Where did the AFM go?

Status
Not open for further replies.
HeWhoOvercomes

HeWhoOvercomes

Vrooom VROOOM
Apr 23, 2011
56
0
6
The Corner of Happy & Healthy
Sorry guys, I have a noob question. I've noticed that when a lot of 7M guys install a big turbo, they have a 4" intake with a big K&N filter; but the AFM is gone. How does this work, or where did the AFM go?

Thanks,
Jordan :)
 
MPR

MPR

John 3:16
Dec 17, 2011
221
0
0
Toronto, Ontario
jetjock;1869386 said:
Even standalone requires some form of measurement and none is more accurate than an AFM. In the technical sense MAP is a step down.
Click to expand...

Not really a step down. I'd rather my ecu take a MAP and IAT measurement directly from the manifold than assume what just went through the AFM will enter the manifold a moment later (isn't always the case, especially when people go and use an external BOV on an AFM metered engine...) and restrict it by way of causing unnecessary turbulence in the process. ;)

MAP>AFM :p
 
toyotanos

toyotanos

What will we break today?
Staff member
Super Moderator
Nov 29, 2008
2,841
2
38
Coon Rapids, MN
It's a step down because MAP based systems are not as exact as MAF based ones. Speed-density takes the MAP and IAT readings, then applies them in a mathematical equation and comes up with the fueling it thinks the engine should have. MAF just looks how much air mass is moving into the engine, which is more accurate.

I like MAP due to the simplicity, but there is nothing wrong with ther MAF system. Well, not unless you're a ricer and wanna hear that awe-inspiring whooopssssshhh :p


Edit: People usually go MAP based when they go to a standalone computer (AEM, MoTeC, etc) or an advanced piggyback (maft-pro, MAP ECU, etc). It's all about control- how much can you change fueling and timing on the stock ecu, vs how much can you change with a fully adjustable ECU?
 
MPR

MPR

John 3:16
Dec 17, 2011
221
0
0
Toronto, Ontario
toyotanos;1869393 said:
It's a step down because MAP based systems are not as exact as MAF based ones. Speed-density takes the MAP and IAT readings, then applies them in a mathematical equation and comes up with the fueling it thinks the engine should have. MAF just looks how much air mass is moving into the engine, which is more accurate.

I like MAP due to the simplicity, but there is nothing wrong with ther MAF system. Well, not unless you're a ricer and wanna hear that awe-inspiring whooopssssshhh :p


Edit: People usually go MAP based when they go to a standalone computer (AEM, MoTeC, etc) or an advanced piggyback (maft-pro, MAP ECU, etc). It's all about control- how much can you change fueling and timing on the stock ecu, vs how much can you change with a fully adjustable ECU?
Click to expand...

Oh no doubt AFM/MAF is accurate. There are trade-offs to each method. To each his/her own. :)
 
Nick M

Nick M

Black Rifles Matter
Sep 9, 2005
8,894
38
48
U.S.
www.ebay.com
MPR;1869390 said:
I'd rather my ecu take a MAP and IAT measurement directly from the manifold than assume what just went through the AFM will enter the manifold a moment later
Click to expand...

You are 180 degrees out. The MAP sensor information is used to calculate the volume of air, as opposed to directly measuring it. The best way is a hot wire mass airflow sensor. The turbo Ford GT laid down 1000 rwhp on pump gas mix with stock electronics. Think about that one.
 
MPR

MPR

John 3:16
Dec 17, 2011
221
0
0
Toronto, Ontario
jetjock;1869408 said:
The MAP is an assumption while the MAF is not. That's the entire point.
Click to expand...

Nick M;1869412 said:
You are 180 degrees out. The MAP sensor information is used to calculate the volume of air, as opposed to directly measuring it. The best way is a hot wire mass airflow sensor. The turbo Ford GT laid down 1000 rwhp on pump gas mix with stock electronics. Think about that one.
Click to expand...

I never said AFM/MAF's don't work and don't work well. Chill out guys. lol

Forgive me for not adding "IMO" after "MAP>AFM" in my first reply. It's what I prefer to use/tune with.

As long as the stock electronics can keep up with and measure/compensate for what they measure (and the fuel system can keep up) then of course it'll make 1000rwhp. The ecu still has to read AFR and make adjustments according to that regardless of the air intake sensor type.
 
Poodles

Poodles

I play with fire
Jul 22, 2006
16,757
0
0
43
Fort Worth, TX
The main advantage of a MAP based system in a boosted application is that if you blow a charge pipe, your can still drive the car home.
 
S

Skeezix

Supradope
Dec 30, 2009
229
0
16
Regina, SK
Poodles;1869442 said:
The main advantage of a MAP based system in a boosted application is that if you blow a charge pipe, your can still drive the car home.
Click to expand...

Fuck yeah, I had to lay under my car in -40*C to hook a charge pipe back up just so I could drive it home
 
Nick M

Nick M

Black Rifles Matter
Sep 9, 2005
8,894
38
48
U.S.
www.ebay.com
MPR;1869427 said:
I never said AFM/MAF's don't work and don't work well. Chill out guys. lol
Click to expand...

I didn't offer a rebuttal to the statement you didn't make. You said the MAP was better and why. And from a technical standpoint, you are 180 degrees out. I could have just said your wrong and left it at that. I will next time.
 
MPR

MPR

John 3:16
Dec 17, 2011
221
0
0
Toronto, Ontario
Nick M;1869500 said:
I didn't offer a rebuttal to the statement you didn't make. You said the MAP was better and why. And from a technical standpoint, you are 180 degrees out. I could have just said your wrong and left it at that. I will next time.
Click to expand...

Fair enough. Don't need a bunch of people telling me the same thing repeatedly. Lol. That was really my beef. But I have no issue admitting I'm wrong. :)

Sure a MAF is more accurate at measuring air flow vs. MAP. When it comes to tuning with a stand alone it makes little difference in the end. Two different ways to do the same thing.

Sent from my LG-P970g using Tapatalk 2
 
jetjock

jetjock

creepy-ass cracka
Jul 11, 2005
9,439
0
0
Redacted per Title 18 USC Section 798
Well, you have no problem admitting you're wrong as long as you know you're wrong. The problem happens when you don't know and that's where we still are. However you're definitely right about MAF being more accurate than MAP at measuring flow since the second one doesn't. No point in arguing though. As long as the membership learned something.
 
Status
Not open for further replies.
Top Bottom