Let talk mpg and how timing vs fuel helps

[Me78569]

So while Mike is happy with the power of the quad he is struggling to get good mpg out of the unit, unlike Tyler and myself.  Bothersome because we didn't even have to try it just came with the lack of smoke.

 

I think Tyler did 21 on his first try with his firehouse injectors and I did 24.7 without trying with my 100's

 

Mike however is struggling to hit 20.

 

We are all running the same timing map, but different tuning on the canbus fueling.

 

I am however down at nearly sea level now running Mike's tune and I am smoke free so I know Mike's tune is WAY under fueled since he has 50's.  I am betting Mike has get away with a starting point of 98 or even 100 rather than the 93 he has with his current tune.

 

Watching the timing number I can see what I get high timing at high revs and low throttle / load.  

 

At 1500 rpm 55 mph and flat ground low tps you can easily see 22 or 23*  as soon as you increase throttle to 25-30% timing drops like a rock to 14-16*.

 

Once revs get up above 2200 then timing starts getting high again.

 

 

So what makes for good mpg, I have never bothered to look or research but I am assuming we are dealing with timing advancement before TDC?  Am I off on this thinking?

 

My current thinking is since Mike is under fueled due to the low canbus tuning he is having to us significantly more tps which is dropping the timing.

 

 

So any thoughts on this?  I am assuming that Mike's issue is the under fueled tune causing him to need higher tps at cruising causing the oem map to retard.

 

 

[Wild and Free]

I have said this for many years and having been a heavy diesel tech my entire career and worked on back to back serial number fleets of equipment be it 200hp ag tractors to 2400 hp mine trucks in the exact same operating conditions running side by side every piece of iron has a personality to it as different as 2 people born in rooms next to one another in a hospital. No matter what is done there will never be exact consistency. Live with it and be happy.

Edited September 25, 2016 by Wild and Free

[TFaoro]

4 hours ago, Me78569 said:

So what makes for good mpg, I have never bothered to look or research but I am assuming we are dealing with timing advancement before TDC?  Am I off on this thinking?

You're correct on this thinking, but I'm surprised the timing is actually that high. My brother's CR is sitting at around 8* for the "fuel mileage" area. I wonder where mine is sitting for cruising... maybe you should help Mike see his timing so he can compare it to yours. 

 

Note: This is an old map.....

 

Edited September 25, 2016 by TFaoro

[Mopar1973Man]

I've got to drag the RV back from Walla Walla, WA. So far roughly watching the fuel gauge and odometer. 17.5 gallons at half and and travelling roughly 170 to 180 miles this is the lowest since I left the Edge Comp.

[Me78569]

11 hours ago, Wild and Free said:

I have said this for many years and having been a heavy diesel tech my entire career and worked on back to back serial number fleets of equipment be it 200hp ag tractors to 2400 hp mine trucks in the exact same operating conditions running side by side every piece of iron has a personality to it as different as 2 people born in rooms next to one another in a hospital. No matter what is done there will never be exact consistency. Live with it and be happy.

 

There is a tuning issue here, the truck doesn't lose %25 fuel economy because it is feeling bad.

 

Not saying you aren't right but there is more to it.

 

 

Tyler 

 

So in theory mor timing advancement at low load makes better mpg, correct?

 

I am gonna talk with Spencer about opening up timing.  It is very helpful to see when tuning.

 

Our trucks seem to sit between 14* and 24* Durning normal operation.  This is of course assuming the timing is displayed how I think it is.... Ugh

[AH64ID]

Yes typically more timing at low load is needed for fuel economy but there are other factors. A stock 05 runs more cruise timing than a stock 03 but the 03 burns less fuel. 

 

Does the ECM report engine load? That can help determine what part of the timing map it's in. 

 

I assume Michael is hand calcing the numbers and not using the OBD data?? 

Edited September 25, 2016 by AH64ID

[Mopar1973Man]

 Right now just odometer vs fuel gauge need  second fill I verify my calibration on the OBDLink.

Edited September 25, 2016 by Mopar1973Man

[AH64ID]

Then I would get some real numbers before going too far with troubleshooting. 

[Me78569]

I am digging deeper into the code for the timing stuff.  It appears that the timing doesn't work as they say it does so the timing advancement was not as great with the latest tune. 

 

As for engine load I have no idea if the ecm repors it.  the pcm reports it, but who knows how that number is calculated or where it comes from.  

 

 

I am still sorting out the code, but I think we are making progress.   Mike,  you said the last tune was "better" corect?  So at least we are working in the right direction?

[Mopar1973Man]

Find out when I get fuel today I'm Lewiston, ID. Gauge vs. Odometer appears better like closer to 90 miles for quarter tank. Quarter tank is 8.75 gallons. Compared to 65 miles in quarter with the previous tune.

[Me78569]

Good that means we are heading in the right direction.

 

With the tuning you really should have your starting point as high as possible while keeping smoke at a good level.  If that starting point is too low you will be using much more TPS input to go down the road and lower timing.  

 

The tune you are running now has timing scaling set to %30, which would also hurt MPG....now that I read through the code.  You should custom tune what I PM'd you with timing scaling at %100 to allow full timing advancement.

 

 

[TFaoro]

1 hour ago, AH64ID said:

Yes typically more timing at low load is needed for fuel economy but there are other factors. A stock 05 runs more cruise timing than a stock 03 but the 03 burns less fuel. 

 

Does the ECM report engine load? That can help determine what part of the timing map it's in. 

 

I assume Michael is hand calcing the numbers and not using the OBD data?? 

Very good point. Timing is good to an extent, but too much is a no no. 

 

Now the question is what parameters does the ecm actually use to pin-point the timing it wants. 

 

23 minutes ago, Me78569 said:

Good that means we are heading in the right direction.

 

With the tuning you really should have your starting point as high as possible while keeping smoke at a good level.  If that starting point is too low you will be using much more TPS input to go down the road and lower timing.  

 

The tune you are running now has timing scaling set to %30, which would also hurt MPG....now that I read through the code.  You should custom tune what I PM'd you with timing scaling at %100 to allow full timing advancement.

 

 

My best mileage with these injectors was 8* 100%

I have run all the way up to 14* and 100% though it might be a bit high. 

 

 

Nick, I'm going to spew some information from the UDC pro files for a 2002 manual. 

 

Inj timing MAX: 13.95*

 

Inj timing max rpm & overspeed: 0*

 

Inj timing max advance at low rpm: 10*

 

Inj timing max advance at high rpm: 20*

 

Inj timing min at any rpm: 3*

 

Inj timing transient: 

 

 

Inj timing steady state: 

 

 

Inj timing boost adjust:

 

 

Inj timing ect adjust:

 

Edited September 25, 2016 by TFaoro

[Me78569]

Very interesting.  

[leathermaneod]

This doesn't apply to the quad, buts it's something I always wondered about. I always got better mpgs with the Smarty than I do with the edge comp. smarty would get me almost 22 on the highway, where I don't think I've ever broken 19 with the edge. Just something odd ive noticed. I don't know enough about how either of them fuel to know why this is, other than the the smarty fully re writes the ECM and the edge doesn't. Sorry is this isn't relevant, just seemed like a good spot lol

[Me78569]

as a side note tyler.  Timing scaling is reversed what I thought it meant, if you have %100 then you get the full timing if you have 20 then you get %20 of the timing.  

[TFaoro]

37 minutes ago, Me78569 said:

as a side note tyler.  Timing scaling is reversed what I thought it meant, if you have %100 then you get the full timing if you have 20 then you get %20 of the timing.  

Okay, he definitely needs 100% then. If he was at 30% and 8 deg, he was likely sitting at a 2.6* increase. 

Given the tables above that would put him around 5 or 6* of timing. If that's bumped up to around 10 I bet he'll see a significant improvement. 

[Me78569]

Those numbers seem very low for overall timing.

 

Do our trucks retard timing after TDC?  From what I have read from various places the vp44 uses a timing range from about 8*- 30*.

 

The timing value I see is right in that range.

 

Idle timing when warm is 16*

When cold 24*

 

 

Are the numbers that I am seeing way off?

[AH64ID]

Wow, that seems like a lot of idle timing. 

 

I don't like pushing much over 20° of timing to a stock head bolts so 30° of stock timing seems very advanced, but maybe I am being overly cautious.

 

What are you seeing at 1500 rpms and 30% load?

 

Edited September 25, 2016 by AH64ID

[TFaoro]

I'm with @AH64ID here... those numbers seem crazy high, especially after looking at the maps. I'm not even seeing those numbers called for anywhere. 

 

On a side note, I don't really see 20* as super high, but the two that I work on are studded. My brother's was at 29* of timing simply to try and keep the spray from happening ATDC. Now with 100%s I have his much lower. 

[AH64ID]

Yes with studs it's much safer to go higher. 

 

Even with my duration lower than stock I would need to have my timing at 30° and 3000 rpms for that to happen (or 20° at 2000), not to mention I think it would be lost power having all the fuel injected BTDC. I don't like to go much more than 50-55% BTDC to keep negative torque down (Fuel combustion BTDC). IIRC peak pressure at 12-15° ATDC is best for power.