DarinS4Turbo

It has been suggested that significant airflow can be gained by removing the MAF pre-screen, so I decided to test that theory with VAG-COM air flow measurements. I did 3rd gear runs, both with and without screen, on the same stretch of road, and the tests were within 15 min of each other. The car was at full operating temp for both tests (i did some driving around before testing.)

In both cases the curves basically matched each other and leveled off in the 250-260 g/sec range at higher RPMs. In fact if anything, WITH the screen gave a measurement of a couple grams higher at some RPMs.

Now I also have an AWE intake. Interestingly enough my g/sec graph mysteriously matches donps in the K&N filter testing article, esp. at higher rpms. Both of us level off at just under 260 g/sec. Coincidental? Maybe, he likely has different mods on his car, the test conditions were different, etc. so no comparison can really be made. Still, I wish I had enough ambition to put my stock filter back in and retest to see if the AWE intake really makes 25g/sec difference... i.e. does my car really only flow 230 g/sec with the stock filter???

As one more test I stuffed a rag into the snorkel inlet behind the grille, significantly choking it down to a small gap where air could get through. I would say it blocked a good 60-70% of the narrow rectangular inlet which isn't very big to begin with. Even in this test it lowered the MAF intake by only 10 grams/sec (it still hit just under 250 grams/sec). However turbo lag was definitely more noticable. Still, this shows that unchoking a major restriction only added 10g/sec. Again, and the AWE intake adds 25 g/sec? Nothing against their intake, I think it is the most ideal setup you could have.

But I have to wonder if ANY intake/filter solution out there is going to add noticable power gains.

frank

I'm curious

DarinS4Turbo

Yeah, probably another day when I get a chance.

DarinS4Turbo

Both DonP and I peaked out at around 255 g/sec. On this GM 3.8L page they describe how the MAF maxes out at 255 g/sec, after which you can't necessarily tell how much air is flowing in (by the MAF measurement alone). Coincidental? Hmmmm.....<ul><li><a href="http://www.thrasher-ep.com/chips_htm/cal_hints.shtm#15">MAF reading</a></li></ul>

frank

do they use a Bosch MAF?


also the MAF on my 99 BMW (also Bosch),

supposedly reads airflow in and out..

so as not to be confused by low velocity

turbulence at or just off idle speeds

SMOKINA4TURBO

Have you thaught about going to a larger MAS?

DarinS4Turbo

So not only did I see > 255 but it is also a float which requires more than one byte anyway to do the A/D conversion in the ECU. But still, maybe the original MAF calibration (max voltage) was based on that 8-bit value, who knows.

frank

so I think it can go higher

DarinS4Turbo

Since the firebird here only maxes out at around 225 g/sec, and I go up to 256. So yes, my combustion is producing more energy (power). BUT of course there is the little issue of some of my power being used to spin the turbos. So my net power is not necessarily more ;-)<ul><li><a href="http://www.ws6.com/ramtest.htm">Ram-Air test</a></li></ul>

frank

chipped 225TT with Catback exhaust and aftermarket DV