rich or lean?

[matt98eclipse]

today i installed a safc and i noticed at wot my o2 sensor volts are readying around 88, 89 volts is this bad or good? My air/fuel gauge was reading the last 1 or 2 green bars.

 

[DSM4me44]

0.96v is perfect. anything lower is lean I believe.

 

[AWDfrank]

Eveyone is going to say that every car is different and because the o2 sensor is a narrowband it is not accurate at WOT only stoich*. Mine changes on each run when at WOT, so I don't even bother with it.

 

[JayRolla]

Exactly I dont look at o2 at all. Just tune the car to detonation but be reasonable. Running more boost than you should for a setup and trying to cover it up with fuel will cause EGT's to rise drastically.

 

[matt98eclipse]

K so just dont even bother looking at the narrowband. So i should wait intell i get a wideband before even trying to tune it. I have also noticed that theres no airflow percentage showing on my safc is this common? I hooked everything up right

 

[JayRolla]

Do you have it set to karman sensor, that my be your problem. You can tune it with just a logger. Here is a good link.

http://www.ca.dsm.org/cgi/ultimatebb.cgi?ubb=get_topic;f=16;t=000317;p=0

 

[AWDfrank]

Thats what I am going to do. It is best to tune with a datalogger and wideband, but a datalogger will do. I can't afford 280 or so for a wideband yet, I got my datalogger for $100 shipped.

 

[dsmclipse97]

I was under the impression the the SAFC was pretty useless for the 420A motor... by that i mean you can control larger injectors with it but leaning your A/F ratio is impossible...

 

[matt98eclipse]

I have the SAFC set to pressure sensor at 6 in and 6 out. Do u guys know of any websites where I can buy a data logger? And how does a data logger work?

 

[Blitzeclips]

Trash the narrowband and get a wideband o2. Those narrowband A/F gauges are nothing but lights shows.

 

[matt98eclipse]

Im definetely gonna be getting me a wideband here soon, Were can i buy a datalogger?

 

[DSMcrazy3]

Those narrowband A/F gauges are nothing but lights shows.

I've said it once(more, actually) and I'll say it again. No they are not. In a few cases the Walbro's have tended to fail(in turbo 420a). When the fuel supply was limited the narrowband gauge responded precisely, immediately diving into red. If you're in a state where you need a wideband o2 sensor to monitor, but currently don't have the money, a narrowband isn't a waste of money.

 

[matt98eclipse]

I didnt think it was a wast of money to it seems to be pretty helpful at wot, now im sure its not going to be as accurate as a wideband but still does help!

 

[cs82685]

I don't think their an entire waste of money, there are definite differences in readout when you adjust the fuel. It's probably more noticeable when you have a digital readout one than a blinky light one, but if you know that a certain level is accurate their good enough to go by. Mine has saved me quite a few times properly diving to lean when that was the case. On the other hand I've always heard .93-.95 was where you wanted to be and I always ran between .88 and .91 and never had any problems

 

[totaleclipse_05]

I've said it once(more, actually) and I'll say it again. No they are not. In a few cases the Walbro's have tended to fail(in turbo 420a). When the fuel supply was limited the narrowband gauge responded precisely, immediately diving into red. If you're in a state where you need a wideband o2 sensor to monitor, but currently don't have the money, a narrowband isn't a waste of money.

I completely agree. My narrowband air/fuel gauge saved me a motor. I couldn't figure out why I was leaning out really bad under boost when I first turbo'ed my car. The gauge would dive into red over 3 psi. Finally figured out it was my fuel pump not being able to keep up with higher pressures. Had I not had that gauge telling me it was lean, I would have kept boosting and probably would have blown the engine. Josh said it once before also: "I would rather have a narrowband gauge than nothing at all."

 

[cs82685]

I completely agree. My narrowband air/fuel gauge saved me a motor. I couldn't figure out why I was leaning out really bad under boost when I first turbo'ed my car. The gauge would dive into red over 3 psi. Finally figured out it was my fuel pump not being able to keep up with higher pressures. Had I not had that gauge telling me it was lean, I would have kept boosting and probably would have blown the engine. Josh said it once before also: "I would rather have a narrowband gauge than nothing at all."

The exact same thing happened to me. I was using a gsx pump b/c from what I read it should have been ok, it wasn't. Definetly saved my ass a few times. Thought it was the fmu, switched to sfmu, same problem $400 later I realized it was the gsx pump and spent another $100 for the walbro pump and all was well aside from my pocket

 

[Blitzeclips]

Their readings are completely off. Don't display real time, and can't give you accurate readings even at WOT. I understand it's better then nothing, but you can ask any real tuner and they'll tell you the same thing. IMO, not worth the time or money.

 

[DSMcrazy3]

Those narrowband A/F gauges are nothing but lights shows.

Then this sentence is contradicted by, "I understand it's better than nothing."

By no means am I saying they're ideal tuning devices, just informing the OP that if he doesn't have money for a wideband, not to trash the idea of a narrowband a/f gauge as a temp. solution as they do provide enough information to potentially save your motor in case of fuel delivery failure.

 

[vbeclipseracer]

I use the narrow gauge also. It works ok when telling you if your rich lean or stoich. but to fine tune your car (i.e. high boost), i would recommend a wideband o2 and the datalogger.

 

[Blitzeclips]

Then this sentence is contradicted by, "I understand it's better than nothing."

By no means am I saying they're ideal tuning devices, just informing the OP that if he doesn't have money for a wideband, not to trash the idea of a narrowband a/f gauge as a temp. solution as they do provide enough information to potentially save your motor in case of fuel delivery failure.

Obviously he's tuning his car to an extent further then you think. He's using an SAFC and probably trying to get the most out of the air/fuel mixture. If you're going to bother using that and tuning to any degree, trash the narrowband and wideband o2. This is something I recommend for his (the OP) situation. Not yours. He's using an SAFC and tuning, you didnt and aren't. His situation is different then yours. Therefore, I'd trash the narrowband and recommend the wideband o2. If you're doing ANY TUNING AT ALL, you need a wideband o2. That Air/fuel gauge may help when you are just monitoring the general lean/rich condition, but when you're ADJUSTING these things, you need something to display in real time, give accurate readings, and better readings at that.

So, OP, if you're adjusting feul/air ratios, I'd defintaely get the Wideband o2, and sell the narrowband.

 

[VelocitàPaola]

I can't say I really agree with either party here...

As useless as I think narrowband O2 gauges are, I do suppose they're better than nothing. On the other hand, it seems pointless to purchase a gauge that's so inaccurate that they inevitably end up replaced.

So, I propose an alternative. In the future, rather than telling a new member to buy a narrowband over a wideband, or telling them to buy a wideband, even after they explained they can't afford it right now, we'll just tell them to buy an EGT gauge.

It's the best of both worlds in my opinion... it's not as expensive as a wideband, it's pretty damn accurate, and rising EGTs will quickly tell you your AFR is lean.


And by the way, no offense, but I highly doubt a busted fuel pump will make the car run so lean it ruins the motor - worst case scenario: the engine shuts off!

 

[Blitzeclips]

And by the way, no offense, but I highly doubt a busted fuel pump will make the car run so lean it ruins the motor - worst case scenario: the engine shuts off!

I agree. Ment to mention that earlier but it slipped my mind. Ever run out of gas before? The car just shuts off. It's not going to blow the motor..

 

[totaleclipse_05]

And by the way, no offense, but I highly doubt a busted fuel pump will make the car run so lean it ruins the motor - worst case scenario: the engine shuts off!

I agree. Ment to mention that earlier but it slipped my mind. Ever run out of gas before? The car just shuts off. It's not going to blow the motor..

So WOT at 5-6 psi with fuel pressure maxing out at 70psi on a 12:1 FMU, 255 hp, and stock injectors won't do any damage to your engine?

 

[Blitzeclips]

So WOT at 5-6 psi with fuel pressure maxing out at 70psi on a 12:1 FMU, 255 hp, and stock injectors won't do any damage to your engine?

Nope. Not if it's done right.

 

[VelocitàPaola]

That's not what I said... if the fuel pump were to suddenly stop working, no damage would occur. If you try to force fuel through 190 or 255cc/min injectors at 160psi, then damage will likely occur.

At these early stages of modification, when timing isn't adjusted, what are we looking to prevent? Not knock... the stock ECU will work to prevent that. Just high EGTs from lean AFRs. A narrowband AFR gauge costs $50 or so? Why not just spend the extra $50-$60 for an EGT gauge?

It's a gauge you'll use for the rest of the modification process, and it's not quite as expensive as a wideband O2 gauge.