Tuning with A/F data

J

JasonCzerak

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https://www.facebook.com/photo.php?v=581361518638561&set=vb.100002941555106&type=2&theater

Never mind the refresh rate. It appears to work as expected. I have like 5 miles on it after I found a USB->serial cable and calibrated it's range.

Cruses at 36-38:1
Idles 95-98:1
Idles in gear at 45:1
Coast on the highway, 20:1. (rail pressure relief? where the map goes super big duration at 0-6% load?)
Acceleration is around high 20's.

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So. what does everyone know about tuning with A/F data? Looking for all areas of input.
 
We use it with the stand alone but it is calculated air mass (cylinder swept volume + IAT and MAP). This works exceptionally well spooling turbo's and can be used for maximizing full load fuel ratio as well along with just generally keeping the smoke down.


Here's a quick log spooling a promod 88mm/gt55 hotside.

Spoolexampleairfuellimitation_zps6c254ec0.jpg


Pink line is rpm's the jiggling like is throttle position, green line fuel mass and bottom red line is boost.

As you can see fueling rises with throttle until it get to the air fuel limit then it is in air fuel limitation and ramps up perfectly with boost regardless of throttle input (throttle could be mashed to the floor yet still just fuels to the air fuel setpoint).

Haven't fooled with a lambda sensor yet.
 
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Jason I can't open the link but those ratios seem very lean to me. The 20:1 is about right but the 90:1 seems like it may not be right. I've calculated my a/f ratio based on charger specs and injector flow and I try to stay in a range around 14-15:1.
 
It will be entirely dependent on load. At idle we show 300:1+ full load max torque you should be in the 14.5:1. (Pretty smokey) Cooling with fuel well below that yet.
 
Takedown95, at idle it's reading 100:1. Maybe this gauge doesn't read beyond 100:1. Jon F, says his '11 TDI idles at 80:1.

Any idea why it would read 20:1 at coast and in gear? Did this even down to 5mph. I'll put the trans in neutral and see if does the same thing.
 
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about the only useful information AFR gauge gives for diesel is smoke limit AFR. The lower you can get AFR without smoke the better you are mixing fuel with air, meaning good injectors, good intake swirl and optimal timing. Modern high pressure commonrails and unit pumps should run clean under 17:1 AFR, best I have seen is 15.5:1

Whose lambda sensor and gauge can measure 100:1 AFR ?
 
Also, I've gotten the ScanXL software as well as a bluetooth based PLX kiwi box to log ECU info

http://www.palmerperformance.com/products/scanxl/index.php
http://www.plxdevices.com

With all of this, should have a good running truck finally.

Thus far with my first 5 minutes of dataloging the ECU I was surprised where the caculated load is for the amount of "seat of the pants" acceleration. Should help figuring out where to change the tune finally!
 
Jason, that was my 98 Passat, and I set the gauge to 80 on top so I don't watch it bounce between 85 and 99 - distracting. 2009+ have wideband stock with smoke limiters which is very awesome for tuning.

Cruising should be mid 30's, idle pretty high, full throttle with little smoke should be around 17:1 14.5:1 or lower will be very smokey. The optimal value will depend on a number of things, atomization, etc.

AFR is a very useful tuning tool, you can dial in timing and duration very well with it - if you're smoking at high AFR, you have too much timing. Made a huge difference when developing my timing map for my TDI.

Coasting at 20:1 in gear is really weird, that should max out the gauge. It shouldn't be fueling, at 20:1 it should be making power.
 
I have a decent thick haze at WOT at 20:1 WOT from 2500 to 3000-ish. The other thing is boost was about 65-70psi while drive was nearing 100.

We have a bit of work to do soon here :)
 
JasonCzerak said:
I have a decent thick haze at WOT at 20:1 WOT from 2500 to 3000-ish. The other thing is boost was about 65-70psi while drive was nearing 100.

We have a bit of work to do soon here :)
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timing way too retarded.
 
Leiffi said:
timing way too retarded.
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Well, we are stepping into things slowly with out going nutz to blow crap up. :)

Curious, what should be the ball park for timing for something like my application? Obviously getting on the dyno and measuring till gains are minimal is what we need to do, but besides that where should we be at 2500, 3000, 3500rpm?
 
JasonCzerak said:
Well, we are stepping into things slowly with out going nutz to blow crap up. :)

Curious, what should be the ball park for timing for something like my application? Obviously getting on the dyno and measuring till gains are minimal is what we need to do, but besides that where should we be at 2500, 3000, 3500rpm?
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my Volvo D16 was set 1degree/100 rpm at max load, that's a rule of thumb I've heard from many diesel tuners, from 2 litre VW engines to 16 litre pulling engines.
 
Leiffi said:
my Volvo D16 was set 1degree/100 rpm at max load, that's a rule of thumb I've heard from many diesel tuners, from 2 litre VW engines to 16 litre pulling engines.
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huh. I suppose based on that I have a bit more to go.
 
Finally! A thread I can Learn from. Thank you!
 
Leiffi said:
my Volvo D16 was set 1degree/100 rpm at max load, that's a rule of thumb I've heard from many diesel tuners, from 2 litre VW engines to 16 litre pulling engines.
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so, is that 1degree per 100 at my desired duration? so if we were to apply the fuel split methodology one would have more fuel btdc than atdc?
 
Turbo Performance said:
Huh. Damn near 2K posts and you've just picked something up. I have to say I'm impressed.
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For the longest time, I was wondering why lambda and A/F ratios were not always talked about. I kept my mouth shut, so that I would not feel the backlash. A while back, I was told, that there was no way to measure from the exhaust the A/F ratios. When I was visiting some of the Nordic countries, lambda was always talked about when referring to diesel tuning. I never was able to learn.
 
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That's to much, I'm spinning up to 5k and no way I'm feeding it 50 degrees advance. Maybe mechanical injection.
 
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