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://evoempire.org/index.php/topic...nsity-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:

Originally Posted by GST Motorsports

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/ecuflas...ifference.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

[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]

Originally Posted by 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.

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/ecuflas...hramod-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

Originally Posted by JohnBradley

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/ecuflas...irst-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

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:

-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 ?!?

[turbotalon1g]

sounds cool, and pretty much what everyone on link has been saying.
A PITA to dial in, but once done everyone loves it.

[bananas]

Very cool stuff! I'm jealous I can't do this kind of thing with my car. Of course, if I could I'd probably end up blowing something up!

[scheides]

^your owwdee will run speed density from the factory! You know how you can just unplug your maf and it keeps running? yea. punk.

[scheides]

So much for 'waiting till this weekend' LOL!

The big improvement since yesterday is in the fuel trims, I have them dialed into right around 0% for LTFT mid. Also leaving from a stop the car would want to stumble and die, some logging showed that load jumped into the 80 range and AFR leaned out to 18:1. Tweaked the SD MAP VE map a bit and fixed that, stays in teh 14's now as I leave from a stop and no stumbling!

Here's where I'm at:


My LTFT Low is still at -12, but I haven't let the car idle a ton. While giving my buddy a ride the other day he was semi critical of the idle, which I had left around 1200-1250 rpm. I was super happy because of how it would not dip below that at all, and he was saying he thought it really should be lower for me to say its 'solid'...anyways, I made one tweak to idle rpms (haven't touched any of the ISC Stepper tables or anything yet!) and bam, the car idles at about 900rpm, maybe 925. Logs show 900-950-1000 but the tach needle just sits dead inbetween the 800rpm and 1000rpm tick marks. Kelford cams, ported head, ported everything else, not a single dip or stall, its absolutely mindblowing!

Going to review some of my WOT logs and see where timing is at, but boost is set at 19psi now and afr is in the high 10's on my wideband. Ready to get back up to 24psi and try and get dialed into my old tune. I have yet to touch AFR, timing, injector scaling or latency values aside from translating or copying them over from my old map.

Ooh, also, the car seems jittery while its warming up, and I've noticed that at 2000-2500 rpm while cruising sometimes it feels goofy to. AFRs are around 14.5-15 so need to see what else is going on to cause this. It is very subtle once warmed up.

[scheides]

Friday update. Back up to 25psi! Its amazing how fast the car feels after its been down on power (or limped or whatever) for a few days. All of the little boost control mods v7 has to offer really make the car responsive and when its dialed in the car just rips! BBK is holding 25psi dead flat from 3800 out to 7700rpm (highest I've logged so far) with about 84% WGDC. Bryan@GST did note that he had to tweak WGDC a bit to bring boost inline with where it was before, and here's what I noticed: I needed a bit more WGDC down low during boost onset, and had to take a little bit out up top, boost was off by about 2-3%. I literally made two changes and logged a few pulls in a few different gears and its perfect again. I LOVE this ecu controlled boost setup once its dialed in!

More on topic, I have yet to touch my AFR or timing maps that shane@DB made for me (and I hope to not have to, this tune has served me VERY well this summer ) My load up top is a bit high now, so I'm droping down the highest valve on the MAP VE table from 430 to 410 to see if I can slowly get load back to where it was before on the street. It's peaking in the 330's and tapering to ~300, before I was peaking at 280 and tapering to 250 or so. I'm also now using 1byte load vs 2byte load, so I'm focusing more on the timing values the car is running moreso than the actual load numbers I'm logging.

I had accidentally misread the EGR timing advance under cruise bit and disabled it (vs enabling it, the bit is backward, it reads 'disable EGR timing advance' 0 is enabled, 1 is disabled). I knew about this already and totally spaced it. Anyways its worth mentioning because my car drove like isht when it was cold and wanted to jerk when warmed up and cruising at low speed. As soon as I turned this back to 0 and put my EGR Timing Advance timing tables bumped up to where I had them before (bumped just slightly from stock, 6's and 8's) the car drove as it had before.

Still getting this ever so slight jerkyness when under low low load while cruising in the 2000-2700rpm range, which is a fairly widely known issue with this speed density setup and I would rate it at very mildly annoying and often not noticable...but Slo_crx1 on evoM posted up last night that he thinks he has eliminated this issue using the new tables that mrfred posted re: advanced fuel control and globally increased the values in the Asynch vs TPSDelta table (sort of a TPS tip-in type control I think). I'm going to try this out today as this is potentially a huge break through on this project.

I'm going to try these settings out, dial in my loads as mentioned above, and just bomb around for a few days and see how it goes! It's SO easy to focus on the laptop its getting to be time to just drive the car and see how it feels and just enjoy it. Once I'm happy, alky will be flipped back on and back up to 30psi!

Oh, does anyone know, can I just unplug my MAS? I'm toying with the idea of either gutting out an old MAS I have (w/ a destroyed honeycomb) or getting a 3" inlet perrin filter and just strapping it to the end of my buschur intake.

[jrohner]

Yeah you can get rid of the MAS. It's not being used for anything. It won't trigger a CEL or anything as long as you have an IAT sensor somewhere else, which you do.

[turbotalon1g]

SOunds awesome, that delta tps tip in deal is only used for enrichment for a very slight second, depending on how bad your hesitation problem is that may or may not be it.
good luck.

[Matt D.]

How has your cold start idle been?

[jrohner]

Mine started up and idled great on SD (idle was better both cold and warm on SD), but trying to take off on a cold/cool engine was a bitch.

[scheides]

Cold start has been fantastic, as well as initial cold idle and warm-up idle.