Good reason to run a 6.2 on premium fuel

[Snowbound]

I’ve found the tech2 to be a little laggy myself. But it still shows good info especially during playback. Maybe the 1.2ms is as low as that will go in that programming during DFCO. I remember seeing .5ms on another vehicle that was where I pulled that number from.
seeing the timing drop to single and even negative numbers seems to be more during shifts which is all in the torque management. Some good info there. I didn’t get a chance to review my data logs on HPTuners because I’ve been driving the scoot the past couple days. I’ll try to get that up here to see how that compares to what you have going on.

 

[wsteele]

I’ve found the tech2 to be a little laggy myself. But it still shows good info especially during playback. Maybe the 1.2ms is as low as that will go in that programming during DFCO. I remember seeing .5ms on another vehicle that was where I pulled that number from.
seeing the timing drop to single and even negative numbers seems to be more during shifts which is all in the torque management. Some good info there. I didn’t get a chance to review my data logs on HPTuners because I’ve been driving the scoot the past couple days. I’ll try to get that up here to see how that compares to what you have going on.

It is an old piece of hardware, no doubt about that. There is probably more processor horsepower in my Casio watch. But it does provide really interesting and useful access to what is going on in the old gal. Thanks for all your insight as well.

 

[Snowbound]

I guess I was having a brain fart because seeing the timing advance on decel is normal. It’s been a while since I’ve been playing with my software but I was seeing the same as you. Sometimes hitting 32° on decel without DFCO playing a factor. I should do another log and add DFCO to the list of things to monitor. I usually only pull up the tables on just the stuff that is important for the thing I’m tuning for. It can get busy with a bunch of info you don’t need.
On my Esky the DFCO minimum injector pulse width is 0.760ms. So yeah, maybe yours is that 1.2ms that we saw.



From my data log here you can see the timing almost having an equal and opposite reaction as MAP.

I’d still like to target DFCO and watch exactly what it does and how it effects things.

 

[wsteele]

I guess I was having a brain fart because seeing the timing advance on decel is normal. It’s been a while since I’ve been playing with my software but I was seeing the same as you. Sometimes hitting 32° on decel without DFCO playing a factor. I should do another log and add DFCO to the list of things to monitor. I usually only pull up the tables on just the stuff that is important for the thing I’m tuning for. It can get busy with a bunch of info you don’t need.
On my Esky the DFCO minimum injector pulse width is 0.760ms. So yeah, maybe yours is that 1.2ms that we saw.
View attachment 345846

View attachment 345847
From my data log here you can see the timing almost having an equal and opposite reaction as MAP.
View attachment 345848
I’d still like to target DFCO and watch exactly what it does and how it effects things.

In number 37 above, that clip has DFCO status and a sequence of pretty close to WOT and the off the gas. DFCO cuts in, strangely a full thousand RPM after I cut the throttle. The shortest injector pulse width I see on the Tech 2 is like 1.2 and it get back to idle widths pretty quickly.

The one thing that seems like it might could throw my observations off gets back to that Tech 2 sample rate. It could be that the injector pulse width get down sub millisecond and I might never see it on the Tech 2 display, as those periods may have been skipped in the sample rate obfuscation. With new equipment monitoring the tune, it might be very apparent that they actually are getting down where you thought they should,

Looking at that segment of that clip, like starting 5:40 in, the advance drops to low single digits during the DFCO enabled period, we just might not be seeing the injector fuel cut.

Just a guess from someone whose sole EFI programming experience is a Megasqurit ECU on a primitive air cooled engine, using a pair of old Weber downdraught carburetors as throttle bodies.

 

[swathdiver]

In number 37 above, that clip has DFCO status and a sequence of pretty close to WOT and the off the gas. DFCO cuts in, strangely a full thousand RPM after I cut the throttle. The shortest injector pulse width I see on the Tech 2 is like 1.2 and it get back to idle widths pretty quickly.

The one thing that seems like it might could throw my observations off gets back to that Tech 2 sample rate. It could be that the injector pulse width get down sub millisecond and I might never see it on the Tech 2 display, as those periods may have been skipped in the sample rate obfuscation. With new equipment monitoring the tune, it might be very apparent that they actually are getting down where you thought they should,

Looking at that segment of that clip, like starting 5:40 in, the advance drops to low single digits during the DFCO enabled period, we just might not be seeing the injector fuel cut.

Just a guess from someone whose sole EFI programming experience is a Megasqurit ECU on a primitive air cooled engine, using a pair of old Weber downdraught carburetors as throttle bodies.

I haven't done it with those parameters but you might try running a graph of the DFCO and pulse widths to maybe get past the sampling rates. With the Tech-2 that is.

 

[wsteele]

I haven't done it with those parameters but you might try running a graph of the DFCO and pulse widths to maybe get past the sampling rates. With the Tech-2 that is.

I will give it a try next time I do some capture work. I tried using the graphing function once when I was doing the runs that yielded the two clips above, but I had too many parameters selected and the graph was unintelligible. I will try it with just the DFCO function and the pulse widths selected. Good idea, thanks.

 

[a4edwin]

I read somewhere that the 07 6.2 is the same motor that is in the Escalade. That the only difference was the tune so it can take 87. And the purpose was so Cadillac could say they had the 400hp Escalade. Is there truth to this?

 

[Geotrash]

I read somewhere that the 07 6.2 is the same motor that is in the Escalade. That the only difference was the tune so it can take 87. And the purpose was so Cadillac could say they had the 400hp Escalade. Is there truth to this?

Yes, that's my understanding as well except that I can't even verify that they had a different tune. The only difference may well have been the operating guidance provided by GM. Both vehicles have the the identical L92 6.2L engine.

 

[swathdiver]

I read somewhere that the 07 6.2 is the same motor that is in the Escalade. That the only difference was the tune so it can take 87. And the purpose was so Cadillac could say they had the 400hp Escalade. Is there truth to this?

The L92 was used in all Denalis and Escalades in 2007 and 2008. The difference was that the Denali in those years was tuned to run on 87 octane and so it was rated at 380 horsepower. The Cadillac 6.2s were rated for 403 horses as they were tuned to run on premium fuel.

 

[Snowbound]

Caddy engines have higher compression and that’s why you can’t run them on 87. Can’t tune for 87 on an engine that has 10:1 compression.