AFR and FCD mods

Author
Discussion

glenno

Original Poster:

35 posts

247 months

Friday 21st April 2006
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Could someone explain exactly how an AFR and an FCD improve the performance of the Impreza? I already have a four stage boost controller fitted, which is excellent. I'm weary of upgrading and overstressing an already impressive engine. Not adverse to more power and speed though!

dnb

3,330 posts

248 months

Saturday 22nd April 2006
quotequote all
An AFR? Not sure what one of these is. Do you mean an AFR gauge? (which gives no performance benefit - just a means of seeing if you're running lean)

An FCD similarly won't give you any extra power either - it is simply a means of stopping the car switching off the injectors if you turn the boost up too much - so is simply a safety system bypass. Personally I don't like them as they aren't actually fixing the problem.

What are you trying to achieve? I've had a hand in tuning quite a number of Imprezas now so may be able to give you a few hints. (See my profile for some details of the two I've owned) You should be able to get to something like 260 bhp from your car (I assume it's MY98) with an ECU remap (or PowerFC) and no engine mods.

Impreza engines are also pretty robust as long as you don't let any detonation happen - eg by letting them run lean on boost!

glenno

Original Poster:

35 posts

247 months

Monday 24th April 2006
quotequote all
dnb
Thanks for your words of wisdom. I'm very happy with the current standardish set-up even with the boost 'off'. It is such a joy to drive, so balanced. I've only considered modifications since a friend has been offering me bits and bobs. Perhaps further down the line when I have settled a little more with the car (and the bank balance has settled!), I will think about mods. Re-map, de-cat pipe and tightening the handling up would rank high on my list. Nothing too stressful on the car. I will definately seek advice from yourself nearer the time.
Cheers, Glenno