What tuning results have you found after adding an O2 sensor kit and then tuning your carb?

Where you close on your original tune?

What circuit did you find that was close and what circuit did you find that was way off?

How much improvement (if any) did you find after tuning with the O2 kit?

Thanks

I used one to tune a 225cid /6 with a holley 350cfm 2 barrel. I found I had to restrict the power valve channel restrictions to get acceptable performance from the power valve circuit. By cutting down on the fuel delivered from the PV I was able use the PV circuit (had to run a plug before) to lean down the mains and get a crisper throttle and better milage.

My 408 smallblock got an O2 kit last year when I moved close to work. I had been cruising I95 every day and the highway blasts kept it running clean. A little richness in traffic gave it decent manners. Once I moved near work I was constantly fouling plugs driving behind 90 year old grannies and suburban idiots doing 35 in a 40.

I switched to an HP holley main body and was able to tweak my air bleeds to get a better fuel curve for stop and go traffic without losing WOT performance.

No matter what you do the wideband will show you just how much of a compromise you have to make to get the car driving how you want. It still takes a real wizard to get everything perfect, but with a wideband and a vacuum gauge in the car you can tell which circuit is working in your carb and how close it is to where you want it.

Good Luck!

rdr

Radar I need a wideband to tune my errant 1406 eddy. Once I get it dialed in that'd pretty much b all I'd need it for (until the next one) & would have no need for a consant readout. I have no knowledge on these/which one etc. What kit/sender or?? would you suggest I buy??

A friend of mine uses one to adjust snowmobiles after he turbo's them, it also worked on a big block swap he had done. He just stuck it in a tail pipe with an adapter and power supply to run the gauge. Tim

For the realitively little my LC-1 kit w/ analog gauge costed me, I won't run another modded car without one. Some of my tuning by feel was pretty close, some of it was pretty far off. Was a real eye opener for warm vs cold engine on choke characteristics.

Like he said-

I run the innovate stuff. It can be a little buggy if you don't ground it properly and the sensors themselves can go bad if you foul them with carbon but for the most part I have been very happy with them.

I have bought the 'lambda cable' for two different cars. I got the fancy gauge the first time but I didn't ever use the logging feature or anything so the second time I got the one that just reads the numbers with no fancy programmable dials and led lightshows.

I don't have experience with other systems, but I think some of them are getting pretty affordable too.

Good Luck

Thank you for the responses. I have been waiting to test my FAST #170634 O/2 kit and so I wanted to see what everyone else was experiencing until I got mine hooked up.

I finished my install today and got it started up and got my first trial of an O2 kit. I left the carb setup over the Winter with the same settings as when I last drove/parked it in November (apx 52 degrees). I started it up today and as a reference (50-54 degrees), I had it setup with .071 IAB's and all four metering screws were out 1 full turn. At my normal idle in N, the gauge read 13 with no other changes. I wanted this for a reference point to start my changes. My first changes was to change out the 071's to 075's to see how much of a change that made, and the gauge settled at 13.9-14.1. So almost 1 full point leaner with just the IAB swap.
So I wanted to lean it out a little more so I played around with the four ms's for a while and ended up with the front two at 1 full turn out and the back two at 3/4 turn out which showed up as 14.2-14.4 on the guage. This is using .028" IFR's which appear to be about right for this setup. The carb came stock with .033" IFR's (which was a mistake from QF) and last year I leaned them down to .031's (supposed to be stock on the QF #SS-750-AN) and then again to the current .028's to keep the ms around one turn outward.
My next test is to check the choke setup and see where it reads now that I changed the IAB's. Before the choke was doing its job with readings at 12.5 to 13 during the cold start up.

Thanks again and I will check back in when I get some more testing done. But our weather is going to keep the car in the garage for a while.

I was all happy until I let the car cool back down and tried to start it up cold with the new settings. Once the choke came off the gauge jumped up to 18 and I could not keep the engine running. I then changed the secondary metering screws back out to 1 full turn (matched the primary side) and I got it to run but it was struggling in the 17 range until the engine got some temp in it and then it went back down to 14 again but it was not completey up to temp yet.
How can you achieve 14 plus in N and have it rich enough to get it to warm up?
I cranked my electric choke to the max setting and I left the ms's set at 1 full turn and I will try and restart it again once the engine is completely cold again and see what happens on the guage. If this does not do it, I may consider adapting a manual choke.

Would using the 071 IAB's and tightening down the ms's be better than using the current 075 IAB's and loosening the ms's, or is this achieving the same thing?
From what I seen earlier today with the 071's, I am guessing that I would be less than 3/4 turn outward on the ms's to achieve the 14 at N.
I am wondering if 14+ in N is just too lean of a goal. I just read a thread where someone said that it is better to run the N reading in the 13.0-13.5 range. I am not sure where to aim for now. The 13.5 range would allow the cold startup to improve until the warmer outside temps get here.

Note: This was in 53 degree temps which is a little cooler than I usually drive the car if this matters or not.

Thanks

I have my afr at around 13 at idle. It seems to stay on without too much work on cold startup and doesn't dip the rpms too much when I slam the throttle closed after a good blast (stick car). I have a Holley main body with no choke so I have to pulse the acc. pump for a few seconds then hold it at 2000 for 30 seconds then give it a minute at 1200 to warm up before I trust it not to stall. I usually just do that then drive gently for a bit

You gotta set the choke up, mine idles at about 12-13 when cold after it settles down and the choke opens its right around 15, the second I touch the throttle it goes to 12 or so until it burns off the accelerator pump spray.

Dave,
I think what you're finding are the concessions that have to be made for a carbureted engine. Because they are so limited in terms of setting for every situation, you can get them perfect for one thing and another suffers. So you need to find your acceptable compromise. Keep after it... (Like you need to be told that...lol)

Thank you for all of the replies and please keep them coming. I have a little while before the weather breaks for Spring around here so I am learning some tuning tips before then.
If you have an auto car, please let me know what your in D (foot on the brake) gauge readings might be too.

It appears that the reading might be different from car to car depending on the engine setup. Good info!!

David,
I can't wait to start tuning with this gauge on the street. It's killin me

Thanks

Daytona thank you very much!. I've done all the guessing on the eddy 1406 I can & now it's time to b scientific about it . I wont b doing any downloading/recording and I wouldn't necc keep it mounted permanently in a vehicle one I get the mixtures dialed in & would want to check several cars. Still the LC-1 kit? Would you suggest a source & a part # as I have no clue what all I need other than the gauge and a sensor of some sort

Robert, just go to ebay and type in innovate lc-1 or lm-1 and they will pop up.

The LM-1 is the bit more expensive one. It's a hand-held unit for around $300 on that auction site. If you want a unit to move between cars, it's the preferred choice. With that one you get a cigarette lighter power adapter, 9v battery, you can get an rpm converter so you can datalog o2 vs rpm and you can get a metal adater so you can stick the o2 sensor up the tailpipe instead of welding a bung into your exhaust system for it.

The LC-1 is the cheaper alternative. On ebay for about $170 you get the sensor/controller and a standard automotive type permanent mount o2 gauge. That unit needs to be properly wired in to power and ground. It would not be nearly as convenient to transfer between vehicles as the LM-1, but for the $ savings you could I suppose. I still needed to briefly hook up the o2 sensor to my laptop to configure it for my analog wideband o2 gauge, not sure if that would be necessary with the digital gauges most of the kits come with. For the price, I just chose to do a permanent install because I like having it. For the most basic setup you need a wideband o2 sensor, a sensor controller and a gauge so you can read the output. For around 170 on ebay you get a kit that comes with all that.

Daytona w your advice I will get on it

I have been doing some reading trying to take notes on what the correct A/F range should be with a carb'd "street" motor.
I know that this will be a little different across the board, but this is what I have found so far (+ many revisions of this). If you have any additions or changes, please let me know.

12's: Right after cold startup
13's: during the warmup (before actual running temp)
13.8-14.5: N idle (actual running temp)
Hi 13's: in D with foot on brake (example: stop light)
??.?: Stop light to light accel?
14.5: Cruise
12.5-12.9: WOT

Thanks

That looks good, however I like to be lean while idleing it seems to keep the engine from loading up. I also believe with it lean at idle its just starving for me to tap the accelerator, i've never had a bog with a lean idle. I'm running 2X4's Carter comp AFB's and a bog is something you have to really tune out.

Added: Your cooling system needs to be good for a lean idle, some engines will try to overheat.

John,
Is yours a 4 speed or auto?
I am assuming that the 4 speeders can be setup a bit leaner in N than the auto guys due to the idle in D issue. Another variable is the outside temps. I am assuming that in the Summer, I can probably get into the 14's. But right now our temps are in the 40-50 range so I am running mid to high 13's on warmup.

What kind of A/F ratio from a stop (steady accel) ?

Thanks!!