I'm finally getting everything together to put my car back together. Here's what I've got coming:

Buschur Head
FP green
850cc injectors
ETS 2.3l stroker kit

I should have the car running in the next couple of months and I'll be working with Bez to nail down the speed density patch.

 

subscribed -

I have bought maft pro since your last endeavor.
Better luck this time. If there is anything I can do to help let me know.

I'm more than a little curious to see how far you get with it.

 

can someone give a brief rundown of the advantage of using speed density over MAF? (apart from not having to run a MAF which is one less restriction.)

cheers
d.

 

Well, one of the main reasons is removing the restriction, like you metioned. Another one is to remove the limitation of the stock MAF. The stock Evo MAF is only accurate to somewhere in the 60-70lb/min range. That should be good for 99% of us, but for those building 700HP cars, then the restriction and the ability to read at those airflow levels goes out the window.

Also, it removes a few minor issues like venting BOVs, stalling due to different flow characteristics of different turbo's, misadjusted BOVs, etc.


Eric

 

so basically unless you change your turbo then there is no point in doing it?

 

Nice! Good to see you back in action Matt.

In preparation, can you confirm I will need the stuff you mentioned in your previous thread:

 

I don't know for sure yet. If I remember correctly, part of my problem was that the AIT's were incorrect. Once I get the latest patch from Bez and get fully into testing, I'll know more.

Fortunately, I now work at a local shop, running the dyno. So in between tuning and flashing all the STi's and WRX's that come through, I can test MY evo on the dyno all I want.

 

I'd actually go farther than that (speaking to the archive reader, not necessarily tephra): unless you know (and can explain coherently) exactly why you need to do it, you don't need to do it. A MAF is much more forgiving and, as Eric said, it's perfectly fine for 99% of the people out there (and even the 1% that could effectively use it can usually find workarounds).

(This is one of those things that people latch onto, thinking it's something they need, when they have no clue how much of a pain in the backside it can be. Think re-tuning for seasonal weather changes and elevation. I've seen too many people switch to speed density on an AEM EMS, and then spend the next year getting their car to run half as good as it used to on a stock ECU w/MAF.)

 

EMS brings its own set of complexities along with the transition to speed density.
The pitfr is dealing with ALL of it. Or people inexperienced in using it.

With the stock ecu still doing most of what it does (run the car) - the overall disadvantages that you blend with speed density itself in your statements... Will be limited.

The trick is getting the speed density emulation to 'fit' as well as possible with the stock ecu. And ensuring that its fuel calculations are as close as possible.

Honestly I agree with you that XX% of people DO NOT need it. But I think more people could use a more practical application of speed density itself minus the standalone. Personally the A/F inconsistencies between gears - same load cell. Made me seek an alternative.

 

I switched to MAFT Pro like Dustin. One thing I noticed other than getting the main scale set properly to emulate the load where the car should be (and therefore everything else about my prior tune), is the AIT. MAFT pro just leaves it as fixed value that doesnt really leave me feeling like its "correct" but it works with that unit. I got some ideas on that though so I am not too worried about it. Now to the subject at hand.

Matt awesome that you are gonna make give it another go and make it work. I can see an immediate gain without that maf there though. I mean its a restriction when its there no matter what. Lucas and I both noticed immediate gains ditching it.

Now when to ditch it? Anytime you have a combo that would max the table at 379. A really high boosted Green can do that on a 2.0 and I would be willing to bet a .3 will make it that much easier. Any turbo that is bigger than that wont have any problems pegging it and i would reckon no one buys a bigger turbo to just run on pump and nothing else. If they do they should be looking at other cars really. I mean a laggy low powered turbo car is something straight out of the 80's I think.

My 2 cents.

 

Why not just run a map sensor and tune things to run with it?

Closed loop operations have the o2 sensor keep the target 14.7 a/f ratio while open loop (wide open throttle) have the map sensor monitor things to stay within the intended a/f ratio.

 

A maf translator devices that uses the GM MAF to replace our Karman MAS fixes the AIT and baro because the GM MAF is a mass airflow sensor. Our Karman MAS is a volumetric airflow sensor. Our ECU needs the baro and ait to then calculate the mass airflow. That's why the baro and ait sensors are in our MAS. When using the GM MAF and MAFT, our ECU still needs the AIT and baro input to keep it happy, even though the mass airflow is now being measured directly.

Also, I'm sure you know this already, but for the rest, keep in mind that speed density is a bit different than using a GM MAF in place or our stock Karman MAS.

It's been years since I used a MAF translator in my Eclipse and I know there have been advances, so I can't speak to what is out there now. For example, I noticed a few threads where people say they are running speed density with the MAFT pro. I never looked into that, but speed density doesn't use a MAF at all, so I'm a bit confused by that, but never looked into the newer MAFT Pro.

 

I have a MAFTPro, and I tried using it's speed density setup with a 3bar GMMAP sensor. I could never get the throttle tip-in settings correct so it would lean out terribly during large throttle changes. I even had turbobob try to help, bu it never worked for me. I ended up getting a GM MAF and running like that for awhile until the MAF sensor **** itself.

BTW, Eric, the MAFTPro can do speed density, the MAFT does translation only.


BlueEVOIX, that is basically what I am doing. I have a JDM 3bar MAP that is taking the place of the stock MAF sensor.

 

I am running the Pro in AFC mode currently to iron out the terrible variances between gears I was getting. The A/F tracking works like a charm. Assuming you turn lean spool OFF. Otherwise A/F just oscillates. I will be switching over to SD mode soon. I 'm using the JDM map instead of the GM 3 bar to keep installation simpler. Bob has already made a provision at my request in the newer updates to work with it instead of the GM 3 Bar.

Honestly where it is now. I have 0 variance between gears. I flashed a bland A/F map across the board in line with where I wanted it - and I have A/F tracking do the rest. Zero tuning involved. THIS ALONE solved my problem with A/F tiering and the stock maf between gears. Even tho I'm still running it.

Lean spool works from 2500~4000 then OFF and A/F tracking kicks in. Works like a charm. It will hold anything I want. Which means my 5th gear ISN'T in the 10's now, and first isn't 12-1.

I'm having the opposite problems with throttle changes. I go too rich. But thats because the stock TPS enrich settings + vta bov = fireballs. I imagine this setting would curb your tip in lean problem no sweat Matt. If I can add enough fuel to blast 3ft flames out the *** end of my car on reapplication of throttle - there has to be enough to sort out your tip in. I had to almost turn this off to keep this from happening.

It allows for how much / how long etc. And should cover any lean spots with some tweaking.

I'm running it w/ the stock MAF because I never used Pro before (for those who are wondering) and I wanted some experience with it before I jumped off the bridge. So far it works like clock work.

 

I am set up using speed density with an AEM 5 bar not a GM maf actually I know the 5 bar is overkill but it was sitting on the shelf and I dont typically like to wait when I have a solution in front of me.

Dustin, I havent started with the AFR tracking yet but I kind of thought that was going to be more or less the results. I am not currently having in tip in issues. I need to either bump the scaling on the injectors or start messing with the fuel table because it seems that even though the ECU is in the right load areas as before (stock maf that is) it is globally richer than it should be for those loads.

Then again I changed a ton of things all at once so its not easy to point at one thing and say its the issue or not.