Speed Density on Evo ECU

[t-revzr]

Unplugging the maf? Curious how does that help? Whats the benefits not using it?

[Kevin 1G Drummer]

He's running speed density now (the whole point of this thread) so he doesn't need the maf anymore.

[t-revzr]

Originally Posted by Kevin 1G Drummer

He's running speed density now (the whole point of this thread) so he doesn't need the maf anymore.

Ya but how do you benefit from not using it that was the question!

[jrohner]

Well there's no point having it just sitting there if it's not being used.

[Kevin 1G Drummer]

Originally Posted by t-revzr

Ya but how do you benefit from not using it that was the question!

He doesn't need it anymore, so why leave it in there?

[Forced Fed]

Originally Posted by Kevin 1G Drummer

He doesn't need it anymore, so why leave it in there?

I don't think he realizes that with Speed Density there is no use for a MAF anymore, therefor the reason he unplugged it and now deleted it.

[jrohner]

Instead of having an airflow sensor read the airflow, you use a MAP sensor (reads manifold pressure) and calculate what the airflow should be by using a VE (volumetric efficiency) map. Wikipedia speed density, or read about it on ecmtuning's website.

[t-revzr]

Originally Posted by jrohner

Instead of having an airflow sensor read the airflow, you use a MAP sensor (reads manifold pressure) and calculate what the airflow should be by using a VE (volumetric efficiency) map. Wikipedia speed density, or read about it on ecmtuning's website.

Thank you!

[scheides]

Random update. All evo8's that want to run tephra v7 (i.e. pretty much anyone that wants to run one of these out-of-the-box speed density roms) run the 9653xxx6 base rom, which does not come with the EGR and fuel evap code from the factory, so as a side effect you do NOT need to run mrfred's manifold air temp (MAT) logging hack at all, just wire in the sensor into the appropriate pin and go! The stock IAT table is re-scaled for the standard GM IAT sensor, and you simply log MAT on MUT11, done.

Car has been running a little iffy while cold, since it got a bit colder over the last week. This has been a good test of this speed density patch IMHO, because it really needs to adjust for climate changes to be effective. I've been crossing my t's an dotting my i's and making sure I'm not doing something to cause this myself. I will be doing a bit more logging, and possibly messing with the two warmup tables. I really don't want to though, I never had to before! As some of the other issues, this is a minor problem, and not enough to kill this whole project for me.

I can still fire the car up, either let it idle (rock solid @1400, slowly falls to 1000 as it warms up) w/o touching the gas pedal, or simply drive away and deal with a bit of tip-in stuttering that.....now that I think about it, is really no worse than the warm-up timing pull that all stock evos have.

I am ordering an Omni 4-bar MAP sensor today from JohnBradley on evoM, as my car sees 30-31psi regularly and my EvoX MAP sensor is rated at 3.25 or 3.3bar (depending on who you ask) but ultimately is only good up to ~33psi. Anyways, just looking for a bit of extra headroom. If anyone would like to buy my EvoX map sensor, shoot me a PM.

[scheides]

Scored this new filter from perrin to replace my MAF, Vibrant MAF adapter and 4.5" perrin filter:





Apparently its made to fit a scooby; inlet is 3.125" so it fit perfectly over my buschur 3" intake

[goodhart]

Can't you vent your BOV to atmosphere with speed density also?

[FattyBoomBatty]

Pretty dang cool all the junk you can do with a stock car.

[scheides]

Originally Posted by goodhart

Can't you vent your BOV to atmosphere with speed density also?

Sure can! I just didn't want to incur the expense of a new intake pipe and haven't made up my mind on whether or not to get a different BOV, which may then mean a new UICP (or some fab)....anyways, ya. This was the easiest route and it def got the job done. I may look at other options in the future.

[asshanson]

Why not just keep the recirculate if you already have it setup?

I guess if you wanted more noise just plug the hole on the intake pipe, I did that for a few months with my RFL haha. I love the ricer days. No need to buy a different pipe.

[Shane@DBPerformance]

He also might not want his open unfiltered BOV sucking in dirty air.

[scheides]

Originally Posted by ecoli

He also might not want his open unfiltered BOV sucking in dirty air.

Damn, good point, I hadn't thought about that in a long while! Is this a problem on VTA BOV's? I don't recall having problems with either of the Tials I had on my 1G and 2G.

[Shane@DBPerformance]

Some BOV's are open at idle. A few, like the Blitz, have filter options.

[scheides]

Soo, the car has been having this random issue leaning out leaving from a stop and when lugging in traffic. Turns out the fix is in two spots:



mrfred's Fix2 has been working flawlessly for me concerning the small jitter issue.

I received my OmniPower 4bar MAP sensor last night and discovered that its not just a simple 'swap' in, I will have to re-scale (and thus re-tune) my SD VE tables I'm a little less than psyched, but at the same time I feel its worth doing if I end up ever running over 32psi. Safety, if nothing else!

I've added the above notes to my HowTo, and will be adding more when I swap in the 4bar sensor (probably next week).

[Kracka]

After spending 6 days doing tons of logging and tuning...

SD ROM v27 is a success! I was just out making multiple clean WOT pulls and the car feels great! Time to order a Perrin air filter that will fit directly to my intake pipe. Last week I built my speed density patched Tephra v5.10 ROM and right away I could feel how much smoother the low speed/RPM drivability was.

Also, a special big thanks to Scheides for always being willing to look over logs and giving me pointers along the way since he's already converted 3 cars!

[scheides]

Who'd have thought we could get those loppity loppity FP 4R cams to idle so nice! With the driveability improvement, you must be in heaven. Enjoy buddy