Curious: Anyone have bungs on their headers for air/fuel mixture sensors?

[Dangerous Doug]

I have my side pipes off for their annual freshen-up painting. I'm thinking of having some bungs welded on so I can use air/fuel mixture sensors (I think this is actually an O2 sensor) to tune my Holley.

I would have them welded onto the inside (meaning toward the transmission) so as not to deface my pipes, just down from the collector (I have a 289 FIA, so my pipes are different than most of you.).

Anyone out there doing this? Are you using a guage in the vehicle or a handheld meter? If so, what products do you use?

I've read very little on the subject and am just getting into researching it. But, it sounds like a pretty cool hi-tech way to quickly learn how to properly tune a Holley, and keep it tuned---not to mention the ability to tune for altitude.

Anyone?

DD

[MFE III]

I welded an O2 bung at about a 45 deg angle down on the inside of the collector. I only did one and haven't had a chance to use it yet. Had my eye on some A/F mixture reading gauges in Summit, but haven't gotten that yet. It's particularly helpful if you wanna dyno your car.
You can pick up the weld on bungs with a plug at Summit, Jegs, etc.

[RICK LAKE]

Dangerous Doug The problem with side pipes is not enough mixer from all the cylinders in 1 spot because how short the area is after the collector. Having a side pipe with small muffler inlets and outlets helps get more back pressure and a better reading of the A/F ratio. They have a clip on kit for just checking the A/F with the car running. Not sure if they stay in place on a road test with out screwing them(clip) into the outlets of the side pipe.
Mine are as far back as I could get and still be in the header pipe. The other thing is using an infared gun for exhaust temps on the pipes. Want the temp to be about 100F or less for a well running motor. Around 1,150F to 1,250F is a good number. Any higher and you may be running lean or too much timing. Going to a chassic dyno and spending $500.00 is worth it to get the best all around performance out of the motor in all conditions of weather. Rick L. Ps wide ratio O2 sensors are better than narrow ones. Want to see how rich the motor goes on accell. The old numbers where about 12.5-13.2 A/F for most motors. Last couple of years they have gone up to 13.5-13.7. I stay soft and a little rich. Spark plugs are cheap to replace or clean against melt down in the holes.

[bobcowan]

I have them welded into the collectors. I have EFI and run a wide band sensor all the time.

I've been using an LM-1 from Innovate Motorsports Innovate Motorsports Wideband Air/Fuel Ratio Tuning It's a little old, purchased around 2005'ish. But still works great, and integrates easily with my EFI for closed loop operation. Right now it's velcro'ed under the dash. I will probably install a LC-1 this summer; maybe.

The LM-1 can also receive input from a variety of sources, like RPM, manifold vacuum, TPS, etc. And it can data log, with a fairly easy download to a computer. I know you have a carb, but it's not that difficult to set up sensors for monitoring. If you do it that way, it doesn't take long to dial in your mixture in a variety of driving conditions. And if you change something - like the cam - it's easy to make adjustments without going to the dyno.

[undy]

I've got my bung just after the collector, inside on the right sidepipe. It's used for chassis dyno pulls.

I'd bought a wide-band A/F gauge system and was going to permanently mount it, gauge in dash and O2 in one of the sidepipes. I just couldn't find a good way to install it where the O2 and wiring wasn't vixible. I still have the $300+ unused kit sitting in my garage collecting dust.

[Got the Bug]

Doug,

Steve Wood has installed bungs on a number of Cobras to accurately measure results during dyno pulls.

[ItBites]

I have bungs in both sidepipes after the collector merge. I use wideband system from Dyno jet with a gauge in the dash. The Dyno jet system has settable indicators for too lean etc.. and also data logs. I get throttle position, rpm, and AF ratio in my simple data logs. This is enough to take a drive, come back, review the log, and then adjust the fuel map (I run a Haltech FI). Very useful and easy to install and operate.

[mickmate]

I have welded them in to several exhausts I've done. I have used the 18mm fitting and as you said if it is not on the bottom (for moisture) and not on the inside where you can see them but somewhere in between they seem to work well with the hand held technology available.

[Cobra #3170]

I have them in both sides just aft of the collector, we used them initially on the dyno to set up the injection and monitor it. I just use one side now for a wide band sensor that is tied into the injection. I use Alpha N but still can record data from the sensor for air fuel ratio's. I set the bung up on the inside facing toward the body but angled down to clear the body side.

[wolf k]

Doug, I welded bungs in my ERA FIA, approx 12 inches after the collectors. I use a hand held meter by FAST. I screw the sensors in only when I am doing tuning. Run the wire up the shifter hole, have to be creative for a power source, do not have cigarette lighter. A/F meter is great tool for tuning carbs, I will never do it any other way.

[Dangerous Doug]

Great feedback, guys!

wolf k: if you get a chance to read the FAST model number, post it here.

I'll be putting the bungs on my sidepipes as I JUST had my headers re-ceramic coated (silver---beautiful!) and this hit as an afterthought. I need to figure out the best placement. 12" after the collector, hhmm? I'll have to look at that.

Thanks, guys.
Cheers,
DD

[Dangerous Doug]

Almost forgot, I've been so freak'n busy: tomorrow I expect my Keith Craft 331 street/performance 331 short block to arrive!

DD

[Mdman352]

Use the LM-1. great tool for tuning.

[Tom Wells]

DD,

Here's an older reference to the Cobra bung question: First Coast Cobra Club • View topic - Header & Collector O2 sensor bung locations

Both locations seem to work fine for tuning the EFI with the wide or narrow band sensors. The wideband sensors are greatly preferred.

Here's another set of photos of the Zephyr's bungs: First Coast Cobra Club • View topic - Zephyr October update (last one this month I promise LOL)

They work great for carb tuning using the LM-1 or 2.

Hope this helps,

Tom

[wolf k]

FAST wide band A/F meter from Jegs 244-170402. It is only an A/F meter. The LM-2 does a lot more for about the same price. Let us know what you decide.

[Dangerous Doug]

Got lucky: I had picked up a couple of bungs and caps on Saturday, and a hot-rodder buddy that lives up the hill stopped by and offered to weld them in place for me. Caught him at a good time and so the bungs are in place.

Time to start looking for sensors and a reader.

DD

[Jerry Clayton]

Innovate Motorsports.com

LM2
plus some accessoies to log by rpm----

[jdean]

I'm a believer in tuning with a wide band O2 sensor. I've used the Innovative handheld quite a bit but later installed the kit for in-dash A/F meter. I use the Speedhut gauge since it matches my set of gauges. I have bungs in both collectors, installed at about 60 degree angle. Not noticeable unless you are looking for it. Good feeling when you can see how your fuel mixture is behaving under all conditions, whether carb or EFI.

[bobcowan]

Originally Posted by jdean

I'm a believer in tuning with a wide band O2 sensor. .

Hmm. That is Most Interesting.

[Gaz64]

I run an analog wideband gauge from widebandcommander.com

Datalogger and user adjustable outputs.