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accurate a/f sensor??


Guest Anonymous

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In my experience the cheap a/f gauge will tell you rich or lean, just not how rich or how lean. If you smell rich at idle and the gauge tells you lean, you may have an ignition miss. If there is oxygen in your exhaust, it will register lean regardless of how much actual fuel or CO in the exhaust as well.

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If you want an "accurate" AFR meter, you need an industrial unit that can read AFR, and not just O2. Problem with just O2, is that the generic units just aren't accurate enough.

In another post I was talking about the unit that I recently borrowed from work (many thousands of $$$) that show AFR to 2 decimal places, as well as %O2 and Lamda.

Problem with O2 reading is that if you are zero, you still don't know what your AFR is. If there's no oxygen, there's no oxygen.

Tim

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Guest Anonymous

Are these things just another "just to have" gauge?? Ive got an autometer air/fuel gauge and the thing reads lean idling and corrects on 3/4 wot... But it smells rich when its idling. Any body know of an accurate good priced air fuel ratio setup??

thanks,

franklin

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  • 4 weeks later...

http://www.techedge.com.au/vehicle/wbo2/default.htm

 

I've got a couple of those kits, STILL being worked on by a friend of mine. In the meantime I bought an FJO -> www.fjoinc.com from Horsepowerfreaks.com and LOVE it! If you're tuning seriously, especially a forced induction motor you NEED a W/B or you're flying blind...

 

P.S. Looks like Techedge just came out with an IMPROVED box and will be coming out with another soon that can handle more than one type of O2 sensor. VERY nice IMO!

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The 13volt requirement was a worry for me - my voltage in the Supra drops below 12volts with everything turned on :( The new box looks NICE and I will likely buy one and if it's as good as my FJO possibly buy another to have "portable". The Z will get one and I may get my Mustang running with an AEM EMs here soon too.

 

Having tuned with a W/B now I'll NEVER tune without one again - period! IMO this is a "must have" sort of gauge if you're trying to tune and go-fast. Scottie - I think you need one of these!

 

Peak power on the Supra isn't above OEM levels yet and I'm having some serious ignition issues but in some parts of the curve I've gained as much as 50RWHP over the stock OEM ECU rockon.gif Much of this is due to timing, better sequential operation of the turbos, and some BIGTIME A/F fixes - the stock ECU was running 10:1 under high boost shifty.gif I couldn't have done this without an EMS and a W/B.

 

I paid $660 for my FJO and display - this was a DEAL at the time and it has no data collection capability included in that price. Look at the $300 or so pricetag of the Techedge 1.5 w/data collection. You'll need to add $100 or so for the sensor but geez that's CHEAP! Wooot!!!

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If yours was a cheap under $200 unit, its probably a narrow band O2, those are HIGHLY innacurate outside of 14.7:1 since they were created that way to keep catalytic converters happy (stoich), they can switch quickly within only a very narrow band.

 

A cheap wideband O2 by itself costs about $175 last I checked, not including eletronics.

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NTK W/B O2 sensor by itself costs $135. The posts above give plenty of options for true W/B measurement on a budget. Guess I'mnot sure what post you were referring to, both Pete and I were talking about "real" W/B using the same NTK sensor Motec and others use only not getting raped for it. Follow the links...

 

Pete the new 1.5 unit looks sweet, I'm talking to a guy who's going to get a prototype 2.0 unit too using the Bosch sensor. Some kind of way this guy is able to get the Bosch sensors for just $38! :eek: That box will be able to use both NTK and Bosch sensors. Best of all from my standpoint is the fact that their new boxes are LINEAR across a 0-5volt scale. When using them with an aftermarket ECU this makes life MUCH easier and I wish my FJO did this. With electrical loads like lights I'm seeing signal change of .2volts and with the sensor being non-linear that can be a big swing depending upon where I am in the A/F range at any given moment :( Will order one of those puppies, just not yet. Their price doesn't look too bad IMO and the new boards look easier to build too... sour.gif

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it is not a wideband. it merely takes the signal from your existing,(assuming you have one), narrow band O2 sensor.

The cheapest you can find any wideband setup that you don't have to assemble the circuits is the techedge one listed. By the time you factor in a $110 sensor,(the cheapest I found one), and shipping, it works out to be ~$430.

-Bob

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No, narrow band is narrow band, there is no added benefit to running 2-50 of them, unless you were running 1 per cylinder, but still they are accurate at stoich ONLY, they are not used for any WOT calculations in the ECU/PCM/ECM of any cars because they are not accurate. Closed loop fuel trims contribute to estimations used in the WOT calculation, but are usually overly rich as pointed out in the Supra example.

 

Stock many cars will run in the 11.x-12.x:1 area at WOT, and can pickup 15HP or so by tuning, if not more.

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2 gas measures CO and O2, I know a guy that delves more into this stuff than I do and he is turned on by them, so its a thought that may pan out.

 

There are also up to 4 and 5 gas sensors, but usually far too much moola for me, and since I'm not doing home smog checks I can live with less smile.gif

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