Shit how did that happen, just re-read the initial post....change of medication coming up.

For a 2.5 bottom end if you can use the genuine heads, you're going to need a better ECU anyway so why not a full wire in. The guy that I got the manifold and heads from did this (set up by Steve at MMS) and it pulls like a train.

The wiring and setup is not huge for the AVCS alone and by retaining the original gear you get a better oil feed setup for the turbo, and you don't need to factor in the raise in compression from using 2.0 heads on a 2.5.

I don't think the compression ratio will change just from swapping heads.
It usually a factor of the Pistons dish volume or head gasket thickness used.

Use all the standard EJ257 bottom end stuff and standard head gaskets and everything will be sweet.

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"You can turn your back on a person, but, never turn your back on a drug. Especially when it's waving a razor-sharp hunting knife in your eye." - Raoul Duke

AVCS is not primarilly for emissions. they give you the advantage of a big cam with small cam driveabillity.

its not a fault with AVCS if some workshops or people dont understand the technology.

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Long live the WRC

Hear Hear... they will all convert someday Stace

Do it correctly the first time.

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"You can turn your back on a person, but, never turn your back on a drug. Especially when it's waving a razor-sharp hunting knife in your eye." - Raoul Duke

exactly, hondas have been doing it for years, along with toyota, nissan and mitsubishi, even most of the euro's

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Long live the WRC

I've seen results with torque arriving 500rpm earlier, and falling off 500rpm later with a custom AVCS map, configured by someone in Perth.

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MY93 Impreza GX 1.8L, 0hp, 0nm

The volume of the 2.0 heads is a fair bit less due to the smaller piston diameter.

Bath tub cut out in the head is 92mm not 99mm, more metal = less volume hence it's probably going to bounce the ratio up a small amount .2 to .3 or something.

I've tried to compensate by using the thick 2.5 head gasket but it will still be up.

Since I'm not intending using less than 98 or more than 1.3 bar I should be Ok unless the excess side area of the bath tub starts to retain heat.

Could be wrong, could need a new engine soon, oh well suck it and see I guess.

May as well steal the thread completely...
EJCALCS
Calculating the Dynamic Compression Ratio is as important if not more than static...static CR ratio means diddly squat if the valves are not shut.

Back to our AVCS discussion, yes technically I know its a step forward, but as for bang per buck with older model conversions its not value. KISS!

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Speak to Shane @ SMC Tyres, Unit 6/385 Sevenoaks St Beckenham WA 6107. Mobile 0413 128 087. Tell him Maddog sent you!

Cheers, the link is quite informative. At least it makes me feel better about the head gasket choice. John at Regents was a big help in this regard. Don't often get parts people associated with Subaru that give a shit nowadays, Milton at Melville is another one that doesn't treat it like a Coles checkout. Suppose it also depends how you approach people too.

So desirable, so bloody hard to achieve!
This is why I HATE the 08 so much, the classics are so close to the pure sports car ethic....I can see them (08's) coming standard with baby on board stickers and comfy slippers. Noooo sir, I don't like it!

Reckon you stole the thread hehhehehe