Rossco I have much respect for your knowledge thanks for shedding some light on this topic... Yeah definitely I agree if i don't put on the correct afm i will damage/ blow the engine. That's why I'm trying to figure out witch afm i can use... Only reason why I wanted to change afm was I was thinking there might be a air restriction when going to 2inch diameter pipe into a 3inch diameter pipe for turbo induction inlet.....

I'm not sure witch ecu I have but I think it's somewhat stock ecu because my car went passed 180km and didn't cut out....also it has a few little mods so I take it the ecu can be tuned? For example I have Vf22 sti turbo.... 3 inch turbo back Exhaust.... Gc8 22b tmic....injectors I think stock..... And I think I have a fule pump upgrade cause I can hear the fule pump nose a bit louder then average... So maybe I do have bigger injectors... Last own did say he did push some big boost with it.....

Turbo I'm changing to is a mamba GT2871R.... Here is the link GTX Billet Ball Bearing Turbo SUBARU 3

What Rossco said ^^^^^^ and BTW if you have an all black no label MAF from new that a mechanic fitted remove it from your car place it on the ground and hit it with a hammer .

Do yourself a favour replace it with a genuine correct coloured MAF . No point diagnosing a factory ecu with second rate crap sensors . The no label MAF sensors are renowned for being shit they are cheap for a reason.

You can change and upgrade those items on a GC8 without needing a tune.

Any VF22/23/24/30/34/35 turbo, 3 inch exhaust, and big intercooler, will all work without a retune. You can even wind the boost up a little bit... to about 16 or 17 pounds (depending on what year you have)

Hmmm interesting.... I fail to see how u can put more air breathing performance parts on your engine and your ecu adapting to it with out a tune....I know stock gc8 ecu is a self learning ecu but boosting up the boost even then the ecu can read it and correct it? I can probably understand it will still run but run lean with the extra air added and that's danger zone?

Thanks for the info I've always wondered if this no labeld afm was rubbish and it sounds like I can happily Bin 🚮 it with joy and get the correct afm.... From what rossco is saying I may need the original oem purple label afm witch is perfect for my turbo inlet connection because it's 80mm in diameter 😀😀😀

If your WRX is a 98 model, and has the coil pack in the centre of the intake plenum (directly in front of the throttle body), the ECU cant be flashed so its going to be "un-tuned", and if you need evidence that the car runs with these modifications, go and take your own car for a drive .

Just before anyone else pipes in, yes, it could have an aftermarket ECU but it would be likely you'd know about it, and it would be unlikely to be running the factory air flow meter.

Ok cool thanks for the info Matto20v... It is a 98 wrx and it does have the coil pack in the centre of the intake manifold.... But I'm confused because stock ecu can't go over 180km witch I have hit 220km and previous owner did say he did push high psi with it.... So it's leading me to think it's not a stock ecu but I will have to take it to sti docklands to connect it to the obd2 port to see what it has

Stock ECU will allow you to exceed 180kmh, so I've heard.

And Matto, the PFC runs fine on a standard AFM, although you can fit the Z32, as Ross has said.

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Air is for pussies.

The only speed limited factory GC8 ecu's are the V5 & V6 STI ecu's which speed limit at 180kph.

Unless you motor has been rebuilt with some 'goodies' in it that GTX turbo is going to suck ass on a stock EJ20T.

I don't know why you've settled on a turbo with a 3" inlet anyhow - are you going for a rotated turbo mount??

You need to find yourself a tuner, buy a decent ECU & heed your chosen tuners advice before you waste your money on a combination of parts that won't work well together.

'High boost' on a stock ECu is 16-17 Psi.......... High boost for me is 25psi+

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[CENTER][COLOR=#ff0000]Built Ej207: Semi-closed RA Cases - Wiseco Forgies - Manley rods - BC 272 cams - GDA Heads - billet f/whl - Vi-pec - WbO2 - 800cc Yellow tops - TD05-20G - 409Hp ath @ 1.75bar on E85[/COLOR][/CENTER]

Can't use open source tuning on 8 bit 1998 Wrx Ecu's.

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[CENTER][COLOR=#ff0000]Built Ej207: Semi-closed RA Cases - Wiseco Forgies - Manley rods - BC 272 cams - GDA Heads - billet f/whl - Vi-pec - WbO2 - 800cc Yellow tops - TD05-20G - 409Hp ath @ 1.75bar on E85[/COLOR][/CENTER]