I’m thinking of purchasing an AF meter to use for testing, tuning, diagnostics. Only for temporary use would not be permanently installed. I installed bungs in the exhaust pipe(s) right behind the header flange. I don’t want to spend more than is needed but I’m willing to pay for something decent (“value” is the word, don’t hear it much these days). Suggestions?
I would recommend a meter that uses wideband sensors. You will spend more but get more accurate tuning data.
Good Quality/brand Yes $240 plus wide band , I tune on leanest cylinder , on chevy Gen 1 sbc/bbc is #6
Years ago someone gave me an old (at the time) Innovate LM-1. It still works, so I still use it occasionally. The modern replacement is the LM-2, but it costs $500-800
Mine. Uses a wide band lambda sensor it came with. I installed in in a pistol case to make it portable and keep the wires tidy. https://www.aemelectronics.com/prod...nce_gauges/wideband_gauges/x-series_wideband/
Mine is a Speedhut brand wideband, it's always in the truck. I watch it more then any other gauge. https://speedhut.com/gauge-applicat...alog-out-o2-gauge-8-5-18/?dd-link=0ldtcryzj5b
They work great, I just think the money spent for the A/F Meter for a carbureted application could be better spent somewhere else.
I disagree. You can't read plugs with today's unleaded, especially on a road car. I know from experience I can not tell lean from rich by the seat of my pants. It's amazing how bad carburetors are, yet all these cars have gotten by with them. These things make tuning a cinch. I have an Autometer I bought 10 years ago that was not cheap, but I've dialed in 4 different combos with it in no time.
I’ve used one in combination with a vacuum gauge to dial in power valves and transition circuits. It was very helpful.
A wide band is handy for those times when you make changes like carbs, intakes, cams, exhaust, etc. And especially handy for supercharging. They're not that expensive compared to the cost of replacing a broke engine.
Mine ran pretty good all the time, and gas mileage wasn't that bad. I installed the A/F gauge and found it was rich and lean where it shouldn't have been. With different metering, and a slight timing change, fuel mileage picked up almost 7 mpg on the highway, it runs better at all speeds, doesn't stink, and starts better.
Yup, like he said, once you have one, you will want 1 on anything. My car ran fine but found out it was running basically Wide open throttle readings at cruise. Once I got it dialed in my mileage went from about 12 to 20.
They have one designed for sprint cars. It's the whole laptop deal though. They use the crap out of them tuning sprint cars.
I have one on my injected 4 cyl. I still can't figure out what to do with it. Pretty much runs at 10 to 1 in most all conditions, (I am driving on the street). But I think my pump is going bad as it will go to 18 to 1 and its dying. Would of never seen that without one.
I find myself looking at the gauge more than necessary. When the engine is warmed up at idle there is a nice 14.30-14.70, at wide open throttle I’m around 12.30 ish. There are a ton variations in just normal driving such as light acceleration on a uphill grade will dip into 10-11 range. After a drive I still end up pulling a plug or two for look.
I use it to see how the carb is set up, then remove it once I'm ok with how it's working. Most carbs give numbers that are "ok", but nowhere near what you'd expect with a well tuned efi system. If you can improve your mileage by 7 mpg using an AFR meter, then something must have been really out of whack before! It's surprising how bad the numbers can look on a carb that runs really well, though.
Get one with a digital readout. Also, while you don't need a really high dollar unit, I wouldn't get the cheapest one either. Have some wiggle room on the price. This probably isn't the last car you will ever want to tune, so make a bracket that is easy to mount and remove.......maybe with a magnet.
All good suggestions here. I ran a autometer. It worked good and wasn't that expensive. Something that hasn't been mentioned yet regardless of the cost of the gauge the info won't be of any use if there are any leaks. Examine very closely for any soot indicating a exhaust leak. It will throw off your info. When I put my car on the chassis dyno the operator did a inspection. He didn't like even the smallest black dot on a weld. Needless to say out came the welder to close any leaks.
Here's another approach: Get the AF setup and carb tune working well, then add the vacuum setup to get to the next level. https://thecarbcheater.com/
I've got an AFR gauge on my latest build and to say I'm amazed is an understatement. I put on the carb Holley recommended and it seemed to run pretty decent but was pig rich at cruise. When everybody says the recommended carb should be close that's not necessarily the case. Ended up changing idle air bleeds and main jets by a lot of numbers, and high speed air bleeds by several numbers. It made me wonder how much better my other junk I've built over the years could have been. One other thing I noticed is just changing brands of gas can change it by half a point.
I use one on the drag coupe when the street pipes are on. Wide band high dollar unit. Works great for tuning and keeping me safe with a blown radical SBC. However , Jim-Squirrel stated years ago in a post, do NOT get to hung up on the numbers, you will drive yourself crazy. Yes, check plugs as well and the seat of your pants performance and feel , reaction of the engine.
I'd get one but afraid to see the numbers. I can get 15mpg at 80mpn/3000rpm. Tank of gas will be good for about 4 hrs, I'd have to pee way before that. Lol.
https://www.innovatemotorsports.com/mtx-l-plus-digital-wideband-air-fuel-ratio-gauge-kit-8-ft.html https://www.innovatemotorsports.com/o2-sensor-exhaust-clamp.html
Carburetors are perfectly logical. Nothing but simple physics behind how they work. Well, maybe not all that simple always, but physics. Anyway. An AFR gauge will help just about anyone tune anything. Engines can have a WIDE range where they run fine without obvious issues, while the range where they run best and most economical is far narrower. The butt dyno only gets you so far, an actual dyno is great but spending tuning time in one of those isn't cheap. The AFR gauge is a great aid for the DIYer.
Dumb ? Where is the best place to install the sensor bung on header equipped cars, should you have an AF meter for each bank? Thanks Dan
Only if you have a multi-carb set up with isolated runners. On mine I don't use a bung you can get an adapter to clamp on the tail pipe..
I'm not sure I'd trust that adapter, it's sitting so close to the end it may get air from the exhaust end distorting the reading. Probably less of an issue at full throttle and high rpm than idle or cruising.
The Jalopy Journal
