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      09-23-2010, 08:55 PM   #1
shiv@vishnu
 
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Drives: PROcede v5
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Smile Procede User Software v4.20 (now with Adjustable "Smoothness")

Hi guys,
There has been a lot of discussion as to subjective "smoothness" when it comes to different tunes. But what most people are feeling is the relationship between applied throttle angle (your right foot) and boost onset (the moment at which the engine transitions from off boost to on boost operation). As well as the applied throttle angle that full boost is demanded.


The Stock Tune
Generally speaking, with the factory n54/n55 tune, boost is not requested until applied throttle goes beyond 40-50%. Which means that the first half of the throttle pedal, the engine feels like a naturally aspirated lowish compression 3.0l engine. Nothing very inspiring. But easy enough to drive smoothly for those with heavy boots or heavy feet.

Beyond 40-50%, the DME starts to reqest boost. The more throttle, the more boost demand. But by 80-90% throttle, the factory tune requests full boost. Which means that the last 10-20% of throttle doesn't do anything. But with only 6-8psi of boost to play with, this delayed boost onset (40-50% throttle) and nonlinear boost demand ramp up isn't particularly bothersome or noticeable. In fact, most may find the on/off boost transitions exciting. And the fact that full power is available before full throttle, the tune gives the impression that the engine is more powerful than it really is.

For cars equipped with a Sport button (n55), the applied TSP boost onset point is bumped up from the standard 40-50% to 30-40%. A small change. But enough to make the engine feel more "eager" and willing to respond. And with full boost is requested at an earlier 70-80% applied throttle, the driver experiences full power at a lower applied throttle angle. The end result is a car that is not only more eager to respond to throttle input but one that also feels more powerful. Despite offering no more power at full throttle.



Procede v4
Given the it's unique abilities to integrated with the factory DME via the CAN bus and to drive the solenoids directly, the Procede can literally re-write the rules on throttle/boost relationships. Unlike other piggybacks, it is not influenced by throttle/boost nonlinearities in the factory mapping. This means it does not scale up this nonlinearities as it scales up boost target. And unlike what seems to be the case with reflashes (and of course other piggybacks as well), the Procede also rewrites the boost control algorthims (namely Proportional, Integral and Derivitive corrections) to be more suitable and effective in high boost applications. Which is why it controls 20psi applications just as effectively as it controls 10psi applications. With virtually no sizeable positive boost errors that would otherwise result in unwanted throttle closure/oscillations. Especially at partial throttle which is where most of us drive on a daily basis.

In re-writing the throttle/boost relationship, we made it a point of spreading the no-boost and full-boost demand points over a wide-as-possible range. This meant we wanted boost onset to come at an early 15-20% (depending on RPM) with full boost not being demanded until 100% throttle. This gave us an 80-85% range at which to "spread out" the boost demand. And since most of our customers run at 12-20psi of boost pressure, spreading this range out of a wide range of applied throttle makes power easier to modulate and more controllable. At high power levels, there is no reason to add any nonlinearities to make the car feel even more "eager" or powerful as it would just make the power harder to modulate.

New Update:
Taking things a bit further, we now give the user the ability to adjust the boost onset point. So instead of having boost target start its upwards ramp at the usual 15-20% applied throttle, the user can make it so that boost onset occurs much later. The advantage of this is that some users will find it nice to have more throttle to play with before boost is demanded. This will make a car feel "SMOOTHER" since the Procede will be less sensitive to what your right foot is doing at the beginning of the throttle range. The downside is that once the boost onset threshold is crossed, there is less range to "spread out" the boost demand. Of course, different users, with different applications, will have different ideal settings.

From what I've found/heard, users with 6ATs or 7DTCs will find running a more delayed boost onset point will find that it's easier to drive the car smoothly since since they are less "in control" of their cars. While us old school 6MT guys like the standard early boost onset since we are in full control of how our car accelerates (ie, gear selection).

So what we did is add a new User Adjustable entry called "Boost Reponse" (see attached pic). This is adjustable from 0 to 100%. 100% is standard v4 mapping. Which means boost onset will start early in the applied throttle range (15-20%). With this setting, the car will be very responsive and predictable to the throttle. Something that has always been the trademark of Procede v4.

Decreasing this value will delay the boost onset point. Setting it to 50% will make the throttle point for boost onset increase to 40-45%. And from that point onwards (to 100%), boost demand will increase linearly.

And decreasing this value all the way to 0% will delay boost onset to 60-70% throttle. And from that point onwards (to 100%) boost demand will increase linearly.

So What Does This All Mean?
-If you love the way v4 drives, don't make any changes. Objectively speaking, this is ideal as it follows the orders of your right foot perfectly.

-If you want a more "re-flash" like throttle/boost relationship (more responsive during the first half of the throttle pedal travel and more responsive during the second half of travel), then set this value to say, 50%. It will have all the perceived "smoothness" of a reflash but with ALL the on-tap power, boost targeting accuracy and throttle control of the Procede v4. This setting may be nice for those with heavy right foots, 6AT or 7DCT transmissions.

-If you want something that feels stock like until you put your foot closer to the floor, set this value to 0

The nice thing is that none of these setting will change power output at WOT. Or will even effect your 1/4 mile performance. But it will give you vastly different subjective driving experiences.

And we have made it so that you can adjust each map independently. So, in essense, you can make map1 a smoother, less responsive map (by lowering throttle response) and map2 more responsive (by leaving throttle response at 100%). And just change them on-the-fly depending on what you need/want

The new firware update (#29) and User Software (v4.20) will be posted up tomorrow.

cheers,
shiv

Last edited by shiv@vishnu; 09-23-2010 at 09:02 PM.
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