Boost the meter or not?

[Loco_R]

I have seen a couple of proyects where people acutally placed the flow meter after the intercooler, and other times more frequently, before the turbo on the inlet side, what are the difernces I can imagine that with less restrictions the turbo will spool up faster than with the meter.
so what i better?

[yunvmyegt]

its really not as much of a restriction as you would think... you can try it and see what it does, but i say leave it....

[psiturbo]

I have it that way and it works like a charm.

I had a friend with a boosted BP who had the same location, meter after the intercooler. I think, IMO, it makes more sense to have it after the intercooler as the meter is really reading the air and temperature that is coming into the engine, compared to having it before the turbo where it is only ambient air and totally different volume, temps... just my two cents.

Foreword had it the same way when he had the blue 323 and he did 13's easy with his setup. I asked the same question in miataturbo.net and they laughed at me as if I was a total failure, got burned in a heartbeat, bunch of Kokzukers in that forum, well they are driving a miata, LOL!

That is why things I read on the web, even if someone else has a DIY or video, I take them with a grain of salt. It will NOT hurt your engine to just try it, see how it works... If you decide to do the experiment...

1. Mark the AFM current location on its teeth.

2. Be ready to move a few teeth CCW to loosen the flap.

3. It may be possible, as each case is different, to adjust the TB idle screw.

Foreword states to place the BOV between the AFM and the intercooler, I disagree.

When the TB closes the door, pressure kicks back closing the AFM flap violently, if the BOV is placed between the TB and AFM the pressure is released preventing the AFM flap from closing and the pressure from the turbo will keep it open as well as it wants to go somewhere and at the end preventing turbo lag.

Foreword prefers (starting on the Intake manifold): TB/AFM/BOV/FMIU

[therieldeal]

idk mazda engineered the thing to be first in line after the air filter... it isnt designed to hold boost or read boosted air. i have never in my life seen an OE setup on ANY car with a blow-through vane air meter. mazda, toyota, ford, vw, many others used this style airflow meter on turbo cars and it is ALWAYS before the turbo.

but if you guys think you are smarter than the engineers who designed your fuel injection system... so be it

[bomdoutscort]

If you look at psi turbos post above this one he is running a meter after the turbo and so far he is doing fine

[psiturbo]

Its about a month now and so far so good, got a few modded STis (with aftermarket exhaust and intake @ 18-20 psi) who have been owned at just 10 psi, LOL.


I honestly do not see any restrictions, stock GTR intake manifold and TB, no porting on cylinder head. Only settings is on the cam gears besides that its just tweaking with the flap. Car runs strong, does not overheat, drives like naturally aspirated while on vacuum, fuel consumption is acceptable with 550cc injectors and Walbro fuel pump. No cloud of smoke, back firing, engine knocking, no overheating, no burning of oil, etc...

Only only sometimes my idle is a littl bit off but thats when it is very cold at night, but nothing to lose sleep about.

I always thought the AFM was going to explode when under boost, but let me tell you that AFM has seen its fair share of boost for the last month and (knock on wood) still working good.

[psiturbo]

idk mazda engineered the thing to be first in line after the air filter... it isnt designed to hold boost or read boosted air. i have never in my life seen an OE setup on ANY car with a blow-through vane air meter. mazda, toyota, ford, vw, many others used this style airflow meter on turbo cars and it is ALWAYS before the turbo.

Here is a Toyota Paseo 1.5 turbo, it has Mazda 323 wiring harness, 626 ECU and rev limit is controlled by MSD, RX7 AFM, RX7 NA injectors, Aeromotive FPR. It is set at 25 psi and last I heard he rebuilt the whole bottom end and now is at 30 psi, check the turbo, that is one huge hair dryer. According to him the AFM has not given him any problems at all, his car is running strong doing 12 second passes on 626 ECU and boosted meter.

If you notice the AFM is set exactly as mine, the owner of the Paseo has done 12.5 easy with a slipping clutch, NO MS, no standalone at all...











Note: Not to contradict anyone, but just showing you the setup does work and so far nobody has complained when having a boosted meter.