AFM delete but retain stock airbox

[finnthehuman]

Hi there,

I am currently installing the Ms Labs MS2 megasquirt ECU and I am replacing the flappy AFM with an AIT sensor instead.

My aim is to retain as a stock looking engine bay as possible, I also do not like open air filters due to the fact they are inheriently near to the exhaust manifold and can inhale warm air.

My plan is to retain the stock airbox whilst removing the AFM.

I plan to achive this by using a 1.8 airbox top as it flows better than the Square inlet on the 1.6 box and then manufacture a replacement pipe in the stock 1.8 MAF sensors place. This will have a welded bung on top to allow for insertion of the AIT sensor. The stock airbox will then be plummed into the bulkhead to hopefully enjoy some of the cooler higher velocity air in the same vein as the randall intake.

My question is, has anyone else completed this? If so, what were your methods and do you have any pictures?

Thus far it is proving difficult to make the pipe stay inside the 1.8 airbox top as there is little for it to be bolted onto due to the way the MAF fits in. My current frame of mind is to have a machine shop make a replica of the 1.8 maf from alloy but without the restrictive inside parts.

Any help is appreciated.

[vortexblue]

I built one of these about 3-4 years ago.
Drew it up in SolidWorks and printed it out on the 3d printer using ABS. The build area was too small, so I made it in 2 parts and epoxied it together. It's for the 1.6 airbox, for my 1.6L running MS3. It's held up just fine.

http://chris.chemidl.in/images/cars/mazda/90/airbox.jpg

http://chris.chemidl.in/images/cars/mazda/90/airbox2.jpg

[finnthehuman]

wow vortexblue that looks amazing! that is essentially what I am trying to do, just with the stock top piece.

Would you consider selling the STL file so that I could have one printed here? (a one use license rather than sell the design)

[vortexblue]

Sorry I haven't been back in a bit.

I would consider it; I sent a PM to you. The file is in 1 piece; whomever is printing it for you will need to have the ability to split the STL to fit the build area. The Stratasys software I used on the above print made that wobbly line to get a good 'puzzle fit'.

[freedomgli]

Instead of doing the IAT/MAP route for speed density tuning, why not simply use a hot wire MAF from a NA8? That is about as stock looking as you can get.

[vortexblue]

Are there any benefits to switching the IAT/ MAP setup to the MAF other than looks?

I'm running my MS3 it IAT/ MAP and it works ok, but I'm always looking to make things easier/ better...

[finnthehuman]

Instead of doing the IAT/MAP route for speed density tuning, why not simply use a hot wire MAF from a NA8? That is about as stock looking as you can get.

Thank you for the replies.

I remember reading online I beleive someone tested the flow and the 1.8 MAF was actually more restrictive than the the 1.6 flappy AFM.

I am looking for as good a flow as possible really.

[finnthehuman]

Are there any benefits to switching the IAT/ MAP setup to the MAF other than looks?

I'm running my MS3 it IAT/ MAP and it works ok, but I'm always looking to make things easier/ better...

I am doing it due to the restrictive AFM/MAF as I want improved airflow, which is also why I am looking to change the top of the airbox as the 1.6 square outlet is smaller than the 1.8's round, but it is impossible to attach a joiner pipe to this box as it does not protrude enough.

This website details some of the restriction in the 1.6 intake tract. (it suggests that the afm accounts for 29% of the restriction)

http://www.autospeed.com/cms/article.html?&A=110680

I can't find any literature to support my claims of a restrictive 1.8 MAF but I do remember one.

[freedomgli]

I remember reading online I beleive someone tested the flow and the 1.8 MAF was actually more restrictive than the the 1.6 flappy AFM.

The 1.6 AFM is the most restrictive. The 1.8 MAF is not a significant restriction for most folks below ~300hp. The MAF is more accurate than MAP/IAT. There is a reason that all modern OEMs use a MAF. Some people say it's a little bit easier to tune MAP/IAT than MAF but at the end of the day it's simply a matter of personal preference. Everyone has different skills and priorities and goals. I have no direct experience with tuning MS with MAF so you'll need to do your own research there.

Is one really better than the other: MAF/MAP based tuning (http://forum.miata.net/vb/showthread.php?t=224799)

Just how restrictive is the MAF?? (http://forum.miata.net/vb/showthread.php?t=18715)

[finnthehuman]

thanks for all the replies. took me a while to get the car back in the road after graduating and moving.

my solution was to just fit a 1.8 airbox lid and a straight pipe to replace the maf. i also did the randall intake whilst i was there.

https://i.ibb.co/5GTjN3S/20191210-202143.jpg