I am in the market to buy a A/F Ratio kit to help tune my q-jet in my 75. I have searched through threads but I didnt find exactly what I was looking for. I know there is the cheap voltmeter way of checking,but that it doesnt give the tuning capabilities of the wideband ones.
What are you guys using out there? I don't want to spend a lot of money but I'm not sure exactly what I need.

Since I am running sidepipes do I need to have dual sensors or will one side be the same as the other? Can I use a one sensor and weld a bung in each of the collectors and swap it out or is this uneccesary? And where should I weld the bung on my hooker side pipes (pics)? Can I weld on the jet hot coating and what do I need to use to seal it?

What kit would you recommend? Whats the difference between the LC-1 and the LM-1? Is everything I need to tune included in those kits? Other suggestions?

Sorry for so many questions.

thanks,
Sean

 

I use an LM-2, but if you don't need the added inputs for datalogging, an LM-1 will work fine. Everything may be in the kit depending on what you really need. If you need a tailpipe clamp, that would be extra. If you need longer cables...extra. It really depends.

 

I am going to install an LM2 on my vette when the motor is done. I use an LM1/LMA3 aux box on my bike with the XD16 AFR gauge....The Innovate stuff is awesome... On my Vette, I want to use the new LM2 because it has a hi-def display built in the unit so I can watch the AFR and look at the logged data right there on the display. It also has the RPM converter built into it. Then just unplug the LM2 and take it out when not tuning. I am gonna run the dual O2 sensor model, mainly just to keep tabs on both sides of the engine.

Wideband O2 tuning is the only way to go....

 

I just saw the LM-2 Basic kit($350) for just a little more coin than the LM-1. What is the difference? Will I gain anything with the LM-2. The basic kit doesn't include a rpm converter.

Will the tailpipe clamp be as accurate as a weld in bung near the collector?

Can the weld in bung be used permanently with a gauge in the car or is it a temp for tuning.


Sean

 

The LM1 is the first model, they are not even making it anymore. You will want to get the LM2 if you want a live read out with a display. If you just wanted to log the data, and then view it later with your laptop, you could get a DL32 but....thats way more then what we need for what we are doing. I haven't read the EXACT details with the LM2 but I thought the RPM converter was integrated into the LM1.....maybe not. You could easily get by with running the single O2 sensor, you want to mount it as close to the header collector or even in the collector for the best results. You could remove the oxygen sensor and put the plug in the O2 bung when not tuning. You don't want to leave the sensor in the collect if you're not running the LM2 as the sensor will quickly foul out without the power it gets from the LM2.

The tail pipe sniffers are not NEAR as accurate....way too much stuff occurs in the exhaust system before the exhaust makes it out of the rear of the car.

You "could" get the LC1 and the XD16 gauge if you want to see live data all the time and not worried about logging but.....for not much more, you can get the LM2 which will do with the xd16/LC1 combo does as well as logs....Not to mention you can just unplug it from the cigarette lighter and take it out when you're done tuning......This is the route I will be going. I think the LM2 I was looking at was $599 with dual 02s.....the dual O2s are definetly not needed, but I just figure it would help in diagnosing a problem down the road.....Good luck.

 

Thanks for all that info. Looks like I will go ahead and get the LM-2 with the single sensor.

Where is the best place to put the O2 bung on my hooker headers(header/pipe)? I'm a newbie welder, but I think I can handle this. Can I weld on the Sterling jet hot coating? What do I put on it afterwards to protect the weld?
Is it safe to weld with it on the car or do I need to take the header/sidepipe off first?

For those with the single O2 sensor, did you weld bungs on both sides of the exhaust and check both sides, or can you assume that both sides will run the same?

 

I am no welder, nor am I familar with the hooker side pipe headers but..... You want the O2 bung as close to the collector as possibly, if not in the collector....somewhere after the merge of the primaries. As for the welding, you won't be able to weld on top of the ceramic coating, you will have to sand/wire off the coating, then weld the bungs, then probably just hit the bung/weld with some high heat paint....maybe you could just spray some in a cup and then apply it with a brush to only the welded areas. Make sure to weld the bung in so that the oxygen sensor is pointing upward from around 9 oclock to 12 oclock.....11 oclock is usually the best for fitment of the sensor. You do this so condensation will not drain down into the tip of the sensor, if the tip is on the top of the pipe, no water contamination usually occurs.

As for single vs. dual....ofcourse it would be better to monitor both sides but.....from a tuning stand point only, a single sensor will get you pretty damn close.... Dual sensors are good for keepding an eye on each bank during and after tuning....if you have a weak hole, the O2 will show it. That being said, we tuned my LS1 car with a single sensor on the left side.... But I will run dual sensors on the vette....

 

Look at Jegs.com lookup AFR gauge or air/fuel ratio gauge.

 

You might also look at the new FAST wideband air fuel meter. It comes with dual oxygen sensors, has onboard datalogging and display....No need for a laptop at all.... Jugs has em for $435.....not bad....might be a good and more simple option then the LM2.

 

I am ready to buy one myself and have looked into this just this week. My neighbor has one and three really fast carbureted cars including an '80 Vette that does mid 12's or better every time and has a wideband A/F meter on board for tuning.

It seems the only thing to condider is a wideband A/F meter and corresponding 5 wire heated O2 sensor. I don't think you are suppose to put the O2 sensor in the headers as they get too hot. Anywhere in the exhause pipe on the hot side before the muffler would be o.k. You only need one side with the O2 sensor but you could swap to the other side if you felt you needed to.

I ran across this article a few days ago that was very helpful. I didn't settle on their top choice but it gives you a good sense of what to look for and what's important.

http://paceperformance.com/paceperfo...ndshootout.pdf

I settled on this LM-2 A/F kit from Summit. It also doubles as an OBD-II scan tool but I already have one.

http://www.summitracing.com/parts/INN-3806/

 

I don't think you will have a problem over heating the sensor....They work best when at full temp....Closer to the heat, better analysis of the exhaust. You don't have to put it in the header, it could be right after the connection of the collector and exhaust pipe....

Look how close my O2 sensor is to the turbo....no overheating problems and I run it wide open for a standing mile with 18-20lbs of boost.

Notice the sensor at about 1-2 oclock in the dump pipe, it is less then 2" from the turbine side of the turbo....no sensor problems


Here you can see the large hex head plug where the O2 sensor goes....notice how close to the turbo it is?....

This was before I finished installing the logger and hadn't installed the sensor yet.. I leave the wideband running all the time, I have the XD16 gauge on the dash that reads AFR constantly, I can also remote start the logging function of the Lm1 by pushing a button on the face of the XD16...... Cool stuff but way over kill for tuning an old carb'd vette...

 

I think a LM-2 with a single sensor is the way to go. Its ability to record many parameters at the same time is unbeatable ( RPM, MAP, AFR, TPS are the most important ).
Then you have all the time you want to decrypt the infos on your laptop PC. The only thing I could blame in the LM-2 is its extreme sensitivity to signal noises ( analogic inputs ).
Not unsuperable, but sometimes painful ! Shielded cables are a must to eliminate the radio interferences a car can generate ( alternator, ignition, electric accessories ).
And always use the latest firmware for the device. If you don't intend to use the OBD-II features, the basic kit is enough.
About the O2 sensor location, you can weld a bung at 1-2 feet from the back of the head, anywhere between the 10 o'clock and the 2 o'clock position.
More infos here :

http://www.lsxtv.com/forum/innovate-...-air-1659.html

Here's mine :

 

If you want more infos / pictures, I started a thread about tuning with the LM-2 a few months ago :

http://forums.corvetteforum.com/c3-t...-finished.html

Hope it helps !

 

also look at the zeitronix kit.
www.zeitronix.com

it can log wideband, rpm, throttle position, boost, etc
and can be used with a laptop or palm pilot

 

Nice write up 73streetrace, I bookmarked it so I can check it out when I start tuning. I do have a set of 8mm msd wires, hopefully that will work.

I got a new LM-2 off ebay for a good price, so thats what I will be using.

I think i'm still stuck about the positioning of the sensor on my sidepipes. The collector is outside the frame, and I want to be able to hide the bung and plug. Not sure where I can locate it between 12 and 2 and have it not hit the frame or be highly visible. Ideas?

Sean

 

The sidepipes will limit your choices here. Even if the best location is between 10 and 2 o'clock, it is still acceptable horizontally.
But in no cases should it be mounted below the 90 degree point - directly to the side of the pipe - or condensation will destroy the device too quickly.
A good idea would be to weld a bung on each sidepipe, even if you only use one sender. This will allow you to check if one side isn't leaner than the other side.
If you can find ( or make one ), use a stainless steel bung and/or anti-seize high temp grease ( ONLY on the threads, and NOT a huge amount ).
It will prevent some painful problems if you intend to remove the sender after some time.
And remember that once your engine is correctly tuned, you can remove the sender and plug the hole(s), if you think it's not an aestheticly pleasing feature.

 

I'm not sure what kind of steel the LM-2 comes with, but I will make sure to use anti-seize when installing.

I searched through threads about sidepipes and O2 sensors and only came up with a couple solutions.

The first was just to weld it at 12 o clock and deal with it. (not happening)

Another put his around 4 o clock and said he hasn't had a problem in over a year. I don't get much condensation out my pipes...at least I think, can't really compare it. Not sure if I want to chance it.

I measured and I have 2 inches from the collector side to the drivers side frame at just above 3 o clock(2 3/4 on passenger side). I figure the bung sticks out about 1/4 inch. How long is the sensor itself? It looks about 3 or so inches.
I could either notch the frame to bring it in sideways or I could drill a big enough hole through the frame to feed it in.

I really don't want it to be very visible, especially since it won't be coated like the rest of my pipes.

 

You need about 3 inches from the bung if you don't want to bend too much the sensor wires.
The sensor itself is about 2 inches length from the bung.
The worst conditions for the sensor are cold engine + wet/cold weather.
Some water droplets on a hot sensor can have disastrous effects on its lifetime.
Once engine is at normal operating temperature, the risk is lower.

 

75vettehelp, I just purchased a LM-2 also. I have only had it for a week so and don’t have much experience with it yet. I’m logging AFR, RPM, MAP and secondary air valve position. I got a GM 1bar MAP sensor from the junk yard and built a 5volt regulator to power it. Works like a charm. Spend some time on the Innovate LM-2 forum if you haven’t already, lots of good info and complaints. Getting a good RPM signal from an HEI can be tricky. 73StreetRace is correct, the LM-2 is very sensitive to noise, both analog input and power. Use shielded or twisted pair cable on everything. Grounding is very important also. The only issue I currently have getting mine setup is I can’t connect my laptop to the LM-2 while the engine is running.

 

Doesn't Autometer have one of those?