james_ukm

My warranty is going to be up on my 05 Sti in the next couple of months which means i can start modifying her. Firstly i want her to be quicker. I dont have loads of money to do this in one go so i need to do it step by step. Where is the best place to start???

mikef04

iTrader: (7)

work out what you want, then best and safest way to get it.

aXeL

Great advice - both concise and useless in one sentence. Not very encouraging for new starters. He also said 'quicker'; at least read the post before dismissing him.

James, there are number of easy and cheap/free tweaks you can do safely which will improve the car's response, e.g.

Modify/replace the stock induction so the engine breathes more easily.

Port matching the headers is another easy win which will improve engine response. i.e. you grind down the edges of pipes where they join so that the air flow isn't restricted. Fractions of a percent improvement in flow can be felt in engine response if it's done right.

Porting the intercooler y-pipe is also relatively straight forward and removes quite a bit of restriction. I also did my throttle body but you have to be very careful not to damage it.

If you're handy with tools and brave you can do this yourself (I did)

If you're a nerd (like me) you can also get learn to reprogram the ECU, however this requires months of studying fuel injection systems, physics of combustion cycles, partial pressures, stoichemetric ratios etc. (Nerd heaven). Then months of data logging to learn how your car behaves. Very dangerous if you get it wrong or don't use the right kit but exceptionally rewarding if you learn to do it right. I've remapped my own car at least 30 times already and have almost completely dialled out the turbo lag without going too hot or lean or knocking. Still not finished yet but now I have a car with a lovely twitchy throttle in any gear.

Anything tickle your fancy so far?

greatgonzo

iTrader: (1)

Decat and remap is the cheapest way of getting lots more bhp, and it can be tailor made to what you want

360ste

iTrader: (1)

Rather than going for more power you would be better off optimising the suspension and brakes first. Engine power is nice but if the car feels scary to drive then you won't use the power you have paid for. Get a full four wheel alignment from a reputable place. If they comment about wear in the bushes replace them with poly bushes (for example power flex). Upgrading the brake pads so you don't get fade along with uprated hoses (for example Goodridge) will improve the feel. On e-bay you can get a brake stopper this bolts onto the inner wing and pushes against the brake master cylinder to reduce the bulkhead flex, making the pedal feel a lot better. Next step would be further suspension component tweeks to tighten things up, then go for uprated suspension.
The main thing to do is write down what you want from the car, how you intend to use it and how much you want to spend, it can go wild. Browse through Scoobynet and SIDC to see what others have done and if they made a mess in their choice. If in doubt ask and read all comments with a sheet of paper to write down pro's and con's.

widdows

Very sound advise from 360ste there, ive had first hand experience of what happens when ou go for power before anything else. Had a talbot sunbeam (bear with me this does get better) fitted a c20xe redtop from an astra gte on twin 45 dellotro carbs.
approx 190bhp through the rear wheels on not very good suspension and practically std brakes resulted in many in the hedge experiences and in the end a car which I was too scared to push to the limits.

upgrade the suspension and brakes first this far outweighs power upgrades as it gives you the confidence in the car when you are `on it`!

tayfun

I have a 2005 sti , it went through 2 stages, after the first stage it was running about 320bhp with 1.4bar and was not very costly. All i had to do is change the fuel pump(255 walbro) £65, cheap induction kit off of ebay £50, decat exhaust 3' all the way £400 and a remap £500.
Second stage included Andy Forest TD05 20G turbo £500 (second hand with no play), and an electronic boost pressure regulator £150 and a remap £200 tahts it , now runing 380bhp with 1.55bar.

53

iTrader: (41)

Don't get your dremel out quite yet

Simple decat/partial decat, panel filter change and remap would be the cheapest and best start. Budget c.£800-£1000 assuming new and depending on the extent of exhaust parts replaced.

The best list for your average 'I wanna go faster' scooby driver is pretty much...c.325-340bhp/310ftlbs (2ltr MY05)

• Decat or Sports Cat/Decat combo
• Green Cotton Panel Filter
• 3Port Solenoid
• 255 Fuel Pump
• Zero Sports Cool Thermostat, Motul Oil Change 300v, Colder Plugs (service items as a nice to have).
• Front and Rear 22/24 ARB's - Handling is key to enjoying your Impreza.
• Alloy Drop Links

This list can grow or shrink depending on your budget and aspirations for your car. For me these would be additional handling modifications such as springs, anti-lift kit, lock bolts,full geo set up, new tyres etc...the list is endless.

From the beginning though have a do it once and do it right approach. Try not to **** about with the car doing dribs and drabs before getting it mapped. Staged approaches between mapping sessions are a good idea and a safe way to achieving the car you want.

Ultimately the cheapest start would be a second cat decat and remap. This doesn't commit you to the full decat option (MOT friendly) and leaves the decision of whether to go sports cat till a later stage.

HTH

wayner845

iTrader: (2)

fuel pump , performance panel filter insert ,full decat down pipe and exhaust,ported headers would be nice or tubular and performance upipe.remap. Maybe 350bhp.
Its never cheap .

james_ukm

Cheers guys. Iv got a pretty good list of things to do now. Just bought some Perfomance friction pads and some goodridge hoses to start with. i think it is going to be new panel filter and decat pipe next can i put the decat pipe on before getting it mapped without problems?. what the difference between a decat pipe and a sports cat & which one is better?

wayner845

iTrader: (2)

One difference is you should be ok for mot without having to put the cat back on (with a sports cat) everytime which is a bit of a pain .Definately change fuel pump before remap ,its a relatively easy job to do yourself.

rewindnottm

the 2.5 STI's are pretty sorted but i would go for

£50 - Panel Filter
£350ish - For a full decatted system, scoobyworld is good
£80 - 255 Fuel pump
£350 - Custom remap from open mapping

so about £800(ish) for all the parts

you will not go over 300bhp with the pump being replaced

so you should be around 350+bhp after