got a A/F ratio meter yet?

[grumpyvette]

thats a good question for this forum,and ILL point out a few factors

Ok Ive got one and have tested several of them.

 

http://www.3barracing.com/product_3.htm

 

http://www.rbracing-rsr.com/rsrgauge.htm

 

http://www.scirocco.org/tech/misc/afgauge/af.html

 

http://www.innovatemotorsports.com/products/lm1.php

 

http://thedynoshop.net/prod01.htm

 

heres my take on them, short answer, they are a big help but a P.I.T.A. to set up and use if your not going to semi permenantly install them on your car.

 

 

IVE come to use reading spark plug condition,

 

http://www.digitalcorvettes.com/forums/showthread.php?t=80783

 

http://www.digitalcorvettes.com/forums/showthread.php?t=85537&highlight=plugs

 

use of a good timing light and vacuum gauge , fuel pressure gauge and use of a GOOD HIGH TEMP INFARED THERMOMETER (THIS ONE)

 

http://www.professionalequipment.com/extech-high-temperature-infrared-laser-thermometer-501-ds-42545/infrared-thermometer/

 

as a very quick to use and accurate set of tools. :thumbsup:

 

OK WHY???

 

well your main concern when tuning an engine is to keep the all the cylinders running aproximately the same ratio and at about 12.8:1 for max power up to about 14.7:1 for low emmissions and good mileage,

 

so whats the advantage/disadvantages

 

a fuel air meter uses a o2 sensor, if you place it in the header collector it gives an AVERAGE of all the cylinders on that cylinder head,If theres an (X) installed close to the dual collectors reversion pulses can occasionally even give data from the other side of the engine, so in theory and in practice you can have two cylinders run lean and two rich and the AVERAGE tends to look RICH to the O2 sensor as it SEES unburnt fuel, if you place it in the individual primary header tubes you either need eight O2 sensors (VERY EXPENSIVE, and keeping the wires from burning or grounding outs a TOTAL P.I.T.A......IF you don,t succeed you destroy the O2 sensor and need to replace it.) or you need to be constantly swapping very hot and fragile O2 sensors and bung plugs constantly, but with the IR thermometer you can almost instantly see which cylinders are running hotter or cooler and adjust the jets or look for vacuum leaks, or other CAUSED for the TEMP DIFFERANCE, ETC, far faster too get all the cylinders running at approximately the same temp, indicating the same fuel air ratio, youll be amazed at how close the temp follows the fuel/air ratio, and you can confirm it with plug condition and the other test equipment. run any cylinder too lean and detonation can break rings or melt pistons, run it too rich and you can wash the oil off the cylinder walls and ruin rings/scuff pistons, you need to know whats going on in EACH CYLINDER not the AVERAGE of all cylinders.

 

SO, if your going to install a decent wide band fuel air ratio meter on your car thats fine, its going to be an asset to your tunning skills, if you install the indicator/gauge inside the car and weld in a couple extra bungs in the collectors for tunning and wide band O2 sensors which are a big help, but you will quickly find that its a P.I.T.A. to use it for tune ups on all your buddies cars with the welding collector bungs and installing plugs and O2 sensors while the IR thermometer route is fast and very simple and you can confirm with oplug reading the condition of the engine.

 

YEAH! theres meters that you can stick in a tail pipe, but they read THE AVERAGE, not the individual cylinders ,

think about AVERAGEs

AS my old physics proffesor once said,

IF, I pour molten lead in your front slacks pockets and pack your butt in solid with DRY ICE,.... ON AVERAGE your comfortable:D

[proxlamus©]

This is what you need..

 

EGT guage for EACH cylinder.

 

 

http://www.aircraftspruce.com/catalog/inpages/gem1.php

[dsommer]

What the heck is a 6 cycle engine????????????????????????

 

GEM Series 602 6 Cycle Single Engine Kit

[TrumpetRhapsody]

Oooooh I'm so getting one of the EGT gauges someday, that is AWESOME!

A little pricey for my budget currently though, haha.

[John Scott]

From a carby guy's view I'll chime in on the pros. Reading plugs and exhaust temps is a fine skill to have, but lets say the track conditions are changing rapidly or your dialed in setting in the dyno cell is 2000' lower than the track you're visiting today. A look at the guage will tell you right now what's up. Ditto with the high speed air bleed you just swapped in. Now how did that affect the fuel curve? Many afr guages are easy to set up with a datalogger and record the fuel curve on the run. I run only one sensor so once in a while its always good to pull ALL the plugs and confirm how things are doing, but I found it to be the best addition to my tuning tools yet. Not that I'm not willing to help out a buddy, but I'd never dream of trying to run my guage from another guys car! I'm lightyears ahead of the old make a run and pull the plugs. Hmmm was that surge from a lean or rich condition? Did you know if your carb has a flat afr or a lean or rich hook at the top end? No temp guage is going to tell you that while putting your car through its paces, but a look at the guage will confirm instantly. I installed mine (AEM) in an hour, then ran to the muffler shop to weld in the bung. The guage has allowed me to get into the airbleeds and restrictors and tune it way better than out of box. 14:1 cruise, clean idle, 12:5 at WOT. Easy mid 20s mpg, I love it!

[getZ]

I've got an Innovate Technologies one and I have found it to be great for tuning carbs. Checking left bank versus right bank, idle, etc. I bought a bunch of extra bungs to put on other cars after I bough the thing. There is a support forum on the vendors web site that I have found useful as well.

 

Feed back after adjustments is instantaneous. My next step will be to get it hooked up to a data logger. If you are serious about making power, especialy turbo guys, you need a wideband O2.

 

I'm not so sure about EGT's. I've never used one, but I see guys who use them say they are only good for relative measurments and are engine/exhaust specific.

[m4xwellmurd3r]

I know a guy with a pretty fast (10 second i think) turbo vw that uses an EGT sensor. he only uses one, but he's also only using one side draft delorto on his setup. just based of the exhaust temps he could figure out a lot about how the car was running. Once his EGT's were all messed up, and he said with the way the exhaust temps were, he should've been making such and such boost and such and such rpm. he found out after he pulled off all his header wraping that the humidity had rusted holes in it and it was leaking bad.

 

I think the egt could help a lot since it's the temp of the combustion chambers, you can tell if they're too lean or rich based of temp can't you?

 

So probably a combinatino of the average given by teh o2 and the EGT's you could tune it better eh?

[BobbyZ]

Would it be possible to just use the stock narrowband sensor in the 280zx along with a multimeter. One of the sites listed above states that the output of a narrowband should be 0.5 volts at 14.7:1.

 

I was thinking about adding some connections to the o2 sensor and wiring it into the cab of the car. That way when I make any changes to the engine (boost, porting, whatever) I can connect a multimeter to my test points inside the car and make sure that I am still getting enough fuel. Just looking for a cheap way to read out some AFR information, and this method is free.

 

Eventually I could just build my own meter for the narrowband using LED's. But for now a multimeter seems like it would work just as well.

[280zwitha383]

what are ideal temperatures? and where?

[getZ]

Would it be possible to just use the stock narrowband sensor in the 280zx along with a multimeter. One of the sites listed above states that the output of a narrowband should be 0.5 volts at 14.7:1.

 

I was thinking about adding some connections to the o2 sensor and wiring it into the cab of the car. That way when I make any changes to the engine (boost, porting, whatever) I can connect a multimeter to my test points inside the car and make sure that I am still getting enough fuel. Just looking for a cheap way to read out some AFR information, and this method is free.

 

Eventually I could just build my own meter for the narrowband using LED's. But for now a multimeter seems like it would work just as well.

 

A narrow band is not a direct replacement for a wideband. It's not as simple as just measuring the resistance. There are physical differences in the makeup of the different types of O2 sensor and that's why there is such a huge difference in price. It don't remember exactly what the difference was now, some exotic metal or something like that.

[grumpyvette]

"what are ideal temperatures? and where?"

 

theres NO IDEAL temp. COMPRESSION RATIO,TYPE of induction, ETC. effect results , each engine combo will be slightly differant, but theres a comon RANGE for N/A applications and I usually point the IR temp gun at the header tubes about 3" from the heads, while I hold the rpms steady at 1000 rpm, or so.... your looking for CONSISTANCY and cylinder temps that vary significantly indicate potential problems, 1000F-1250F is a normal range once the engine heats up.

reading the plugs helps a good deal also.

what I look for more than anything else is REASONABLY CONSISTANT CYLINDER TO CYLINDER TEMPS

[BobbyZ]

A narrow band is not a direct replacement for a wideband. It's not as simple as just measuring the resistance. There are physical differences in the makeup of the different types of O2 sensor and that's why there is such a huge difference in price. It don't remember exactly what the difference was now, some exotic metal or something like that.

 

I realize that this is not to be considered a replacement for a wideband. I am just looking for a cheap way to get a rough idea what the AFR's are in my engine. This would not be for tuning as much as troubleshooting.

 

Here's a for instance, when my engine is warming up it has no power, ZERO I can barely move. I already have a narrowband installed in the exhaust of my car, and I also have a multimeter. I should be able to measure the voltage output of the O2 sensor to see if I am way rich because of a problem with the cold start circuit.

 

I am looking at this as a replacement for buying a narrowband AFR meter.

[grumpyvette]

http://www.thirdgen.org/o2tuning

 

bits of usefull info here

[hughdogz]

A narrow band O2 is soooo different than wideband. A wideband can detect a wide range of AFR's maybe 7-20 AFR.

 

A narrow band is nearly a "binary" sensor since the voltage versus AFR function is nearly vertical around 14.7 AFR.

 

Basically, a narrow band can tell you if you are rich or lean, but not by how much.

 

[Edit: I meant voltage versus AFR, not voltage versus time...]

Would it be possible to just use the stock narrowband sensor in the 280zx along with a multimeter. One of the sites listed above states that the output of a narrowband should be 0.5 volts at 14.7:1.

 

I was thinking about adding some connections to the o2 sensor and wiring it into the cab of the car. That way when I make any changes to the engine (boost, porting, whatever) I can connect a multimeter to my test points inside the car and make sure that I am still getting enough fuel. Just looking for a cheap way to read out some AFR information, and this method is free.

 

Eventually I could just build my own meter for the narrowband using LED's. But for now a multimeter seems like it would work just as well.

[RTz]

I realize that this is not to be considered a replacement for a wideband. I am just looking for a cheap way to get a rough idea what the AFR's are in my engine. This would not be for tuning as much as troubleshooting.

 

Bobby,

I gotta play party-pooper here. The intention of this thread is advanced tuning. Its a good topic and I'd like to see it stay on that track.

 

Grumpy,

I'm moving this to Fuel Delivery.

[BobbyZ]

http://www.thirdgen.org/o2tuning

 

bits of usefull info here

 

Thanks for that grumpy, exact information I was looking for. I just wanted to see if you could do that without damaging the sensor.

[dladow]

Great thread. Here is another DIY A/F meter link:

 

http://www.autospeed.com/cms/A_0217/article.html?popularArticle

 

David

[Careless]

What the heck is a 6 cycle engine????????????????????????

 

GEM Series 602 6 Cycle Single Engine Kit

 

technically, an Otto cycle (as well as any other kind of engine) is not really a "X cycle" engine, rather it is a single cycle engine (again, most engines would be) with X amount of steps within the cycle.

 

to have a 6 cycle engine gauge is to monitor 6 individual "X Steps" cycles.

[Six_Shooter]

AS my old physics proffesor once said,

IF, I pour molten lead in your front slacks pockets and pack your butt in solid with DRY ICE,.... ON AVERAGE your comfortable:D

 

That's AWESOME!!

 

It was said that that tuning the engine engine at a different alitude in relation to where you are will have an effect on AFR, which is completly true, but I think Grumpyvette is wanting to discuss cylinder to cylinder tuning here, which once the engine is tuned accross the cylinders to get them even, they generally stay that way, regardless of barometric pressure. That being said, if there is a very problematic cylinder, this will usually be exagerated with a change in barametric pressure, and could cause even more problems. This is where the IR temp gun that Grumpyvette is suggesting to use comes in handy again.

 

I don't own one currently, but I will as soon as I get my truck together or get the turbo in my car, as it is a very good tol to use to tune with, it doesn't replace other tools, just adds to the ability to read what the engine is doing quickly.

 

Little story, where an IR temp gun saved me loads of diagnostic time.

I had an '85 Buick Skyhawk (I miss that car ), that I swapped a V6 into, and had a lot of fun with. Well one day a friend of mine and I decided that we would wash under the hoods of our cars because we were going to a J-body bash a few days later and while hers was a show car, mine was just a daily driver, with some spunk to it. Anyway, we sprayed the engine bay down, used the pressure gun at the local car wash, and cleaned the engine bay off, nice a shiney once it was all done. The only problem afterwards was that it wasn't running quite right, I had a dancing lights guage hooked up to my NBO2 (Autometer), and it pegged rich, it NEVER pegged rich, and even if I held the RPMs high it would barely come off pegged. So I drove it to work and pulled out the IR temp gun and started gong over the cylinders, I found a pair of cylinders that were colder than the rest, and this corresponded to a single coil. Swapped it out and done. Without the IR temp gun I would have been pulling my hair out trying to figure it out. There could have been a multitude of problems that would indicate the same thing on the dancing lights guage.

 

I think it's important to be able to read both AFR and temp of the exhaust, to tune with. Tune to get all cylinders as even as possible first, then using an average you can monitor what the engine is doing and see if any problems arrise, at which point you go back to finding out if it's an engine wide issue, or a cylinder specific issue.

[Noddle]

http://www.14point7.com/JAW/JAW.htm

 

Cheap , works very well

 

Nigel