ScoobyMaz

iTrader: (1)

A quick question for the more technical minded (more than me anyway):

I am toying with the idea of getting the HKS Dump Valve for my 02STi, basically I like the noise and being 34 with a family, this does concern me a little (it concerns the wife more....you're not 18 anymore was the comment when I mentioned it ).
I have read that there is no specific advantage to have one fitted, so my question is this: how easy is it to fit the dump valve for meets/cruises/tunnel runs etc, and then put the standard one back on for when she uses it as a daily runabout....and secondly would occasional swapping over cause any problems??

frayz

iTrader: (7)

No problems directly. It would be 2 bolts and a hose to swap over.
Swapping to the HKS will do your head in after 5 min anyway.

The car will be much smoother and responsive through gearchanges and chnges in throttle at low speed with the OEM valve fitted.

I had an HKS on my 02 sti and swapped back to the stock one. The car runs much nicer on the OEM item.

Budgie

iTrader: (4)

the simple answer to this is
weither you are technically minded or not
its always the same

i am the man of the house and this is what i am doing luv

budgie

frayz

iTrader: (7)

Remember mate this is the ESC.

That rule doesnt apply to most lol. No matyter how much they say they wear the trousers. We all know who's boss lol

MrBush

If ya fancy a Bailey D12 DV I have one for sale..........

Only done about 3000 miles and I removed it from my 03 WRX before I sold it.

wozzaa

I find it normally drowns out her moaning about it

Nate

iTrader: (2)

I have a Forge Dumpvalve, and you can alter the springs to suit your needs

ScoobyMaz

iTrader: (1)

That is what I always say to her.............





















after she has gone to sleep or just walked out the room!

ScoobyMaz

iTrader: (1)

Sorry Nate, I know very little about these things......what does altering the springs do?

frayz

iTrader: (7)

Alters the maximum boost pressure that the valve can handle.

The HKS one is a diaphram design that is actually held shut with boost pressure. Therefore it can never leak. The more bopst you run, the tighter the seal. It has a fully adjustable pressure screw and can also have different inserts installed to alter the sound of the valve.

Id save youre money TBH and buy something that actually improves your car

ScoobyMaz

iTrader: (1)

Thanks, I will come and have a chat with you tomorrow, but in the meantime, I would like a little more out of the car as I am getting used to it now. Apart from a decat and remap, what else can be done to improve performance? I will get a remap done sometime after Xmas, but don't want the hassle at MOT time for a decat, and also where i work the car gets searched by the police quite a lot and an over eager pc might spot the decat! What would a new air induction kit do? (I have seen them mentioned, but as I said before, I know nought about cars)

madmooro

i know most say they make no actual performance gain they just go woosh .but do they make any thing go bang (as in does it make stuff wear out quicker) and i know this is going beyound the normal road car route but why do rally cars have them ??

wozzaa

I thought they kept the turbo spooling

All I know they work well with flame kits

frayz

iTrader: (7)

Wait till your remap, you'll see almost no gain with any mod beforehand.

Get yourself a sports cat, panel filter and a fuel pump. Get that little lot mapped together and you'll be looking at a healthy gain in bhp/torque.

This is exactly the setup that fozzie has and its supprisingly nippy for the ltlle work thats been done.

Dont **** about with little bits to aid engine performance, they do nothing. If you want to spend a small amount of money on your car. Get a rear anti roll bar and a decent geomtrey setup at a proper tuners.

This will improve your driving experience massively.

ScoobyMaz

iTrader: (1)

I can confirm that...........Lesson No. 1 don't sit too close to Wozzaa's bumper on the tunnel run hope the car is running better than the other week when we were out and about.

frayz

iTrader: (7)

Rally cars dont have them, turbo response is better without them, as boost is kept within the system.

frayz

iTrader: (7)

They dont keep the turbo spooling, they just dump the pressurised air in the system and stop it from going back through your turbo. They do nothing to help response.

They help your flame kit as the dumped air is not read by the ecu or compensated for so the unwanted fuel is stilll added by the ecu. This creates a rich condition and results in unburnt fuel exiting the car.

ScoobyMaz

iTrader: (1)

What sort of cost would I be looking at, I know the remap is aprox £450.

I have had the laser alignment done at XS is that what you mean by geometry?
What effect does the anti roll bar have?

frayz

iTrader: (7)

remap is approx £450 @ mocom, sports cat is approx £300, panel filter £40 and fuel pump £90.

Alignment is the same as the geometry but what settings did XS set it to. If its not done to the correct settings it will be soggy and unresponsive to drive.

Heres a small article i wrote on adding an uprated rear anti roll bar and droplinks.

Want your Impreza to handle the way it should?

Here’s the first step you should be considering.

Whiteline 22mm adjustable rear anti roll bar (ARB).
Noltec billet drop links.
Whiteline heavy duty mounting kit.

All of the above can be found on Mocom Racing - Performance car and trackday products

Test car: 2002 Subaru Impreza STi

First of all, let’s start at the top.

Why would we want to fit these parts anyway?

Well, depending on how hard you drive your impreza, you will have undoubtedly noticed the cars tendency to understeer. Especially noticeable in wet conditions.
Understeer is when the cars tries to continue in a straight line when “turning-in” hard. This is due to insufficient grip at the front of the car. This characteristic is common on most production vehicles and is to promote safe handling for the consumer. Certainly for your average driver, a car that promotes understeer is always safer than one of which the back comes out unexpectedly.
Understeer can be caused by many things such as geometry, damping, spring rate, roll centre and anti roll bars (ARB’s).
Any one of these is causing the rear of the car to have more grip than the front during cornering.
However; It’s the last item on the list we are going to address, the anti roll bar (ARB) or sway bar as it’s called in the US.

As a general rule of thumb, you should always stiffen one area before softening another in order to resolve your handling problem. To do this we are going to fit a thicker rear ARB to the car. This thicker 22mm bar is much stiffer than that of the OEM 19mm item and subsequently reduces roll at the rear of the car during cornering. This reduction in roll in theory actually reduces grip at the rear of the car and due to weight transfer adds grip to the front. It may seem a little unusual that you want to remove grip, but when setting up a chassis, this is how it’s done. It’s all about weight transfer within the chassis.
Take note that changing the ARB will not stiffen your overall ride, as an ARB has no effect on overall damping; it only helps to control the sideways roll of the vehicle.

The new ARB being thicker and stiffer than the stock item will put greater pressure on the stock mounting points of the bar, possibly leading to mounting failure. For this reason we are going to fit the HD mounting kit also manufactured by Whiteline.
The ARB is connected to the rear trailing arms of the car via the use of drop links. These are a “C” shaped connection link with a rubber bush at both top and bottom mounting locations. The OEM items are a polymer based material and although cope fine with the stock ARB. They will tend to flex under the added pressures created by the new bar, not allowing the bar to work efficiently.
These will subsequently be replaced with billet aluminium versions from Noltec. The aluminium items also have a polyurethane bush in place of the stock rubber items. This further reduces flex at the mounting areas and allows the ARB to work most efficiently.

Fitting the new items is a genuine, straight forward swap from the stock items using all the original hardware. The only slight modification needed is a small amount of trimming on the fuel filler tube cover. This fouls the new HD mount on the RHS of the car.
Fitting of all these parts can be undertaken by anyone with reasonable mechanical knowledge and a spanner/socket set, and should take no longer than an hour at most.

On the road

The new ARB has 3 hole positions to mount the drop links to, this alters how much effect the bar has on the car. The outermost hole being the softest setting, the innermost the stiffest, Or biggest reduction in roll.

I personally have mine on the stiffest setting as it makes my car handle the way I want it to. But feel free to experiment with the mounting positions to find your desired setting. I recommend the middle hole as a good starting point.

Out on the road the car is a lot more responsive to steering input and generally feels more alive in the hands of the driver. “Turn in” is now sharper and the car tucks its nose in to tight bends with little or no fuss. Understeer on tight roundabouts is greatly reduced and nice progressive oversteer in the wet can be had with the application of some power.

I chose to write about this mod as I personally feel its one of the best value for money changes I’ve made to my car. There are lots of changes out there that can be done but this one is instantly noticeable and complements the impreza chassis perfectly. I strongly advise that the geometry on the car be setup by a specialist to complement your new additions. Its by no means compulsory but will really bring the best out of the chassis you have, and is also not a bank busting service.

In my opinion, this is how they should have been out of the factory. However, if they were perfect from the start we’d have no fun improving them.

Drive safe.

ScoobyMaz

iTrader: (1)

I remember reading that when you originally wrote it. I never really thought about the handling of the car as I never really push it too hard around corners anyway, but recently have started to push it a lttle and I have noticed that I can get understeer.......might be an idea to try that route first.

frayz

iTrader: (7)

You'll gain more form chassis dynamics and brakes than you will from power mate.

ScoobyMaz

iTrader: (1)

ok, this may sound like a stupid question, but how does better brakes make the difference except for I guess track days? The brakes on the STi are the best I have had on any car. I really notice it when I drive our work car, and then drive the scooby......first junction I come too normally results in aquick lunge forward for the wife.

frayz

iTrader: (7)

If you can brake later you'll carry more speed for longer and thus will make you faster.

If you havent found the limits of the stock sti brakes, youre not trying hard enough

ScoobyMaz

iTrader: (1)

I wish i got the use of the car more often on my own, but I normally have the wife and litte'un in the car with me, so rarely get to test it out to the limits.

frayz

iTrader: (7)

Get some time with just yourself behind the wheel and then find out what you dislike about the way the car drives. Then you can make subsequent chages to suit.

If you feel you dont use the car to its current potential, what reasons do you have for trying to add more power?

ScoobyMaz

iTrader: (1)

I suppose I am just getting used to it, and don't always get that wow factor that I had when I first got it. I still want to get it remapped, as I guess this will make the acceleration smoother.

frayz

iTrader: (7)

It shouldnt be any different with regards to smoothness, just more of the same mate.

ScoobyMaz

iTrader: (1)

Why does everyone recommend the remap then, what advantages does it give, or is it the mods that result in the need for the remap to make them effective?

frayz

iTrader: (7)

Exactly that mate.

The mods you make will not be working efficiently without a remap. More oftenm than not they will make the performance worse and possibly cause engine damage and possible failure.

It appears to me as though youre pining for a remap yet dont actually know why you want one.

Drive your car and decide what you feel needs improving. This is the ONLY basis by which you should modify the performance of the car. Asthetics are up to yourself.

ScoobyMaz

iTrader: (1)

Typical bloke I guess....have a little bit of money in the bank, need to spend it (could save it for a rainy day......but not our style). Could spend it on the house, the car, the wife or for something for me
I am going to sleep on it, and will probably come to my senses in the morning.
I should just go and get an XBox!!