bern11

iTrader: (13)

Just been reading another thread in the general section about power and i was wondering if newage sti's have forged pistons??

Thanks

TonyBurns

iTrader: (3)

Ah well here we go as its complicated lol
MY01/02 JDM STI cars have forged STI pistons, MY02-05 UK/EU STI cars have STI forged pistons, the MY03 JDM STI onwards (twin scroll engines) have hypereuetic (sp) pistons which are still pretty strong but a little brittle (all the above are 2ltr 1994cc engines) then the MY06 STI 2.5ltr onward UK/EU/US cars have hypereuetic pistons but not as strong as the 2ltr JDM ones.
Hope that sorts it out

Tony

PS its the rods that make alot of difference in these engines too (and the crankshafts which are different again on the above)

bern11

iTrader: (13)

Thanks for that The reason i asked is my car is due to be mapped again soon and i wondered if it is safe or not to run more than 1.5 bar of boost if needed??

thanks

Splitpin

Assuming you're going to a tidy mapper and not some copy and paste wallah, he'll be able to make judgments like that.

bern11

iTrader: (13)

I know you know your stuff!!!! So in your opinion can they go above 1.5 bar safely??

thanks

a16pse

I had my 06 sti mapped by JGM and is mapped to 1.5 bar boost and has been fine for quite a few hard driven track days so i can recomend JGM, and ps mine is running on a safe map and as above i do a lot of track days, nurburgring trips, sunday blasts, cheers steve.

Anders_WR1

iTrader: (8)

I recon it depends on many factors like turbo size, and supporting mods - FMIC etc. The standard MAP sensor reads up to about 1.65 BAR, so you can't run more than that on a standard ECU without changing it.

I've read up a fair bit on this and some people are running 1.7/1.8 BAR on standard newage STI engines. I'm running 1.55 BAR on mine running remapped stock ECU / MD321H with supporting mods. When the Solaris is on along with a 3 BAR MAP sensor, I won't mind if it goes up to 1.7 BAR.

At the end of the day increasing boost pressure is putting more strain on the engine. I will chance it and will accept if it goes bang.

Anders

MartynJ

AFAIK and based on every factory fresh 2.5 we have ever built, all of the 2.5 cars be they WRX or STi have cast pistons as standard. This also goes for the later hatch cars. These are as you quite correctly stated nothing like as strong as the 2 litre versions.

scooby tech

iTrader: (2)

Interesting.
So are the stock pistons in a 2005 sti (uk 2.0l) forged or cast ?.

bern11

iTrader: (13)

just gonna ask that myself!!!

TonyBurns

iTrader: (3)

Read the first post again

Tony

scooby tech

iTrader: (2)

Hi,sorry.so yes bern yours are forged pistons as i thought they were 400 bhp will be fine mate.

bern11

iTrader: (13)

Thanks for the replies chaps!!

dunx

iTrader: (3)

Mine has withstood 2 bar so far.... 2002 STI

But only due to an actuator hose failure !

dunx

jd5217

mine has hit 2.3bar...............with a knackered boost solenoid. lol

bern11

iTrader: (13)

Seems to be quite a few running over 400 with no problems (newage) that is!! So going over 1.5 shouldn't be to much of a problem should it???

jd5217

currently running 1.7bar peak, holding 1.6bar to redline on a MD195S (GT30 bybrid)

bern11

iTrader: (13)

Good to know
Thanks for that

jd5217

Been running this setup for over 2 years now.

a16pse

surley if a 2.5 sti is mapped properley it should be good for a good caning from time to time, thats what their built for isnt it, you must still have to go some to blow up or break an sti 2.5, cheers steve..