AEM AFR or Gunsen Gas Tester

[Kemo]

is one better than the other? I have not had the best of luck with Innovate so looking for a different solution for AFR tuning on my SC

Thanks!!

['76 911S 3.0]

Can't go wrong with the AEM 30-0300 X-Series Wideband. Also does not require a free air cal like the Innovate does.

[T77911S]

what is wrong with the innovate? I am assuming an LM-?

sometimes if you let it idle too long you get bad readings.

[Lyle O]

I've had the Innovate less than 3 years now, and the unit is shot, and I have had to replace the O2 sensor as well. Mine is the MTX-A (tried to keep it looking more period correct). Now, the needle rotates past the stop, and sticks at various points whenever it feels like. The data are good, though. Only issue is, you can't really log engine RPM with AFRs on the same log. Not very useful. Oh, and the re-calibration in free-air is a PIA. I will probably go with AEM digital next...

[juanbenae]

ive had two AEMs in two different cars and could not be happier.

[spuggy]

Originally Posted by Kemo

is one better than the other? I have not had the best of luck with Innovate so looking for a different solution for AFR tuning on my SC

Thanks!!

Depends what you want. Gunsen is a stand-alone, temporarily installed device for checking/tuning idle mixture CO %, and requires a fairly long (5-10 minute) calibration cycle, IIRC (I sold mine on years ago).

It's fine for that; I got pretty much the same reading as my wrench's much more expensive 5-gas tester. But it's a one-trick pony...

The AEM is a permanently installed Bosch 4.9LSU wideband oxygen sensor with an AFR gauge.

Very different kettle of fish. And in the same price range, which makes it almost a no-brainer if you have a bung to screw the sensor into...

[304065]

Gunson gastester, maybe if you were doing a diorama of an auto shop in 1978! I also sold mine years ago. Wideband, LM-1 or LM-2 or Lambda cable, from Innovate, a great way to go!

[darrin]

I'm interested in a wideband sensor for my carrera but don't want to install a physical gauge -- see that suppliers are offering wifi/cellphone solutions -- what's best for use with my iphone?

[Mahler9th]

Used an AEM wideband for monitoring purposes for about a decade. 4.2 oxygen sensors. Leaded fuel, racing engine. When the sensors would begin to load up, the readings would pretty much tell you.

Quite a few friends with the same use case, product and experience.

In the past few years, it seems that something has changed with the sensors. I suspect something in the supply chain. Sensors would not last nearly as long, and readings did not provide obvious signs that it was time to change. Again, this is with leaded fuel.

Years ago I tried an LM-1 so I could log readings, but could not get it to work.

Just bought a unit from Ballenger Motorsports. Options for 4.2, 4.9 and several different NTK sensor models. So far so good. At least one other person I know has also switched from AEM to Ballenger.

['76 911S 3.0]

Originally Posted by Mahler9th

Used an AEM wideband for monitoring purposes for about a decade. 4.2 oxygen sensors. Leaded fuel, racing engine. When the sensors would begin to load up, the readings would pretty much tell you.

Quite a few friends with the same use case, product and experience.

In the past few years, it seems that something has changed with the sensors. I suspect something in the supply chain. Sensors would not last nearly as long, and readings did not provide obvious signs that it was time to change. Again, this is with leaded fuel.

The sensors used now are LSU 4.9 rather than LSU 4.2. LSU 4.2 uses a calibrated trim resistor that is used as a reference when measuring the exhaust content. This resistor value represents the current required to maintain the correct oxygen content in the measurement chamber on a brand new sensor and is compared to the actual measured pumping current to determine the lambda value. This is why you could tell when the sensor was degrading.

The LSU 4.9 does not have a trim resistor and the method for monitoring the exhaust gas content is directly related to the Nernst cell pumping current required to maintain a specific oxygen content in the measurement chamber. This method allows the sensor to still read accurately even as the sensor begins to degrade.

You are correct that leaded fuel does rapidly decrease the life of an oxygen sensor. I have found the NTK to be the most robust and resilient to leaded fuel. However, the NTK sensors that are very robust tend to be on the very expensive end.

If you are using this for a road car, the AEM will work just fine.

If you are seeing a decrease in life with the 4.2 sensors, then disregard my comment.

[Mahler9th]

I am familiar with all of the different sensor designs, including the old Bosch LSM-11 units. I have data sheets on file for most of them.

The use case for street cars using unleaded fuel and installing a device for just monitoring purposes, my main message is to be careful about the source of your sensors. If you buy from companies like AEM, then I am sure that they will stand behind their product. But there are a lot of choices, for example, suppliers on Ebay, and there are apparently some counterfeit sensors out there.

You can get an AEM replacement from Summit for like $86. And there is at least one Ebay listing for what may or may not be the same thing at $40. So please be careful out there.

Ballenger sell what they call a production grade NTK for about $150, and what they call a cal grade NTK for about $250.

But they give you NTK part numbers, and you may be able to find lower prices. I have one of each that I am going to try. But again, my application uses leaded fuel, so the potential for greater tolerance to its presence is somewhat desirable for me.

[dicklague]

I have had a Daytona-Sensors AFR gauge model Wevo IV installed in my 73 RS 2.7 MFI for over 10 years. Great accurate self contained unit with over 2 hours of data storage, Measures AFR, RPM, and MAP pressure.

A Micro USB connector on the front panel connects a USB cable to a laptop for data gathering. I have found a permanently mounted AFR instrument is bes to really sorting out AFR....especially with MFI.

This unit is sold by our sponsors and I have found it very reliable with great customer suppport.

IV

I have tired most of the units on the market and this is the best.....believe me.