[Scott Stoneburg]

I went to the track last Sat. and was real happy with the results overall. I had the AFR meter in and thought i knew how to read it... no such luck. it showed lean at idle, and part throttle. and only came close to "optimum" just prior to the shift points. There is also a set of numbers running across the top of the readout. I have no idea what they represent. I ended up doing the tried and tested tune it for mph. ended up pulling almost 2 MPH out by the end of the day. (6 hours) a little in jetting, after all the meter was telling me i ended up leaning it down even farther. a little with an old school K&N stub stack. (the 850 still has the choke horn on it.) and some in the 1" spacer I switched from an open to a 4 hole and it responded well. I kept the AFR meter in the whole time, i just need to figure out how to operate it. If anybody is using the FAST AFR stuff and can shed some light on it please let me know.

Baseline when i started was 10.55@ 129.05 end of the day 10.44 @ 130.92
once again actual testing trumps any simulation or computer guesses. go figure.

Scott

[bad69bird]

I never used the FAST AFR, but I can tell you that it is a valuable tool. Good luck and congrats on picking up some ET/MPH!

[Motor Daddy]

Originally Posted by Scott Stoneburg

I went to the track last Sat. and was real happy with the results overall. I had the AFR meter in and thought i knew how to read it... no such luck. it showed lean at idle, and part throttle. and only came close to "optimum" just prior to the shift points. There is also a set of numbers running across the top of the readout. I have no idea what they represent. I ended up doing the tried and tested tune it for mph. ended up pulling almost 2 MPH out by the end of the day. (6 hours) a little in jetting, after all the meter was telling me i ended up leaning it down even farther. a little with an old school K&N stub stack. (the 850 still has the choke horn on it.) and some in the 1" spacer I switched from an open to a 4 hole and it responded well. I kept the AFR meter in the whole time, i just need to figure out how to operate it. If anybody is using the FAST AFR stuff and can shed some light on it please let me know.

Baseline when i started was 10.55@ 129.05 end of the day 10.44 @ 130.92
once again actual testing trumps any simulation or computer guesses. go figure.

Scott

Let's see the log of the runs.

[Scott Stoneburg]

MD I'm not sure how to transfer the log onto the PC just yet. and once i return the meter to normal read position i think it erases the recorded log. again i dont completely undrestand how i'm using this meter yet. but i'm not giving up on it either. i'll just call the company to see if there is a tech line.
I agree it can be a valuable tool once i out smart the instructions.

[shaker455]

Scott,
I use a FAST system, read the book and look over the graph...very easy.

The lower the number the richer it is.

@ WOT you should substain about 12.5

Cruise is leaner in the 13 to 14 range.
Jeff

[grnmnstr]

Scott,

What part number meter are you using?

I have a FAST meter as well. I would like to hear what others have to say about it too.

[Scott Stoneburg]

shaker, i understand that number, mine reads from 15 at idle/ loaded up on the strarting line to 12.2 just before i shift. there is a bar graph that corresponds to the AFR number being displayed. but along the top of the display there is another set of numbers. smaller and they just line the top. i thought this was a time interval, but then while looking at it something made me think it was not. i'll have to try again.the booklet did not mention these numbers
grnm, i have the dual port monitor # cca170402. once i understand what i'm looking for in the read out i'll be able to tune it better. i just saw a RPM adaptor to upgrde it so you can tell what RPM your AF # is being read at. i will look into adding that to my system.

[David Holmberg]

The RPM adapter is nice, but as you've seen the shift points are pretty clear on the graph.

[grnmnstr]

Originally Posted by Scott Stoneburg

grnm, i have the dual port monitor # cca170402. once i understand what i'm looking for in the read out i'll be able to tune it better. i just saw a RPM adaptor to upgrde it so you can tell what RPM your AF # is being read at. i will look into adding that to my system.

Scott,
I have the same model.

I also saw the RPM adaptor, which I think I will need to get as well. The reason I bought this unit was because it says you don't need a laptop to tune it, but they didn't say you needed to add things to it to make it work. This unit by itself may work great on a street car, but not on a drag car. I guess I will now have to shell out another $150 for the RPM unit. (Check ebay for best $$$)

I also agree on the directions, very vague.

[Cliff R]

A/F meters are a nice tool, but I would recomend to use them for reference only. In any and all cases, tune for best ET and MPH, no matter which way the A/F meter is telling you to go.

I still have to see much over about a tenth on back to back to back runs going from "pig" rich to lean where the engine is just starting to surge a tad. On numerous occassions, I've went from .030" secondary rods to mid .050's, in .005" in incriments. The entire spread of ET for all runs is seldom much more than a tenth, and never to date more that 2mph from fastest to slowest.

I've had several customers chase A/F ratios to DEATH, is search of perfection across the entire speed/load range.....and just about the time you get close, the weather conditions change, or you go another day with completely different conditions, and you are right back to square one.

I quit making any A/F changes a couple of years ago, in my own carburetor. We installed a custom machined set of metering rods, eliminated the primary side power piston and metering rods, and run straight off the jets. I also quit cooling it down between runs, and leave at full operating temperature. Comparing notes, we aren't giving up much ET or MPH, and changes from run to run are much easier to predict. Besides, I'm to the point in my life where the LAST thing I want to do between rounds is work on the car!......Cliff

[cgeise]

You never said if you had full exhaust sytem or open headers - if open headers - the only "good" reading you will get is at WOT - going down the track - there is to much reversion and fresh air getting in the collector at other times - It may help to add a 12 in long extention on that header to help -

[stags]

I got the exact same advice as Cliff gave above from Nickerson Carbs. He's a well known, local performance carb specialist. He says a lot of guys are trying to tune to A/F's or EGT's (I was one) and it doesn't work. Both are excellent tools but not by themselves. I took his advice and put the "fat" jets back in - exhaust temps went down and I picked up a tenth.

[Cliff R]

Just to clarify, there is absolutely nothing wrong with all this "technology". It does not however make up for dyno, street and track testing. Just because an A/F meter tells you that you are within, close to, or right on a known acceptable level, doesn't mean that the car will run the quickest ET, or MPH at those settings.

Those devices are also not needed, if you have good tuning skills, and keep good records.

Case in point. When we were asked to pull the 455 engine from our Ventura a few years ago for dyno and subsequent track tests (some of you may remember the KRE head swap articles that appeared in HPP and Popular Hot Rodding magazines), it made the most power as delivered. Any attempt to move the timing one degree in either direction, or move the fuel curve resulted in lost power. We tuned it for the weather that given day, based on how it performed at the track in similiar conditions.

One last thing. We aren't chasing a lot of ET with fine tuning. If/when you see dramatic changes in track performance, something that you were using was WAY off the mark in the first place.

One advantage that I see with A/F meters, is that it can or could help you cut quickly to the chase, if you aren't that versed in setting up carburetors, or really have no idea at all where to start? They should also be helpful for trouble shooting, with stumbling, hesitation, bog, flat spots, etc, in the power curve. Especially if you lack the experience to know what the engine is wanting when it doesn't act just right in all areas.

I'm still pretty old fashioned, and prefer to trust my experience and judgement with these things, rather than some electronic device. I'm not even a big fan of fuel injected stuff. After 3 years I still can't get my 2003 fuel injected Road King to run nearly as well as my carbureted 2001 Electragluide. Even with a custom fuel management system for the FI engine, which provides full control of A/F at 9 levels plus or minus 30 percent, the carbureted engine ran WAY better at idle, off idle and much smoother at lower rpm's. They are just about equal everyplace else.

I spent a total of about 30 minutes jetting/modifying the Mikuni CV carburetor, I've got at least 100 hours pissing around with my fuel management system and computer stuff, and still can't it to work as well.......Cliff

[67cruiser]

Cliff, please explain further for me in your first statemant, 4 pharagragh, ok, i eliminated the power piston and metering rods, running off jets only, and installed custom metering rods, are you refering to secondary rods then, right?? kinda confused?? Without a power piston its kinds hard to run metering rods.

[wheelspin]

I am using my new FAST afr meter to improve my classic Pontiac's cruising mpg by confirming that jet/rod changes are not too LEAN, following thorough drive testing/racing. I still prefer to set the idle screws for the highest vacuum.

When gas was $2.50/gal I wouldn't have spent $400 for such a tool, but $5 gas makes it worth it, provided I can increase cruise mileage by 15-20%.

Les

[Scott Stoneburg]

Cgeise...it has full exhaust, the sensors are at the ends of the collecters.. the only instructions for the placement was no closer then 20" from the head.
Dave...the numbers change so fast that i dont readily see the gear changes, so far i can not figure out how to run the play back in slow motion. but i'm new at it and will eventualy out smart it. do you have experience with this meter? i still have questions.
cliff...i have to agree with old school tuning. so far if i would have tuned for the AFR i would have added jet. but i was able to remove plenty of jet, get similar AFR readings and go faster. but i will keep poking around with this tool. i might even put the EGT probes back in to use along with the AFR.

[Cliff R]

"Cliff, please explain further for me in your first statemant, 4 pharagragh, ok, i eliminated the power piston and metering rods, running off jets only, and installed custom metering rods, are you refering to secondary rods then, right?? kinda confused?? Without a power piston its kinds hard to run metering rods."

Correct, NO METERING RODS on the primary side of the carb, I run straight off the jets. This is simply done to clean up the fuel curve slightly, as pulling fuel thru a jet with a metering rod dangling in it is not quite as accurate as running straight off the jet. You would be surprised how efficient this set-up really is with a q-jet, once you determine the correct jet size for your application. I still get excellent fuel economy, very little difference from when I ran metering rods and the APT system.

I wouldn't recomend this move for street cars, but it's fine for street/strip and full race stuff.

Scott, I would run the EGT probes in conjunction with the A/F meter, nothing at all wrong with knowing when EGT's are starting to get pretty high. As with the A/F probe, the closer to the cylinder head the better......Cliff

[Scott Stoneburg]

when i had the EGT probes in the old headers they were within 2-3 inches of the head but the FAST book recommends no closer then 20 inches of the head