Let talk mpg and how timing vs fuel helps

[TFaoro]

7 hours ago, Mopar1973Man said:

So basically you cannot tune to be smoke free and have MPG at the same time really. Your cruise boost pressure needs to be high in the 100's percent range to get the MPG up.

This is 100% false when you're talking in general. Maybe for your truck, but on mine I started in the high 60's and was in the mid 70's for cruising boost.

 

I like Nick's idea of leaving the cruising number alone while tuning down the low boost to stop smoke.  

 

7 hours ago, AH64ID said:

Light fuel will be higher timing because it's harder to ignite a small amount of fuel so it needs more timing to do so. 

 

If you injected WOT fuel like you did cruise fuel you would be down on power and up on cylinder pressure BTDC. 

 

Seems weird to do most the tuning off of boost. There is a boost fuel limit table for HPCR's but it's just max fuel and not how much fuel is delivered under normal circumstances. 

Our proplem here is we don't have as much control over fuel as you do. With the different maps you can tune for very high hp and very low smoke using the different variables. The set limits for yours are awesome too because you can cut the smoke through a limiter. Without writing a complex program to take everything into account we might have to work with what we've got. 

[Me78569]

8 hours ago, Mopar1973Man said:

I would have to say that is more likely due to less rolling resistance and the rotational mass is maybe down just a few pounds per tire.

Less mass and better highway tread means less tps to keep moving, you would be surpised how fast timing drops off with just a few % tps increase over 22 or 23

 

Last fill for me was 15.56 mpg which isn't bad at all considering we were driving in glacier national park all day.  Very steep and 25/35 mph speed limits, stop and go.

 

 

I have been mulling over the timing stuff.    I am going to change the timing map to use load rather than boost.  So it will be load vs rpm.  This will allow me to create an island for a few more % of timing at cruise.  I still don't know how to allow for "custom" timing like we do canbus.

 

[Mopar1973Man]

Just in the quick tune I created for my truck I'm back to 22 MPG (Uncalibrated) on the OBDLink. So far this is the best number so far I've seen from the Quadzilla. Like on my way home tonight from work I passed one semi-truck and it pulled like a scalded ape. Excellent power. As of the OBDLink it a rule of thumb for now till I can get through the calibration process.

[Me78569]

Curious to see what you hand calculate.

 

 

Any smoke off idle starting at 100?  Or is smoke only in wiretap range?

 

 

[Mopar1973Man]

Modified to 1-5 positions to 105%. No smoke really launching and driving normally. Since my last tank is a fill I can math out a number to verify. Also I got hired by "4 Elements Waterproofing". So I'll be driving back and forth to Homedale, ID to do a high school roof so I'll get plenty of time to check out the tune and how it does. I'll be doing rubber roof coating on a high school.

[Me78569]

Good to hear that you are still smoke free starting at 100.  I really under shot your first tunes lol.

 

 

[TFaoro]

1 minute ago, Me78569 said:

Good to hear that you are still smoke free starting at 100.  I really under shot your first tunes lol.

 

 

I think you were too used to playing with the firehose injectors  

[Me78569]

Hey my starting point is 84 right now.

 

 

However the altitude is HUGE in terms of how much fuel you can throw at it.  I was running a smoke free 94 starting point down here at 2000'

 

Curious part is my mpg didn't suffer between my 84 starting point and 94 starting point.

Edited September 28, 2016 by Me78569

[Me78569]

Another leg done going through yellow stone 15.4 mpg.

 

Headed home today so it should be all highway, we will see if I care to do 55 or if I end up wanting to get home faster..

 

I am going to be curious how my truck does with the new tires and no camper.  

[Mopar1973Man]

Last tank hand calced is 11.5 MPG. OBDLink is close to that number as well at the time of fill. Mostly towing the RV around on that tank.

 

243 miles / 21.119 gallons = 11.50 MPG.

[Me78569]

@AH64ID

 

Or anyone else.  

 

Do we know how cummins calculates engine load?  

 

[TFaoro]

2 hours ago, Me78569 said:

@AH64ID

 

Or anyone else.  

 

Do we know how cummins calculates engine load?  

 

Good question.... what are you wanting to do with load or parameters? 

[Me78569]

trying to understand if we can even use load as a tuning variable or not.  

 

Does Cummins calc load based upon what is possible via canbus ( 235 + 65 hp) or will it take into account wiretap fuel.  

 

Edited October 1, 2016 by Me78569

[TFaoro]

7 minutes ago, Me78569 said:

trying to understand if we can even use load as a tuning variable or not.  

 

Does Cummins calc load based upon what is possible via canbus ( 235 + 65 hp) or will it take into account wiretap fuel.  

 

Way I see it there's no way for it to take wiretap fueling into the load calc directly. It's just holding a solenoid open. It may inadvertently do it through boost and other things though.

 

I do think it is a viable tuning variable though, especially since what we are trying to improve most is the spool and cruising timing. 

[Me78569]

Well the Quad doesn't calc load in the same manner as the ecm.

 

idle load on the quad = %9 idle load from ECM = %1 according to obdlink program. That doesn't actually mean the obdlink program knows how to decode a load value from the ecm, but something is up. 

 

Way I see it we are going to struggle to tune using the quad right now as it doesn't match the ecm.  That is why the map is using boost since there is a full range.  

 

I might be able to find what the PID is for load via canbus.....maybe.... I wish I had some documents for the protocol.

[TFaoro]

6 minutes ago, Me78569 said:

Well the Quad doesn't calc load in the same manner as the ecm.

 

idle load on the quad = %9 idle load from ECM = %1 according to obdlink program. That doesn't actually mean the obdlink program knows how to decode a load value from the ecm, but something is up. 

 

Way I see it we are going to struggle to tune using the quad right now as it doesn't match the ecm.  That is why the map is using boost since there is a full range.  

 

I might be able to find what the PID is for load via canbus.....maybe.... I wish I had some documents for the protocol.

Might have to throw out the ECM's timing all together and use the quad alone with the data it has to build a map. 

 

Is that possible? I know you guys say it has a "good" map already, but in reality it does not for every setup. 

Edited October 1, 2016 by TFaoro

[Me78569]

I dunno map the ecm does some pretty nifty stuff.  

[TFaoro]

6 minutes ago, Me78569 said:

I dunno map the ecm does some pretty nifty stuff.  

Well.... what do you think is a good starting point? 

Edited October 1, 2016 by TFaoro

[Me78569]

Starting point is always the hardest to find haha.  

 

 

 

[CSM]

4 hours ago, Me78569 said:

Starting point is always the hardest to find haha.  

 

 

 

 

12 valve static timing as a jump off point?