Please see the attached file for a 2011 Mustang V6 3.7L with Procharger. We are trying to retard the timing without success. Can you advise us what is the main spark table to reduce timing
We have a lots of tables for MBT Spark and Borderline spark, what mean every table because teh borderline has a 13 tables
procharger.png
You need to datalog Map 0-14 and OP in order to see their weights, once you know their weights you will know where to adjust. It's normally always Borderline tables, not MBT.Originally Posted by ammar.alqisi
Happy tuning
How i can datalog the map from 0 to 14 ?
And if i changed the tables from 0 to 14 , the timming will be changed ??
The Borderline tables is the starting lookup table and the MBT tables are max timing caps. So borderline is used to calculate total timing, but it will never be greater than MBT.
You need to log which mapped point the engine is running in. You need to list all Mapped Point channels in the scanner to see which ones are used for the running condition you are in. It is likely you will need to modify 3 or 4 of the Borderline and MBT tables
The MBT is not a maximum or cap that spark cant get greater than. Refer to MP2 in loads less than 0.35 on a 2015 mustang gt. The eco boost have areas between .6 and .8 load where borderline is greater than MBT.
MBT is the spark value that the engine would produce the most torque with the most efficiency, IF the fuel did not knock first. Most people confuse the borderline and MBT as they think they can find MBT on a dyno when really they are finding the borderline of knock. MBT takes into account the effect the explosion pressure has on the pistons force as its still traveling up and the engines maximum torque. There will be a point where cylinder pressure has a power robbing effect on the piston still traveling up. Most fuels will knock before this point at WOT. At part throttle Its easier to get to MBT as cylinder pressures are not as high and knock is much less likely. Its easy to have too much spark advance at low loads and not have knock. Higher then MBT spark does help with fuel economy and engine responsiveness in the low load areas.
The torque model uses the MBT spark values to give a maximum torque value the engine could be making. This value is compared to what the engine is actually making and whats requested by the driver. depending on where these values are the ECU can determine an appropriate action. This is also used to determine engine load and compared in a similar way to make sure The engine is not over performing or under performing.
You also need to datalog "spark source" to see where it is obtaining the spark values in whatever conditions you're trying to work with.
A quick way to limit spark is to change the Cylinder Pressure Limit table also. It will also limit your spark and let you figure out about where things need to be so you don't have the change almost every entry of the Borderline tables more than once. I, for example, don't have any boosted V6 Mustang experience so instead of guessing what to put in Borderline then bumping them all up over and over I would just cap spark at the Cylinder Pressure Limit then see what the knock sensors are doing to get an idea of what to put in all the Borderline tables. From there I would bump up Cylinder Pressure Limit and go set all the Borderline tables and fine tune based on logging Mapped Points from there.
You can leave that Cylinder Pressure Limit table to cap spark too
Murf, thanks for that explanation!
Say you have an NA car which you switched to E85. You can log knock sensor to determine how much timing you can add to the borderline tables (BL), so should the spark difference between the stock BL table and the new E85 BL table be added to the MBT table to create a new E85 MBT table?
Finding the true MBT value after switching to E85 you would need to measure the cylinder pressure and calculate the flame acceleration rate. MBT would then be when acceleration rate is at its peak at TDC. We don't have a way of logging cylinder pressure. We can make an educated guess based on certain properties of E85. E85 burns slower than 93 so MBT will be more advanced. E85 would be more knock resistant so RPM/load where you could run MBT timing or more would be greater. In the areas you are limited by knock the MBT value would be closer to the borderline than 93 because of its higher octane rating.
So on a dyno you could find MBT spark in the low load/RPM area by watching the torque value. You could then find the borderline in the knock limited areas. From there it would be a guess to how to modify the MBT tables, but usually not more than 1-4* higher than where it knocks as E85 is a high octane fuel.
Has anyone noticed that some of the spark advanced values logged don't match what is in the borderline/mbt spark tables? As an example, I would log a spark advance of 12.5@2000 RPM at a load of 98% with a KR of -1. My scanner would indicate 100% for an MP21. I would open up MP21 for borderline and MBT and it would show 6 and 20 values for that RPM and load respectively. MY KR advance was set to 10 for everything. I’m thinking that maybe the scanner is showing the wrong MP percentages? Anyone else notice this? Maybe the ECU knows it can only add 6 degrees of advance there instead of the full 10? Just trying to figure out how the ECU figures that out.
I have made all the borderline MP tables from 14-26 all the same to make it easier to dial in the spark I want. I was just curious as to how it actually works though.
There are multiple modifiers to the borderline knock tables you have to take into account. Iat, ect lambda etc.
I guess there is no way to know for sure then or figure out why the spark advance number is what it is.
I gave up trying to find a direct correlation. To increase spark, I'd just add X degrees to the cells in each of the mapped point Borderline Knock Tables. But first, log Spark Source to ensure you're on the BKT when at WOT. I noticed my SHO was using Base as the spark source until I made a few changes.
what were the changes? I find my car sitting in "base" often and dropping spark without knock.
I was thinking Base was just when spark was being limited by MBT but could be wrong.
Id have to go thru my notes. It had to do with a few of the spark tables like cyl pressure limit. I think the latest published guide shows what tables I changed under the spark tab.
Base will be used when one of the tables under spark correction section has a larger effect on borderline value than knock advance/retard. I think it is used as a "catch all" to include cylinder to cylinder offset. The other areas will show their own correct source.
I couldn't control spark at WOT with base as the spark source. And that was how the SHO was set up from the factory. Then again the SHO was the oddball EcoBoost in terms of stock spark. It would ask for 11 to 12 degrees at WOT stock, and MBT was about 35 degrees WOT. The F150 has single digit WOT spark with MBT around 20 to 25 degrees.
My 3.7 mustang goes to base at WOT. I used the tuning school's method for getting the spark to do as commanded, and it does exactly what i tell it. There might be a quarter, to one degree discrepancy, but I just think that's in the scanner, it's like it's a cell behind at times. I haven't logged at high polling intervals and minimum PID's to verify. My car doesn't seem to be taking any spark (we're talking like boosted 5.0 timing here) I need to get under the car and look for any signs of exhaust contact. I will need to see what the spark source was prior to me formatting the tune this way.
The scanner does lag behind. I have a fast laptop with RAID 0 SSDs and if I log to many parameters I see things like MP12 80% and MP8 60% reported at the same time. It's most noticeable when I'm tuning an Ecoboost and logging all different things. I have been planning on creating a few different channel configs for them for a while but just never have gotten around to it.
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