Speed Density on Evo ECU

[scheides]

I'm ready to give it a try to see how much driveability improves. Wondering if anyone on here has tried it yet? There's supposed benefits: improved driveability and potentially more power.

The extra power has been potentially debunked:

http://norcalmotorsports.org/users/bryan/mods/EVO/evo_tunes/jesse_e85_120408/111509/jesse_MAF_vs_SD_111509.jpg

http://evoempire.org/index.php/topic/5853-maf-vs-speed-density-wno-maf/

Same AFR, same boost, same timing, no power gains. Now, if running SD allows you to run a bit more timing or boost on a given setup safely, that's yet to be determined.

Yup, everyone is always saying the MAF is such a huge restriction; obviously even at this power level it is not.

A few interesting notes:

No a larger K&N was used. I believe it was 4" by 6" but I might be wrong about the length.

MAF was using a 4" induction off the turbo to a reducer to the MAF to a MAF sized filter. No MAF was 4" all the way to 4" filter.

...

All is not lost however, the car drives great with the VTA Tial BOV and the idle is rock solid with no "clutch-in" dips, etc. I don't think I have ever seen a Evo lock on to target idle RPM so well before.

- Bryan

The idle stuff makes me interested again....

I'd love to see more data on this subject, this is the best comparo I've seen so far.

JohnBradley did one and saw some power gains up top, but he was able to add timing, and there were other changes made (i.e. NOT a direct comparo):
http://forums.evolutionm.net/ecuflash/453807-speed-density-airflow-difference.html

So I think I'm going to try it out this week/weekend.

[jrohner]

I don't think there has been a single person post on EvolutionM that didn't have driveability issues on Evo 8's using the speed density posted there (9's were fine). I got fed up with it and gave up, especially after my extremely disappointing numbers at the dyno day.

The 2 2d VE maps make it pretty easy and quick to dial in, so it's not hard to give it a try if you feel like it. Acceleration enrichment and coolant temp enrichment are a lot less fun to get right though.

[Halon]

Speed Density offers improved drivability? That's a new one to me. The only reason I've ever seen to go to speed density on our setups is when you reach a point when you are out flowing the MAS.

[turbotalon1g]

^Im opposite of you.

[scheides]

Yup, that's what people have mentioned. Rock solid idle and I guess we'll just have to see. My plan is to load up a rom that should work on my car, turn the boost way down, and just do basic cruising/starting/stopping/traffic type driving and see how I like it. If it addresses some of the issues I'm trying to fix, awesome, I'll go from there. If not, test complete :)

This will cost me $0 since I already have a 3.3 bar map sensor and MAT/IAT sensor on the car :D

[Goat Blower]

I'd say the driveability with the MAS would be better, but SD is really nice for packaging reasons. Having an aftermarket BOV venting to atmosphere is nice, as well as being able to drive if you blow off a IC coupler and don't have any tools with you.

[123abc]

I'd say the driveability with the MAS would be better, but SD is really nice for packaging reasons. Having an aftermarket BOV venting to atmosphere is nice, as well as being able to drive if you blow off a IC coupler and don't have any tools with you.


That's whats nice about having a gm Maf-t right before the bolt-on tb elbow.

[scheides]

So, I did a little research today, here's my plan.

I'm going to start with the phenom out-of-the-box 96531706 rom. My car has the GM IAT sensor and evoX MAP sensor on it already so lots of the settings should work 'out of the box' but I'll be double-checking everything.

http://forums.evolutionm.net/ecuflash/451836-tephramod-v7.html
(evo8 option5 in post #2)

After some reading, apparently the big trick is getting the car to line up your current load values with its new kpa values. Seems like roughly 1:1 is a good place to start, but since JohnBradley posted this, I think I'll try it:

http://forums.evolutionm.net/7674344-post25.html
I have been finding the ratio is definitely off from 1:1 like I had posted originally. The ratio is non-linear but I have it here for those that want to try it out:

MAPVE-

41-40
61-63.5
101-103
121-124
340-430

Kpa to load will be pretty close to spot on with the 4 bar, your fuel map will look pretty close as well.

These numbers work for me on my 3586, stock turbos, stock appearing turbos, 3582s, Evo3 16Gs, etc.

Another approach is making everything 1:1, and then foking with the MAF smoothing table:
http://forums.evolutionm.net/ecuflash/403577-easy-speed-density-first-test.html

I'm going to base everything and try and get back as near as possible to the tune that shane put on my car w/ the MAF, and after I get the car running and driving, I'll work on WOT fuel/timing.

[scheides]

Goodbye MAF :D

Spent a few hours converting over my ROM and trying out a few iterations based on some stuff I had seen posted online. Initial impressions: WOW! The car is so smooth. Idle is ROCK solid (albeit a bit high, gotta work on that, 1300rpm), and any stuttering/bucking I had while on the freeway before is GONE. The car is SO smooth now its amazing.

A few notes:
-It took a few iterations to get the car to start/idle correctly. It wanted to idle in the 11's and load was way high. I got one that would work ok, made a few trips around the block, and all seemed decent.
-initially I set my WGDC all to zero. No boost! I'd hit about 9-10psi and confirmed seeing AFR in the 10's under 'boost' before trying anything more. No alky on or anything yet. Baby steps.
-Made a few more iterations to the SD maps this AM on my way into work. Tried a bunch, with mixed results. Ended up going back to almost exactly what I had the night before:
http://scheides.com/misc/pics/evo/speeddensity/sd-test2.JPG
-turned up boost to about 19, just keep it simple. AFR in the 10's and high 9's (I used my old afr map from my tuned rom @ DB Performance) and while it is SMOOTH as silk this new rom has lean spool completely disabled, and i don't think my previous one did (my bad).
-Got all the way to work and got CEL for fuel trims. Oops, forgot to log those, even though I had been watching AFR all the way. low/mid are -12/-12, so now I need to try and figure out what to do to fix that.
-lastly, the car wants to buck if I leave from a stop w/o revving it up to ~2000rpm. It would do this before, but I'd give it more gas and away I'd go. Now, it looks like it is leaning out as rpms drop to ~500 and then I need to feather them back to life. Not sure what's causing this, but I'm sure my messed up fuel trims have something to do with it.

[rose0529]

Nice! Gonna wait till this weekend huh ;)?!?