So say you are in one of these middle load cells and you want to richen up the mixture and retard the timing a little. So you increase the amount of air that the ECU is seeing. But that increase in air doesn't just increase the fuel injector duty cycle. It also can affect what timing and fuel load cell you are in. So the increased MAF signal bumps you up in the factory ECU's load cell map. And that load cell could have a completely different fuel map than the one that the xede thinks it is pointing to. Perhaps it is leaner than the original load cell. So then you have to up the MAF signal even more to compensate and hope that doesn't bump you up to yet another load cell. More likely, though, the new load cell is richer than the lower one, which results in too much fuel being injected for the given airflow. And if you bump down the MAF signal, how do you know you don't end up returning to the original load cell. Ugh!

And the new load cell could also have a completely different timing value, which you are building upon with the xede, not replacing.

It just feels like you probably end up chasing your tail quite a bit trying to get everything to work well. Especially if you are really trying to fine-tune the car.

Also, messing with input signals to the ECU as all piggybacks do, has other problems, not the least of which is compromised datalogging ability.

Not saying that you can't get it all to work well with a load bearing dyno, but it seems like it is a royal pain. And it is why I'm not a big fan of piggybacks.

Incidentally, Shiv, if you don't have a load bearing dyno available when you go to other cities to tune cars, how do you tune them well?

 

And likewise, I and many others, would claim any engine control system that alters airflow is going to be inherently limited as well. There's only so far you can reduce the airflow signal (and the indices into the load tables) before you compress the operating range of the ECU into such a small space as to produce an overly complicated system to tune. You start having to undo the effects of the the very thing you're using to tune.

And I disagree; at least in the parts of the table we're talking about here. Let me offer another example. When you reduce the airflow signal, you not only reduce the absolute value seen by the ECU, but you also alter the rate of change seen by the ECU. Your example of having to pay particular attention to the areas where HP increases rapidly is a very good one, I think. It illustrates what I'm talking about here. The rate of change as well as the value itself as seen by the ECU has been altered. To undo the effects of that slower progression through the enrichment and timing tables, you have to tweak things in the load cells in that area via the Xede product. It's great that the Xede product provides that functionality. But I still contend that those functions aren't necessary in the first place if the airflow signal is left alone.

You and I will probably never agree 100% on this topic, I'm sure. We'll both just keep offering conjecture until we're blue in the face. But I guess that's what open discussions are all about. Hopefully we'll both walk away with a better understanding of each other's system.

Thomas Dorris

 

If I understand you right, one thing you can do would be to reflash the ECU with maps that have zero timing across the board (let the XEDE maps be the authority on timing). Then reflash the fuel maps with a fine gradient of values that's appropriate to the application. Now you don't even have to trim MAF to get the fuel you want and you have full "operating range" too, no? I think Shiv suggested a variation of this idea for people wanting a near-standalone type system with a XEDE/XFlash combination.

And yeah you still couldn't get any useful timing information from the OBD-II port but my understanding is a datalogging solution for the XEDE is forthcoming

 

Yup very soon there will be no "other system" benifits available to kling to short of a full standalone

 

I suppose something along those lines could be hacked up to work kinda like a standalone. But I might have to question why not just go standalone at that point and avoid the clutter. If you're going to take it upon yourself to tune the ECU completely out of the loop, why not just remove it?

Thomas Dorris

 

You little sneak your fast! Anyway it wasnt to inflame your product in any way Im sure its just fine and as soon as that vapor wafts my way Ill surely take a big long whiff and check it out. Im mearly stating that the "ECM wars" shouldnt be a war at all the xede got here firstist with the mostest. The link and Utec will be just fine but the growing pains of new products will need to be hashed out while the xede "and its methodologies" will have alot of track time under its belt

 

Not the expert, but I'm guessing it's the same reason you keep most of it? Knock suppression, coil charging, injector firing, etc.?

 

So Thomas, how long until "EVOLink?"
Shiv, totally sorry for bringing this up in your forum, but I couldn't resist!
Don't mean to disrespect!

 

ANr for a grand, plaus whatever the datlogger set up runs, you pay the same price to have it.