Builds DIY FJZ80 Low Budget Turbo Build (2 Viewers)

[lilevo]

Any idea what would happen if you changed the coupler to a 3.5" or 4" versus 3"?

 

[scottryana]

You would get too much air at idle. And would see less than the 1v

 

[landtank]

Any idea what would happen if you changed the coupler to a 3.5" or 4" versus 3"?

To do what you guys are trying to do you need to change the sampling size of the unit.

Going with a larger diameter MAF tuned for the same displacement only yields less restriction.

Back when Toyota was turboing 2.2 ltr 4 cylinders they would basically use a Air Flow Sensor from a 3.0lr engine and then augment the injector size accordingly.

So going from 2.2 to 3.0 was an increase of about 40%. And if you look at the flow rates between the two injectors spec'd for the 2.2 NA and T'd you will see the same relation ship.

Following their lead, if you increased the injectors by 40% going from 305 to 427 (440) you would want a MAF tuned for a 6.3lt (4.5x1.4) engine.

Now an ID of 3.5" is about as large as you can go with that sensor I mentioned and I'm betting that if you dropped in the larger injectors with that sensor mounted in a 3" PVC coupler (3.5" id) that engine would start and run.

 

[lilevo]

Ok, put in a 2006 infiniti M45 maf. The o.d is a little bigger than 3".

Stft and ltft are both slightly negative.

No cel's, everything works as it should. Idle is a little lumpy and weird, but otherwise drives great. Definitely notice some low rpm torque increase and smoothness going into boost probably due to less restriction.

Unfortunately the exact same problem exists (maf plateaus around 3500 while at wide open) so I'm back to the drawing board.






Now I'm really interested to see what this voltage clamp does. It should prevent this issue from happening - I'm hoping. Seems to be the ticket for a lot of non turbo to turbo conversions on other models with MAF overrun issues.

 

[NKP Garage]

Just get a 3.5" pipe with the correct MAF flange on it for whichever MAF sensor you want to use, insert an air straightener pre-maf inside the pipe, and you'll have plenty of MAF resolution to tune with There are Toyota sensors that fit both of the following flanges and have the correct connector/plug on them:

Here are two commonly used ones that already have the flange welded on:
http://www.treadstoneperformance.co...er+Pipe,+Subaru,+Scion,+Mazda,+Toyota,+Lexus+

http://www.treadstoneperformance.co...ge+Pipe,+Subaru,+Scion,+Mazda,+Toyota,+Lexus+

 

[landtank]

WOW, there you go!

 

[lilevo]

I don't know how that would help. I just tried a 3" MAF and had the exact same problem.

 

[NKP Garage]

I don't know how that would help. I just tried a 3" MAF and had the exact same problem.

Larger maf housing with the same amount of air passing through means that the maf sensor reads a lower voltage. Therefore giving you more headroom given the same sensor. It will allow you to move much more air through before maxing out the sensor.

 

[lilevo]

I know, but I just tried a 3" MAF in the post right before your first post and the results were nearly the same as the stock MAF. Some type of cut off and the MAF readings stopped at around 3500

 

[NKP Garage]

I know, but I just tried a 3" MAF in the post right before your first post and the results were nearly the same as the stock MAF. Some type of cut off and the MAF readings stopped at around 3500

Very big difference between a 4" and 3.5". There's always a chance hour maf sensor is bad as was suggested earlier. Which maf sensor are you using?

 

[scottryana]

Well and didn't you swap in a Nissan sensor? Lots of variables.

 

[lilevo]

Oem maf at WOT in anything other than 1st gear cuts out, feels like fuel cut, maf reading goes flatline at 3500cfm or whatever the obd2 value is.

Swapped in an 06 M45 3" maf. Better low end off boost and into boost. Same result WOT. Maf readings flatline.

3" gm maf does not work at all.

95-01 Nissan patrol, maxima, skyline maf cuts out worse than stock at wot and its very lean

 

[lilevo]

Hotwire sensor is the same Nissan Toyota, etc. 0-5v, its all the same thing.

 

[landtank]

The diameter of the MAF is not what you are looking for. It's the sample ratio that needs to be altered.

The sensor that I use in my mod will also work in the tubes that Baktasht listed.

That sensor in a 2.9" bore replicates the output of a stock MAF

Now take that same sensor and put it in a 3.5" bore and across the range the output drops. Because at any given amount of air, it is traveling slower through the larger pipe than the smaller one.

You could have a 10" bore and if it was tuned for a 4.5l engine the results would be the same as the stock sensor.

 

[NKP Garage]

You need to stick to one known good sensor and go to a larger housing. Going from a 3" to a 3.5" housing gives you about 37% more flow before maxing out the same sensor.

 

[scottryana]

They can't all be the same thing if they give you different results....

Yep Baktash beat me to it.

 

[lilevo]

Ok, then I misunderstood that the 21010 Toyota sensor was similar or the same as the oem 95-97 MAF.

 

[scottryana]

No it is a Toyota hot wire sensor. It fits in the MAF housings Baktash linked and the LT housing which is larger than stock just not all that much larger

 

[lilevo]

Ok makes sense now. I will find that sensor, pipe, and report back.

 

[landtank]

Ok, then I misunderstood that the 21010 Toyota sensor was similar or the same as the oem 95-97 MAF.

that sensor is used in multiple applications and as the displacement changes they also change the bore that it is in to keep the voltage range constant.

What you are looking to do is to expand that range so you have room for tuning.

You do that by placing it in a larger bore than what it should be fore that application.