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]

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]

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]

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]

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:

http://scheides.com/misc/pics/evo/speeddensity/perrin-3.125-filter-1.jpg

http://scheides.com/misc/pics/evo/speeddensity/perrin-3.125-filter-2.jpg

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