420bhp to 450bhp
 

Hi getting my 2.5 hatch sti forged prefer driveabilty over larger numbers and added cost would i be happy with 420bhp

Will be plenty for the road with good response too,

What blower you considering ?

Something Twin Scroll ?

Closed Deck, 14mm studs, Injectors, all the trimmings I'd expect a bill close to 5-6k (poss even more) if you want drive in drive out.

Stock ECU should be enough there as well or add another couple k ontop.

i would expect considerably more than 5-6k to hit 450, prob 10-15k by the time you factor in all the extra parts you'll need for a reliable 450.

Second hand parts would save some money but would you really wanna spend that much and only get a part to fail and put you back to square 1?

15k lol for 450bhp,

is that including the Car lolol

Engine is getting forged by steve whitson not sure on full spec as much as i remember
Mahle pistons is it 2618
Rods
Closed deck insert
14mm head stud
Cosworth gaskets
As for turbo not sure any ideas welcome

From what i have guessed
Gt spec headers
Asperformanc uppipe
650 injectors
3”exhaust
Turbo not sure which one
Avcr controller if pushing 450bhp maybe

usual suspects, md321, sc42/46

would sc42 be better suited to my 420bhp for quick spool compared to sc46 md321t

42 should outspool the 46/321t however it varies from car to car and you need to consider the whole setup.

Yes i understand it all depends on other factors Cheers tidgy

Is there any other turbos to consider

It depends where your coming from and what you spec for.

At 450 i'd be sacking the standard ecu for sure and running a syvecs which will be 2k, turbo will be 1-2k, injectors £400, front mount £1000 (for a decent one), clutch £500, i'd be adding oil cooler £450, inlet pipe, 3 port, 4 bar map sensor, mapping time, build time etc etc

Plus whatever you have add on 20% for vat, it all adds up and that assumes it doesn't need headwork, the block isn't so badly warped it needs to be scrapped or linered and the ancillary parts coming off are reusable.

Im trying to see if spenging more money on
Tubular headers £600
Harvey up-pipe Dont know price
Avcr controller £250 second hand
Sc42 sc46 md321t Is it worth the extra 40bhp roughly from 420 -460

For a 2.5, a sc42 is not suitable imo, go with a sc46 as that's what it's made for, you don't need a syvecs unless your wanting to brag as half of features won't be needed, link ecu are good ecus, better than most others imo apart from syvecs of course and circa £1k and does everything and real simple to map.

Busta why is the sc42 not suitable in your opinion Not keen on changing ecu

What is the limit of the std ecu?

Steve is running over 500 on a std ecu iirc, no issues at all.

So if the OP wanted to run a 321T or similar on the 2.5 BASIC mods needed would be , plugs, fpr, injectors and?

https://cimg8.ibsrv.net/gimg/www.sco...c8c507f045.png

This is from andys website just not keen on going avcr controller

I think the SC turbos could perhaps be easier to fit. I have a twin entry 321T+ with the big 3" compressor housing. It wasn't even possible to use the stock AVCS hardline that runs to the AVCS solenoid and turbo oil feed. It would run straight into the actuator bracket. And the normal cutting of the lug on the block of course.

Doing it again I would have gone for a SC46 or Blouch 1.5 Xtr twin scroll.

Curious...What power have folks ran on the std air box?

Because on a 2.5 engine which will have loads of spool, maybe too much hahaha, and may run out of puff. It's just the sc46 was designed For the 2.5 engine as the housing is bigger for the greater engine combustion to flow. And hence the sc42 was designed for the 2.0 engine in mind.
But as you say in title 420-450. The sc46 will give you 440-450 with good spool just like the sc42 will be good spool to match on a 2.0, but you will gain more hp on the 46.
Put it this way, if I had/or using a 2.5 then I'd use a slightly bigger turbo to gain that free extra hp as spool will be on par when thinking of a 2.0.

(Note I'm using a sc42 on a 2.0.....soon will be a 2.1)

Not saying the sc42 won't be great on a 2.5, it will be pretty mental if I'm honest but you could gain 'free' extra hp on a bigger turbo hahaha.

All depends on your end numbers really. If 400 then the 42 will be top.

P.s I do have a sc42 near new for sale if interested :D (see my above post is me not pushing my sale but giving my version of opinion) :thumb:

I would like the sc46 or md321t but the extra cost could be the price of your sc42
Andy f sent me this message
Depends if you want the 420 or 460 end of the scale. You don't need headers, fuel pressure reg, grade 8 plugs or AVCR for 420ish
So say i go sc46
Added parts above will be roughly £1100 then fitting cost

I would speak with your mapper, not sure the AVCR is needed on the hatch STi, just a good 3 port boost solenoid.
I'd expect around 430bhp from the SC46 & MDX321T on V-Power and safe boost with the spec you've mentioned. Any more would be a bonus.

Andy forrest said avcr if going 450 level

He knows best :)

Will this be a daily drover? Have you considered going the methanol mix route as well just to throw that into the mix...

R666ory This is my sixth impreza
last one blob jdm running 432bhp 409ft/lb
One before that widetrack 410bhp 385ft/lb
Dont track but attend scottish scoobies monthly meets and go on sunday country runs with a few of the boys

Yes daily so no methanol