Dyno Comparison Text: DBX VS PMAS MAF

[modo]

1700+cfm... nuff said

if its just cfm that matters then tell me why on a blow through setup you will lose headroom and a meter will peg sooner?

 

[Addermk2]

And for comparison purposes... here is an LMAF vs the black sample tube 76mm C&L i'm running (it was cheap, and I needed my car to run) As you can see.. it flows pretty damn high before it will "peg"

1200CFM aint nothing to sniffle at.. so do I think venom's completely over priced and under powered tank of an engine would be fine with an LMAF.... yup

 

[Addermk2]

if its just cfm that matters then tell me why on a blow through setup you will lose headroom and a meter will peg sooner?

because as amazing as this may sound... some people are still stupid enough to put the maf AFTER the turbo or S/C

MAF's cant read pressure. and in a pressurized environment, the maf will not read properly and you can't get as much out of it

 

[Paul]

I don't know enough about the LMAF to have an opinion on this, but does anyone have the transfer tables to back up the 475 hp "pegged meter" claim?

i don't have any maf stuff on my computer anymore since i ditched mass air all together a long time ago. a quick search on the corral or hardcore5.0 will show the same as i have stated or a quick email to bob kurgan / don lasota will provide the same.

While alluding to authority figures is nice and all, I prefer to see data to back up a claim like that. Do you have some info that you could share?

I hate MAF as well, and was very happy to see it go on my last car, but that is irrelevant to the discussion.

Paul.

 

[modo]

if its just cfm that matters then tell me why on a blow through setup you will lose headroom and a meter will peg sooner?

because as amazing as this may sound... some people are still stupid enough to put the maf AFTER the turbo or S/C

MAF's cant read pressure. and in a pressurized environment, the maf will not read properly and you can't get as much out of it

really... then why do they sell blow through meters if a meter will not read properly

 

[modo]

I don't know enough about the LMAF to have an opinion on this, but does anyone have the transfer tables to back up the 475 hp "pegged meter" claim?

i don't have any maf stuff on my computer anymore since i ditched mass air all together a long time ago. a quick search on the corral or hardcore5.0 will show the same as i have stated or a quick email to bob kurgan / don lasota will provide the same.

While alluding to authority figures is nice and all, I prefer to see data to back up a claim like that. Do you have some info that you could share?

I hate MAF as well, and was very happy to see it go on my last car, but that is irrelevant to the discussion.

Paul.

sure if you consider helping tune cars on the dyno enough verification. i do not have anything on this computer as i don't mess with the factory eec computers much anymore. just fast, aem, bigstuff etc

 

[Paul]

How about instead of posting snide questions with an arrogant tone, you start conveying information? I don't permit bullshit in my tech forums.

 

[Addermk2]

if its just cfm that matters then tell me why on a blow through setup you will lose headroom and a meter will peg sooner?

because as amazing as this may sound... some people are still stupid enough to put the maf AFTER the turbo or S/C

MAF's cant read pressure. and in a pressurized environment, the maf will not read properly and you can't get as much out of it

really... then why do they sell blow through meters if a meter will not read properly

notice a maf must be "calibrated for" or "tuned for" blow through... its because they have to set ridiculous values to get proper readings from them.

you dont really think that a company would make a product and claim that it will fix your problems.... do you?
I would be willing to bet the title of my car on the fact that a pre-charger maf system is not only more accurate, but easier to tune, than a post-charger, or... blow through

 

[modo]

How about instead of posting snide questions with an arrogant tone, you start conveying information? I don't permit bullshit in my tech forums.

http://www.lasotaracing.com/Late%20model%20maf.html

about 1/2 way down...

 

[modo]

if its just cfm that matters then tell me why on a blow through setup you will lose headroom and a meter will peg sooner?

because as amazing as this may sound... some people are still stupid enough to put the maf AFTER the turbo or S/C

MAF's cant read pressure. and in a pressurized environment, the maf will not read properly and you can't get as much out of it

really... then why do they sell blow through meters if a meter will not read properly

notice a maf must be "calibrated for" or "tuned for" blow through... its because they have to set ridiculous values to get proper readings from them.

you dont really think that a company would make a product and claim that it will fix your problems.... do you?
I would be willing to bet the title of my car on the fact that a pre-charger maf system is not only more accurate, but easier to tune, than a post-charger, or... blow through

actually a blow through maf is easier to tune especially on cars with high boost since the bypass valve usually creates a lot of back wash to the maf and can cause a lot of driveability issues. a maf can read properly under positive pressure as it is just calculating volume

 

[Addermk2]

not many people run "bypass" valves anymore...just an FYI

Ive tuned a couple hefty runners, and never have I had more trouble.. then when the maf was put after the charger.

Putting the MAF into the charge side subjects it to the inherent rise in temperatures found in the intake path of a boosted car. The ambient values would not be skewed as much, or rather ARE NOT skewed when the maf is kept pre-charger.

 

[Paul]

How about instead of posting snide questions with an arrogant tone, you start conveying information? I don't permit bullshit in my tech forums.

http://www.lasotaracing.com/Late%20model%20maf.html
about 1/2 way down...

Now we're getting somewhere.

For the rest of you since modo elected not to copy/paste the information:

Usually on a stock 1989-2004 GT, the MAF is good to around 300 RWHP - some will peg sooner, some later. 80mm Lightning MAFs add a little to that, about 350-375 RWHP, while 90mm Lightning MAFs will peg at about 450 RWHP. SCT BA 2400 MAFs are good to around 625 RWHP and the BA 2800 are good to near 800 RWHP or so.

That said, I don't believe everything I read on the interwebz. While LaSota is probably not making this stuff up out of the blue, there seems to be an obvious disconnect between an air tube that flows 1700 cfm, and one which pegs at such a (relatively) low horsepower level. 1700 cfm can certainly support far greater than 450 rwhp, so I'd like to know WHY it pegs so early.

Paul.

 

[modo]

not many people run "bypass" valves anymore...just an FYI

Ive tuned a couple hefty runners, and never have I had more trouble.. then when the maf was put after the charger.

Putting the MAF into the charge side subjects it to the inherent rise in temperatures found in the intake path of a boosted car. The ambient values would not be skewed as much, or rather ARE NOT skewed when the maf is kept pre-charger.

without the bypass valve you would have compressor surge so i don't know what you mean by the fyi unless you are referring to a bov and venting to the atmosphere, either way they are the same and are needed.

inlet temps are best measured in the intake runner #5 at the factory location. moving it to the discharge tube or father away from the intake valve is bad practice. poor mans way of adding timing. regardless the maf has no bearing on the inlet temp measurements on the eec-v

 

[Addermk2]

without the bypass valve you would have compressor surge so i don't know what you mean by the fyi unless you are referring to a bov and venting to the atmosphere, either way they are the same and are needed.

they are definitly NOT the same, and should not be treated as such. This isnt my first pony show. ive been doing this stuff for quite some time.

inlet temps are best measured in the intake runner #5 at the factory location. moving it to the discharge tube or father away from the intake valve is bad practice.

so thats why ford opted to move it away from the manifold?? im pretty sure it more had something to do with the fact that the metal of the manifold itself was infact radiating heat into the sensor, causing false readings. Pretty sure I could prove this too, but I dont have the spare cash to waste on supplies!

poor mans way of adding timing.

again... ford must be "a poor man"

regardless the maf has no bearing on the inlet temp measurements on the eec-v

actually, on an EEC-V system, the maf has EVERYTHING to do with inlet temps.. thats there the 6 wire plug came into play. the 6 wire maf's read ACT

 

[Paul]

regardless the maf has no bearing on the inlet temp measurements on the eec-v

Just for argument's sake, could inlet temperatures significantly above ambient (perhaps approaching or exceeding 200 degrees F) artificially affect the rate at which the MAF filament cools (or in this case fails to cool) causing irregular airflow-to-voltage readings? I guess I could imagine this type of occurrence in a blow-thru setup.

 

[modo]

without the bypass valve you would have compressor surge so i don't know what you mean by the fyi unless you are referring to a bov and venting to the atmosphere, either way they are the same and are needed.

they are definitly NOT the same, and should not be treated as such. This isnt my first pony show. ive been doing this stuff for quite some time.

inlet temps are best measured in the intake runner #5 at the factory location. moving it to the discharge tube or father away from the intake valve is bad practice.

so thats why ford opted to move it away from the manifold?? im pretty sure it more had something to do with the fact that the metal of the manifold itself was infact radiating heat into the sensor, causing false readings. Pretty sure I could prove this too, but I dont have the spare cash to waste on supplies!

poor mans way of adding timing.

again... ford must be "a poor man"

regardless the maf has no bearing on the inlet temp measurements on the eec-v

actually, on an EEC-V system, the maf has EVERYTHING to do with inlet temps.. thats there the 6 wire plug came into play. the 6 wire maf's read ACT

i have been playing with mustangs since the mid 90s. you see that car in my signature. 9.20s on pump gas, self tuned.

now, a bov and a bypass functionally are the same, one dumps it back to the inlet, since it is metered the other dumps it. they both prevent compressor surge. now here is a fyi, all vortech and paxton kits today come with bypass valves. procharger kits come with bov due to the blow through maf

the inlet temp sensor is suspended in air and insulated, as long as it is functioning correctly it is not going to be heat soaked. i don't know about you but i want the readings controlling my ignition timing as close to the intake valve as possible. putting the iat sensor in out of the intake imo is bad practice. i like my pistons

i meant to type iv... i forgot i am on a sn board. only thing you got me on

 

[modo]

regardless the maf has no bearing on the inlet temp measurements on the eec-v

Just for argument's sake, could inlet temperatures significantly above ambient (perhaps approaching or exceeding 200 degrees F) artificially affect the rate at which the MAF filament cools (or in this case fails to cool) causing irregular airflow-to-voltage readings? I guess I could imagine this type of occurrence in a blow-thru setup.

shouldn't the meter is designed for that in a blow through style. proper tune based on iat would add fuel / pull timing at that point anyways... that is up till i believe 2003 when ford took the ability to add fuel based off of iat away. no idea why since it is a great safeguard when using meth injection

 

[modo]

How about instead of posting snide questions with an arrogant tone, you start conveying information? I don't permit bullshit in my tech forums.

http://www.lasotaracing.com/Late%20model%20maf.html
about 1/2 way down...

Now we're getting somewhere.

For the rest of you since modo elected not to copy/paste the information:

Usually on a stock 1989-2004 GT, the MAF is good to around 300 RWHP - some will peg sooner, some later. 80mm Lightning MAFs add a little to that, about 350-375 RWHP, while 90mm Lightning MAFs will peg at about 450 RWHP. SCT BA 2400 MAFs are good to around 625 RWHP and the BA 2800 are good to near 800 RWHP or so.

That said, I don't believe everything I read on the interwebz. While LaSota is probably not making this stuff up out of the blue, there seems to be an obvious disconnect between an air tube that flows 1700 cfm, and one which pegs at such a (relatively) low horsepower level. 1700 cfm can certainly support far greater than 450 rwhp, so I'd like to know WHY it pegs so early.

Paul.

easy answer to why it falls short even though the cfm is high is simply resolution. by spreading more cfm across the voltage you are basically allowing for larger injectors. the cfm isn't a true measure to base max hp off of.

 

[Paul]

shouldn't the meter is designed for that in a blow through style. proper tune based on iat would add fuel / pull timing at that point anyways... that is up till i believe 2003 when ford took the ability to add fuel based off of iat away. no idea why since it is a great safeguard when using meth injection

I see. That's a good point - I hadn't thought about that when I was running through this in my head.

Couple things here:

1) I have to agree with modo on the bypass/BOV comment. Functionally they do the same thing. A speed density setup (i.e. one in a FAST or AEM) will not care where the vented air goes to. In a MAF setup, the situation would obviously be different.

2) I think Addermk2 raises a good question about why Ford elected to move the IAT sensor from the #5 runner on foxbody cars to the air inlet pipe before the throttle body on the 94-95 5.0s. Fundamentally, my preference would indeed be for the #5 runner, but it does beg the question... why did a room full of engineers at Ford move it to the inlet?

3) I still don't know why a 90mm LMAF will peg at such a low horsepower number. What is so different between that meter and a similarly-sized aftermarket meter that one outperforms the other to such an extent?

Paul.

 

[Addermk2]

i have been playing with mustangs since the mid 90s. you see that car in my signature. 9.20s on pump gas, self tuned.

now, a bov and a bypass functionally are the same, one dumps it back to the inlet, since it is metered the other dumps it. they both prevent compressor surge. now here is a fyi, all vortech and paxton kits today come with bypass valves. procharger kits come with bov due to the blow through maf

the inlet temp sensor is suspended in air and insulated, as long as it is functioning correctly it is not going to be heat soaked. i don't know about you but i want the readings controlling my ignition timing as close to the intake valve as possible. putting the iat sensor in out of the intake imo is bad practice. i like my pistons

i meant to type iv... i forgot i am on a sn board. only thing you got me on

lets get away from the bov vs bpv talk for right now because you clearly arent picking up what im putting down.
I can totally understand wanting to read IAT as close to the actual cylinder as possible. In a perfect world. yes, you are correct.

but what kind of velocities do you recon the air charge is moving at.. lets say... 4500RPM's, WOT...

now at at 900' down the 1/4... after the car has been sitting in the staging lanes for a half hour.do you really think the ECM is gonna read two terribly different things from the IAT vs the ACT? Sure there may be SOME variance.. but from a tuning perspective... its already covered.