Hi I've recently bought a wrx 2005 221bhp and I have been told if I change the rear exhaust box and a new air filter I can get it tuned and It will be 250bhp is this true ?.
Also with my old car I had a little box I could plug in the car and ether have it tuned to performance or tune it back to standard for economy is there any thing for impreza' s

 

A filter and an exhaust and a good remap and you could see anything between 250 and 280.
You will need an uprated fuel pump too.

 

Ok cool that much

 

Your turbo will be maxed out at about 280bhp.

 

The rear box isn't going to help much. A whole system with decat will. Then a remap and yes you will get your power.

There are ecu's that allow multiple maps. That's the only proper way of having a performance/economy mode. But it's going to cost around £1000 or more.
Just drive sensibly when you want better economy or walk.

 

sports cat downpipe open mouth this has one high flow cat up top not two
or go decat but wont pass mot

up pipe is a must as it has a cat pre turbo this is a massive restriction and can fail.You can fit an sti up pipe this has no cat from factory or smash the cat out of your std up pipe cheaper way,you need to fit a resistor into the loom plug as you no longer use the egt sensor in the up pipe 2.2k ohms will sort the cel light on dash

I am still running my std fuel pump my mapper said its good for 300 bhp anymore it will need upgrading

fit a panel filter to std airbox good for 350+ bhp get a foam insert if you can as the oil on the k and n filters can still do damage to the maf sensor (i have had to change the maf on mine due to oily residue on maf)

then get it mapped by a good mapper i use neil @ slowboy racing he has done work on all my subaru's

you can get three main types of map generic/reflash maps avoid as not custom setup on your car they read the cars map email it over it gets tweaked the reflashed back to your car AVOID!!!

open source mapping is a custom tune this is what neil does at slowboy racing one off fee he flashes a pre written tried and tested map to your car
plugs in loads of different sensors,egt ,knock,boost,afr and drives the car fine tuning all the fuel trims on the go
takes between 2 and 4 hours costs £400 ish

or

ecutec same thing but you have to buy a licence so costs abit more

im running all the above mods with open source map its running 280 ish
1.3 bar of boost and when not driving hard ie off boost the mpg is amazing

i was getting 60miles to £20 of v power thats like 20 mpg

now i get anywhere between 75 and 100 so 25-30 mpg

the map will pay for its self in 6 months

sorry for the long thread lol any questions drop me a pm

 

Scaffff do the following and report back to us your BHP.

Full decat exhaust system (possibly with sports cat downpipe)
DEI Heat wrapped GT Spec Gen 2 Headers & Up Pipe
Heat blanketed Turbo
550cc STI pink injectors
NGK PFR7B spark plugs
3 port boost controller
255l Walbro fuel pump
STI or FMIC intercooler
Samco, SFS or Perrin Silicone Turbo intake hose
Lightweight pulleys
Aircon removal
TGV deletes
Phenolic Manifold spacers
Millers Nanodrive 10/50 engine oil
Do Luck panel Filter
Remap at 1.4bar

 

550 pinks with std turbo???

 

I ran 440s on FPR at 350bhp

 

I suspect the 440's (pretty sure 380's on a 2001-05 Newage) will be getting close with what I believe could be 310-320 at 1.4bar. You don't want the actuator vacuum hose splitting on an icy cold day with Injectors bordering on maxed.