leans out from 4,000rpm until about 6,000 rpm and then the auxillaries kick in (vacuum draw) and the car goes towards the heavier/richer mixture and drops from 13 back to 12.5 at 6K.... then gradually leans itself again.

You don't feel any of this
but you can see it

in fact on the first lap out it doesn't follow this pattern and runs lean for 1 lap
my theory is that the aux enrichments need to "prime" or build suction and it takes about 2 hard runs to redline before they are primed or full of fuel

I can watch the weather change on the guage
I run lean in the mornings and rich in the afternoons based on the change in ambient temp.

again you don't feel any of this
but you can read it on the guage and change your jetting

[roadster fan]

I have been looking at doing this as well. You might want to check this out.

http://www.plxdevices.com/products/dm200/


james

Thanks for posting the link James, nice stuff! (IMG:style_emoticons/default/wub.gif)

Jim

[Gint]

We've been running an LC-1, with an XD-16 for about 3 years constant now
we leave it in and turned on for every single run, every single day

our tracks vary in altitude from 5,000 to 900 foot and we rejet for each different one.

it's interesting data actually and can pick up on things you would otherwise miss
3 weeks ago we went to texas for a 3 day weekend.
my Innovate told me something was wrong at full throttle as it started spiking lean intermittently

turns out I sucked an intake gasket slightly

you couldn't feel it by seat of the pants.
but you could see it on the guage.

I added the rare and often unused auxillary enrichment circuits to my IDS carbs this year and completely had to re-think my jetting. I could of never done this without the innovate. the car feels absolutely the same but I'm now able to keep my AFR from 12.5 tp 13.5 (1 full point) where I was only able to run from 12.5 to 14.5 (2 points) previously.

the LC-1 shows a double curve now that the car gradually leans out from 4,000rpm until about 6,000 rpm and then the auxillaries kick in (vacuum draw) and the car goes towards the heavier/richer mixture and drops from 13 back to 12.5 at 6K.... then gradually leans itself again.

You don't feel any of this
but you can see it

in fact on the first lap out it doesn't follow this pattern and runs lean for 1 lap
my theory is that the aux enrichments need to "prime" or build suction and it takes about 2 hard runs to redline before they are primed or full of fuel

I can watch the weather change on the guage
I run lean in the mornings and rich in the afternoons based on the change in ambient temp.

again you don't feel any of this
but you can read it on the guage and change your jetting

That's a great post. Thanks Brant.