Egt question

[Mr Overkill]

Ok dont mean to sound dumb or anythihng but what does a wideband do ????


reason i ask is i need to get a new af gauge and was gonna get a dawns device from chris . Is a wide band a reallyyyy expensive af meter? does it do anything else ???


i already am running a autometer Egt meter



Alex

[phantomrt]

"Wideband" is referring to a style of oxygen sensor used to read air/fuel ratios.

Long story short, standard oxygen sensors, a.k.a. "narrowband", a.k.a. STOCK, are accurate only around 14.7:1 air/fuel ratio. They have an accuracy range of 13.7:1 to 15.7:1. Everyone will have their own opinion on what this range really is. Beyond this range they do not do their job so well anymore. In fact, our engine computers only use oxygen sensor feedback to achieve stoich. Any time you're heavy into the gas (not even NEAR WOT) it is ignoring oxygen sensor voltage. If you want to run a safe 11.7:1 ratio, you are shooting in the dark with a narrow band sensor because it is well out of its range.

A wideband sensor will read accurately from 10:1 all the way to 18:1. These sensors require a control module which is what makes them on the expensive side. They are stock in many late model cars to achieve ultra low emissions. When you're at WOT, the engine computer is STILL reading oxygen sensor voltage to ensure optimum power and emissions.

You can probably get a wideband air/fuel guage in the high $200 range now. For a good one that does datalogging and stuff, it will be in the mid $400 range. The more horsepower you make, the more critical precise air/fuel ratios become, and the more important wideband air/fuel monitoring becomes.

I use a dynojet wideband commander. http://www.widebandcommander.com/ The only way I can see it being better would be the ability to datalog EGTs also. It has an easy-to-read analog guage instead of the pidly lights which was the deciding factor in getting the dynojet model. There is a red warning LED on the guage itself that can be set to illuminate under various conditions. Mine is set to light up whenever air/fuel is leaner than 15.1:1 and/or when RPMs are over 5500. I cannot think of anything that I do not like about it. The bosch sensor has lasted me 10,000 miles so far, and its response is lightning fast.

[Mr Overkill]

ok but with a computer system like ours once the cal is set its set unless you swap the computer the only thing you can change is the fuel pressure

so the only thing it does is meter the air fuel very very good

hummmmmmmmmmmmmm

[Mr Overkill]

http://cgi.ebay.com/ebaymotors/Innov...05492188QQrdZ1

why does that unit have a led read out and the typical lights around it that sweeps around the gauge are they the same thing?

[phantomrt]

That looks like a pretty cool air/fuel guage. I still like my analog one. *brag* This one looks good to me. Notice I said "looks".

There are wrist watches out there that sport both an analog clock and a digital display. It looks as if the concept is the same with this air/fuel guage. Whichever it is easiest to glance at.

There are narrow band air/fuel guages that look the same--with the sweep going around the perimeter. The function is the same, but it still cannot meet the accuracy and range of a genuine wideband sensor. The display says 9.3:1!!!!!!!!! That is RICH. I can easily peg my wideband guage at 10, but needing to read richer than 10:1 is kinda pointless in my book. Also, leaner than 16:1 is pointless too.

For awhile I was running an estimated 8:1 air/fuel ratio. The guage was pegged so I have no idea. I turned down the fuel pressure like 10 psi before the guage would quit pegging. At this rich, there is a SIGNIFICANT loss of power. No good.

[phantomrt]

Quote:

Originally Posted by Mr Overkill ok but with a computer system like ours once the cal is set its set unless you swap the computer the only thing you can change is the fuel pressure so the only thing it does is meter the air fuel very very good hummmmmmmmmmmmmm

Correct. You can change the size of the injectors also though. Its good for say, you install a better intercooler, it WILL lean your air/fuel ratio and these air/fuel meters will tell you by how much. We're always making changes, modifying stuff, and this is a good way to tell what mod is getting more air into the engine vs another.

With a narrow band sensor, you cannot tell the difference between 13:1 and 10:1. 10:1 is lost power, 13:1 makes real good power, but at high horsepower levels it risks blowing holes in pistons. It'll let you tune your fuel pressure to a desired safe level, and you can watch it throughout the RPM range. I currently have NO boost pressure getting to the pressure regulator via a check valve bleed. With my ported head, big injectors and stuff, this setup works quite well at 24 PSI static fuel pressure. At over 5500 rpm it starts to lean out, but not bad. This is something I'd never be able to figure out without my wideband guage.

[phantomrt]

Or you want to see how safe and accurate this new $400 custom cal works. Or if you cannot get a 2 or 3 bar map calibration and add an extra injector and zener diode to fool the map sensor into not seeing more than 14.7 psi, air/fuel ratios jump all over the place.

[Mr Overkill]

ok i see what you mean i didnt know that a 13.1 is what you want to shoot for and stuff like that


ok if i do get a wide band or dont what is a safe area for a egt what would be considered 2 rich or 2 lean

thanks all just trying to see what to do

btw a wide band sensor goes in place of the factory one correct?

[Timmay2]

12:1 - 12.5:1 is usually deemed the best mix of power / safety.. All really depends on who you talk to.

14:1 my car blew a piston ring. woo!

[phantomrt]

13.1:1 will give you a very optimal amount of power, but I do not consider it a to be a safe ratio. I was hoping more people would chime in there--they all have their own ideas on what a safe air/fuel ratio is. I would shoot for about 12-12.5:1 ratio. I wish I had the ambition to see what ratio a stock engine gets. Lean is mean but for insurance and longevity reasons, rich is better although you lose power.

A wide band sensor will be a 2nd oxygen sensor for the car. The stock ECM cannot read the 0-5 volt output of a wideband sensor. Traditional oxygen sensor output is 0-1 volts. Some wideband guage modules have a "narrow band emulation" output which essentially just reduces the voltage to narrow band levels, enabling the sensor to power both the guage and provide appropriate input to the engine computer. This means you only need one sensor;the wide band one. Othwerwise, you will have to drill a hole in the downpipe and weld in an extra bung, which should be included with the kit.

Some say that safe EGTs are 1550, some say 1200. That is a big gap. Mine happens to be a HOT 1550 at freeway cruise (stoich). When I get on the gas it drops to the 1300 / 1400 levels. Someone else should be able to answer this question better than I can.

[Mr Overkill]

ok so from reading this i see that a dawns device wont work.

now i was going to get a new boost pressure gauge anyway so i saw this

http://www.boostcontroller.com/index...60f42ed3567a75

it will measure a/f EGT and boost

dont know anything about them so what do you think?

[phantomrt]

It sure looks to be a powerful module. I do not know anything about this particular model, but it pretty much covers everything that I would ever need to monitor. Plus you won't have to install a 2nd oxygen sensor by the looks of things. I have no idea how well our engine computers work with the "narrow band emulation" but if done right it should be fine.

[Mr Overkill]

yea it looks sweet and i have everythihg in one place (gauge wise)