4" Card-Style MAF

Z

ZNix

Young-Gun
Joined
Jun 17, 2009
Hello everyone, I wanted to bring this topic up for discussion. Recently my stock MAF went on me, and now I am looking to find a suitable replacement. Since I was doing it all over, I figured I would just go with a 4" set-up and never have to worry about it again. I've been reading and researching quite a bit over the past few days, and the general concensus I have heard about the 4" card MAFs is that they cause idle problems, and problems at cruise with cutting out. I researched this on LS1Tech and found that people using the LS7 sensor were also having these problems. I stumbled across this thread:

http://www.hptuners.com/forum/showthread.php?26546-100mm-Maf-kickin-my-Butt!!!

and here is the link to the honeycombs:
http://www.saxonpc.com/100mm-cells-for-100.html

Now, I am curious, do you think the honeycomb or airflow straightener will work? Could that be the solution to the MAF problems some people have been having with the LS7 MAF? Or is it something to do with the MAF Translator? The reason I was looking at these sensors is because A. They are cheap B. They have an IAT sensor in them and C. They are just a weld in flange.

Please discuss,
Thank you,
Zack
 
I can't say it's 100% the MAFs fault.

A 4" pipes cross section area is almost twice that of a 3" pipe. The engine is going to be flowing "X" amount of air at idle (and it's not much)... On the 4" pipe that airflow will be going almost half as fast. When the FPS going past the sensor gets too slow I have to assume the resolution is going to suffer.

Depending on what the logs show, the best patch would probably be an open loop idle.

That might be why the cross section area of a "3.5" LS1 sensor is so small (and has the wing in it)
 
But the new style LS MAFs are plastic and have no air foil in it. Many are using them with no issues. There is a member that has a thread on how he used a Spectre Performance intake piece to mount a card style MAF in. He claims he doesn't have any issues with the MAF.
 
the flag style sensor is designed to be used in a min 4" pipe its ability to read only suffers in a smaller pipe. The pipe becomes part of the sensor and moving the sensor in the pipe or changing the shape of the pipe will change how it reads which can make it richer or leaner. The translator calibration is based on the pipe we used to make and worked very well. I wish there was enough demand to keep making them. Anything differernt will require some tuning but will work fine
Mike
 
They aren't exactly cheap, $75 or so just for the sensor, plus you'll need a translator, and a extension for temp sensor, and 4 inch pipe, couplers with the 4 inch slot style Spectre adapter. Be sure the entire intake is 4 inches. I have a stroker, so maybe it uses just a bit more air than a stocker at idle. Scanmaster reads 4-7 at idle (I think mine is set at 850 or so).

Every now and then it goes lean on the wideband (17-18) approaching a light under braking, which I assume is the chip doing its magic, don't know if its maf related.
 
Okay, so what you guys are saying is that the MAF is not the problem, and our engines just don't suck in enough air at idle and cruise. When we are cruising and idling, our air requirements are much lower than an LS7 or bigger cubic inch motor, so the air in the 4" intake isn't moving fast enough to register much if anything on the sensor. My thoughts were that maybe the air straightener would help with turbulence and maybe increase the velocity of the air passing the sensor, but that makes little sense when I think about it. The honeycomb isn't really going to speed up the air. I was thinking I would go with a 3.5" set-up, but I just wanted to discuss this with you guys to see what you thought first. There happens to be a 4" MAF set-up for sale on the board right now, and I was seriously considering it until I had read about the problems. That's the only reason I am not jumping on it right now.
 
The MAF can only measure the air that physically hits it. It has to assUme total airflow based on the pipe it's supposed to be mounted in. With different IDs and/or shapes, you have to tune around any errors.

I.E. Imagine you mounted that 4" MAF inside of a 10" pipe... It would report much much lower airflow than it's actually going through there. On the opposite end of the spectrum, if you mounted the MAF inside of a 2" pipe it would assume there's airflow it doesn't see, yet there won't be much if any. In that case it would be reporting higher than actual.

It's just a factor of the MAF not being mounted in a calibrated passage.
 
earlbrown said:
The MAF can only measure the air that physically hits it. It has to assUme total airflow based on the pipe it's supposed to be mounted in. With different IDs and/or shapes, you have to tune around any errors.

I.E. Imagine you mounted that 4" MAF inside of a 10" pipe... It would report much much lower airflow than it's actually going through there. On the opposite end of the spectrum, if you mounted the MAF inside of a 2" pipe it would assume there's airflow it doesn't see, yet there won't be much if any. In that case it would be reporting higher than actual.

It's just a factor of the MAF not being mounted in a calibrated passage.
Click to expand...

Okay, I understand what you are saying now. And because we really don't have the ability in our computers to tune for each scenario, it causes issues. I was just curious if this honeycomb could fix some of the issues were are having trying to run the MAF sensor.
 
It's simple physics, the air outside the air filter is pushing into the filter, which is pushing into the intake and to the turbo and to the IC/upipe/manifold/cylinders. The easier it is, the easier it is. More air in there is fine, the computer will hopefully adjust the fueling.

I think a full 4 inch intake all the way is the key, no 3 or 3.5 inch adapters anywhere bottle necking until it hits the turbo. FWIW - all else being equal, I can spool up the turbo faster with a 4 than my old 3 inch LT1 maf, and way faster than a stock MAF, and know that I went 130.8 on the stock MAF in the 1/4 with both screens in it...
 
I just bought the setup. I'll see if I can get it to work. If not, I'll sell the 4" stuff and go with a 3.5" ls1 setup.

Posted from the TurboBuick.Com mobile app
 
I run a 4 inch with the card style MAF it goes very rich and has a slight stumble as soon as I let off the throttle but catchs back up quickly I have not tried to tune around it but I'm sure could with the Genll.
Other than that works like a hot dam sounds good too can really hear the turbo spool up.
 
the slot sensor in a 4" pipe can have some wierd turbulence issues at low flow coastdown. It is easily tuned around. That is probably the lean spot you are seeing.

note that the air temp sensor in that MAF is a different calibration than what the ECM is expecting, so I don't use it.

What chip are you using at the moment?

Bob
 
TurboBob said:
the slot sensor in a 4" pipe can have some wierd turbulence issues at low flow coastdown. It is easily tuned around. That is probably the lean spot you are seeing.

note that the air temp sensor in that MAF is a different calibration than what the ECM is expecting, so I don't use it.

What chip are you using at the moment?

Bob
Click to expand...

Bob, do you think the honeycomb would be able to fix the turbulence issues we are having? Might be an option for those who are having trouble.
 
I know someone that has a 2000 SS Camaro. It's missing the screen on the MAF from a previous owner. He's going to try that honeycomb stuff to see if it helps his car behave better. I will find out if he sees any improvement.
 
Jerryl said:
ZNix, how did it turn out?
Click to expand...

Jerryl, I haven't had a chance to put it on yet. I have two weeks left at school, then Ill be able to let you all know how it went. If it has the problems that I have read about, I will order the honeycomb piece and see if that fixes the issues. If it doesn't, I will try and find a way to fix it.
 
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