O2 Sensors

[Kilgon]

Been thinking about adding O2 sensor(s) to help with tune up and performance.  I've been looking around and there is such a wide range on pricing and functions.  Lambda vs air fuel ratio, single vs dual sensors, units which also show rpms. I saw on Summit that Innovate makes a digital dual gauge to read both sides of the exhaust and you can select lambda or AFR.   Also be nice if  it could be used with a EFI down the road.   Searched the site but not a lot on who has what.   I was wonder who is using what out there.  Also weld on bung or if clamp on type would be okay.   

 

[Bill73Ragtop]

Properly welded bung located far enough downstream is highly recommended if you go ahead with the sensor.  Clamp-on could have the potential to loosen & develop leak if long term.  Probably same amount of effort to install either way so its worth installing bung which (if you are just using to do initial tune) can be sealed with screw-in plug when finished.

The ability to use O2 sensor with future EFI depends on the system.  Holley uses proprietary Bosch sensor which is outrageously expensive, but is the only one the system will function with.  

 

[tony-muscle]

Most newer EFI systems use wideband sensors. The FiTech uses a Bosch as well, but I don't know if it is interchangeable with the Holley. Probably not.

In regards to placement, you want it downstream from the collector, but not too far so if it is used for EFI, then the feedback can be as quick as possible. Per example FiTech recommends "The ideal location for the Sensor is 2-4 inches after the exhaust collector." They recommend locating it in the #1 cylinder bank, or passenger side for us. I have always wondered if there is a noticeable difference between banks.

 

[Kilgon]

Properly welded bung located far enough downstream is highly recommended if you go ahead with the sensor.  Clamp-on could have the potential to loosen & develop leak if long term.  Probably same amount of effort to install either way so its worth installing bung which (if you are just using to do initial tune) can be sealed with screw-in plug when finished.

The ability to use O2 sensor with future EFI depends on the system.  Holley uses proprietary Bosch sensor which is outrageously expensive, but is the only one the system will function with.  

Most newer EFI systems use wideband sensors. The FiTech uses a Bosch as well, but I don't know if it is interchangeable with the Holley. Probably not.

In regards to placement, you want it downstream from the collector, but not too far so if it is used for EFI, then the feedback can be as quick as possible. Per example FiTech recommends "The ideal location for the Sensor is 2-4 inches after the exhaust collector." They recommend locating it in the #1 cylinder bank, or passenger side for us. I have always wondered if there is a noticeable difference between banks.

Location is not an issue.  Having to work under the car sitting on 2 ramps and 2 jack stands makes welding difficult although I have done it for the exhaust system.  I was thinking that having dual sensors would provide a better picture of what the compete engine is doing vs just one bank.   I would think that a foul plug or other issues would show up on a dual system by a spread in the different readings for the right and left banks.  Not for sure yet that I want to go efi in the future but if I do I was thinking either Holley Sniper or a Fitech.   Summit also has their own that is good up to 500hp that I might consider.  

 

[TommyK]

Most engines usually have one cylinder that runs leaner than the others due to distribution issues. It is usually easily identifiable by looking at the plugs. On mine it is number 4.

For safety sake you are always going to tune for the demands of the leanest cylinder, so the rule of thumb is to install the sensor on the side with the lean cylinder.

Since it is nearly impossible to tune individual cylinder a/f ratios with a carb, I don't think the trouble or the expense of multiple sensors is warranted.

If/when you upgrade to a throttle body FI system I would use the sensor that comes with the unit. The bung you weld in now should work with any sensor.

 

[Kilgon]

Most engines usually have one cylinder that runs leaner than the others due to distribution issues. It is usually easily identifiable by looking at the plugs. On mine it is number 4.

For safety sake you are always going to tune for the demands of the leanest cylinder, so the rule of thumb is to install the sensor on the side with the lean cylinder.

Since it is nearly impossible to tune individual cylinder a/f ratios with a carb, I don't think the trouble or the expense of multiple sensors is warranted.

If/when you upgrade to a throttle body FI system I would use the sensor that comes with the unit. The bung you weld in now should work with any sensor.

Makes sense and I will agree with tuning for the leanest cylinder.  My thought on the dual as mentioned in the above previous post is to have the capability  of monitoring both banks.  As engine conditions change such as plug wear, fouling and plug wires breaking down you would be able to get a snap shot of what side it is occurring on.  Yes the price is about twice as much for the dual set up and I do have to ask myself is it worth it.  I was also hoping to find out who is using what brands and how well they like it.

 

[c9zx]

I have an AEM, 30-4900, gauge and it seems to work well. It come with a Bosch sensor. It is single channel and I use it tune carbureted cars. It makes it easier and take a lot less time. It has way more capabilities than I need or use so I probably should have bought a less expensive AEM gauge. I asked two engine tuners and my dyno guy what they would recommend and they all said AEM. The dyno guy uses Daytona Electronics in the shop but he is set up to monitor all 8 cylinders. Chuck

 

[Kilgon]

Thanks for the info Chuck.  Good to know what is rated high out there. AEM products have lots of user ratings on Summit's web site so they are a well seller.  I looked up your model and it's a little more than I want to spend.   I checked and AEM has another unit (30-4110) that includes everything I need for just a little over $200.   I'll look up the info on it at AEM's web site.