Fuel/Air Ratio Meter
Thread Starter
Melting Slicks
Joined: Sep 2000
Posts: 2,406
Likes: 418
From: Chester Virginia
Fuel/Air Ratio Meter
Has anyone used a fuel/air ratio meter to help tune-up their older car? Many years ago I had a fuel/air ratio meter from Heathkit that you could check the exhaust with to verify how rich the engine was running. I found a meter from AutoMeter that uses an oxygen sensor. I am thinking about getting a oxygen senso from the parts store and connecting it to the meter. Then just put the oxygen sensor at the tailpipe.
Roger
Roger
Team Owner
Joined: Aug 2006
Posts: 24,125
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From: Columbia Missouri
When I want a tune that deep I will go to a local shop that has either a 3 gas or 5 gas detector. The new ones are even portable so they can have a probe up your exhaust while you drive and get readings at all speeds and engine RPMs. I got mine tuned like that for less than an hour's labor and it would pass emissions regulations with no CATs, no smog, intake and cam, and side pipes...though we don't have emissions regulations here.
Team Owner
Joined: May 2001
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From: Exiled to Richmond, VA - Finally sold my house in Murfreesboro, TN ?? Corner of "Bumf*&k and 'You've got a purdy mouth'."
CI 6-7-8 Veteran
CI-VIII Burnout Champ
St. Jude Donor '06-'10, '13
You can't put the sensor in the tailpipe. It should be at the collector.
Tuning with a narrow band O2 sensor is almost impossible. There is such a fine line between rich and lean on those gages that you will just watch it flicker back and forth from full rich to full lean.
To do it right requires at least a wide band O2 and better is the 3 / 5 gas detector on a load bearing dyno.
Tuning with a narrow band O2 sensor is almost impossible. There is such a fine line between rich and lean on those gages that you will just watch it flicker back and forth from full rich to full lean.
To do it right requires at least a wide band O2 and better is the 3 / 5 gas detector on a load bearing dyno.
Le Mans Master
Joined: Mar 2004
Posts: 7,502
Likes: 1,510
From: Little Rock AR
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
You can't put the sensor in the tailpipe. It should be at the collector.
Tuning with a narrow band O2 sensor is almost impossible. There is such a fine line between rich and lean on those gages that you will just watch it flicker back and forth from full rich to full lean.
To do it right requires at least a wide band O2 and better is the 3 / 5 gas detector on a load bearing dyno.
Tuning with a narrow band O2 sensor is almost impossible. There is such a fine line between rich and lean on those gages that you will just watch it flicker back and forth from full rich to full lean.
To do it right requires at least a wide band O2 and better is the 3 / 5 gas detector on a load bearing dyno.
The probe they used on mine was almost five feet long.
Drifting
Joined: Jul 2003
Posts: 1,868
Likes: 294
From: West of Burlington, Ontario Canada
My vote is the innovate as well. They were the first on the market with an affordable AFR tool for the do it your self tuners and are still the best in my book. Sure beats burning your fingers on the headers to pull and read plugs. The new LM-2 (I have the LM-1) is an easy to use tool but you have to do your homework on carb tuning if you are using a carburetor. I'm getting 24.5 MPG (HWY) with a 447 HP 350 ZZ430 engine and a 750 Holley. It's one of the best tools I have in the box.
Last edited by GMJim; Jul 18, 2008 at 12:07 PM.
Melting Slicks
Joined: Oct 2002
Posts: 2,317
Likes: 111
From: St Louis MO
I've used an Air-Fuel Ratio indicator from Howell Engine Developments in my '78 for about 10 years. It has about a dozen LED lights arranged in a lazy S shape and indicates lean to rich with stoichiometric in the middle. Although it only uses a narrow band oxygen sensor (I installed it in the left header collector), it has been a valuable tool for tuning for optimum performance with both Quadrajets and Holleys. When combined with a vacuum gauge, I can find whether a particular circuit needs tuning, and know which way to go. 
For full throttle operation, it is very close to the far limit of its display, but, of course, adjustments at WOT are best based on track results, not on gauge indications.
For other operations such as cruise, it will really show whether the main jets are right, the transfer mixture, and the idle mixture, all of which I set close to stoichiometric. And then, when going towards full throttle, one can see the enrichment come in as the power valve opens (or the metering rods rise), and at what vacuum level.
Unfortunately, it is no longer made by Howell, but there are similar devices made based on oxygen sensor voltages. In fact, if you have a responsive digital voltmeter, one could even know where the mixture was by reading the voltage!
For full throttle operation, it is very close to the far limit of its display, but, of course, adjustments at WOT are best based on track results, not on gauge indications.
For other operations such as cruise, it will really show whether the main jets are right, the transfer mixture, and the idle mixture, all of which I set close to stoichiometric. And then, when going towards full throttle, one can see the enrichment come in as the power valve opens (or the metering rods rise), and at what vacuum level.
Unfortunately, it is no longer made by Howell, but there are similar devices made based on oxygen sensor voltages. In fact, if you have a responsive digital voltmeter, one could even know where the mixture was by reading the voltage!
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Le Mans Master
Joined: Mar 2004
Posts: 7,502
Likes: 1,510
From: Little Rock AR
Has anyone used a fuel/air ratio meter to help tune-up their older car? Many years ago I had a fuel/air ratio meter from Heathkit that you could check the exhaust with to verify how rich the engine was running. I found a meter from AutoMeter that uses an oxygen sensor. I am thinking about getting a oxygen senso from the parts store and connecting it to the meter. Then just put the oxygen sensor at the tailpipe.
Roger
Roger
http://www.bob2000.com/carb.htm
DIY narrow band
-Mark.
Race Director
Joined: Mar 2001
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From: Living in the Hartland
Le Mans Master
Joined: Jun 2008
Posts: 5,284
Likes: 235
From: Rockledge FL
this is the best wideband on the market
http://www.zeitronix.com/Products/zt2/zt2.htm
279 bucks
includes wideband sensor.
it realtime datalogs
airfuel,
egt,
rpm
vacuum/boost
throttle position
You either can hook it to your laptop and take it for a drive or
it can synch up to a pda.
The best part is you can hide the control module without having to find a place to install a gauge when you dont want to datalog.
http://www.zeitronix.com/Products/zt2/zt2.htm
279 bucks
includes wideband sensor.
it realtime datalogs
airfuel,
egt,
rpm
vacuum/boost
throttle position
You either can hook it to your laptop and take it for a drive or
it can synch up to a pda.
The best part is you can hide the control module without having to find a place to install a gauge when you dont want to datalog.
