First, apologies because I know this has been covered somewhere but both local and Google search have failed me.

I'm heading to uncharted waters. All I know about O2 sensors are they are handy for measure A/F for tuning carbs and where to mount the bung. I have no clue about what is a good affordable sensor to buy for tuning a set of 40IDF Webers for a 2.0L engine. Don't even know whether wide band or narrow band is best. Just clueless really. Help Please!

I know many on here like the Innovate AFR. But I can't speak to that.

I have the Autometer Wideband AFR, Maybe a bit more $$ but I like it.

Have one on the Harley for over ten years without any problems. So I went with what I know when it came time tp buy one for the 914.



Click to view attachment

This is what I've wondered about a O2 meter rental service, more than just a meter rental, include in the kit jets, jet reams, jet gauges, bungs, bung plugs, sync snail, etc.
For carb guys you only need all this kit for is tuning, once you're done it can be a lot of expensive of kit that is almost useless.

I figure any parts used could be done à la carte, the kit could be direct shipped to the next in line and the bung could be shipped before rental date so you have lots of time to get it installed before hand. Likely I'd want a deposit that covers the value of the kit, with a balance refunded once the next person gets the kit. This method I'd likely have to service the kit at least once a year, although I'd likely include a extra lambda in the kit.
If successful I could bring on line more kits, I'd likely have at least one meter in reserve just in case of issues. I'm thinking a 3-4 week rental so you have lots of time.

Right now I have a meter with a very easy, built tough and stealth temporary install cable, with two simple connections (keyed power and ground), not counting the bung it installs in minutes. The cable is long enough to use on just about any car and the meter works on any fuel.

Big question is what would a kit rental like this be worth?

BTW I have asked this before but no one seemed interested, if there's no interest I wont bother.

You need a wideband for tuning. Bosch makes them all so any Bosch wideband o2 will work, including stock OEM versions. I think most cars had them by 2005 when they started going lean burn highway cruising. All the WBo2 look the same (holes not slits).

This is the cheapest kit I've seen. It's used alot by aftermarket DIY ecu users. 14point7.com

You can make an Arduino gauge with data logging cheap.

Think of o2 sensors as speakers. The original standard is a 4" speaker, the WBo2 is a 3-way 6x9.

Wow....that is a beautiful information panel you have there....very nice! Do the a/f numbers change a lot while driving? Thank you,
gg

I currently have a Wideband sensor and digital display. I will likely change to an a analog display.

My onboard GoPro doesn’t sync to the display, so I am not able to view that gage when playing back videos. Not sure if that could be important to you it thought I would respond.

My O2 air/fuel mixture metering system experience in my 2.7L 911 engine with carbs, is as follows:

1. I have INNOVATE's double channel DLG-1 model that includes two O2 sensors, one in each exhaust header, some 4" downstream from the header pipes' converging point.

2. They supplied two Bosch model LSU 4.9 O2 sensors (P/N 3890 - 3' harness), and two 1" long bungs. These bungs place the sensor in the correct position, where as the typical 1/2" bung places the sensor too far into the gas flow, resulting in a short life of the sensor (ask me how I know!).

3. This kit's harness is long enough to install the gauge in the dash.

4. I have been on a long learning curve installing and tuning my carbs. I believe my carbs are optimally tuned which would not have been possible without; a) Paul Bennett's excellent information (Performance Oriented), and 2) INNOVATE's O2 air/fuel metering system.

5. Being able to monitor air/fuel mixtures while adjusting the carbs and driving the car, teaches one a lot about the consequences of changing various fuel and air jet sizes and adjusting air/ fuel mixture screws.

6. This journey was a lot of fun, and I agree with Mark that once installing and tuning carbs is complete this air/fuel ratio info declines in value. However, the continuous air/fuel ratio monitoring info is there in my dash and satisfies my "tech" instincts.

Thanks all! This is fabulous info that gave me what I needed to figure this out.

My application is exactly as Mark describes - a one-and-done operation to set up the carbs. I'm not looking for any permanent monitoring. In fact, I'll be installing the bung in a Bursch muffler and then swap that muffler for @mb911 's quiet muffler once the carbs are dialed in. I would think a rental kit as Mark describes would be very appealing for guys like me. In my case, a local member ( @dr.tim ) has graciously offered to bring his jetting kit and walk me through the process so I'll only need to replace what we use. I also have a synch snail so that leaves me with the O2 sensor. Just like Mark says, it will probably get used once and then sit in a box as a fairly expensive bit of unused kit.

The next best option to a rental is a relatively inexpensive kit.

The Spartan 2 kit by 14point7 previously linked looks like a great option at $125 including the sensor. The also have a gauge for $50 so at $175 + a bung and maybe some additional cable, I'd be set. Although I enjoy tinkering with Arduino on various projects, I think it will be hard to beat that gauge on price to have something rugged enough to be useful.

The one I think I'll go for though is the INNOVATE LC-2: Complete Lambda Cable Kit (8 ft.) For $189 it's a complete kit including 1" bung. What I like is that the controller provides serial outputs to connect to my computer for monitoring and data logging. Should work great for temporary cable routing to my laptop in the passenger seat. It also won't be the worst thing to have this in the toolkit because some day I may look at converting to modern EFI where it might find a permanent home.

Thanks all

I would be interested in a rental for sure. Let me know Mark if you end up doing it.

The Innovate says it uses the 4.2 or the 4.9 LSU, but there has to be an adapter as the two LSU's don't have the same connector.

If it does you could buy the cheaper $150 kit and I'll send you a 4.2 LSU part #17014

Hi Ben
The wideband, snail and jet reams I have, just let me know when your ready.

Are you tuning /6 weber IDA's? I can also include the float level gauge and shims which is very important.

What size engine do you have?

Good compromise, but a permanent installation will assist you trouble shooting fuel and or ignition issues.

Good point and I've considered this. If I decide I want longer term monitoring/trouble shooting capabilities, I'd probably build an Arduino based solution with Bluetooth to a phone. I've done this for other (non car related projects) and it works well. I'm keeping my interior stock, so as much as I'd like to add a few gauges, I won't, but am seriously thinking of adding virtual gauges (CHT is at the top of the list) via BT and smart phone.

The other issues is my exhaust. Ben's mufflers don't have a great spot for installing a bung so that would mean monitoring just one head or even one cylinder if I install it in an HE (I assume that's were a dual sensor setup shines?). I have a spare Bursch that I can install the bung in the collector pipe which seems ideal, but it isn't the muffler I will run with permanently. I know swapping mufflers could affect the A/F a little but from what I've been told, not enough to make much difference.

Compromise is a good word here. I need to learn more about what a WB sensor can tell over the long term and also trade-offs to the limited sensor placement options.

One more 2 cents worth. A sensor in each header gives you valuable A/F ratio information, which along with air volume (snail tool) info, helps you get near perfect balance operation of the carbs in a twin carb system in our porsche engines.

There is a spot for an 02 bung in my mufflers if you really want to it can be done.

Mark,

I dont need it yet. I have the snail already and a good amount of extra jets and yes IDAs . I have the float level gauge and shims as well. I would likely just need the wideband and the jet reams but to make this program work you may want to send everything and then I will send to the next person. I am about a month away from ready with this snow and salt gonna stick around at least that long.

Yes and no

I have two bungs and I had two meters, it's TMI and will just drive you nuts. Personally for carbs add the two bungs but only use one meter, swap the LSU around if you must.
I only use one meter and honestly I was going to remove the remaining O2 meter in my carbed /6 conversion, but now I'm going full aftermarket EFI and I'll need one.

One thing when tuning is you want it all jetted the same.
If you even have to think about jetting to each and every individual cylinder there's something seriously wrong with your engine and you/re likely only going to make it worse. A slight variance will not effect tune or performance.
#1 thing needed for a successful tuning job is a sound engine, you can't tune a turd.

Must have missed that on the other thread. I should probably make note of the location in case I need to park a WB permanently in it. Then there is the intimidation factor. I'm pretty sure I can match the quality of the Bursch welds, but not yours. Might need to take it to a pro to do justice. I don't want to deface that work of art.

As I said though, I'm seriously thinking of moving to a modern EFI on this engine in the future. Two reasons: 1) because of where I live, it would be really nice to have real altitude adjustment in the system 2) an EFI with ITBs would let me keep my cool intake system

FYI, the INNOVATE system has one gauge that displays both Header A/F readings simultaneously.

If you have a long duration (carb) cam, EFI and ITB's.... for altitude correction you'll be disappointed. The pizz poor vacuum signal makes you run in AlphaN, which means TPS only, thus your MPS is no longer works so no altitude correction.

One of the reasons why i'm going to try a plenum based intake on my EFI 3.0 /6 intake project.

Which is why I'm putting carbs on now. I have an Elgin 6408-18 cam with 256 duration. I believe that is slightly longer than stock but not too crazy. Elgin's note for this cam says, "Wide Torque Band. A little rough with FI." I'm completely ignorant about acceptable limits for modern EFI or even the old D-Jet for that matter. At this point, going to EFI is just an interest. The plan is to run these carbs for a few years and see how I like them. Then I can decide whether I want to open a new can of worms to upgrade the fuel system either going back to stock FI or a modern version. Obviously a system that would work with this cam would be a plus, but I have a lot of time to research and ponder before I get anywhere close to serious. It sure would be nice to be able to zip between 10K and 3K feet and even pop over to Seattle without having to worry about fuel mixtures though.

MAP-only EFI with key-on barometric is kinda old school. Altitude correction would be just fine provided you have a dedicated barometric pressure sensor. Then it's just a simple PV=nRT correction...could even keep the same single altitude alpha-N tune and just have a compensation table.