Wilky_Boy

Hi everyone ! Hope you are having a good Christmas !! I have a 2004 WRX which I am hoping to lightly tune. I am just wondering what further mods I can do myself at home which will allow me to get the maximum benefit from the ECU remap that I am saving for. So far I have changed the air filter for a 'Green' panel item, removed one of the CATs and replaced the majority of the exhaust pipe work. I have also installed a Forge VTA but from reading a lot of posts on here I may have actually done more harm than good. Am I better reverting to the original Subaru part ? Basically I want to do as much as I can ( as a basic DIY mechanic ) before handing my car over to Scooby World for a ECUtek remap. I know I am not going to get silly amounts of power but in the region of 270 BHP would be good. Any advice or comments would be really appreciated. The car's a weekend toy only so not really bothered about fuel economy, etc...

Cheers,

Wilky.

BlueBugEye

iTrader: (12)

Not sure how far you can go safely without a remap - many on here have fully decatted and no remap without blowing up their cars however I wouldn't recommend it.

If you click on view my Scooby you'll see the spec I've got to take mine to 275 on a remap (Powerstation). Basically you'll want to de-cat the up-pipe, and the exhaust (I've got a sports cat in mine, the Milltek units are now in the centre section). You need a panel filter which I see you have, I also got the fuel pump uprated at the same time as they can run lean when tuned, when being mapped mine needed a two port boost valve fitted as the standard one could not take the upped boost (prodrive part).

I fitted an APS dual port boost valve early on having the car which in my opinion smoothed out gear changes, this only vents to atmosphere if I change gear on full boost, otherwise it recirculates.

The best mods I made to the car were the ARBs (drop links to follow). I also want an ALK as these appear to make a massive difference to the handling. Hope this helps!

daijones

I can highly recommend the ALK, it's much better at putting the power down on bends and greatly improves the steering feel, but you'd really need to get a four wheel alignment done after fitting it. Use a scooby specialist who'll be able to set the geometry to suit your preferred roads etc.
If you're taking the WRX up to 270, which is a reasonable post-remap target with the work you've done, you probably want to look at upgrading the brakes. I used Godspeed's 335mm upgrade, which keeps the standard calipers so saves cost. It works a treat: High Performance Brakes - Supplying AP and Brembo brake kits for road and motorsport use
Apart from the mods BlueBugEye suggested, you could think about upgrading the intercooler to a larger/more efficient model: that should help the mappers get a little more out of it. The emphasis is on the little, if you're lucky an extra 10hp, but when I fitted mine I did find it pulled noticeably better from lower in the rev range. The cheap option is to look for a used STi TMIC on ebay or from a breakers, eg Jap Performance Parts : Home or ScoobyBits | Home Page, but you'd want to change the scoop shroud as well, to make sure air's hitting the intercooler fully - the standard WRX shroud would be too small. I went for a Process West intercooler (PROCESS WEST - Welcome to Process West Competition Aluminium & Aluminum Engineering - Wollongong, Australia) and shroud cos I saw a good deal on ebay, but it was a bit of an indulgence. I won't get the full benefit until I fit my new turbo though.
Something else you might think about is a "resonatorectomy". Induction kits have got a mixed reputation, hence many tuners just using an upgraded panel filter. The standard air intake has a resonator inside the driver's side front wing, basically a box filled with foam to reduce engine noise. Taking the box out and either leaving the void empty or fitting a replacement elbow is said to lead to a small increase in power because the air flow is less obstructed. It also increases the intake noise a smidge. Instructions are available here:
ScoobyTuner.com - Engine, Suspension, Brakes, ECU Tuning and more for your STi, WRX, Legacy, & Forrester
You can see some of these on my car here:
Dai Jones's Photos - Car | Facebook
It's the 2.5 litre so gets more power than an 04 would do, about 290bhp before I changed the intercooler.

D