Let talk mpg and how timing vs fuel helps

[Me78569]

We can do that but we first need to be able to be sure how the timing message is formatted. 

 

I am Guessing at this point, but what I am seeing seems to be high.  

 

How do we figure out what the true timing is? Buy a diesel timing light would be my first though.

[Me78569]

Alright,

 

I did some math based upon the Quadzilla Code when using 1* of timing increase.  This in theory gives you what the canbus message size is for a 1* of advancement.  

 

How do these numbers sound.

 

 

Idle, 13*

cruise 17*- 19*

Low Boost High load 12* - 14* ( going from cruise state to pedal down)

WOT 27* max I have seen.  

 

?

Edited October 2, 2016 by Me78569

[TFaoro]

Still sounds high.....

 

So when I had it set to 8* in theory cruise state would be 24-27? 

 

@AH64ID do you have any thoughts on this? You probably know more than the rest of us. 

[Me78569]

No because the timing added is on a map in the quad code.

 

as an example, At cruise it would add ~%20 of the user timing, 8 * %20 = 1.6

 

So cruise timing say 18* from ECM, plus %20 of your 8* advance would give you 19.6* total

 

you only get the 8* you tuned when the timing map is at %100, which is VERY high in the revs and boost.  

 

This is where the timing scaling comes into play.  If you have it set at %100 then you get that 8* up top, if you set it at %60 then you would get 4.8* up top, BUT lets use the same cruise state so %20 of the map.   so you would take your 1.6 * %60 = .96* timing still.

 

the OEM timing from the ecm reached 25* on it's own on the last run I data logged on lvl 0 

 

so we know that the max timing for the vp44 is somewhere between 25* and 30* so using a number like 15 will not give you stupid timing up top, just dumb timing down low.  

Edited October 3, 2016 by Me78569

[Me78569]

At normal operating temperature, I'm seeing 11* at idle, and about 16* at 2000 RPM. Light load (little or no throttle) at 2000 RPM the timing is closer to 20*.
The map that controls the base timing shows 24* at full load 3500 RPM.
Normally, driving around town, I never go past 3000 RPM. I took the base timing table and added 2* to it, and I've been driving around that way for a while. I'm a little afraid of the full load timing at 3500 RPM now - it is 26.4*, which seems awfully high. Of course I can just trim that back down.

I left the light-load timing map alone this time - cruising light load around 1800 RPM is showing right around 20* now. Running like this for the past several days, it looks like I've picked up .4 MPG.

More info from jdonoghue.   My timing numbers now seem to match his about spot on.   

[AH64ID]

That still seems very high for cruise timing. WOT and idle seem believable.

 

Didn't most 12V's have 14-15° all the time?

[TFaoro]

37 minutes ago, AH64ID said:

That still seems very high for cruise timing. WOT and idle seem believable.

 

Didn't most 12V's have 14-15° all the time?

I though so as well, but all research is pointing in the direction of Nick's numbers being correct.

 

You're correct. They were 13.5-14 depending on the year.

 

Sending you a PM.

[Me78569]

I found in the scipod software where he was calcing out timing

 

	/* Timing conversion */

	rval = lval;

	sval = rval >> 7; /* sval is the whole number part */

	rval &= 0x7f;
	rval <<= 1;

	rval = (rval * 100) / 256; /* The fraction part */

	printf("%d.%02d\t",sval,rval);

	fprintf(OF,"%d.%02d\t",sval,rval);

My bitwise math is a little dusty, but it looks like he takes in the timing number "lval"

then shifts by 7 to give you the whole number of the timing, then and's the same value to get the remainer and shift by 1.  then he does some math to move it into place and prints on the screen.  

 

according to this my numbers are still off, 1440 would = 11.25 and 3300 ( my max so far) would be ~24.xx my cruise would be ~ 17.xx

IE:

Warm idle ~ 11.25*

cruise ~ 17.25*-19*

WOT ~24*

Do those sound better to everyone?  

Edited October 3, 2016 by Me78569

[TFaoro]

7 minutes ago, Me78569 said:

I found in the scipod software where he was calcing out timing

 

	/* Timing conversion */

	rval = lval;

	sval = rval >> 7; /* sval is the whole number part */

	rval &= 0x7f;
	rval <<= 1;

	rval = (rval * 100) / 256; /* The fraction part */

	printf("%d.%02d\t",sval,rval);

	fprintf(OF,"%d.%02d\t",sval,rval);

My bitwise math is a little dusty, but it looks like he takes in the timing number "lval"

then shifts by 7 to give you the whole number of the timing, then and's the same value to get the remainer and shift by 1.  then he does some math to move it into place and prints on the screen.  

 

according to this my numbers are still off, 1440 would = 11.25 and 3300 ( my max so far) would be ~24.xx my cruise would be ~ 17.xx

IE:

Warm idle ~ 11.25*

cruise ~ 17.25*-19*

WOT ~24*

Do those sound better to everyone?  

 

To me, YES.... but what the hell do I know  

Honestly, they do. Amazing what 3*  difference really is. 

[Me78569]

I really wish  jdonoghue  would get back to me.  He did a year or so ago, but nothing since.  

 

 

[CSM]

Add more timing till tylers head pops.  Thrn back it off a little.  

[Me78569]

hahaha,  I can see the map now.  a bunch of %100 markers from 1200 revs up lolol

Edited January 21, 2017 by Me78569

[TFaoro]

12 minutes ago, CSM said:

Add more timing till tylers head pops.  Thrn back it off a little.  

 

11 minutes ago, Me78569 said:

hahaha,  I can see the map now.  a bunch of %100 markers from 1200 revs up lolol

 

Let's do it  

[CSM]

11 minutes ago, TFaoro said:

 

 

Let's do it  

 

[Me78569]

only if I can ride with you the first time....nothing bad coud happen with the vp44 turned to static 25* timing

 

 

 

alright so now that I know what I am looking at in regards to a timing number.  

 

At what point does timing start to drop mpg at cruise?  Can you have too much other than breaking something?  I know every truck will be different depending on configuration, but how do you typically go about building a base map, or is there such a thing.

[AH64ID]

I think my mileage starts to drop around 8-9° lol. But that's with a pilot. I idle nice at 8° warm without a pilot but I'm guessing the pressure is higher and no pop delay. 

 

Im thinking the pop delay at cruise pressure is the biggest reason for the timing.  

 

With my fueling and injectors my wot timing is low, around 19° at 3500 rpms and only about 10° at 2200. That's all at approx 22K psi and no pilot wot at those rpms. WOT and 2000 rpms is less than 8°...

Edited October 4, 2016 by AH64ID

[Me78569]

I would agree the pop delay is what causes the seeminly high timing numbers on the vp44 trucks.  

 

 

Tyler,

 

once you get your truck back on the road with the iquad app I would love to see what load% your truck reports at cruise.

[Mopar1973Man]

Grabbed my fuel log book and this tank again was all trailer towing some of it was bit hard and heavy (understandable). I turned out 11.21 MPG and my OBDLink showing 11.00 MPG so my calibration is nearly prefect yet. I'm using volumetric effiency of 77.5% which is 14.5% offset from factory 63%. So OBDLink is good enough for data logging for MPG Data.

[Mopar1973Man]

This being said I need to work on the tuning of the quadzilla adrenaline. 

Edited October 4, 2016 by Me78569

[Me78569]

The canbus tuning max for 0-5 psi has been raised to %115 rather than 105%.  this should allow more fuel at cruise, which should lower TPS input and raise timing.   From the images I posted before the OEM timing map appears to have an high spot in the %15-%25 load range.    This is ECM load and not Quad Load.  Mike it might be handy for you to play with your tuning while watching load on your OBDlink and see when at cruise, looking for high mpg, try and figure out how to use the canbus tuning to get ECM load% in the middle of that timing high spot.

 

This island is pretty small so it wouldn't take much to make your truck start sucking fuel, as we figured out with the first tunes.  

 

I have been watching timing when driving a lot more carefully now that I am all but sure the numbers are right.   The ecm does a pretty good job of adding and pulling timing when the situation calls for it.  One big thing I have noticed, which I find very interesting, is that during normal city driving and short highway trips you will never see more than 16- 17 * timing from the ecm unless revs come above ~2200. HOWEVER if you are driving down the road for ~10 minutes at a speed greater than ~45 timing jumps from 16* to 18-19*.   I posted some info before in regards to this strange behavior, but it appears that there is a timing map that is only used when the ecm code senses that throttle input hasn't changed significantly in a long period of time.    It also does this at idle state if the ecm senses that you have been idle for too long.  I dunno if this is intenetional or just an effect of the code in place to try and get good MPG when at cruise.  

 

Since the Quad allows you to add timing based upon user input this is VERY critical to remember.  If you are trying to tune for MPG and you aren't doing longer runs on the highway you run the risk of adding to much timing for longer trips.   The ECM will add ~2*-4* of timing on it's own to cruise state once a longer period of time goes by.

 

The timing scaling is also a tricky thing to understand.  When you input a max timing value you can't expect to see a huge jump in timing while at cruise.    The max timing number just tells the quad at the top of the timing map add this much over stock.  At cruise you might only be getting %15-%25 of that timing.  

 

I did do some code to show OEM timing when on lvl0 and oem+quad when lvl1+ so you can compare how much timing the quad is actually adding overall.  Keep in mind the OEM timing is VERY dynamic, just a few % pedal articulation can cause timing ot drop by 3* or 4*

 

 

 

Hopefully this info is interesting to some haha.   I plan on doing a good bit of driving on lvl0 to get a better idea of the oem timing outputs from the ECM, because there has to be a better way to effectively custom tune timing...theres aways a better way