Predator tuning with a wideband sensor?

[Xcessiv]

Tomorrow, a friend of mine will hook a decent wideband sensor on a '01 GT and we're going for a spin to get real time data and find the peak a/f values.

I have some questions...
1 - what is the highest, safest peak value? 12.9-13.0?
2- which load (gear) will produce the highest value and at what approximate RPM?
3- which parameter should I adjust first to get the most out of the car? Spark advance or fuel? If both, which one should be increased the most?

Thanks!
Best regards

 

[Xcessiv]

Ho BTW, this is a '01 GT with basic mods

 

[propellerhead]

12.8:1 is the a/f ratio I see a lot for NA cars. I'd tweak that, then the timing. From what I've read, the a/f ratio affects the chances of pinging. But timing won't affect a/f ratio.

 

[Give Me TP]

12.8:1 is the a/f ratio I see a lot for NA cars. I'd tweak that, then the timing. From what I've read, the a/f ratio affects the chances of pinging. But timing won't affect a/f ratio.

Agree with what propellerhead says, except I believe advancing timing could cause pinging at a given A/F ratio. Xcessiv do you have a Predator or similar device to adjust your fuel/timing during your road test? Also if you have cats do you have a bung ahead of them to place the O2 sensor into? Unadjusted readings behind cats will be higher than those ahead of them. The wideband O2 monitor will probably remain in the mid to upper 14s until you go to higher rpm (above 3000 or so) at WOT, or at least mine does. It's hard for me to find a place other than a dyno to go at WOT in third or fourth gear in my area. BTW the last time I checked my wideband O2 monitor against that used at my favorite dyno facility they agreed pretty closely, with mine suprisingly being a little higher in A/F readings than theirs.

 

[Xcessiv]

Agree with what propellerhead says, except I believe advancing timing could cause pinging at a given A/F ratio.

So which values should I begin with for both fuel and timing advance?

Xcessiv do you have a Predator or similar device to adjust your fuel/timing during your road test?

Yep!

Also if you have cats do you have a bung ahead of them to place the O2 sensor into?

There are no cats anymore so I'll place the wideband sensor at the rear O2 sensors.

Other info would be appreciated. Thanks!

 

[jstreet0204]

Your target should be 13:1 under WOT. Stock the EEC shoots for 12:1 above 4000 rpm. For timing, I would start by adding about 5 degrees across the range.

 

[Give Me TP]

Also datalog spark advance and RPM with the Predator while your checking the A/F ratio at WOT.

 

[Xcessiv]

Also datalog spark advance and RPM with the Predator while your checking the A/F ratio at WOT.

Why? Isn't the A/F the only critical point to check?

 

[Give Me TP]

Why? Isn't the A/F the only critical point to check?

To see what the unmodified timing is set at first, and then if you advance the timing with the Predator to see how much it's actually advanced while driving and to see if the ECU is pulling timing in case of pre-detonation.

 

[propellerhead]

Agree with what propellerhead says, except I believe advancing timing could cause pinging at a given A/F ratio.

That is true. But I believe a lean condition will make the it easier to ping. If this is the case, then you won't get the most timing advance. Once you set the right a/f mixture, you'd have to go back and see if you can advance it a bit more. If you set the a/f ratio first, then the timing, you shouldn't have to go back and forth.

 

[YardSpecial]

Must Stangs are LEAN from the mods installed.

Called lean ping.

I am in the process of tuning my three pigs.
Let us know how it goes..........

 

[Xcessiv]

Ok, here are the final results:

2-4K range
- fuel: 0.5% leaner
- spark advance: 3

4-7K range
- fuel: 5% leaner
- spark advance: 2

The A/F is really nice, always beetween 12.8 and 13.1 at WOT. My question is... Can I play with the spark advance even more without knocking? I changed the values, but in real-time logging the "spark advance" value always peaked at 28 even when changing it with the Predator.

 

[Xcessiv]

This article about the predator really worries me:

Looking at the data from our wideband O2 sensor we still felt engine was rich. With the factory tune our '01 GT would approach 12.0:1 A/F at wide open throttle. With the canned Predator tune the ratios are leaned up slightly to 12.5:1. We used the Predator's parameter edit mode to further lean out the the A/F ratio in small increments. The Predator enables adjustments of the A/F ratio up to 15% leaner and 40% richer than stock. Surprisingly the engine didn't respond at all to a leaner A/F ratio. We went in steps from 12.5:1 to 12.8 to 13.0 and the power actually dropped 1-2 HP across the board. It appeared that the Predator tune was as good as it was going to get, and that was only a handful of horsepower and torque above stock.
Is there more?
Not fully convinced that a 4.6L 2V delivered from the factory with pig rich A/F ratios has only 5 horsepower to be found from tuning, we emailed the guys at Diablo with our numbers. They indicated that these gains are about what they see on normally aspirated GT's, but suggested going back to the dyno and maxing out the spark advance. The Predator allows for up to 10% more advance over stock and 40% retard from the stock set point. We followed their advice and sure enough that is is where the hidden power was. We picked up an additional 7 horsepower and torque

Does it mean that:
1) I actually lost power by leaning the fuel
2) I can put the spark advance at 10% (max value)?

How can I know that my spark advance is actually TOO high and that my engine is knocking?

 

[Give Me TP]

Are you using the Diablo tune or a modified factory tune?

 

[Xcessiv]

Are you using the Diablo tune or a modified factory tune?

I took the stock Diablo performance tune and modified it.

 

[Xcessiv]

Here's what I understand:
- I'm at 12.8-13.1, which is great
- Now, without using the wideband sensor anymore, I can play with the timing values to have the best value without pinging. +5 on both ranges is the most used value. To detect pinging, I can datalog the spark advance and see if it actually increases (good thing) or decreases (knock sensor decreasing it).

Is it ok?

 

[propellerhead]

I have chased that before and went back and forth with DiabloSport tech support. There's nothing in the Predator that will tell you if you are pinging. You have to listen to it.

Many of us have the timing max'ed out to 10%. Start there and back it off if you hear pinging. I doubt you'll get any pinging with your a/f ratio.

 

[Xcessiv]

I doubt you'll get any pinging with your a/f ratio.

By maxing the timing, wouldn't pinging be MORE probable with a a/f ratio as high as 12.9-13.1?

It was at 12.5-12.6 before adjusting the fuel with the Predator.

 

[Xcessiv]

And will pingning sound loud enough even with a OR h-pipe? I really worry about not hearing it and damaging the engine.

 

[89stang10sec]

Go ahead and max out the timing. A lot of people don't realize that the predator timing adjustments are percentages and 10%(max) equals about two degrees of advance, not all that much. I maxed mine out on day one and drive in hot south texas weather on 93 octane. No problems yet.