Ya, I'm looking forward to seeing exactly what the ratios are at different RPM's, at stock. then tinkering.
I know see why a lot of people are crapping on using the stock o2 sensor. It's pretty much only good for seing if it running crazy lean, stoich, or rich. It's not senitive enough to measure between 12:1 and 13:1. Once it's away from the stocih range, it looses it's accuracy totally, and is pretty much just lean, or rich.
Oh well, in a month or so i'll have the wideband.

I have heard that rotaries like to run richer too, but others tell me they like to run leaner. I don't really know what to beleive. A lot of people just repeat info they heard from others without knowing. Oh well, that's what the dyno's for!

 

Say Bambam, how much will you be paying for the wide band A/F meter? And who are you buying it from?

 

I got the DIY PCB from techedge in Australia- it's coming in the mail soon.
You have to asssemble the PCB yourself, and it doesn't come with the sensor, but hey, for the computer, and display, it's well under a hunder bucks US. The sensor is another 150, it's a specific 5 wire sensor from a 95 Honda.
It supposedly takes about 5-10 hours to fully assemble, test, calibrate, and install the unit.
Just over 200 bucks for a complete wideband 02??
It works for me!!
They now sell prebuilt units, and they are still MUCH cheaper than all others. I think about 160 plus the sensor.
The web link is earlier in this thread.

 

Can somebody recomend a wideband a/f meter??

Thanks

TJ

 

you got $1000+ dollars for one, TJ?
Sean

 

Get the DIY one from techedge.com... its 144 australian, which is about 70 US!!!
You just have to get a $125 o2 sensor...
Oh, and you have to build it yourself...
takes about 6 hours- not realy that hard... just tedius.

 

I have an additional [Haltech]O2 sensor installed in the exhaust pipe someplace (I know that it is near the header) and I have the Haltech and a digital readout wired to it. The ECU is still on the stock sensor. I would have no problem soldering the PCB. So scathcart can go look for a nooby with $1000 waiving in the wind to scam.

BamBam - You gota get a freak'n digital camera!!! I have been following your sorted threads about the S-AFC and I would like pictures regarding the grounding points that you had mentioned. I suffer from a &*@# rough running engine at start, till [something] gets warm. I would like to investigate the vehical grounding issues. I have High Throtle set at no more than -7 at power. I have noticed a great increase in power --probably 200 to 300 hp - hahaha. I have a unit better than the G-tech which I will apply to a couple of runs when I have a chance.

Any way let us know how you end up tuning it ...

TJ

 

Hey tommy? I have the same Rough start with my S-AFC on my GXL UNTIL something warms up WTF???

BAMBAM? Have you done your oxysensor yet? and is your engine still ok?

BAMBAM? Can you post you complete S-AFC AF% numbers pretty please. Im going to do the same but few points off because I dont have a mild streetport(15hp) Mods are

Everything you have except streetport. I want to lean the **** out of it and make some power before I dyno it. This is not my daily driver so shuv it about leaning and blowing ****. THnx a billion

 

Bambam7/// Just to let you know, Wozzoom has pretty much the same mods as you. It wasn't until he dynoed his FC, with the S-AFC, he noticed he actually had to add more fuel! Usually, If anything, leaning It out, especially In mid-range, will yield you maximum results.

Ironically, I will be Installing my Walbro (255) once I get my S-AFC (It's on It's way). I know I don't need all the extra fuel that It will supply but I'll have the S-AFC lean It out - like big time. I just hope the hi-flow fuel pump doesn't overwelm the rest rest of the Fuel System...

 

leaner=faster

 

"Bosch Fuel Injection & Engine Management" by C. Probst Indicates that richer produces more power. They seem to mean for a n/a piston engie and do not mention if this is the case for every possible situation. I read in "The Wankel Engine: Design, Development, Application" (circa '71) that rotaries produce more power when running leaner than their piston counterparts and are more tolerant to lower octane fuel. I don't have the 2nd book infront of me so I'm only 98% on this one.

 

It's definitely not.

I found a website somewhere detailing various bolt-on modifications to a naturally aspirated, 16-valve, pentroof DOHC engine that used a factory speed-density (MAP sensor) ECU, and how the mods affected the air/fuel ratio. It turned out that the optimal air/fuel ratio was about 13-13.5:1. The stock ECU was significantly richer than this. The modifications increased airflow which helped power, and since the computer was "assuming" a given amount of airflow for a given RPM/manifold vacuum, the air/fuel ratio also went leaner which ALSO helped power.

I'll try to find it. If i recall right, they added an aftermarket chip which brought A/F back to OEM too-rich specs and power fell away.

 

Concerning stoichiometric air fuel ratio--do not confuse MPG stoich with power stoich with pollution stoich.

14.7 to 1 has NOTHING to do with power.
14.7 to 1 has EVERYTHING to do with emissions/mpg(mpg/nox/co/hc on a graph). The catalytic is most efficient at 14.7:1.
14.7:1 was the best compromise for the EPA, ecoweenies, and automakers.

Read this acrobat.pdf and view the graphs(air/fuel ratio and catalyst efficiency-pages 29 & 31):
http://www.epa.gov/otaq/consumer/fapmve2.pdf
Also read tech articles 37 & 55:
http://www.autoshop101.com/

All engines require different air/fuel ratios for peak power. Every mod/factor/etc will affect each engine.
mods/factors=intake, exhaust, port, timing, temperature, fuel octane, altitude, weather, compression ratio, chamber compression, rpm, .............EVERYTHING.
Turbos engines run a little rich for engine life insurance reasons.
NAs ran rich because thats the way Mazda wanted it. Thats why NAs respond well to the intake/exhaust/timing and usually aren't running too lean.

Saying the "richer or leaner" makes more/less power is BS. It all depends on the specific engine. No two identical engines will produce identical power. This is why the dyno tune is important. O2 sensors and EGT has its pros/cons. Together they are a useful tuning tool. Just tools, nothing else. Another tool is BSFC.
http://www.rceng.com/technical.htm
http://www.westechperformance.com/pa...ding/bsfc.html

 

Bambam......a little advice. Start chasing down that 02 sensor asap. They are really getting rare. Your going to be sitting there with a fine piece of equipment but no sensor. Serious problem. Not joking. I've been looking for a second 02 and am coming up short.

 

short sidenote....These cars are made to run on the lowest octane stock? is that right? i never really thought about it or checked anywhere and since the 7 is a high performance machine ive just been putting the good stuff in it...is that not right?

 

Honda Civic O2 sensor:
http://www.diy-efi.org/diy_efi/projects/diy_wb/

http://www.techedge.com.au/vehicle/wbo2/wbntk.htm
92-95 Honda Civic, P/N 36531-P07-003 Bosch # 13246
Very expensive at dealer, good luck finding a generic replacement.

http://www.napaonline.com/ has the napa part number os791 for $140

and www.autozone.com has the bosch13246 for $150

 

OOOOOPS! Dead post brought back to life for some reason. Sorry 'bout that.

 

^ cause I wanna know!

 

deadRX7Conv........I have a NAPA. Got the last one in Texas the way they acted. I ordered another and they said there ain't any to be had. Honda is toooooo much dough. Edge Tech fellow named Peter says he has none. Have not tried AUTOZONE. Ain't gonna buy another afr until I find the sensor first.

In my honest opinion.....a person should buy a wideband prior to upgrading to a higher psi.

 

I talked to ROB from Pineapple racing up front and personal. I asked whats the best A/F ratio to use on my 89GXL maxed out BUT WITHOUT a streetport??? He says around 13.5 will yield the most power. I think this is why PPnos is running 14.2/1 because he has more mods like a streetport. The more mods the safer running leaner will be. So thier you have it. I will be shooting for mid 13s on the dyno very soon. Actually I will try 14/1 also and see what happens.