fallwood

Ive been wanting to ask this for a while but wanted to see if anyone else asked first. At the risk of sounding stupid , why does the MY06 have 500cc extra capacity but only adds a couple of bhp over the 2.0 . Is the potential for tuning greater cos I cant see the point of the engine change.

ZEN Performance

The power ceiling is more-or-less defined by the turbo.

Are you comparing the non PPP figures?

Little Miss WRX

The major difference I have noticed is the lessened lag and the responsiveness down low compared to the 2.0L.

It's a torquey little bugger and makes round town driving so much more liveable with. Opening her up is just as good, but much more smooth than before.

AndyC_772

iTrader: (2)

I think you'll find the real reason is emissions. MY06 is the first car that legally has to pass the Euro IV emissions standard, and that means it has to be tuned to be as clean as possible, not as powerful. The extra 0.5 litre is really there to maintain power at existing levels, not increase it.

B0DSKI

iTrader: (17)

Andy's got it spot on it's all to do with the Euro IV emissions tests that have in the wisdom of the European union come into force.
Hence the reason why the Japanese Impreza's all still run 2 Litre lumps

fallwood

So does that mean it has the potential for more power than the 2.0 once tek3/ppp is available.

dynamix

iTrader: (3)

yes

and lots more torque

New_scooby_04

iTrader: (4)

Bingo. But, the added advantage of more displacement is more torque, better drivability at low revs and -theoretically, at least when other supporting mods are in place- more scope for tuning!

Ns04

AndyC_772

iTrader: (2)

fallwood: In theory yes, but there's a lot more to it than just displacement. You still need to flow more air and fuel, and still need to make sure the engine and transmission are strong enough to handle the extra torque without breaking.

I honestly doubt we'll see reliable 2.5 cars that are much more powerful than their 2.0 cousins, comparing like-for-like in terms of tuning budget.

Paul3446

Is it not slightly ironic that by tightening emissions the EU are forcing manufacturers to produce cars with bigger engines?

RJDS

And less economical into the bargain

AndyC_772

iTrader: (2)

A bigger engine isn't really an issue per se. If it's made less efficient, ie. produces more CO2 in order to achieve a reduction in other emissions, then that's just a trade-off which the Eurocrats have made - whether they realise it or not.

The same goes for safety too; a safer car is a stronger and therefore heavier one, so it burns more fuel and produces more pollution. That's another inescapable trade-off, there's no win-win situation.

ex-webby

Perhaps we should start a discussion on how much the standard pistons on a 2.5 will take, as opposed to say a newage 2ltr and then the tuning capabilities using the stock 2.5ltr engine may look less appealing. In essence, I think I will stick with my feeble under torqued 2ltr.

Regards,
Shaun.

Col Stone

For euro IV the My06 has grown from 2.0L to 2.5L and for the same reason the Toyota Coralla TTE has now added a Supercharger to get it through euro IV ! So although I know I'm talking total rubbish in theory by euro VIII we could have compound charged 5.0L nitros cars!
Col

ScoobyDoo69

iTrader: (17)

with 150bhp

scoobfan

I'm hearing stories that the 2.5 is not as "tuneable" as the good ole 2.0,
can this be true

Rob

Leeroy

Are the quoted power figures for the new Sti/WRX accurate - or are they conservative like skyline etc to keep under 280 'gentlemens agreement'?

davedipster

Me too, does the 2.5l just have a longer stroke or larger pistons?
Are the cylinders thinner?
Are the pistons made of ****ite?

God knows, we do hear some stories on here though...


dipster.

davedipster

I think the 280hp agreement died a long time ago.

dipster.

Bob Rawle

The std 2.5 engines are definatley not as "relatively" tunable and do have piston issues if pushed too far. Also the WRX has the Forrester intercooler which is little bigger than an early slanted one, that alone will/should give tuners cause for caution, that said its still tunable with its limits.

As Shaun points out the 2 litre is still "relatively" better to tune in std guise.

cheers

bob

JIM THEO

I have been told from local Subaru sales dept the new Impreza will be again 2.0lt with a new 6 speed sequential/automatic gearbox!

wah

The imported MY06's are 2.0 litre as oppesed to the UK which are 2.5 litre

Robocop

I wonder what's been done to the UK supplied 2.0 ltr 2006 Evo IX engine to pass the Euro IV emissions?

LitchfieldImports

I would imagine the Evo's that are in the country were built before the begining of 2006. The Evo's engine set-up is better suited to emissions testing than the Impreza.

Iain

JIM THEO

I mean the forthcoming models guys will be 2.0lt not the JDM parallel imports!