Whats your a/f ratio's

[droppinbottom]

Just seeing what everyone has tried to tune their a/f ratios to.

thanks

db

 

[Scott_S]

14.7 is ideal

 

[Coder24]

Just seeing what everyone has tried to tune their a/f ratios to.

thanks

db

I thought everyone's ratio's are going to be different...it depends on your car.

 

[91BlackLaser]

I thought it was supposed to be 11.5-11.8.

 

[jking29]

14.7 is ideal

That is stoichmetric. If you try and run your car there under boost it will do a nuclear meltdown. Everyones car will be a little different since you want to go as lean as you can without hitting knock. But mid 11's is a pretty good A/F ratio.

 

[Wicked96GS-T]

I tune for around 11.5:1, ideally, on pump gas.

 

[droppinbottom]

I thought everyone's ratio's are going to be different...it depends on your car.

That is correct, I was just trying to see what everyone else has tried tuning their car to. I have mine as close to 11.1-11.3 across the board as I can get it.

 

[Coder24]

What dodes everyone tune with? i just got a SAFC and havent got it hooked up yet...its was pretty cheap...$100

 

[MyBeatGSX]

11:5 on 93 octane

 

[SpoolinTalon2]

how do you know/read your a/f ratio? im about to put in my a/f gauge this weekend. thanks

 

[mobythevan]

My megasquirt and LC-1 wideband will be installed on Thursday night and I will be tuning AFR's to high 11's under WOT, high 14's under cruising, and around 13 at idle. I think that is a pretty good starting point. A person would like to lean out to 12.5:1 under WOT if you are running lower boost and don't have knock issues. I have read mixed articles on whether or not richening the fuel ratio past 12.5:1 really helps knock. Most people say it doesn't. But without proof I will stick with better safe than sorry thinking. That is how I had my 280zxt set up on pump gas and it ran great at 14psi with a lot of timing. If my 850cc injectors make it in I will put them on this weekend and see what AFR I get at idle, a little concerned about too big of injector at idle, will see how megasquirt can handle that.

 

[1993eclipseGS]

how do you know/read your a/f ratio? im about to put in my a/f gauge this weekend. thanks

Unless it is a wideband, You can't do anything with it except watch it bounce around.

 

[daren_p]

Yes depends on your car & when it knocks & also what octane fuel you run. I set mine to around 11 to 1 with ultra 94, I like to be on the safe side rather then right on the edge.

 

[BaddAssGst]

11.7:1 According to Dsmchips.

 

[SpoolinTalon2]

so is the only difference between a wideband gauge and a gauge is that you can change your a/f ratios? thanks

 

[Scott_S]

a "normal"a/f guage just tells you what your 02 is reading and it bounces around more than pam andersons boobs on baywatch where as a wide band is a whole nother o2 sensor that really gives you an exact reading of your air fuel ratio

 

[SpoolinTalon2]

so then is there a real purpose to having a normal a/f gauge? what else could you do to change if your car was running lean or rich? thanks

 

[Scott_S]

IMO a narrow band 02 sensor is just a fancy light show. If your car is running rich or lean all an a/f guage will tell you is if its rich or lean, to change it you will need to have some sort of tuning software ie dsmlink, afc, ect

 

[daren_p]

Basically the narrow band O2 gauge only tells you if something is majorly wrong like your fuel trims are so far out of adjustment that the ecu can't bring them back in or that you O2 sensor isn't working. They are useless as far as tunning goes, as they are only accurate right around the stoich mixture of 14.7 to 1, as soon as you get slightly away from this number they peg full high or low. A wideband will have a linear (5v) output from 10 to 20/1 air/fuel. If you look at a voltage vs fuel ratio graph for the two sensors it might make better sense, sorry don't have a link right now.

 

[dsm-onster]

What's driving you a/f gauge (your OEM oxygen sensor) is only accurate within a few percent above and below stoich (14.67:1).

Running stoich provides the most horsepower per unit fuel, while running 13.2:1 yields maximim torque. No one should ever attempt this, however. Detonation will destroy your pistons, head gasket, rings, etc. long before such numbers are dialed in.

Lower octane gas demands lower A/F ratios. Thus, for an optimum 93 octane tune, not many excede 11-11.5:1. I've gone 12.5:1 on pump gas and water injection. Transitional fueling (race gas, water injection, or alcohol injection) seems to prefer 12.5:1, before knock or loss of power from having to run too much injection or octane enhancing chemicals.

 

[mobythevan]

Running stoich provides the most horsepower per unit fuel, while running 13.2:1 yields maximim torque.

First of all I am not trying to be a jerk here, I am just confused a little. Yielding higher torque at higher rpms will always yeild maximum horsepower because hp=tq*rpm. Is that sentence really saying 13.2:1 yields more toque in the lower rpm band(therefore increasing the max torque number of the engine) and stoich yields more torque in the upper rpm band(therefore increasing horsepower but sacrificing some low rpm torque)? I just want to understand it better.

 

[dsm-onster]

First of all I am not trying to be a jerk here, I am just confused a little. Yielding higher torque at higher rpms will always yeild maximum horsepower because hp=tq*rpm. Is that sentence really saying 13.2:1 yields more toque in the lower rpm band(therefore increasing the max torque number of the engine) and stoich yields more torque in the upper rpm band(therefore increasing horsepower but sacrificing some low rpm torque)? I just want to understand it better.

Yes. That equation is a generality. Not an absolution. It's like saying that 10.5 hp is generated from 1 lb/min airflow. It is not an absolution.

 

[darren0828]

Mine run 11.5 on 93. Mine friend's EVO run 11.7(tuned at TurboTrix). I dont think high 11 are that bad if you use 93 and right timing.