Professional Tuners & Enthusiasts: Need your input

[Nate1647545505]

Hi Folks,

 

This mainly applies to the GM crowd but other input is welcome. Do the masses see a need for documentation and potentially an instructional course on GM's new model based VCMs found on most 05+ vehicles?

 

Thanks

Nate

[boostedgtp]

Yes. Id also like a ride in a new zr1.

http://i205.photobucket.com/albums/bb291/boostedgtp/3402_image.jpg

[Brandon]

Why wouldnt we? The more information the better.

[thorne]

I don't do GM but sounds interesting.

[MrMeanGreen]

Yes, we see the difficulties already mounting with early modifying.

[DTM Brian]

The more info the better.

[Nate1647545505]

The reason I ask: The systems GM is producing are still MAF based but MAP and BARO are making up for a larger amount of calculations. There are no "look ups" involved with the E38/E67 platform - everything is calulated real time.

 

The problem I see is the math involved, mainly linear algebra. There's no good way to simplify the applied/engineering math involved. The course would be mostly a math class. Not sure how well that sits with professionals and enthusiasits.

 

Here's s a sample from MATLAB (who'd ever thought you'd actually use this program outside of college) of the response curve that's calculated by the parameters that can be configured in the PCM. The data used is 43,000 samples from an 08 vette.

 

http://img219.imageshack.us/img219/9494/deantrial1ra8.png

 

 

X axis is your RPM, Y axis is your "GMVE", or VE% and Z is MAP kPa. You can see the 30 "zones" (each zone looks like a patch on a quilt) without to much trouble.

 

The nice thing about the function thats used to calculate this data - you can use it ANYTHING with RPM and MAP values. There arer no limits, and no lack of resolution. It is a truely portable solution, whether you have 3 dimensions or 13, the math is the same.

 

<3 GM

Nate

[TurboRust]

nate tuned my lawnmower

 

ps i love you

[99ta]

what?

[Nate1647545505]

what?

 

Welcome to the new world.

[Kevin R.]

Whats with the spike?

[TurboRust]

v-tec

[Mallard]

I don't think you'll have trouble finding people to sign up for this.

[Dave1647545494]

looks like a boost spike

 

 

I'm interested in learning more

[Brandon]

I have seen/ read about something similar to this in the german car world.

 

Matlab....I hated matlab.

 

Nate, so who is offering this training?

[Mallard]

I also wanted to add that everytime you add a cam phasor you add a dimention to the graph, correct?

 

The Z06 has no cam phasor (if I remember correctly), so it's 3D. The LS3 has one cam phasor that phases intake and exhaust together, so it's 4D. The Ecotec's have a two cam phasor's and independently phases intake and exhaust cams, bringing it up to 5D! How would you deal with this?

[Jelloman4571647545499]

luck!

 

 

[Nate1647545505]

Whats with the spike?

 

What we like to call: bad science. There was very little data showing 100kPa at 500-1000RPM. Bad/No Samples leads to bad science.

 

Brandon - I could easily see the Germans using this in the Motronic platforms. Until Conforti comes out with his ODBII editor/data logger there are very few and far between tools to reverse engineer any model based DME out there. The funny thing is - of all of the car companies - Honda is still trying to do it the old fashion ways. The K20 controller has 6 "VE" tables to cover the dynamic states of VTECH and interpolation between cam phases (40 some degrees?). As far as training: you'll recognize a name or two. It's going to become a group effort as there is a vast amount of ground to cover because each platform uses a different temperature estimator, making things even more complicated. Once we have a wider sample of cars, data, and proven results; we'll make a large push to produce documentation and possibly a training class.

 

Phil - You are absolutely correct. You cannot "graph" a 5D quadratic. There won't be a visual aid at this point, but the numbers still work out. At this point, most of the tuning will become empirical. We may hope to expand that, but at the current time we're working in 3D to help bridge the gap and soften the learning curve.

[Trouble Maker]

Phil - You are absolutely correct. You cannot "graph" a 5D quadratic. There won't be a visual aid at this point, but the numbers still work out. At this point, most of the tuning will become empirical. We may hope to expand that, but at the current time we're working in 3D to help bridge the gap and soften the learning curve.

 

Yup, but you can make 2d and 3d graphs with some of those dimensions that make sense. You just have to pick and chose 'correctly'. Any graph is just an aid to interpret what's going on with the data.

 

Or you just look at the numbers.

[Nate1647545505]

Yup, but you can make 2d and 3d graphs with some of those dimensions that make sense. You just have to pick and chose 'correctly'. Any graph is just an aid to interpret what's going on with the data.

 

Or you just look at the numbers.

 

I could see that if you treated n variables as constants. Eg: What does the result look like when our intake cam is locked at 10* and our exhaust cam is locked at 30*.

 

The plan is to start off with the basic cylinder air-mass equation. A 3D quadratic is very graspable to those who haven't had to endure the painstaking 400 level engineering math courses. The ultimate connection I feel is the graph that illustrates what a system response curve is.