Thunor

Just a quick question, I'm sure it has probably been asked before, so you guys can give me a beating if this is redundant.

I bought some headers off craigslist and was wondering if I can screw in some wideband o2 sensors into these plugs on the top.

I'd imagine that the exhaust is gonna be hot as heck and I'll only be getting readings off one cylinder as drawbacks, but would it be possible and/or worth it?

Idea being 1) kinda cool to have two afr gauges, 2) tune my carb up better.

Thanks!!

EDIT: It's a 79 vette if that even matters lol

mobird

Could you? probably. But You would be better off just drilling a hole in the collector after the 4 individual pipes merge and welding an 02 sensor bung in. Any exhaust shop would do that for like $20 if you don't have a welder.

Reason being, you are only getting the A/F off of one cylinder (as you pointed out) and that location is EXTREMELY close to the head where you may have trouble even getting an 02 sensor screwed into there and you still have to route the sensor cable without getting it burned on the block or the manifolds.

Thunor

I'm doing the exhaust myself right now. I made some ugly hackjob cherrybomb sidepipes that I'm trying to fit to the vette, but struggling lol. I'm an awful welder, and the welder I am using right now is pretty unforgiving on this thin metal (using a lincoln 225 tombstone). The concept of just screwing in some junkyard widebands into the top is pretty enticing to a lazy noob like me! But I think I'll grab some bungs from pep boys if they carry them and try my hand at welding those in.

I was just hoping someone would say "Hey that's what that hole is for dummy!!".

lars

You need to install the O2 sensor downstream of the collector in the headpipe. A location about 6" downstream from your collector would be a good spot.

Lars

Thunor

Will do, just wanted to see if I could get away with being lazy!! Thanks everyone.

zwede

Narrowband O2s don't mind high heat, but widebands do. Putting them that close to the head will overheat them. Even in the collector I had to add a heat shield to keep it from throwing an overheat code.

Thunor

I'm on a tight budget with my corvette. I'm gonna buy some of the cheapest afr gauges on amazon, do you know if you can just plug in narrow bands and get information of any use with them? I'm also pretty new to working on muscle cars and stuff (this is my first muscle car). At least narrows are cheaper though, but I dunno if they are compatible with an afr gauge at all. Never set one up.

Thanks again!!

sstonebreaker

No, narrow bands are pretty much on/off indicators only. They can tell you if you're running rich, but not HOW rich, and vice versa. I installed an AFR gauge on my 96 impala using the stock O2 sensors, and it fluctuated constantly - rich/lean/rich/lean/rich/lean.... about two cycles per second. The computer constantly adjusts the fuel to stay in the ballpark because it doesn't have the data to get an accurate AFR.

You need a wide band on a carbed car to give you an indication of HOW rich or lean you are.

DblTrbl

Narrow band gauges are available and very inexpensive. I've seen then as low as $13 new on EBAY. They definitely provide some useful information.

Narrow band O2 sensors are dirt cheap as well.

Make sure there are no exhaust leaks between the engine and the O2 sensor. I've always installed mine about 2-3 feet from the engine. Install with the sensor facing up, but not necessarily vertical

ignatz

IMHO - narrow band is a complete waste of your time and money, as is digital Wideband. AFR is very dynamic, you need an analog gauge to properly tune your car

mobird

Digital Wideband is fine ( unless I misunderstand what you mean).

I'm running an AEM UEGO wideband on my car with a digital display (one of the cheapest wideband kits on the market, think it was a little over $100). The display reads from 10:1 - 17:1 A/F and updates instantly, very accurate since it goes by .2 (ex. 13.2, 13.4, etc...).

To the OP: I would reccommend the AEM UEGO (or any other budget wideband setup that uses the Bosch style 02 sensor). Don't quote me on this, but I think mine came with an 02 bung in the kit and some local auto parts stores actually sell the kit. You just get a drill bit (or dremel out a hole) to a size just a little larger than the small portion of the bung and then weld around it. Super easy even for a noob welder (I am a complete novice with a welder as well and had no problem.

One tip: Weld the 02 sensor so it is parallel or above on the exhaust pipe, not on the bottom as water tends to collect in exhaust pipes and can ruin your 02 sensor.

Well worth the investment in my opinion as it takes out the guess work of tuning and is WAY easier than pulling and reading plugs as you just keep an eye on the gauge in different driving conditions and tune accordingly. The AEM (and I'm sure other brands) even has an output for datalogging if you want to record your A/F values as you drive and then check them when you get home. Personally I haven't used that feature yet, I just watch my gauge (or have my wife watch it when i go WOT) and then record the numbers at home on some paper so I have reference to tune. It has been a life saver tuning the quadrajet, it would take me much longer to figure out what needs to be done at different RPM ranges without it. In my case, my car was lean at idle, and crazy rich at WOT. Wideband 02 was able to tell me this so I knew what needed to be changed on the carb.

ignatz

I do have the AEM, but it's analog which was a deliberate choice over digital, which I will admit I do not have direct experience with. I do have experience with the narrowband with its "spectrum" of green/yellow/red LED's. Seeing that dynamic behavior I decided when I switched that I did not want to have a bunch of numbers flashing at me instantly but rather be able to filter average values mentally. My choice.

mobird

Oh I agree, narrowband is a waste of time.

I was mostly replying to your comment that "you need an analog gauge to properly tune your car" as the type of readout (analog vs digital) has little to no bearing on the accuracy of tuning and didn't want the OP to be confused by that statement since most kits come with digital gauges nowadays.

cagotzmann

Here is what I use

http://www.zeitronix.com/

Wide Band O2 Sensors mounted past the collectors.

I don't have a mounted gauge but this is what I log on the PC.


AFR left & Right bank, RPM , Vacuum.

Rescue Rogers

to the OP, if you want to do this right the first time without pulling out your hair heres some easy steps and tips that my neighbor kept screwing up at the same time i was doing this so i got the benefit of his frustration, and some entertainment. I had stock style side pipes a helper was handy.


1) mock up the down pipe so you can get the spot measured 4" down from the collector
2) circle the pipe at that spot so you can put the bung at different spots

3) grab your sensor and hold it on the pipe and see if the zbar is going to be in the way, any clutch linkage, if your pointing it at the motor and the pan is in the way etc. I would stay on the back side of the pipe because there is alot more room away form the motor mount and power steering stuff. and the vertical surface keeps the water problem down as well

4) mark it and pull the pipe
5) block the pipe up on a flat surface and grab the appropriate size hole saw and drill your hole
6) when you buy the kit buy a plug for the bung as this will make you very happy when you want to screw in the sensor
7)screw the sensor into the bung and look at the depth of the sensor then measure and mock up how deep the bung needs to be to get a good depth into the pipe.

8) remove the sensor and use an anti seize and cover the plug and put it in the bung and grab the plug head with vise grips so you can weld it in the proper depth
9) repeat for the passsenger side


mocking it up will save you the surprises of the obstacles that you wont notice until youre installing the pipe, welding on a flat surface will keep it pretty and the most important, is the plug. If you dont use the plug you can warp the bung or bugger the threads with slag. Others will say its not necessary but when it happens, it will be entertaining for your neighbors. you can install 2 bungs and if you cant afford the second meter right away, leave in the plug until later

Thunor

So give me the quick and dirty. Everyone agrees widebands are the best for tuning your car, but can you still get a half decent tune with narrow bands? WOT seems to be a touchy subject for nb, why is that? Just unruly readings makes it risky to tune for WOT with an nb?

I'm sure there's some hardcore nascar hicks out there than can tune with narrowbands and sparkplug readings, and I'd love to learn their tricks since using sh*tty garbage to make cool stuff kind of appeals to my personality and wallet.

EDIT: My vette's not a nice corvette btw it's a rusty beater.

Shark Racer

The "hardcore NASCAR hicks" tune with spark plug and vacuum readings, a race track and a stopwatch.

A narrow band is very accurate around stoich and quickly falls off after that. You could probably do pretty well by it if you knew what you were looking for.

Shoot for stoich at cruise and idle. Maybe a little richer at idle. Stoich or slight dips to rich with part throttle. WOT really should be tuned with a wideband, but you definitely would want to see rich on the gauge if you decide to try with a narrowband. Much higher cylinder pressures and temperatures at WOT, you don't want to add a lean mixture to the equation. For WOT, frankly, stoich is lean.