Ha the old 350bhp argument.

I can only go by my own experience and Knotty's bug WRX has been mapped at 352 on the standard TMIC for a few years now and is still going strong.

But I'm sure there others that crap themselves at 250, you just never know.

You seem to be a kind of person that likes making free arguments out of nothing I'm not so I will end that right there.To the OP the info that has been given you so far is the primary mods (the usual) route that WRX owners take when modifying stick to the proven advice and you will be fine keep us informed with your progress all the best:).SJ.

Thanks and I will keep you up to date when I start and I sure if I need any help I know where to go thanks SJ

Ive always said that yes it is cheaper just to buy an STI as your already running at 280bhp. However if youve got a decent wrx and you know its history, why change to something else you dont know anything about. Id go for reliabilty and paying a bit extra to get a decent car

I must say you are right on that one and that is what I did but like I said I would like just a but more power from here but font whst to go to mad lol

As a wise old dog with a few Imprezas under my belt I will not say "Do this or do that" that is always your choice. :thumb:

However I can advise. :norty:

I can also link you to Duncan Graham of RaceDynamix that knows a bit about how to tune a Boxer engine as he has done a few. Most notably the one he used to become the 2009 Time Attack Club Challenge Champion. His 2013 Hawkeye based car is running Power : 855bhp Torque: 680 lb/ft from a 2.35 litre engine with a Syvecs S6 ECU using one of his maps.

This was his advice on getting various figures from a 2.0 WRX :-

In standard form they are 220bhp give or take and have boost at about 0.9 bar. The boost profile in the standard map is pretty tame and doesn't come in until 3500rpm assuming the car is standard.

so... choices

Stage 1. Keep the car standard but just remap for more oomph and better fuel economy.
A full custom remap will bring boost in much earlier and hold higher boost levels for longer but the map will be geared to running much more efficiently (which is also more economical) as it won't be possible to push too much boost with all 3 cats in place. Typically a Green/K&N/Cosworth air filter and a backbox are fitted at this stage.

This would get the car to about 250-260bhp

Stage 2. Sports cat in downpipe - remove centre cat
A full custom remap will bring boost in much earlier due to the lower back pressure and hold much higher boost levels. The remap will also aim to get it running much more efficiently (which is also more economical). Typically a Green/K&N/Cosworth air filter and probably a 3 port solenoid are fitted at this stage (on top of the sports cat downpipe and exhaust system).

This would get the car to about 270bhp but a huge boost in torque figures in the mid range.

Stage 3. Fully Decat Exhaust
The low back pressure from removing all the cats is now the equivalent of the turbo running around the garden naked shouting "look at me I'm free". A remap is needed to bring it under control and stop overboosting. The remap will bring boost in as smooth as possible and most likely get full boost at around 2700 rpm and hold higher boost right through the rev range. The remap will also aim to get it running much more efficiently ( which is also more economical). Typically a Green/K&N/Cosworth air filter and probably a 3 port solenoid are fitted at this stage (on top of the decat downpipe and exhaust system).

This would get the car to about 280-290bhp but a huge boost in torque figures in the mid range and transform the way the car drives on the road.

A walbro 255 fuel pump is advisable but not 100% essential.

Stage 4. Getting to over 300bhp
A lot of people want to do this, it is a nice bhp figure for the pub after all. So .. how ? The standard TD04 turbo will not do it unless you are on a dyno that reads very optimistically. It will need a turbo off its bigger brother STi version.

There are many choices of turbo for this VF30, VF34, VF35, VF43, VF48, TD05 16G etc but all of these will need a couple of other changes to the car before hitting the mark safely.
- STi Injectors - 550cc (Pinks)
- Walbro 255 pump
- worth changing the up-pipe for a decat version
- probably an STi TMIC although the WRX will suffice.

It is also advisable to change to NGK PFR7B spark plugs.

There is a lot of info around about the different turbos and what they are capable of - the VF35 makes the best upgrade in my opinion at the moment and should hit a nice safe 320-330bhp. This is pretty much an ideal level for the WRX keeping it within the capabilities of the engine, gearbox and clutch.

Some other info:
- a vent to atmosphere dump valve will not improve the performance but if you must fit one for the sound then stick to a good make - Forge have always been good from what I have seen. (Baileys are less so)
- a FMIC is not needed at this stage and tbh is always the wrong mod to do on a WRX.
- an induction kit will most likely not improve performance as the standard airbox is very good. If you do want more induction noise then go for a cold air induction kit such as the K&N typhoon where the filter is located away from engine bay heat.


So there you have it. I have highlighted the important bit that seems to be the stumbling block for various opinions on power limits. Yes you can reach 350bhp and yes there are owners that have run this through 5 speed boxes for years with no problem. However it's a fact that high levels of torque will destroy the 5 speed box if applied too harshly.

It's all relative. The 5 speed box is good and adequate for normal use plus a bit of ragging on top. It's just something to keep in mind when you start moding your WRX and getting STI power levels out of it. Driving style will also matter a lot. Initially by design the engine, the 5 speed box and the clutch were obviously not meant for that kind of power. They have a bit of headroom but not as much as the STI.

My MY03 WRX was running mostly Stage 3 plus a few tweaks for nigh on 6 years and never missed a beat or should that be a meet? :thumb:

Thanks Mark that makes for a good read !!! That really helps thanks

No problem. :thumb:

I have 04wrx running 320bhp @ 1.2bar. its satisfied me for over 3years,I am actually now after more power but im being greedy :) it still pulls like a train! Mods are: uppipe to turbo,prodrive sports cat downpipe,2.5" middle section,scoobyworld racebox backbox,vf35 turbo,550 pink injectors,front mount intercooler,scoobyclinic induction kit and scoobyclinic remap.pretty sure I only have a 2port solenoid (I will have to check that).