Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

HP Tuners - Max Load at HDFX Points

Practical Reflash Tuning

Forum Posts



Tech Articles

Discussion and questions related to the course Practical Reflash Tuning

= Resolved threads



The tables I am talking about are located here: Airflow -> Speed Density -> Maximum Load

I am on a Focus ST, but these tables should apply to all EcoBoosts :) Are these limiters? Feed forward tables to estimate load?

I currently work in the COBB software and these same tables are referred to as Max. Load at WOT and Closed WG" Under "Load Tables" I assume the "Closed WG" refers to the "WGDC Max (Closed WG)" value - so it SEEMS like this means these tables show the max load that should occur under these HDFX VCT conditions with the WGDC at or above this 'closed max' value.

I am hitting loads higher than these values at peak TQ where only HDFX 14 is being used at 100% so these do not seem to be limiters. My question is - what are these tables for? What are they doing or used for?

Thank you!

Attached Files

I don't have a direct answer for you but I have a few things to consider to help understand what those limits do. If you set all the HDFX maximum load values the same in all the tables (set every cell in every table to "1" or maybe 0, or maybe 9999 or whatever), does it do anything? Basically, deactivate the limit and see what happens (BE CAREFUL, watch knock and AFR)

When actual load exceeds the HDFX maximum load values, is HDFX now ignored? Meaning, is it switching to some other kind of calculation and changing the HDFX table has no effect on air mass related calculations?

Hi Raymond!

I will give that a shot, probably just set them all to 1. The description in either HP Tuners or COBB AT is not helping lol, it mentions in COBB you can use a 3D limit table (LSPI) by setting all those Max Load HDFX tables high since it will always use the lowest load limit value - but in my case I have all the Max Load HDFX tables stock and my LSPI is at 2.5 across the board above 3000RPM and stock below that RPM. This leaves the Max Load HDFX tables the lowest values, but LSPI seems to be the real limit that comes in to take action.

It was cold enough this weekend to actually trigger a throttle closure as boost was coming on since Load Actual went above the LSPI Load limit for a second at ~2700RPM. That it more indication that the LSPI is the true limiter. The Load Max HDFX tables seem to come across in logs as "Load Max Ach. – The maximum achievable load under current conditions."

It is strange as these tables seem to indicate they are limiters but they do not act like it - I will set them to 1 across the board and see what happens. All my other limiters are at 2.5 so it should indicate if these do ever come in and limit load. I will watch fuel trims under this condition too to see if making the HDFX load values completely wrong has any affect on fuel calculations - if these things are references for load and used for some sort of fuel calc, I want to know :) (which I am thinking they may be, otherwise what would be the point of using HDFX to define them...maybe..spark??)

As we have discussed before, I am trying to put some of that OEM saftey logic back into the tune, as the base map (COBB) I started with basically removes all limiters. I am especially interested in load limits since I am seeing quite a large dip in fuel pressure at peak TQ on E30 fuel, which has been really showing up as the weather cools off... If it were to get cold enough and the air dense enough it is looking like I could have a fueling issue if I dont limit it.

Thanks - I will report back with what this experiment yields.

Well, I have taken some data and just trying to go through it. I sampled the following:

**Adjusted all Maximum Load HDFX Tables to 1.2 - no effect on load actually produced by the car, the parameter for max load achievable and max load HDFX did reduce however - they just did not seem to limit anything

**Same as above but defined max WGDC to 40% instead of 95% - same results, actual load and WGDC unaffected

**Adjusted LSPI Load limits to 1.2 - this one actually did use the throttle blade to limit load

I still have to study the data some more but I did not see any trends or changes in fuel trims or anything with any of these changes.

I also need to check around and see if perhaps there is a switch somewhere that is toggled that is telling the computer to ignore the HDFX load max entirely as a load limit. I suspect this may be the case as I logged the same parameter list on my tune as well as a well known e-tuner's map I purchased before I started doing this myself. The HDFX load under WOT on that e-tuners map stays stead at 1.6, WAY below even stock max loads the car would produce. I am now thinking this is either disabled as a load limit in the software OR that is a load limit only at part throttle. I plan to increase the threshold for power demand to 90% and test again at part throttle to see if it will then use that as a load limit.

I will report back! :)

So far this does not seem to impact fueling however which was my main concern with it being left inaccurate.

I did also see an issue I have not run across, likley because it is colder out now - my TIP Actual is spiking (and holding for 1k RPM or so) above TIP Desired. WGDC stays flat through this area and the car just closes the throttle partly until TIP Actual reduces below TIP Desired. I am going to have to play with my WGDC comp tables to correct this! In the summer my Actual never went above desired with these same settings - horray for boost weather!!

Sounds like the limit is deactivated, but you may not have access to the tables needed to change that.

Sounds like the limit is deactivated, but you may not have access to the tables needed to change that.

The COBB Custom Features have a slot (1-5) defined load limit as well, this is new, non OEM code that I am wondering may be overriding the factory HDFX load. What is strange is that on the HDFX Max Load tables there is no comment on them being deactivated, or what they do - just a note that the values should be set to be as close to real world max's under optimal conditions (see the pic from my first post for the description right out of the software).

I wish I had an HP Tuners device so that I could load up a tune from that software to see how it reacts... Might have to just get one someday to be able to try both...and learn to tune in both software environments. :)

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?