Removing Gtr Afm Screens

[gtr fan]

Hi All,

I am going to install some garrett turbos on my gtr and will be looking for around 300-330 rwkw and am trying to avoid the cost of buying Nismo AFM's. I read an old article that Tillbrook Automotive in SA (I think) removed the screens standard AFM's, which allowed a bit more resolution with tuning.

Does anyone else agree with this method for what I am chasing or should I be buying Nismo AFM's?

[Blitz]

Wait and see how your current afm's hold up before spending money on replacements.

My factory afm's were fine up to 350awkw in my last GTR.

Aside from that, i can't see how there would be any great benefit in removing the mesh.

[gtr fan]

Thanks Nick.

The article quoted the following food for thought;

de-screen the existing 65mm afm's, which adds around 8% cross-sectional area. This is enough that the tuning process with the Power FC is given more resolution at boost levels close to 1.5 bar.

I will just leave them as they are then and see how it goes.

[Blitz]

Interesting.

Though I have heard of it being done, if I got to the stage where I was maxing my current afm's I would rather replace them all together than remove the mesh, as I see that as more of a bandaid solution.

I guess it also comes down to the car and tune in question - If modifying the stockers works in your situation, great

[STATUS]

It can introduce reversion issues as the mesh helps dampen the pulses at idle and on decel etc.

[gtr fan]

It can introduce reversion issues as the mesh helps dampen the pulses at idle and on decel etc.

Theres and interesting point I hadn't heard of.

Decision is made if they max out, replace with nismo items.

[Swiper the Fox]

Theres and interesting point I hadn't heard of.

Decision is made if they max out, replace with nismo items.

or put a Vi-pec plug-in in it and throw the bastards away.

[gtr fan]

or put a Vi-pec plug-in in it and throw the bastards away.

Whats a Vi-Pec worth? Would also have to plug in a Map Sensor?

No real disadvantages with getting rid of AFM's?

Edited February 12, 2010 by gtr fan

[paulr33]

removing the mesh would achieve zero, if anything as status said, it would cause reversion and probably make it run worse

you can stretch the point at where an AFM maxes, so effectively keep using it even though it maxes out (MAP sensor style) and it is OK, but if you max the AFM at 4000prm this is bad and you need to change to larger scale items. maxing them at 6700rpm is probably OK (map sensor style).

please run up on map sensors and how they work before going to them just because, you can probably make 300rwkw OK with the stock afms

[R31Nismoid]

They max out around 280-300rwkw. However if your tuner is decent and you trust them... you can tune past the max.

It's certainly been done before!

Just be warned though that in varying temp conditions, the tune won't be 100% so it'll be "safer" past the max point that you would otherwise have if AFM's were replaced.

IMO just get the Nismo AFM's from perfectrun.

At the end of the day, your AFM's are more than likely dying anyway after 10+ years. So little "quirks" during tuning can pop up, even intermittent problems you can spend months chasing only to find out its a AFM playing silly games

[lachlanw]

why not buy some rb20/25 ones . theyre cheap as f**k

[R31Nismoid]

And still 2nd hand, which presents the same issues still with regards to reliability and failure.

Seems around the 10years marker that they start to degrade. Obviously a broad assumption (some sooner, some last longer).

But given the issues i've seen with people & AFM's, after 10 years especially if you are upgrading parts for more performance... AFM's are just a given to chance to brand new items.

[STATUS]

And still 2nd hand, which presents the same issues still with regards to reliability and failure.

Seems around the 10years marker that they start to degrade. Obviously a broad assumption (some sooner, some last longer).

But given the issues i've seen with people & AFM's, after 10 years especially if you are upgrading parts for more performance... AFM's are just a given to chance to brand new items.

TBH i agree, most of the tuning issue's we run into with skylines revolve around coilpacks and afm's.

[Duncan]

yes and remember that rb20 or rb25 afms still max out at the same airflow...they just have larger cross section. you need to decide which problem you are trying to solve - restriction (get rb25 or rb20 ones) or outside the resolution/over 5v (get z32 or nismo ones)