Gutting MAF correction amount?

[blindmist]

By what percentage does gutting the MAF allow you to go up to in injector size? 20%?

[UTRacerX9]

I don't know that there is a hard rule for an increase, but I do know that most people only remove the side screens, not the main screen. Removing that seems to cause problems for most people with tuning. I ended up going with a MAFT and Z06 MAF, much bigger.

[mb7050]

I have two mafs one without side screens and one all stock. Is there are way to figure out whether there is any difference difference beetween these two. I have a logger.

[blindmist]

Only if you had a 2nd maf in-line to compare to. I remember someone doing the math for the DSM's and they were 21%

I am trying to figure out if I should run my 360cc's or my 550cc's for engine break in. I think I am going to stay on my 360's for now.

[CoreyB]

I personally would leave it alone. You dont stand to gain much if anything but do risk having it run shitty.

[KeithMac]

It isn`t really linear across the RPMs, low rpm requires more +ve correction to bring it back than higher rpms.

Pulling the sides and lower honeycombs with a bit of mild porting needs +30% to bring it back up to stock hz readings.

[vr3.9]

It isn`t really linear across the RPMs, low rpm requires more +ve correction to bring it back than higher rpms.

Pulling the sides and lower honeycombs with a bit of mild porting needs +30% to bring it back up to stock hz readings.

Yea there is no way I'd run gutted maf with out a way to adjust fuel. For example: with honeycombs my seetings run around -32 all the way across. Leaving just the center honeycomb. +4 to - 20. That's with 550 injectors. I took the bottom small center out of the my stock VR4 which was running a little rich and that seems to work just fine. But I wouldn't take out any more. I think your always supposed to leave the center one in as it straightens the air out over the sensor.

[mb7050]

I just swapped in the gutted maf and it runs like stock maf at lower rpms but when i open it up a little i can see it leans out more (wideband)...

[KeithMac]

Yea there is no way I'd run gutted maf with out a way to adjust fuel. For example: with honeycombs my seetings run around -32 all the way across. Leaving just the center honeycomb. +4 to - 20. That's with 550 injectors. I took the bottom small center out of the my stock VR4 which was running a little rich and that seems to work just fine. But I wouldn't take out any more. I think your always supposed to leave the center one in as it straightens the air out over the sensor.

I ran without the centre screen for a while and it wasn`t very nice, taking the sides and bottom out with proper fuel control retains stock drivability for me (took a while to dial the map in though). I run TD04-16g`s so any less restriction is better!.

I`ve done the Mellon Bypass mod as well, to be honest if I`d started again from scratch I`d just do the bypass and leave the MAS alone.

[steve]

The center one is critical for the MAF to function as it should. It's there to help straighten out the air flow prior to the vortex generator.
As pointed out removing the others changes the amount of air that bypasses the center section but the difference is non linear so it's not a quick fix to balance out for larger injectors.

It's not clear that just playing with the honeycombs does anything for the overall flow rate of the MAF, rather it changes the metering of a given airflow. Some of the other MAFs have air horn differences (restrictions) that do change the flow rates when modified.

[KeithMac]

I`d seen 3150 hz on mine prior to modifying it, pulled the screens for some headroom (same with the bypass).

[blindmist]

Well I am wondering this because I have 550's and my 360's. I need to do an engine break in ~1000 miles. I was thinking that the gutted maf would allow me to run my 550's without having to change the tune in my EMU. I haven't had a chance to even log on this car yet. I think I am just going to put it to the stock setup, run that for the break in, then once I can put power on the ground, start messing with my EMU and my 550's

[KeithMac]

Best way, I wouldn`t mess around tuning it the same time as running your new engine in.

[vr3.9]

Bottom line on gutting a maf. You will need to tune. It will not be easy to tune. Low fuel trims will never stabilize like before. Temperature changes have more effect on tune (at least with an FMIC) Since you no longer accurately measure the true amount of air but a varying % of the air things like timing gears will make it run lean. The results. Much more air flow available quicker spool and pretty sure more HP available.

[lat42MS]

I`ve done the Mellon Bypass mod as well, to be honest if I`d started again from scratch I`d just do the bypass and leave the MAS alone.


Where are the melons on our cars, and how do I bypass them?

Seriously though, never heard of "the mellon bypass mod." Could someone enlighten me?

[i3igpete]

the mellon bypass mod is to leave the BOV recirc port open to let unmetered air thru the hole.