So what is your question?

 

Which method of tuning is correct? Shoot for an ideal A/F ratio or use it as a means to an end (more torque)? Is there an absolute right or wrong way, or do the different methods tune towards different objectives?

 

What I have done in the past (for the safety of my motor) is shoot for the ideal AFR and take whatever numbers that I get. If I want to pust the motor then I know what I have to do to get what I want and in the range that I want it in. This is most common in FI. You will want to shoot for say 11.8 -> 12.4ish (on the rich side @ WOT). Then when I part throttle tune I can datalog and alter accordingly. This is great if you have a romulator.
Does this help you at all?

 

i agree with tepid... i would shoot for that ideal AFR and work from there

 

By the way, UVAWiseDA welcome to T-I. I see that you are new here and already you are on top of your game. You have done some homework and read our articles before you posted your question. I wish that more people like you where here on T-I. All other newer people should use this person as an example. I am sure that you will be a great asset to T-I. once again WELCOME!

 

Thanks for the welcome. Let me see if I understand correctly; tuning to the ideal A/F ratio can be used as an unique foundation to further tuning of the car (as opposed to one-size-fits-all tunes like the stock one or ebay ones)? Later, using the wideband to stay within known safe parameters, the fuel tables can be adjusted accordingly to flatten out the torque curve?

 

Correct. Don't forget about ignition timing too. That is a very important factor as well.

 

there is no 'right' way... it's really an art. that's why there's good tuners and bad tuners. if there was a set way of doing it, there wouldn't be any use for tuners, since anybody could buy a book and read to learn to do it.

what i did closely followed your last (?) method. i went for a generally-accepted good AFR under different throttle positions, etc, and then went to the dyno to tweak it, and look for the most torque.

that way, i was in the ballpark before i went to the expensive dyno. this street-tuning base map is one of the perks of having your own wideband

 

Couldn't have said it better. Having a WB and using it will pay itself off very quickly if you are making lots of changes.

 

most road race teams "tune to best torque".

drag racers are more interested in WOT since they powershift and rarely are part throttle.

to get a highest rpm slope you must get the best tq.

the sites you are quoting from sell widebands. Of course they start off with AF ratio as their endpoint. It's like asking Hershey which is better chocolate or fruit?


But even they will tell you that if you aim for a specific AF ratio and it drops tq, you don't stay there. You tune further until you don't lose tq or head to meltdown.


AF ratio just gets you in the ballpark first and then, you look what trend occurred in tq change as you went in one AF ratio direction. AF ratio gives you a warning that you should pay more attention to the whole picture as you get into leaner and leaner regions. Most people (if they have this available to them) combine EGT AND AF Ratio together simultaneously as warning devices and compasses for their fueling.

some people will say the true sign of imminent detonation is BOTH AF ratio lean out AND higher EGT past a specific threshold temp. like 1300-1400 degrees F. The location of the EGT probe is important here and requires a tap into a header primary (something that most people won't do for obvious reasons). you can have a lean AF ratio but acceptablel EGT suggesting to you that you can lean further without risk of meltdown. if the EGT spikes, then you should pay attention and backoff.


Be careful when you read AF ratios at the high rpms AND what is an acceptable AF ratio (warning sign AF ratio of imminent detonation). If you apply what an NA person uses to an SC person like Sak or turbo, you can run into contradicting limits. FI like it closer to the 12.5-ish range up top in the higher rpms whereas this would be too rich for NA under certain packages.

You have to start to learn to be more precise and not apply what is said for an i/h/e GSR engine to a 12:1-12.5:1 CR 12.5mm lift cammed 2L headported b18c motor to a 11 psi turbo b18c to an 8 psi SC b18c.


you can't paint them all with the same brush.

but what is common to both is that usually do tune to best tq but stop leaning out if the AF ratio tells them it's getting close to detonating even though the tq is starting to improve.

the art is knowing when to stop and the finer changes once you get the direction to go in figured out.

That's just fueling. The true art is combining the ignition and fuel tables in harmony to remove flat spots.


these are recommendations and reminders that the end goal is not a final AF ratio but the best tq you can get because tq is the physical tangible force that moves you down the road, not AF ratio . how you want to get there is entirely up to you. To me it would be silly to aim for a 13.5 ratio and stop there, never to find out that 13.8 gives you significantly more tq without spiking your engine temp. up top.

btw I use an Innovate system and it's reasonably affordable and easy to use with a fast enough responding wideband (Bosch) for most people's needs.

 

but what is common to both is that usually do tune to best tq but stop leaning out if the AF ratio tells them it's getting close to detonating even though the tq is starting to improve.

That's just fueling. The true art is combining the ignition and fuel tables in harmony to remove flat spots.

Exactly, but it does require a dyno to measure the torque.

Another way to tune without a dyno is with a dataloggable G meter that is accurate enough to show your acceleration trend. This way ensures maximum acceleration rather than peak torque. Units like these are used for acceleration tuning.

 

Precision, accuracy and consistency are the keys to achieving a wide, flat torque curve and placing it in the right place along the RPM range. A dyno helps to achieve this in a controlled, repeatable environment.

Tuning on the street using timed accelleration runs will get you close, but can't match the accuracy a dyno (and its operator, along with the tuner) can provide.

I'm there actually, and am seriously considering a dyno tune, even though I'm planning my build. My street tune is significantly better than without, but even my tuner says "its close", not to mention safe (AF ratio wise) There's more for me to be had with a proper dyno tuning session, but its gonna cost me a significant amount. Dyno time is extremely expensive where I live.

 

the old site for road dyno


i actually did the old-school setup, and just bought the software. got some nice curves out of it once in a while, but i wouldn't tune an entire map to it

 

You will be focusing on both those methods of tuning. For WOT tuning, yes you will want rich A/F. Thats why people say 11-13:1 A/F for tuning.

When you have a wideband that allows you to do some datalogging, then you are able to do another pat of tuning that many people can not get at a regular dyno tune (which only does WOT tuning, especially roller dyno's).

If you can get the dalalloging part done, then you pretty much don't have to have two maps like mentioned.You will be able to have a fuel economy map while driving and a power map when at WOT. See what I'm saying?

This is what happened in my setup. Got the car dyno tuned for the WOT runs. Used the WBO2 to do street runs for datalogging. This will help the ECU fill up the fuel map for the areas that you missed when doing the WOT tune on the dyno.

Set the WBO2 to target 14.7:1 when you are in closed loop. Have the ECU set to ignore the 14.7:1 a/f ratio when in open loop so that it reads off the WOT fuel maps.

In essence what you are trying to do is what the manufaturer has done to the stock ECU. Have it target a particular a/f when in closed loop and have a designated fuel map to run off when in open loop. This way you can have both fuel economy and power.

I hope I didn't lose you in there.

 

yeah some of the not so good best guess ECU pre-programmed mail order chips sometimes send ones that run on open loop all the time including at part throttle,

it really kills the emissions and gas mileage.

to go closed loop all the time even with one of the better fast response widebands wouldn't work , especially at high rpm WOT because by the time the ecu has figured out what to change the injector duty cycle time to, the af ratio has already changed. so closed loop really is an emissions deal.

 

Its all about the chemical reaction time in the sensors. The ECU's themselves are more than capable with dealing with the data.

I hate best guess. Its so easy to do yourself.

 

Here is a good log of tuning

Like they said: "Timing changes produce more effects in EGT and fuel changes produce more effects on wideband. Deluded explained some basics to me but most of it flew over my head. "