MAF Help

[Tim99GT]

Ok, so i need some help with this. I've read and read and still cant decide what MAF to go with.
Back info: Im looking to got to the JLT HB CAI and will need either a ba2600 or ba 3000. I currently have a stock cobra intake and a lightning MAF, however, i have not gone to the tuner yet for the new build. Ill be going late next week which is why i need help so i can get this ordered.

Build: Built 2v with KB 2.8H
According to Tim Barth with MPH, i should be somewhere in the 650-700rw range on a 93 octane tune.

So what MAF do i go with?
Is there a chance of me pegging the 2600?
Is the 3000 too big?

I read somewhere that using a MAF that is too big will cause low end resolution problems or something like that. What is that? Is thait a tuning issue?

Thanks in advanced :beer:



P.S. Sorry if this topic has been beat to death. I just need answers quickly so i can get this ordered.

 

[cj428mach]

Ok, so i need some help with this. I've read and read and still cant decide what MAF to go with.
Back info: Im looking to got to the JLT HB CAI and will need either a ba2600 or ba 3000. I currently have a stock cobra intake and a lightning MAF, however, i have not gone to the tuner yet for the new build. Ill be going late next week which is why i need help so i can get this ordered.

Build: Built 2v with KB 2.8H
According to Tim Barth with MPH, i should be somewhere in the 650-700rw range on a 93 octane tune.

So what MAF do i go with?
Is there a chance of me pegging the 2600?
Is the 3000 too big?

I read somewhere that using a MAF that is too big will cause low end resolution problems or something like that. What is that? Is thait a tuning issue?

Thanks in advanced :beer:



P.S. Sorry if this topic has been beat to death. I just need answers quickly so i can get this ordered.

Whats your power output? The stock Cobra/Lightning MAFs are good for close to 500 rwhp. I have a 2400 and it should be good for over 600rwhp. The 2600 I think is good for closer to 650-700ish.

 

[Tim99GT]

Whats your power output? The stock Cobra/Lightning MAFs are good for close to 500 rwhp. I have a 2400 and it should be good for over 600rwhp. The 2600 I think is good for closer to 650-700ish.

HP/Tq wise? I dont know yet. This is a fresh build and i go next week for a base tune to break the motor in. I was just wanting to get this on before going in for the base tune. As stated previously, Tim Barth said i should be somewhere in the 650-700 range with this setup.

 

[KINGCOBRA86]

Are you getting the nex gen high boost cai or a old one?

 

[Tim99GT]

Well i have the older CAI (I need a elbow and maf adapter) but since i will need to upgrade the MAF i was debating on getting the next gen intake so that the maf will mount to the intake itself and then i would sell the intake i have now. This way there would be no restriction on the intake side vs using the old intake.

Thoughts? Worth doing?
I still need a new MAF regardless

 

[KINGCOBRA86]

Your right a big maf will cause resolution problems, the new hb cai puts a sct maf in a 4" tube, so that means your maf will gain more resolution, if you ask me a 2600 will be fine in the nex gen hb cai, another option is a 05 stang maf vmp sale a kit for are cars, the resolution a lot better

 

[Tim99GT]

Can you explain the resolution problem when using a larger MAF than needed?

 

[KINGCOBRA86]

Mostly driveability, you want your maf range at 80-85%

 

[Tim99GT]

Ok, so whats better/ will give me the best drive-ability?

Option 1:
Stock intake/JLT CAI intake i have with VPM 100mm MAF kit (Says supports over 800RW)

Option 2:
JLT CAI intake i have now with ba2600

Option 3:
Next Gen JLT CAI with ba2600 mounted to the intake

The reason for listing the latter(opt 3) is bc i can sell the JLT i have now to my younger brother who has a 04 cobra so ill re-coop some of the money to be able to upgrade.

 

[KINGCOBRA86]

Really any one

I'm thinking Option 1... Option 2 you can do with a mafia and stock maf and turn the dial as you grow in power

 

[Tim99GT]

Ok
Another question:
Given the VPM MAF kit supports up to 800rw, would this not create more of a resolution issue than option 2 or 3? The reason i ask is bc i dont think ill be anywhere close close to this on the 93 octane tune. Im thinking ill probably be around the high 600rw range on the final tune. I mean i hope it makes more by all means but if it doesn't i don't want to have to get another MAF bc of drive-ability issues with the huge VPM MAf. Or am i completely off base with this?

EDIT: I do like the look of the stock intake and VPM MAF kit though lol

 

[KINGCOBRA86]

Call vmp see if they can sale you a stock 05 up maf with there kit,

 

[cj428mach]

Can you explain the resolution problem when using a larger MAF than needed?

I was reading a file on tuning and saw this and thought of you. Maybe it helps answer your question.

Resolution - basically, it has to do with airflow vs. MAF voltage. Two factors affect it: Physical size of the MAF, and injector size it's calibrated for. For example:

(all numbers are hypothetical and just to describe resolution)

Meter "A" - Can flow up to 800 cfm. Calibrated for 19# injectors
Meter "B" - Can flow up to 1000 cfm, calibrated for 42# injectors

Typical MAF airflow during normal driving will range from 50-200 cfm. This is the same no matter what MAF you are using.

Now, Meter "A" flows 800 cfm at 5v. Meter "B" flows 1000 cfm at 5v. 200 cfm difference, big whoop, right? Wrong.

Now, at 1.25v, Meter A flows 200 cfm. At the same 1.25v, Meter B flows 250 cfm. Do you see the trend here? When you start getting into lower voltages/airflow levels, the bigger MAF has a harder time covering the bigger spread of airflow with the set amount of voltage available.

Kinda like fooling with the "mouse" speed on your computer. Set it up to as fast as it goes, and you can easily move from side to side on the screen with a flick of the wrist. Try to select a single letter in a text document at the high speed, though, and it's a whole new ball game. The amount of distance the pointer covers vs the amount the mouse actually moves makes it very difficult to define exactly where you want to be when it is a very small area. Set the mouse speed to slow, and you can easily select what you want.
​

 

[Tim99GT]

I was reading a file on tuning and saw this and thought of you. Maybe it helps answer your question.

Resolution - basically, it has to do with airflow vs. MAF voltage. Two factors affect it: Physical size of the MAF, and injector size it's calibrated for. For example:

(all numbers are hypothetical and just to describe resolution)

Meter "A" - Can flow up to 800 cfm. Calibrated for 19# injectors
Meter "B" - Can flow up to 1000 cfm, calibrated for 42# injectors

Typical MAF airflow during normal driving will range from 50-200 cfm. This is the same no matter what MAF you are using.

Now, Meter "A" flows 800 cfm at 5v. Meter "B" flows 1000 cfm at 5v. 200 cfm difference, big whoop, right? Wrong.

Now, at 1.25v, Meter A flows 200 cfm. At the same 1.25v, Meter B flows 250 cfm. Do you see the trend here? When you start getting into lower voltages/airflow levels, the bigger MAF has a harder time covering the bigger spread of airflow with the set amount of voltage available.

Kinda like fooling with the "mouse" speed on your computer. Set it up to as fast as it goes, and you can easily move from side to side on the screen with a flick of the wrist. Try to select a single letter in a text document at the high speed, though, and it's a whole new ball game. The amount of distance the pointer covers vs the amount the mouse actually moves makes it very difficult to define exactly where you want to be when it is a very small area. Set the mouse speed to slow, and you can easily select what you want.
​

This helps alot! :beer:

 

[cj428mach]

This helps alot! :beer:

My EEC in my street rod has 30pts (basically graph points) of air flow to cover the 0-5 volts the MAF sensor sends out. For each point on the graph you have a known voltage and airflow that happens at that point. So when the computer sees that voltage it says hey I'm flowing this much air, now I need to add this much fuel. So rarely when you're hitting the throttle does it land on exactly one of those 30 voltages. So most of the time the computer has to calculate what the airflow is between any two voltages (points on the graph) to be able to put in the fuel and this number may not be 100% correct.

Now its easy to see that if you had a MAF that flowed 30 kg/hr of air that you have 30 pts to cover (plot you air flow) so each point on the graph would cover 1 kg/hr.

If you had a MAF that flowed 3000 kg/hr of air that you would have 30 pts to cover your air flow so each point on the graph would have to cover 100 kg/hr. So when the eec gets its voltage from the MAF and it falls between two points on the graph its calculation isn't as good.

Ideally you want your MAF to cover the airflow of the engine with just a little safety factor in. For another example, if your engine flows 800 kg/hr and you have a big maf that flows 1600kg/hr then you're wasting approx. half your data points for the EEC to use to calculate airflow that could be used in lower voltages (aka daily driving). If you have a MAF that flows 1000kg/hr on your 800 kg/hr motor then you shifted more of those datapoints down into lower voltages.
here is a maf curve if that helps explain how it all works.

voltage / airflow in kg/hr

maxv 1686.489
4.840 1485.619
4.679 1342.411
4.519 1220.115
4.359 1104.788
4.198 993.581
4.038 887.442
3.877 789.225
3.717 700.196
3.557 619.721
3.397 547.483
3.236 481.899
3.076 421.385
2.916 364.989
2.755 313.029
2.595 264.870
2.434 222.098
2.274 184.712
2.114 153.346
1.953 127.366
1.793 106.138
1.633 87.762
1.472 71.287
1.312 55.762
1.152 41.822
.991 30.099
.831 22.178
.671 16.475
.644 13.941
0 0

Not a perfect answer but it gets it close I think.

 

[Tim99GT]

Thanks for the info and explanation!. I get it now.
I think i may just go with the mafia and call it a day since i already have a 90mm MAF and JLT intake.
If i have understood correctly, i can change settings on the mafia as needed to better the sensor mapping spread (For lack of a better term) for my setup. This would mitigate the stress of buying a MAf that is too large or one that is too small and having to repurchase.