imprezaWRC

I want to know which models comes with Forged pistons as standard.

PS:Please state the model years and model versions .


thanks

dpb

sti all - far as i know .............will be corrected

imprezaWRC

type R ???
Type RA ???
WRX ??? (produced from 1993) ????
WR1 ???
RB5 ???
555 ???
Terzo ???
P1 ???
22B ???
...
...

Tim W

iTrader: (1)

Based on your list;

Classic Impreza (1993 to 2000)

Type R - Forged pistons on the Sti versions
Type RA - As Type R above
WRX - Cast Pistons identical to the Euro spec cars
RB5 - Stock Euro engine with Cast Pistons
555 - Euro 555 editions have cast pistions, Japanese WRX 555 editions also cast, but Japanese Sti 555 limited editions are forged
Terzo - Again stock Euro engine with Cast pistions
P1 - Stock Sti 5 engine with Forged pistons
22B - Forged Pistions

Basically all the classic model Sti Imprezas, along with the 22B and p1, from 1995 to 2000 have forged pistons as standard. All the classic WRX and European model Imprezas from 1993 to 2000 have cast pistons

New Age Impreza (2000 to date);

WR1 - Stock New age Sti Engine with Hiperutectic cast psitons - aledged to be as strong as forged but with the expansion characteristics of cast

All the new age cars have cast pistons including the Sti's, however the cast pistons in the Sti models are a different design and use a Hyperutectic alloy and are slightly lighter weight

Does this help?

TonyBurns

iTrader: (3)

AFAIK, only the JDM STi cars from 2003 have these fitted (twin scroll, uprated engine, redevelopement etc), previous to that and along with the UK/Euro models, there have been no changes to the engine (except the S202), and as the WR1 is a derivitive of the Solberg special edition, which came with the same power as a UK/Euro STi, it too is unchanged mechanically (engine internals) AFAIK.

Tony

imprezaWRC

Well you are great( Tony, you are too ) , your explanations are helped me so much

Thanks a lot

imprezaWRC

one more question

do they use(Subaru factory ) water injection system for the models with cast iron pistons ???

Pavlo

the water system is an intercooler spray, sprayed on the outside not the inside.

The cast pistons are cast aluminium.

Water injection (into the engine) is safe to use on all subaru engines.

Paul

johnfelstead

The USDM 2.5 STi uses Hiperutectic pistons also.

ShyTot

I think the MY02 STIs have forged pistons. The subaru details I have say so anyway.

TonyBurns

iTrader: (3)

Yep they do, the JDM 01/02 STi's also have forged pistons, the cast ones are in the JDM03 onwards, and as John has pointed out, also in the 2.5ltr US STi engine (you learn something new everyday ).

Tony

imprezaWRC

thanks Tony