Speed Density on Evo ECU

[scheides]

Monday update, the part throttle cruise either has gotten worse or I'm noticing it more. I am going to turn my async table back down to stock and see if that makes it better or if the increments I made to the EGR timing advance table make any difference either (I'll try that next).

I unplugged my stock MAS/MAF tonight w/o issue. No CEL, no stumble (did it while car was running), nadda, just plain awesome! Does anyone know if the MAF Scaling and associated tables actually do anything anymore?

Thanks a ton JohnBradley and Bryan@GST Motorsports for sharing your setups with me. JohnBradley's (Ref1 (http://forums.evolutionm.net/7729272-post122.html), Ref2 (http://forums.evolutionm.net/7729303-post125.html)) is something to strive for, perfect fully tuned 1:1 VE tables, definite beauty to that! Bryan@GST, well, my tables look damn near identical to yours (http://forums.evolutionm.net/7730235-post132.html), although I did make a bump near the bottom to try and get some of my midrange load values to line up to my previous maf-based tune. However, our SD RPM VE tables are not so close, I feel like mine are globally down 15% from your or so. I have yet to idle or cruise in full open-loop but the car idled way rich and fuel trims were full -12% negative w/o setting these values in the middle of this table (1000-3000rpm) in the 67-70% region. Anyone have any idea why that might be? Ported head, cams?

I have timing very very close to where it was before and the car feels fantastic. Boost is low 24psi, right where I want it, nice and conservative. I'm nearly ready to flip the alky on except for a few problems: thanksgiving (traveling), rain, and snow in teh forcast. Sigh. :)

http://scheides.com/misc/pics/evo/speeddensity/sd-test6.JPG

[scheides]

oh, I forgot! Any ideas on what to do for an intake when I delete the mas?

I'm thinking of simply bolting one of these to my standard buschur intake:
http://www.perrinperformance.com/products/show/580/Filter-Replacement-2-Piece-3-125-ID?category=3&model=2

[Kracka]

How do the EGR settings play into all this? I'm a bit lost on that considering you don't even have EGR on your car.

[jrohner]

Monday update, the part throttle cruise either has gotten worse or I'm noticing it more. I am going to turn my async table back down to stock and see if that makes it better or if the increments I made to the EGR timing advance table make any difference either (I'll try that next).

I unplugged my stock MAS/MAF tonight w/o issue. No CEL, no stumble (did it while car was running), nadda, just plain awesome! Does anyone know if the MAF Scaling and associated tables actually do anything anymore?


You probably have a better tune now, which is why you notice the stumble more now. It was the same way for me. When it was too rich I didn't notice it, but when I got the AFR's stoich (I want to run much leaner than stoich) it got much worse. I mostly only notice it at around 50-55MPH. I don't usually go that speed, but on a new road near my house they changed the speed limit (for the 3rd time - 45, 55, 50) and it's now 50MPH.

The MAS scaling should still matter, as the way they have the SD set up is to mimic the MAS.

I wish they had the SD set up like hak has ds-map / jackal set up. My new Holset powered 1g runs so awesome. I think 1G's have the best driveability (and idle) to begin with, and they did an amazing job setting up the SD.

[scheides]

How do the EGR settings play into all this? I'm a bit lost on that considering you don't even have EGR on your car.

Despite actual EGR being deleted, there is a subroutine that increases timing off of your timing map while you are at cruise, basically to improve fuel mileage. If you log your car, you'll notice that the timing values while cruising will hover around 40, while the max timing values in your timing table are 38 (on a stock rom). There is a full timing table that allows you to select rpm and load points and how much timing advance you'd like this EGR timing function to add. I don't think it will automatically add 100% of the values in this table, but progressively add some and pull some as needed to keep things running nice and efficient.

On the same note, there is an actual timing table for the cold start/cold coolant temp. It modifies the stock table up to these numbers (they're all negative, right in the cruising area and 0 everywhere else), and the table that we have been messing with over the last year or so (dropped the middle values from 256 to 200, 128, 100, etc) are a reference to this table and the percentage up to which it should be used. Just more ways to tweak tweak tweak!

Anyways, I tried fulltime open-loop and it did not help the 2000-2700rpm studder/jitter problem at all. I tried afrs from 15.5 down to 12.9 w/o any difference (other than it smelled like gas a lot more LOL!). I want to elaborate on this, it is not really THAT bad, it is just a mild 'nervous' feeling the car has in these rpm ranges while cruising steadily. It is really the last thing I do not like with this speed density conversion. My AFR, timing, boost values are all perfect and the car rips on pump gas.

Time for alky :)

[scheides]

Loaded up alky/alt-map stuff last night and tested it this morning. Fuel is spot on, high 11's just perfect. Timing however, is pretty far off, 4-5°. Thankfully they were LOW, otherwise I might be crying right now :) Going to have to adjust the scaling a little to bring it up to where it should be.

I'm taking baby steps, and it is just amazing to me how much power 2° of timing adds on alky, the car just feels like it is waking up! 2-3° left to go. I'm working out what I want to do for a new intake, and still contemplating a new COP ignition setup before I throw it on the dyno for shane to dial it in.

[turbotalon1g]

Do you have some kind of freq flyer miles with shane?
I need to get in there when I get home.
Glad to hear its working out, very cool

[scheides]

I wish. I pay just as much as anyone else :) Discounts are nice, but I'd rather pay full price and know they'll be there whenever I want to go back.

[scheides]

Got alky dialed in today, car rips again! virtual dyno room puts me right back where I was, around 420whp on evoM comparator mode. I had to mess with the load scaling to get timing where it was, but seems pretty good now!

So, I have 2 pending issues:
-knock on spool-up, or tip-in. I'll try messing with the tip-in table, but I haven't logged a lean condition yet and timing seems ok, so not sure what the deal is.
-2000-2800rpm jitter. Still searching, hoping to log it and find a work-around.

Just wanna say thanks to everyone that helped me get this far, I am SO happy with the new speed density setup, it is absolutely amazing.

[scheides]

Well we've been trying to tack down this jitter problem. Basically IPW bounces back and forth when it should be more steady. Today mrfred unraveled one piece of the puzzle:

I've been putting some time into trying to figure out this issue, and there are a couple of areas where I can provide some clarification:

1) You guys may already know this, but the name "MAF filter" is somewhat of a misnomer. This value is used to calculate a weighted running average between the old master load value and the newly calculated master load (from the MAF). The formula goes like:

MasterLoad = [MAFfilter*MasterLoadOld + (256-MAFfilter)*MasterLoadNew]/256

2) SD master load is inserted in place of MAF master load further down in the master load calculation subroutine, so SD master load is not affected this weighting calculation, and thus any changes in the "MAF filter" value have no effect on the SD master load.

However, in looking a little further just now, I do see that there is a flag that gets set at the end of the subroutine where the weighting value is determined. The value of the flag is dependent on whether the weighting parameter is above or below 200. This flag doesn't affect the master load calculation, but it does affect some of the calculations for the fuel pulse width. This is the best candidate that I've seen for causing the jittery IPW issue. I'll see if I can look at it further this weekend and perhaps come up with a patch to test it.

EDIT: Having thought about it a little more, it should be pretty easy to test this. We can create a 1D table for the over/under value, and then set the over/under value to 255. Another over/under value to try would be 0. This value is below all the possible weighting parameter values. For the 9653 ROM, the address of the over/under value is 0x162C. Its a word length value, so use uint16 for the scaling.


So, I'm gonna try:

<table name="MAF Pulsewidth reset (test)" category="Speed Density Tuning" address="162c" type="1D" scaling="uint16"/>

Unfortunately I'm gone till sunday night :P

More info on this subject here, we started a thread dedicated to it:
http://forums.evolutionm.net/ecuflash/460386-speed-density-ipw-drop-out-96530006-patch.html#post7747496