Dubzy

iTrader: (4)

Hi folks

I have owned my 04 wrx for 6 months now, i originally purchased with a view to keeping it for a year and then selling it on. But ive now decided to keep her and start modding . The car has done 40k and has never missed a beat, the only fault i can find is a sqeaky rear shock which i will get done with the 40k belt change service. Right the only engine mods on the car at present are a hks bov and induction kit and big back box. I have the decat down pipe and centre section which the previous owner had fitted and removed prior to the sale and the car had been mapped to suite the decat.

This is my first scooby after owning my rwd saph cos which i had and loved for 10 years. Im very happy with the wrx but now in need of more power. After deciding im going to keep it im about to add 150 kilo in weight in the boot withs amps and subs and now already used to the speed i need more power

Whats the maximum safe bhp on these engines without doing internal or clutch/ box upgrades ?
Im guessing its normal route of bigger turbo / injectors / Ic and remap ??
Can someone please tell me the equipment i need so i can start getting the stuff together

Any help would be much appreciated
Dubzy

Jolly Green Monster

iTrader: (4)

Two main choices spring to mind..

1. stick with standard injectors and turbo, fit the downpipe, panel filter, walbro 255 pump and have a remap to suit.. should see you around 280bhp and similar torque.

2. change the turbo and injectors, along with walbro 255 pump and panel filter and the exhaust downpipe you have and have a 310~340bhp car depending on turbo choice etc.

Choices on turbo are really vf34, vf35, td05 16g fe, vf30 etc...
Injectors you need either the sti items with are 550cc and pink or after market 650cc for example power enterprize.

Have tuned these to 400bhp on standard gearbox and engine.. gearbox usually doesn't like it for long.. obviously with an uprated clutch.. however mid 300s on standard clutch (all the time it is not worn out) and gearbox and engine is no issue.

Simon

Dubzy

iTrader: (4)

Thanks for the reply.

Around 350bhp would be nice and was sort of what i was hoping i could get away with. Which of the turbos would u recomend for road use and price and ease of obtaining ? is the sti turbo of the same age one of the one's you listed ?

dynamix

iTrader: (3)

VF43 is a good option for mid 300's - Originally fitted on the 2.5 sti - it makes a great upgrade turbo on 2.0L's. Generally pick up for around £300 second hand.

VF35 is a good option too - again £250+ (as fitted to the UK sti of the same age as yours) - should get you to 320-330 without too many issues.

Both will work well with 550cc injectors, sti tmic and remap.

scoobiewrx555

I'd be looking at a decat uppipe before changing the downpipe. IMHO that's the single most important change on a std WRX and most affects spoolup along with a decent high flow air filter and snorkus delete mod. A newage STi comes with a decatted uppipe as std for a reason.

I wouldn't bother changing the fuel pump just yet, it's identical to the one used in an STi and will be up to the job of making 280bhp. Spend the money on your exhaust.

Thereafter if you want more power change the downpipe for a high flow sports catted type (for MOT emissions pass) and remove the center cat for a straight through pipe. You only need one cat to get through emissions testing and a sports cat will do that.

Of course you'll need a remap so it's all singing and dancing but in the end you should have more than enough power and torque to hump your sub and amps and a few mates around.

Stick with the std turbo and injectors till you get bored and hopefully by then you'll have saved enough money to take it to the next stage. Believe, 225bhp to 280bhp is a sizeable jump and will make a huge difference to your daily driver.

Dubzy

iTrader: (4)

Thanks for the replies..

i will start getting the stuff together asap.

Any reason i shouldnt keep the hks induction kit as panel filter keeps getting mentioned ??

Also are the Sti brake calipers a worth while straight fit upgarade ??

dynamix

iTrader: (3)

That induction kit will be sucking in hot air from the engine bay and probably costing you power - the std airbox is very good.

STi brakes are a good upgrade - you can pick them up occasionally and particularly with a lot upgrading to ksports there may be some going there.

Jolly Green Monster

iTrader: (4)

you will need the sti rims or similar offset to clear the sti brakes btw.

fuel pump is worth changing on this age of car just so you know it is 100%.

uppipe is a lot of work to change for the gain, downpipe gives good gain for outlay and work.

agree do the uppipe when you change the turbo

Dubzy

iTrader: (4)

Thanks again for the great replies. Getting the downpipe and ctr section fitted over the holidays and will start purchasing the rest. Fuel pump/ turbo/up pipe/injectors and sti ic have now been added to my list to santa.

As the car was previously mapped with decat turbo back would i have been doing it any harm with the cats now inplace for the last 6 months. ie over fueling ??

Jolly Green Monster

iTrader: (4)

unlikely.. ecu is fairly cleaver at keeping things safe.. bit late now anyway

Dubzy

iTrader: (4)

i was told this was the case as it has a clever self learning ecu ?? just thought i would get a second opinion. As u say a bit late now