First Evo X Stock ECU w/ Speed Density

[Murlo26]

Made this thread over on EvoM and figured I would post it here too. I am liking that more and more tuning abilities are coming on the X. Hopefully it will catch up to the 8/9 or surpass it sometime soon :) Also I had 3 posts over there on this.

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http://forums.evolutionm.net/evo-x-dyno-results/602451-worlds-first-stock-ecu-speed-density-tune-i-know.html

It really should say MAFless or something as Evo X's use speed density in conjunction with the MAF on the X's. They then compare both readings of load and use the lower (?) I believe.

I spoke with Tephra about doing speed density and he saw no reason on the X. So I am curious to know what the boys at Cobb (I assume Cobb as its one of their tuners posting it) think going just SD is going to accomplish. However, Tephra is essentially Cobb employed so maybe he cooked this up.

To my understanding the MAF is a restriction on 8/9's but isn't really on the X's with the X having hotwire and being able to go to a bigger intake.

I am all for doing it if its worth it.

What does everyone else think?

Ok, found some more info on EvoXforums here:

http://www.evoxforums.com/forums/showthread.php?t=60395

Here is what Jon from Cobb says:
The maf isn't a restriction really. Since the maf stays in still for intake temps.
Large maf housings are not great and cause turbulence, which then skews the maf reading resulting in jagged load reading. Load is the basis for fueling and timing vs rpm. The smoother the load the smoother the car/timing/fuel/etc

And then Tephra:
yeh its not totally maf-less - it just removes the MAF from the load/fuel/timing calcs

So they keep the MAF in there I guess for IAT. I would love a rock solid idle, mine isn't horrible at all, but this would probably remove any shittiness.

Here is a nice pic...you can see with the 3.5" MAF tube which most of us built motor guys end up with how jagged the MAF gets down low. But this shows when it ignores the MAF and uses just the MAP signal...its smooth as butter.

http://hbspeed.com/SD/mafcalc.png

[scheides]

meh. idk, its neat but I'm with tephra, really not needed. It's cool that they removed some of the MAF from the load calculations as a tuning option I guess, probably worth trying.

Hrm, kinda excited to play with this some day, could be kinda fun when I max out my 3.5" maf :)

[Murlo26]

I would've agreed with you, but after seeing the above pic and how rough the MAF signal can get down low I am guessing this is a very good thing. My car will idle pretty consistent for a while then blip and get a little out of whack and then go back to consistent, then repeat the cycle while idling for a long time.

Also coming to a stop I have had issues before.

It could be your cams are just that much smoother than GSC s2's and your idle could feel better. If its easy enough to do and helps the car smooth out a bit I am for this. But we will see how it pans out. Still early in the process.

[Shane@DBPerformance]

The MAF isn't a restriction on the Evo 8/9, it's main problem is that it can only read so high and you can't just move to a bigger pipe like the Evo X. Other cars like Mustangs and Subarus that have the same style MAF as an EVO X have the same flaky readings, idle problems, bucking at part throttle, etc when they goto big MAF pipes too.

[niterydr]

How much time and effort to people put into proper maf scaling when they change pipe size? When I monkey with cars that have a "cold air intake" I have to spend a lot of time monkeying with that maf transfer.

[Shane@DBPerformance]

Half of the tuning time on some cars is getting the MAF scaling dialed in and doing what it is supposed to.

[Murlo26]

With something as jagged as the above MAF reading, I don't know how you could even get that buttery smooth. I am guessing mine looks like that (the above is a 3.5" intake just like mine).