Running a MAF
TECH Fanatic
Joined: Aug 2005
Posts: 1,691
Likes: 1
From: Sunny London, UK
use search, this topic is old and dead
A MAF sensor is ill-equipped to measure the airflow past it. Most MAF sensors are based on a hotwire system, or a bending reed. Either way, they are designed to measure the speed at which air is passing them, not the density of the air. A MAP sensor is more likely to work correctly because it measures pressure
A MAF sensor is ill-equipped to measure the airflow past it. Most MAF sensors are based on a hotwire system, or a bending reed. Either way, they are designed to measure the speed at which air is passing them, not the density of the air. A MAP sensor is more likely to work correctly because it measures pressure
Last edited by ringram; Feb 23, 2006 at 03:39 AM.
TECH Enthusiast
Joined: Dec 2005
Posts: 512
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From: Conway, AR
The MAF and VE actually do a blending together until 4k rpm. Its more MAF but VE is there to sort of "check" the MAF. I see no reason not to run it, in the trucks at least it also houses the IAT sensor and you need that even if you were using VE only.
Chris
Chris
I have never seen a MAF that is a bending reed. I have heard of a VAF that does just this, but it is was something that was used in the mid 80's on ford turbo vehicles.
I am a fan of the maf.
Ryan
I am a fan of the maf.
Ryan
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
if the search didn't suck so bad right now, I'd tell you to search (been discussed in detail) ... but it's hard to find anything beyond the beginning of the year 
Most you'll find still run a MAF, generally you disable the MAF to get your VE inline and then people will calibrate their MAF against hte new VE table.
If you plan on running a 2 bar or 3 bar MAP then you want to go Speed Density. Or if you have a 90mm intake and TB, then the MAF is a restriction so a SD tune is best.
I run an LS6 intake and ported TB, and run SD full time since now that the car's dialed in it runs great, and I see no need toput the MAF back on.
Theoretically, a SD tune will make more power than a MAF tune since you're eliminating a constriction in the system... but theory and reality don't always coincide... a well tuned SD tune vs a well tuned MAF tune are probably going to be pretty close (I've never seen a side by side dyno of the same car, first running SD and then running MAF)
Most you'll find still run a MAF, generally you disable the MAF to get your VE inline and then people will calibrate their MAF against hte new VE table.
If you plan on running a 2 bar or 3 bar MAP then you want to go Speed Density. Or if you have a 90mm intake and TB, then the MAF is a restriction so a SD tune is best.
I run an LS6 intake and ported TB, and run SD full time since now that the car's dialed in it runs great, and I see no need toput the MAF back on.
Theoretically, a SD tune will make more power than a MAF tune since you're eliminating a constriction in the system... but theory and reality don't always coincide... a well tuned SD tune vs a well tuned MAF tune are probably going to be pretty close (I've never seen a side by side dyno of the same car, first running SD and then running MAF)
Trending Topics
MAFs work, but I believe in the KISS priciple.
I prefer no MAF in the system for simplicity & the quickness in working the tune & troubleshooting that accompany the simplicity.
I prefer no MAF in the system for simplicity & the quickness in working the tune & troubleshooting that accompany the simplicity.
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Joined: Dec 2001
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From: Central Indiana Honors: 4th grade spelling bee contestant
When I had my car tuned, the thought of not running a MAF had me skeptical at first. I'd never heard of anyone not running a MAF. After being reassured that it would be just fine without it, I agreed to disable it. That was last Summer, and I've yet to experience one problem from not having it. Plus it cleans up the engine bay a little.
The bigger you go, the less accurate they will be with small air mass flow.
IMO in general, MAFs do more for you at low engine speeds than they do at higher speeds, where I think there's pretty much no difference in MAF and SD systems besides the added restriction. That suggests that as you increase the size of the MAF, there really isn't any added benefit in operation besides eliminating the restriction. This only makes sense if you're looking for a way to avoid switching to SD and keep a MAF in the system.
IMO switching to SD is the easier and cheaper way.
A SD or MAP based system could very well outperform an oversized MAF system at every engine speed.
Other than the loss in resolution at low engines speeds, there's no reason the 100mm MAF couldn't be made to work as needed.
I have run a MAF that flowed 25%+ more air than my factory unit. I had to recalibrate the entire MAF table, but it didn't cause any problems or take a long time to adjust for.
IMO in general, MAFs do more for you at low engine speeds than they do at higher speeds, where I think there's pretty much no difference in MAF and SD systems besides the added restriction. That suggests that as you increase the size of the MAF, there really isn't any added benefit in operation besides eliminating the restriction. This only makes sense if you're looking for a way to avoid switching to SD and keep a MAF in the system.
IMO switching to SD is the easier and cheaper way.
A SD or MAP based system could very well outperform an oversized MAF system at every engine speed.
Other than the loss in resolution at low engines speeds, there's no reason the 100mm MAF couldn't be made to work as needed.
I have run a MAF that flowed 25%+ more air than my factory unit. I had to recalibrate the entire MAF table, but it didn't cause any problems or take a long time to adjust for.
I am curious, why did GM run MAF on the C5R and C6R if SD would be better. I realize they run different PCM firmware than what we have to work with but if MAF is so inefficient why would they use it.
TECH Addict
Joined: Jul 2002
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Originally Posted by Gordy M
I am curious, why did GM run MAF on the C5R and C6R if SD would be better. I realize they run different PCM firmware than what we have to work with but if MAF is so inefficient why would they use it.
But then not all MAFs are the same.
FormerVendor
Joined: Aug 2005
Posts: 531
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From: Decatur IN.
in there lies the prob currently what I am working with has crap resolution at cruise speed but is capable of so much more airflow (HP) That it needs to be looked over as yet another tool in the BIG HP arsenal.What we are looking @ is very high HP silky smooth tune that leaves the consumer out of having to learn what all this EFI tuning voodoo is all about...Lets face it LSx motors jumping in streetable horsepower in leaps and bounds everyday...cams are bigger blowers are bigger cubes are bigger ,and everybody wants all that HP and wants to drive it everyday...
So I proposed to Bob today that I build A few more of these 100mm and find a few of you guys to test these BAd boys and find out if there worth the price of admission...
I dont know Im just throwing a hat in the ring....
It is a working unit...
It is capable of sustaining WOT timing
It is capable of of mantaining 600 RWHP and 700 ftlb trq
It has only been at its development stage for only one full day dyno session...
I have not "pegged it" yet
It is obviously going to be a lot of work and we are getting so swamped I just dont when we can get it all sorted or if we should ????
So there it is in a nutshell
What do you guys think it is worth it???
or should we just go full onslaught SD and leave the MAF in the dust..
any and all help would be apreciated
Brent 260-244-4808
So I proposed to Bob today that I build A few more of these 100mm and find a few of you guys to test these BAd boys and find out if there worth the price of admission...
I dont know Im just throwing a hat in the ring....
It is a working unit...
It is capable of sustaining WOT timing
It is capable of of mantaining 600 RWHP and 700 ftlb trq
It has only been at its development stage for only one full day dyno session...
I have not "pegged it" yet
It is obviously going to be a lot of work and we are getting so swamped I just dont when we can get it all sorted or if we should ????
So there it is in a nutshell
What do you guys think it is worth it???
or should we just go full onslaught SD and leave the MAF in the dust..
any and all help would be apreciated
Brent 260-244-4808
Originally Posted by Brent@EPP
or should we just go full onslaught SD and leave the MAF in the dust..
I see the benefits of having a MAF in place to be very few, and feel it's very easy to work around.
The resolution problem will always be a hurtle with current designs.
another possible work around could be using a small MAF for low speed resolution, and a bypass that opens to un-metered air once the MAF has reached a certian flow. I haven't seen anyone go that route, but then again it's so easy just to switch to SD mode.
I have tuned/run my 408 both ways, SD and with an 85mm MAF. I prefer the SD for my application. For one thing, it idles better with a big cam - and as stated, it got a restriction out of my way. The car seems smoother running on the street. Can't say about the power differences, cause I made some other changes at the same time I switched. I am running a Flashscan custom operating system with semi-open loop and SD - couldn't be happier.
