Jump to content
HybridZ

MAF Placement?


ihiryu

Recommended Posts

I'm having a hell of a time of getting my car to stay idling.  I think it's the distance of the MAF.  I've got it about seven inches away without a filter.  She'll idle with the hood open, but the moment I shut the hood, no bueno.  I'm trying to figure out how to relocate the MAF over by the intercooler, but I have no idea on  how I should go about it.

 

I would run it as a blow through style, but I don't have a lot of room, and it seems like I've got a good bit of blow by.

Link to comment
Share on other sites

If you have room and running low boost , i'd install it after the intercooler ( better reading on air temp. ) . Check your PCV system for blow-by problem . Most cars i've worked on don't like to idle when MAF sensor is sitting naked without filter or long intake boot . Too much turbulence at the sensor causes to have irractic reading .

Link to comment
Share on other sites

That's the thing, I don't have anything going to the valve covers right now, but I'm starting to see oil leaking from my intake manifold's vacuum ports underneath of the plenum (even though it passes a boost leak test?).

 

So I'm a little iffy if I should place it in a blow through setup.

Link to comment
Share on other sites

Don't do a blow threw setup. Your going to open a whole new can of worms. You want the air flow meter at least 12 inches away from the turbo so you don't have turbulence problems. The farther away the better.

  • Like 1
Link to comment
Share on other sites

Don't do a blow threw setup. Your going to open a whole new can of worms. You want the air flow meter at least 12 inches away from the turbo so you don't have turbulence problems. The farther away the better.

That's why " blow through setup " is better , keeping the MAF sensor farther away from the turbo and the throttle body . It's better to have it after the intercooler for better reading on air temp. . If you have a thin cheap plastic MAF sensor housing and running high boost then this method is not recommended .

Link to comment
Share on other sites

Your going to have tuning issues with a blow though set up. The system wasn't designed for a blow though set up ( ask me how). I learned alot with my rb set up one thing is the K.I.S.S rule... Keep it simple stupid. Just place the MAF 1 foot or more away from the turbo and your done. Drive it and enjoy!

 

When I had my rb20 I had the same problem. I had the MAF placed in front of the intercooler. Nice and cool air. I ran tubing from the MAF to the turbo. Easy as pie. Problem fixed and fixed fast.

Link to comment
Share on other sites

Your going to have tuning issues with a blow though set up. The system wasn't designed for a blow though set up ( ask me how). I learned alot with my rb set up one thing is the K.I.S.S rule... Keep it simple stupid. Just place the MAF 1 foot or more away from the turbo and your done. Drive it and enjoy!

 

When I had my rb20 I had the same problem. I had the MAF placed in front of the intercooler. Nice and cool air. I ran tubing from the MAF to the turbo. Easy as pie. Problem fixed and fixed fast.

Was your MAF sensor on the intake or discharge side of the turbo ?

Link to comment
Share on other sites

I cut a hole in the core support for another pipe to pass through. Then I had to put a 90 degree coupler in. I made a flange out of sheet metal and exhaust tubing for a flange to mount up to the MAF. I think I posed pics on hybridz years ago.

Link to comment
Share on other sites

Nissan MAF runs off a heated wire and it uses that wire to measure the amount of air that passes that wire. The ecu measures the air by how much power it take to keep that wire a certain temp. So when you run a blow threw set up that air intake changes because of the heat generated by compressing air by the turbo. That intake charge temp is a lot higher than it would be if it was stock even when it passes through the intercooler. On a nice and hot day with heat soak your looking at 200f + degrees higher than the intake charge before the turbo . So with that said it will have to be tuned for that blow through set up. And I wouldn't think the stock MAF would stand up to that temp for very long.

 

K.I.S.S keep it simple stupid. Sometimes we try to redesign the wheel when the original wheel works perfect to start with.

Edited by pat1
Link to comment
Share on other sites

Nissan MAF runs off a heated wire and it uses that wire to measure the amount of air that passes that wire. The ecu measures the air by how much power it take to keep that wire a certain temp. So when you run a blow threw set up that air intake changes because of the heat generated by compressing air by the turbo. That intake charge temp is a lot higher than it would be if it was stock even when it passes through the intercooler. On a nice and hot day with heat soak your looking at 200f + degrees higher than the intake charge before the turbo . So with that said it will have to be tuned for that blow through set up. And I wouldn't think the stock MAF would stand up to that temp for very long.

 

K.I.S.S keep it simple stupid. Sometimes we try to redesign the wheel when the original wheel works perfect to start with.

Would it be better to have actual air temp reading after intercooler then before , so ECM can calculate for actual temp before intering the throttle body ? I have read and seen setups where MAFs mount after intercooler , work better and fix idle problem . HKS sells a hardware that fixes ( helps ) idle problem with MAF that mounts too close to the intake side of the turbo . I agree that you need to keep MAF sensor away from turbulence air . If you get 200F + higher than intake side after the intercooler then you need a larger and more efficient intercooler . Blow htrough is just an alternative if you don't have space and try to fix idle problem .

Edited by Domzs
Link to comment
Share on other sites

  • 3 months later...

Sorry to revive an old thread, but those who ran the blow-through maf, did you have to retune after this or was this on a stock ecu?

 

I'm running a z31 ecu on my L28ET, and I just don't have room to route my intake with my A/C Compressor in the way. I'm debating going blow-through, but I'm holding off on Nistune for a little bit longer. I wanted to be sure I could run blow-through on a stock ECU.

Link to comment
Share on other sites

  • 1 month later...

Can some one explain what the turbulence from the turbo do to the maf signal in detail? I currently have mine about 7-8" from the turbo but mine idles fine. My problem is that the ECU starts to freak out as the car warms up and retards the timing as if it is getting a lot more air than it is really getting. When I first start the motor from cold state everything looks normal. The timing is at 15 degrees like it should be but as the motor warms up the timing starts to pull back until it is below zero. There is a Red/Green indicator at the bottom of my consult that tells you if it is running lean or rich and once the motor has warmed up it stays Red/Lean and the motor wont make any power unless the CAS is fully advanced. I have been frustrating my self with this problem for about a year so if anyone has some insight please let me know.

Link to comment
Share on other sites

The turbulence causes extra air flow around the MAF which cools the hot wire faster. This makes the engine think it is getting more air than it is. Moving the MAF farther from the recirc and/or turbo decreases the turbulence and gives a more accurate air reading. Putting a 90 degree bend in the intake piping between the MAF and turbo should also help this problem.

Link to comment
Share on other sites

  • 1 month later...

I know this is super late, but I finally have been able to get back on HZ :)

 

Anyway, I ended up redoing the intercooler piping on the left side.  Flipping some pipes around, rewelding, and cutting the hole a little bigger was I was able to put the MAF in front of the grill.  It runs a lot better, but sometimes still stalls, but at least it's actually idling now, versus never idling at all.

 

Speaking of idle, sometimes she idles really really high....oh well, one step at a time :)

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...