It works so far using MAP as a boost reference. Now we're modifying it to work with MAF. Might release it in beta form towards the end of next week. The purpose of this boost control upgrade is to target on MAF values, not just arbitrary boost numbers. This means that the system will "zero in" on the same airflow/hp regardless of temp and baro which means no longer having to make slight boost adjustments when atmospheric conditions swing wildly. Once stable and tested, the closed loop logic wil be employed on closed loop autotuning via wideband.

Cheers,
shiv

 

Why wouldn't you use a MAP sensor for closed loop control? It seems like this would be a lot easier and more accurate. I would like to be able enter a value (say 23 psi) and have the controller try and maintain this value through the use of the solenoid. Basically, make the XEDE a PID controller.

I understand what you are doing w/ the MAF, but by using a MAP sensor I think that it would accomplish the same thing, but make it alot easier for users to setup there boost control.

 

MAP referencing is always an option. It would just require the purchase of an external 3 bar MAP sensor. The signal wire would feed into MAPin on the XEDE (it is currently be fed by the factory 1 Bar map sensor).

I've always had a jonesin' for MAF referencing since it had not been done before. I've always felt that it is the best determinant for load (since that is what we are trying to control at the end of the day). MAP is 1 step further away, in terms of accuracy, IMHO.

But we can certainly provide both options and see which one works best and is easiest to set up

Shiv

 

This is good news! I already have a Kavilco 3.5 sensor from the Zeitronix and wideband hooked up...can't wait

 

Yea!

 

OK, I'm openly admitting that as of late, I am very interested in the Xede... there will be a lot of crow to be eaten.

 

Why is that?

shiv

 

I've never been a fan of "piggyback" systems... However, I find what has been accomplished with the Xede since it's inception most impressive. I've not spoke highly of the option in the passed.

 

That's it. No soup for you.

j/k

 

So, is the tuning done the same as before? Just enter in the desired boost value, tune, and thats it? You do not to need "the closed loop logic wil be employed on closed loop autotuning via wideband" do you?

 

With respect to CL boost control, all you will do is imput a boost/maf target in a table (RPMxLoad). There will also be an authority range value that you input. This gives the CL system an allowable range for it to work in. Then you run the car and the software does the rest.

The CL wideband autotuning feature will work very similarily. Except, you will be inputting the desired AFR (either in A/F number or 02 sensor voltage).

Does this answer your question?

Shiv

 

Booyah! Now you're cooking with fire.

Sorry for the silly question here, but MAF measures _volume_ of air, not actually mass, correct?

EDIT: nevermind, i'm being retarded. it's adjusted for density, duh!

d

 

I guess what I'm asking is, when you come to Dyno4mance again, and if the the CL boost control is ready, you can tune my car with this feature and I will never have to worry about boost again? (IE: winter boost vs summer) I guess the "autotune" feature is there for anyone that wants to use it, but not necssary?

Thanks!

 

If I've gotten everything straight in my head, [Auto]tuning would have be done (still) with a laptop and wideband attached. Your CAS, knock, and maf tables would still be static (albeit autogenerated). It's the boost level that would then be self adjusting.

It's not an overwhelming improvement, but it's very nice to people who live in crazy climates. Chicago can vary by 50+ degrees in just a few days.

d

 

SAAB uses MAF and this technique works very well.