WRX STI import mods options

[Saoirse]

looking to mod my Subaru up to 450 bhp if possible.

its a WRX STI A line Jap import 2010.

any advise please.

im based in Kent.

[Tidgy]

Forged engine build, suspension set up, brakes, aftermarketecu, etc etc. 450 is a big build so yiur gonna be £20k+ if yiu want to do it roght and reliably.

[Jay762]

The CS400 Cosworth uses forged internals to get to circa 395bhp over the 330s 340 ltd models, none forged but max 340 is really as much as you want to test those. I believe your car currently sits at 296Bhp so your immediate options are

ECUTEK remap, cat back exhaust, hi flow panel filter (Suggest uprated fuel pump optional) will give you about 340bhp with launch control & antilag. This will give you an idea of the chassis performance with the additional power - I believe you will find it soft, front end will lift under acceleration and there will be quite a bit of body roll on the corners. Steering is not the quickest on your steering rack and as you start to get a shift on you will be crossing your arms more at teh wheel - look to replace the rack with a 15+ STI item

You could then look at the chassis, when that can handle the 340bhp how you like - look to the engine

 

As Tidgy said you are looking at a full tear down, replace the bearings, rods, pistons, head gasket and bolts. You will need to uprate the fuel pump and the injectors - an FPR to maintain the right pressure is essential. A turbo which can shift the extra air required as the standard one wont go that high.

More air in = more air out - the standard exhaust is restrictive so look at a turbo back option with or without sport cat

An aftemarket ECU with associated sensors will help pull the solution together

plus the chassis mods you may want to particularly dependant on what you would like to use the car for - track days etc, build on road friendly changes that can handle the 340bhp

I dont know what power your semi auto box can handle though? Buuuut then you could go for a sequemtial item and retain your paddle shift

 

What ever you decide - feel free to create a build thread so we can follow etc

 

[Saoirse]

8 hours ago, Jay762 said:

The CS400 Cosworth uses forged internals to get to circa 395bhp over the 330s 340 ltd models, none forged but max 340 is really as much as you want to test those. I believe your car currently sits at 296Bhp so your immediate options are

ECUTEK remap, cat back exhaust, hi flow panel filter (Suggest uprated fuel pump optional) will give you about 340bhp with launch control & antilag. This will give you an idea of the chassis performance with the additional power - I believe you will find it soft, front end will lift under acceleration and there will be quite a bit of body roll on the corners. Steering is not the quickest on your steering rack and as you start to get a shift on you will be crossing your arms more at teh wheel - look to replace the rack with a 15+ STI item

You could then look at the chassis, when that can handle the 340bhp how you like - look to the engine

 

As Tidgy said you are looking at a full tear down, replace the bearings, rods, pistons, head gasket and bolts. You will need to uprate the fuel pump and the injectors - an FPR to maintain the right pressure is essential. A turbo which can shift the extra air required as the standard one wont go that high.

More air in = more air out - the standard exhaust is restrictive so look at a turbo back option with or without sport cat

An aftemarket ECU with associated sensors will help pull the solution together

plus the chassis mods you may want to particularly dependant on what you would like to use the car for - track days etc, build on road friendly changes that can handle the 340bhp

I dont know what power your semi auto box can handle though? Buuuut then you could go for a sequemtial item and retain your paddle shift

 

What ever you decide - feel free to create a build thread so we can follow etc

 

 

[Saoirse]

Thanks guys, should start with exhaust then, would this require a specialist? 

 

[Jay762]

8 hours ago, Saoirse said:

Thanks guys, should start with exhaust then, would this require a specialist? 

 

Depends on your tool box - exhaust is a straight forward modification a few nuts and bolts and wrestling with the rubber hangers (a pot of red grease helps here)

[Saoirse]

Looking at Scoobyworld. they are offering Hayward and Scott STI 2010-2012 exhaust back box saloon reaf silencers £744.99 and saloon centre section exhaust £294.99.

would this be a good place to start and would it pass an MOT after?

[SF5Fozzi]

You can't go wrong with a h&s system really, they are good quality hand built items. 

An option is to ring h& Scott directly, book your car in for a custom fitment to your requirements, like aftermarket cat converters for MoT. 

450hp wheel or fly? 

turbo dependant, therefore you would have to account for the new downpipe connecting to a future turbo....etc etc. 

It's  a mine field. 

Set your self a clear path & stick with it. 

Nice car by the way. 

[Saoirse]

On 12/5/2020 at 11:34 PM, SF5Fozzi said:

You can't go wrong with a h&s system really, they are good quality hand built items. 

An option is to ring h& Scott directly, book your car in for a custom fitment to your requirements, like aftermarket cat converters for MoT. 

450hp wheel or fly? 

Turbo dependant, therefore you would have to account for the new downpipe connecting to a future turbo....etc etc. 

It's  a mine field. 

Set your self a clear path & stick with it. 

Nice car by the way. 

ah ok, will go with that then, thank you.

[v11sti]

hey bro 

love the car have bought one myself i live over in new zealand and am having the same sorter problems with deciding which path to go for modifications