It was finally caught in the turbo housing right before the compressor wheel it never touched the wheel. Sucks sitting on the side of the freeway at night with no flashlight trying to figure out the problem.

 

What effect would removing the mesh from the mass air have on the cars performance/drivability? I know its probablly not a good idea, but the thought of trashing a 1700 dollar turbo makes me sick to my stomach! lol

SQ

 

I know people who have removed the screen/honeycombs from the MAF. It was actually a common mod on the DSM MAF, but people usually left the screen in the section where the actual sensor was.

The Karman Vortex sensor would work the best if the air was straightened before it was measured, since the MAS sensor is basically counting the number of eddies creating by the obstruction.

Whether you took the whole screen out or sections of it, to get it to function perfectly would probably take a good amount of MAF scaling, but I don't see why it couldn't be done. It all matters whether or not the sensor can have a measurable difference from stock with the screen removed or if removing the screen alters the sensor's reading ability in a way that isn't reproducible/consistent.


Eric

 

I run without the screen on my TT Stealth and the injector scale went form ~ 720cc to ~ 400cc. I also let in some unmetered air after the MAS to further reduce the inlet restriction. I think the injector scale is ~ 360cc which is near the stock injector size hahah

the only reason I haven't done the same on my own car is because I don't want to do anything too radical on the EVO and keep my customers from following me. Eventually I'll max out the stock MAS and be forced to do some experimenting with it. Then I'll do the AEM if I can't reach my goals.

 

So if I were to do this, would it take maf scaling, injector scaling or both to achieve a good tune?

SQ

 

Well, to do it properly, you would need to use the maf scaling. Removing part or all of the screen would change the airflow reading in different percentages per aiflow Hz. So, for example, you may be down 50% at low airflow, but down 20% at higher airflow.

When I have time I can post the corrections that the DSM people used in that past for an idea of where to start.

You can use injector scaling as a global adjustment, but you would need to use MAF scaling to fine tune it accordingly. Your plan of attack would be to do logs with the screen in place at a lot of different airflow and boost/vacuum, and RPMs. Then, do the same exact logs with the screen or part of the screen removed. Then calculate the corrections from there.

If the corrections aren't consistent at the same data points when you removed the screen from the sensor area, then that tells you that removing the entire screen may not be feasible to maintain a consistent tune.


Eric

 

I've never had to do maf scaling...there was enough adjustment within the fuel map and trims.

 

It's definitely doable this way, as long as you can adjust your injector latency and scaling to compensate for the fuel trims at idle and cruise and then use your fuel map for open loop.

The only downside to this would be that your airflow readings, and thus load, would now be inaccurate. If you don't care about that, then you can use this method.

When people were doing this with DSMLink, we always cared about having accurate lb/min datalogging, so any changes to the MAF reading were compensated for correctly, so that in the end, you would still have accurate airflow readings. Also, in our case, it would keep load numbers where they should be. Load is a mass airflow per rev, so if don't adjust the maf scaling accordingly, you can have too high or too low of a load number.

It's all a matter of preference and data integrity.


Eric

 

Checked the mesh, looks good. Not deformed or loose anywhere. I was thinking though, my BR filter has been on the car for over 2 1/2 years now, driven in all conditions 365. Wonder if it could be time to replace it?

SQ