Lean Burn Tuning?

[Marky Dissod]

True on the V4 mode. I purposely buy stuff w/o AFM. I just like good old fashioned V8 power.
I'd be interested in meeting up with someone who does this within a reasonable distance just to learn and see the process.

The underlying problem with V4 mode lies in the fact that it was under-designed.
My guess is that it was INTENTIONALLY designed so that the engines would no longer tend to last 250,000 miles.

Even without Lean Cruise, the GM V8s made prior to V4 mode are likely the longest lasting V8s ever made.
That Lean Cruise improve MpGs without additional NOx is a lot of sweet icing on a moist & tasty cake.

 

[B-train]

The underlying problem with V4 mode lies in the fact that it was under-designed.
My guess is that it was INTENTIONALLY designed so that the engines would no longer tend to last 250,000 miles.

Even without Lean Cruise, the GM V8s made prior to V4 mode are likely the longest lasting V8s ever made.
That Lean Cruise improve MpGs without additional NOx is a lot of sweet icing on a moist & tasty cake.

NOX will go up with lean cruise. Anytime you get a hotter, more complete combustion, NOX will increase, but CO and CO2 will go down. Saw this firsthand on 4000hp diesels. Tier 0 or 1 and the engine was happy as a clam. Program for tier 2 and it was OK, but the exhaust was hotter due to the fact that more heat was escaping and not pushing a piston down.

Tier 3 and 4 killed it. It would do the work, turbos (4 of them) would be screaming and glowing. Fuel rate increased exponentially. Cooling the cylinder with multiple injections per cycle knocked down the NOX, but raises CO and CO2. They rely on post combustion to clean up the rest, hence retarded timing which requires more fuel to push the piston down the same amount.

Like I've stated on other posts, follow the money. Clean air is just a guise to appease ignorant people and fill the pockets of the oil companies and govt with more revenue. This mainly applies to diesels, but newer gas direct inject motors suffer a similar fate. If engines were tuned for maximum efficiency, the EPA wouldn't have a purpose. It's a complete racket.

 

[Marky Dissod]

NOx will go up with Lean Cruise. Anytime you get a hotter, more complete combustion, NOx will increase ...

I was under the following impressions:
Richer than 12.0-to-1 AFR is too rich to be useful ('oink')
From 12.0-to-1 AFR til about 16.0-to-1 AFR, NOx rises
From 16.0-to-1 AFR til about 17.5-to-1 AFR, NOx falls
Leaner than 17.5-to-1 AFR is too lean to be useful (HC actually starts RISING AGAIN)

Lean Cruise should ONLY be active when the driver needs UNDER 100 horses; low loads, cruising on flat ground.
Once any more power is demanded, LEAN Cruise should be impossible.

During the transition between 'standard cruise' and Lean Cruise, there'd be a BRIEF rise in NOx, as the AFR goes from 14.7:1 to 16.0:1, followed by a drop in NOx as the AFR goes from 16.0:1 to 17.5:1.

So, the less time Lean Cruise spends between 14.7:1 & 16.0:1, the better, to keep NOx down.

 

[B-train]

Interesting stuff. Maybe my diesel experience doesn't quite transfer over to the gas side. Learned something new. Good stuff! I got to get EFI live or something like that to try this out.

 

[Geotrash]

Interesting stuff. Maybe my diesel experience doesn't quite transfer over to the gas side. Learned something new. Good stuff! I got to get EFI live or something like that to try this out.

Me too. What’s the consensus on which tuner to get to experiment with? I’m considering HP Tuners anyway.

 

[Marky Dissod]

Interesting stuff. Maybe my diesel experience doesn't quite transfer over to the gas side. Learned something new.
Good stuff! I got to get EFI live or something like that to try this out.

My limited understanding is that combustion & chamber temperatures play an important role in NOx as well.

 

[Mechanic prepper]

Another update....got fuel pump fixed and imported wideband signal through egr pintle voltage so now have a pid in HP tuners that has actual and commanded afr. Will make a quick video on the basics of setting up for those who feel brave enough to try it on own.

 

[Mechanic prepper]

NOX will go up with lean cruise. Anytime you get a hotter, more complete combustion, NOX will increase, but CO and CO2 will go down. Saw this firsthand on 4000hp diesels. Tier 0 or 1 and the engine was happy as a clam. Program for tier 2 and it was OK, but the exhaust was hotter due to the fact that more heat was escaping and not pushing a piston down.

Tier 3 and 4 killed it. It would do the work, turbos (4 of them) would be screaming and glowing. Fuel rate increased exponentially. Cooling the cylinder with multiple injections per cycle knocked down the NOX, but raises CO and CO2. They rely on post combustion to clean up the rest, hence retarded timing which requires more fuel to push the piston down the same amount.

Like I've stated on other posts, follow the money. Clean air is just a guise to appease ignorant people and fill the pockets of the oil companies and govt with more revenue. This mainly applies to diesels, but newer gas direct inject motors suffer a similar fate. If engines were tuned for maximum efficiency, the EPA wouldn't have a purpose. It's a complete racket.

Nox doesn't go up in lean cruise on gasoline. Nox on gas engines is from peak combustion temp..peak combustion temp is 14.1 to 15.1 area...afr wise....lean burn 16 to 1 or higher actually decreased nox and emissions overall.. after 16 to 1 egt ( and combustion peak temp) drop like a rock...pilots use egt temps instead of afr readings.. they tune either rich of peak lean of peak ....

 

[PatDTN]

I landed on this thread because I'm trying decide what to do to the 5.3 I took out thinking it had a failed AFM setup. When the 6.2 I swapped in had the same problems I happened to discover both upstream cats had collapsed and blocked the cat after the Y pipe. All that blockage left nowhere for the exhaust to go so much of it forced its way past the rings and blew the oil out of my oil pan into my intake manifold. At any rate the engine is fine for a 200k mile 5.3 with AFM in my 2009 Tahoe.

The 6.2 will only run on premium. That may be due to finding a script kiddie of a tuner. It's eating me out of house and home and economy is bad enough I don't actually calculate it. The computer is confused. My guess is larger injectors on the 6.2 and the computer only uses duration and pressure to guage fuel usage.

I'd love to have VVT but not AFM when I'm done and swap it back.

The 6.2 has an LS9 cam, no VVT or AFM.