Subaru Performance Handbook
Posted 31 August 2009 - 06:43 PM
I have contacted the guys from Subaru Performance Handbook (as found here) asking if I can post up the emails that you receive when you are a subscriber.
Having not received a response in a few days, I have decided to go ahead and post up the emails I have received thus far until they ask me to take them down.I will post them in the thread however there will be a 48 hour delay in them being posted and there are certain emails that will not get posted up (such as ones that contain exclusive mp3s) to encourage people to subscribe. I recommend subscribing on their website. Even better yet, highly recommend you purchase the book.
ALL INFORMATION IN THIS THREAD FROM:
Subaru Performance Handbook By MRT Performance,
1 Averill Street, Rhodes, NSW, 2138, Australia.
Posted 31 August 2009 - 06:44 PM
Here are some simple ways to improve the handling of your car without having a massive budget. We're talking specifically here about the Impreza models, whether it's an STI, a WRX, or a non-turbo. If you're looking to dramatically or just simply improve the handling of your car so you can have a bit more sporty feel and a bit more fun, the trend sometimes is to fit a front strut brace and a rear strut brace because they look snazzy when you lift the bonnet and have a look inside the trunk or boot of your car.
The unfortunate thing is whilst they look good; they are not necessarily the first thing that you should fit to your Subaru. The best-value way of upgrading your Subaru is by getting down underneath the car and actually starting at the back.
Depending on what year model you've got, this can be affected by some of the components.
Basically to make it easy for you to understand, the rear sway bars that change the stiffness of the body roll or resists body roll are factory fitted on the front and rear of your Impreza and are connected to the suspension by a series of links that move through an arc as the suspension travels up and down. On some models it's a plastic link, on other models it's a stiff, ball-joint style link.
On the rear if you've got a plastic style link which is relatively easy to identify, you need to replace that with either a spring steel or an alloy style replacement link, which is quite easy to source from MRT Performance off their website. Effectively what this does is takes the stretch and the movement of that joint out of the equation, so therefore when your suspension goes up and down the more travel is not absorbed in the replacement part, but taken up by the sway bar.
What that effectively does is increase the rate of the sway bar and puts more load on your suspension as you go around the corner, therefore making the sway bar work better and obviously reducing your body roll. The similar thing applies on the front. Some models have a plastic link on the front; some have this type of solid joint with bolts, a ball-joint type knuckle assembly.
If you get down underneath you can have a look, but to make it easy typically the early model Subarus up until around '01, '02, had the plastic style links front and rear. So you've replaced the rear sway bar links and the front sway bar links with new snazzy alloy ones, they look great, and you'll feel the difference straight away. The next thing to do as you want to invest a little bit more in your suspension is to change the rear sway bar.
You don't start at the front, you actually start at the rear, because by stiffening the rear sway bar, it effectively reduces the under steer in your car. By going to a stiffer rear sway bar you can reduce the under steer of the front and the car will be a little bit more fun to drive, and it's actually quite dramatic in the way that you can feel it.
Typically we recommend going to an adjustable rear sway bar because the small added cost in having the adjustable feature gives you a long-term ability to effectively fine tune that sway bar to suit your preferred driving style instead of not having the other alternative.
Look out for tomorrow's email with some more information about simple suspension improvements.
Subaru Performance Handbook
Posted 31 August 2009 - 06:45 PM
Yesterday we were talking about the value of an adjustable rear sway bar and how, if it's adjustable, it gives you the ability to fine tune that sway bar to suit your preferred driving style. The way the sway bar works by having it adjustable is it has multiple holes in the arm of the bar on the back.
Changing the pick-up point from the sway bar link to one of those holes effectively changes the leverage ratio of the sway bar, and of course that has a big effect on the effective stiffness of the sway bar when it travels through its suspension arc. Of course the shorter the lever, the stiffer the sway bar, and the longer the lever, the softer the sway bar. So you've improved the rear suspension and now you're looking at ways to improve the front suspension.
The next step after all of this is obviously, you guessed it right, changing the front sway bar. You can actually get that front sway bar as an adjustable sway bar, but as it's quite awkward to get to from under the car; typically a lot of people don't always do that.
If you are going to be fairly accurate and enthusiastic about getting your car to handle absolutely the best way you can, then again, it's a good, wise move to go for an adjustable unit.
You don't have as much adjustability as you do on the rear but there is obviously some adjustment which can be noted when you do change it, which long term is an advantage. So you've done the front sway bar links, the rear sway bar links, the rear sway bar, and the front sway bar. I might point out in order of value; you do rear sway bar links first, and then front sway bar links, then rear sway bar, and then front sway bar.
Finally you can go and fit the fantastic looking front top strut brace and the rear top strut brace, and effectively what that will do is stiffen up the chassis and make the car perform better by putting more load through the suspension and making the suspension work the desired way it should.
I hope that is some valuable advice for you. As always, if you have any questions please send me an email directly to firstname.lastname@example.org.
Subaru Performance Handbook
Posted 31 August 2009 - 06:48 PM
We see problems with a lot of aftermarket 500-horsepower pumps, particularly on the turbo Subarus when we're doing upgrades, because we've found that the factory pumps can't deliver enough reliable fuel pressure and flow when you start turning up the power as a result of a fuel leak that may have occurred after doing some modifications or changing the fuel pump.
To access the fuel pump on the '02 model WRX for example, there is a cover that's on the floor underneath the backseat, and also partly accessible from inside the trunk or the boot.
This gives you access to the top of the fuel tank, which has got several very small bolts that hold the cover down with a seal.
You undo that seal and pull the fuel pump out to change it, and when it goes back together you're actually putting the cover back on and the seal can often slip or not go back in the correct location.
You're actually doing it blind because you can't see what you're doing since you're working from the top and you can't look in from the side of the tank because it's all up underneath the back of the car.
It is a very easy trap for people to not put that seal back on properly and something to pay attention to whenever you are working with the fuel pump.
The first sign of a leak is either when you fill the car up full with fuel or if it's got a reasonably full tank and you go for a drive and see signs of fuel spilling out around the side of the petrol tank.
It won't actually come inside the car, but it will come out around the side of the tank and then drip on the ground.
My recommendation is to get that checked out because there's probably every chance that that seal has possibly been pinched, damaged, or just hasn't been put back together properly after the petrol tank was taken apart to fit the fuel pump.
It's certainly something that needs to be checked very quickly because driving around with leaky fuel in the back of the car under any condition is certainly not safe.
So keep this in mind and enjoy your driving experience.
Subaru Performance Handbook
Posted 31 August 2009 - 06:51 PM
Your WRX is a high performance car that has the job of carrying you, your family and friends at speed, so treat it accordingly. In addition to routine scheduled maintenance, get into the habit of checking the car on a weekly basis.
You should pay particular attention to the following items:
Tyres - should be round and black! Seriously, do not confine your checks to just the tyre pressures alone. Look in under the wheel arch and check the state of tread wear. Are you familiar with the tread wear indicators moulded into the face of each tyre?
Are the tyres wearing unevenly? The early stages of premature tyre wear can often be tricky to spot, so if doubt check with your tyre re-seller. An cheap and easy to fix wheel alignment problem can very quickly ruin a set of expensive rubber. While checking the wheels, don't neglect the spare! See chapter on Wheels and Tyres for more detailed information regarding tyre pressures.
Under car checks - prior to grubbing around under your car, take a good look at where it was parked. Pay particular attention to the ground under the engine and transmission. Any serious leaks from the powertrain should be immediately obvious. If your can see any evidence of fluid leaks, wipe down the offending component and then check all engine bay levels to ensure that nothing is dangerously low on one fluid or anther. Then take the car for a
short drive and re-check. If in this short period of time, a significant amount of fluid has reappeared, "Houston, we have a problem", seek professional advice.
Engine oil - check the engine oil level from the dipstick. The best time to do so is first thing in the morning, when the car is cold and all the oil is back in the sump. Make sure that the car is on level ground; otherwise any sort of angle can lead to an incorrect reading. Between the full and empty lines on the dipstick is exactly one litre. Don't ask how many fluid ounces, pints or fractions of an imperial gallon this is. Top up the engine with oil of the same viscosity rating that is already in your engine. If you are unsure about what it should be, check with your service agent.
Remember that it is possible to have too much of a good thing. Do not be tempted to overfill your engine with oil, as this can raise the oil level in the sump high enough to interfere with the crankshaft, causing foaming of the oil, which in turn can create problems with boost and variable cam control solenoids.
Subaru recommends engine oil with a SAE viscosity rating of 5W-30 for turbo engines operating in climactic conditions ranging from below zero Celsius (or lower), up to a maximum ambient temperature of + 40 Deg C. This is a very broad range and should be satisfactory for the majority of owners. However, Subaru does have the following caveat in the WRX owners manual as final word on engine oil.
If the vehicle is used in desert areas, in areas with very high temperatures, or used for heavy duty applications such as towing a trailer, use oil with the following grade and viscosities are recommended:" API classification SL or SJ and SAE viscosity number 30 or 40, 10W-50, 20W-40, 20W-50.
There is more information on engine oils in the Subaru Performance Handbook under Engine Mechanical and Track Days.
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Subaru Performance Handbook
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