Arnie_1

congrats, glad she's back on the road. After all your troubles, that is a major accomplishment! Very happy for you!

do you have a print out of what he was able to get for an alignment? What were you trying to achieve and what did he manage?

You'll definitely need to bed in our pads and disks. Here's a good how to:

http://www.stoptech.com/technical-su...and-procedures

Actually, if you interested in learning about brakes as well as debunking some of the myths propagated online and in the shop, read through all of their white papers. Very informative stuff.

alessio

iTrader: (3)

Cheers!

Good links, some new information there.

Here is the alignment report



I left with less negative camber than I came in with and that's the part that I'm not happy with but since the guy thought he was done after adjuating the toe-in and didn't know about the camber bolts at the front I decided not to push it and try to find some place that knows a bit more about these cars.

bonesetter

iTrader: (9)

Those settings are all over the place (must have felt a tad nervy before the alignment looking at the toe settings lol)

The front wheel toe angle is pointing out, not in as it should be

Why have you got a degree difference of camber between the rears?

Why couldn't the caster be measured?

Edit: positive toe value does indeed mean wheels point inward

alessio

iTrader: (3)

Bonesetter,

Driving to the alignment shop was absolutely ridiculous. It was in very heavy rain and the car just wouldn't go straight at all.

Actually the front wheels are pointing in, as are the rears, and I have no idea why there's a "-" for the rears but not the fronts. I am quite sure that they're both pointing in.

Have no idea about the reasons for the camber difference, it changed to that once the toe-in was adjusted.

I asked the same question about the castor to the guy at the shop during the alignment procedure and he just shrugged his shoulders (the guy that works there and that, according to some, actually knows what he's doing was on holiday ). I have a theory, though - could it be because it was off the scale for the specifications that the system expects?

I was hoping to drive out of there with the settings you'd posted in one of the threads here, which means that a second visit is in order.

bonesetter

iTrader: (9)

Sorry I'm at it now, a positive toe value does indeed mean the wheels are pointing in, so that's OK. They could do with a bit more though, say 0°06'

You may have gained enough caster to go above that upper tolerance limit, but the read out should just show it as out of tolerance, but show the reading

Arnie_1

yeah, that's a pretty **** poor alignment. Toe is ok but, as mentioned, camber is pretty bad. I imagine there isn't a caster notation because he never did a caster sweep. It would show up if he did.

alessio

iTrader: (3)

Will try to squeeze the car in a rally team garage tomorrow morning for alignement - they're extremely busy preparing for a rally this weekend but they did tell me to try tomorrow.

I guess I'll show them this and will ask for something similar



(I guess that's an updated version of this?)

alessio

iTrader: (3)

Good evening, gentlement!

I've realized that I have not found the time to give a little update on the car and my first track day with it. I apologise.

First of all, the alignment. I took the car to a garage that actually has made its name through preparing rally cars. I had an idea of what I wanted to do but it just happened that the owner - a 5-time Estonian rally champion - had some ideas that he wanted me to try and I was not going to argue even if it went against my (and this forum's) understanding of what the settings should be.

This is what we ended up with



Some notes. I thought I'd have more caster with the 10 mm instert but I don't know if I want any more.

There is toe-out at the front. The thinking is that it would help the car turn in. It does.

There is more agressing toe-in at the rear to keep the car stable after the initial turn-in.

The camber and castor are given in degrees and minutes so the difference between the rear camber settings is not as large as it may seem so we left it as that. The toe-in/out settings are given in mm.



Here is a picture of the front left suspension after everything's been done. I believe the only thing remaining from the way the car left the factory are the bolt holes and the knuckle, everything else - lower arm, its rear mount, shocks, springs, brakes, ARB, drop links track rods, etc - has been replaced.



Now to the impressions. I'm very very happy with the way the car turns into a corner on those sticky tyres. Also very happy with the way I can generally turn in even more mid-corner if I need to. Not so happy with the way the car seems to be understeery after the initial turn-in. Hard to explain exactly but it just doesn't flow through corners the way I want it to, so once I figure out what tyre pressures to run and what AGX settings to use I'll revisit the alignment. Unfortunately I wasn't able to spend as much time time testing the various settings because I ran into an issue with the oil temperature and pressure so I had to miss a couple of track days as I'm waiting for a bunch of engine parts (chasing reliability rather than power).

So, thoughts on the whole matter and geometry settings in particular? Blasphemous or just different but interesting? Tyre pressure (running Federal 595RSR-s in 205/45R16) and AGX settings advice is also more than welcome.

Cheers,
Alex

bonesetter

iTrader: (9)

Interesting stuff, and congrats on getting everything sorted and out on track

Have you a pic static and from the side. Interesting to see front wheel position in arch and height

Thanks

alessio

iTrader: (3)

Strangely this is the only one I have - crawling to the starting line so reasonably close to static. Sorry for the half-naked guy



It's sitting lower than I was expecting and has more body roll than I was expecting and your P1 setup looks attractive but with KW CS's planned for next year I'll be sticking to this for now.

Expensive 20 laps with the suspension mods done before and engine mods needed after

bonesetter

iTrader: (9)

Well, I think the castor you've achieved is impressive. I have 3°43' on a flipped pin and ALK set-up, so close on another degree is pretty good

I'm puzzled with the front toe-out choice I have to say. Toe-in helps turn-in as the wheel is already leaning in that direction before turn-in. The tyre has to do less and therefore cope with less directional change - is my understanding.

Other thing is when the Impreza dynamically lowers during cornering, braking etc, toe reduces, so your toe-out will increase even more. Perhaps this may well be a contributing factor to the mid corner understeer...?

Of course, all this is based on nothing more than listening to Arnie and other forum stuff, and playing around with my Impreza's, so take with a pinch of salt. Arnie Will be along shortly I'm sure

Meanwhile have a gander at his on front toe settings and roll...

Arnie_1

Hi! Glad you finally got the car out on the track! A couple of thoughts for you:

Tire size: I was going through your old pictures and only now noticed that the Federal 595 RSR you are running are 205/45-16. Technically, that's the wrong size tire. You should be on a 205/50-16 or 205/55-16. The lower aspect ratio you have with the 45 series will, however give you a shorter, stiffer sidewall for more precise cornering but it shorten your gearing quite a bit. It will also have a smaller diameter and, thus, your car will sit lower.

Body Roll: The STi spring rate and damper setup wasn't designed around a semi slick tire so you will be getting more body roll with the sticky tire you are using. You'll be fine when you get the Clubsports on there. Remember spring rate choice is dictated by the amount of grip of your tire choice. That's why my first question is, when someone asks me what spring rate to choose, what tires are you planning on using?

Mid-corner understeer: As Bonesetter was pointing out and his awesome article touches on, it could be the result of your toe out setup. Toe-out is great for sharpening up initial turn in, but from my experience leads to some mid corner understeer, just as you are experiencing. This is what I think is happening: Your front wheels are toe'd out. When you first approach a turn, upon initial turn in, since the inside wheel is already pointing inwards towards the turn, it wants to turn in already. This gives you that initial fast turn in feel. Problem is, (and this is aggravated by the weight transfer to the outside wheel) the outside wheel is pointing outwards, away from the inside of the turn. Its practically being dragged through the turn rather than scribing the turning radius. This dragging is only made worse because the outside suspension is compressing under weight transfer/load resulting in more toe out. Basically the outside wheel is pointing outward and is wanting to pull the car out towards the outside of the turn, and since it has more weight on it than the inside wheel, it has a larger influence on the direction the car wants to travel. And I believe this is why you're getting mid-corner understeer.

Now, if you were to toe-in a bit up front, the car would do everything opposite to what I described above. Initial turn in might be a bit slow but we're really talking, very, very initial turn in. Once that weight transfer happens, that outside wheel is dictating what the car is really doing and its saying I want to turn in. And then you'll get that sensation that car wants to turn in faster through the turn, as described in the article above. I think at this point, its worth a try. You've seen and felt how the car is with toe out, now see how it is with toe in. If at all possible, don't change anything else! Otherwise you won't know what is making the change in your impression. Just go into the shop and have them adjust your front toe, nothing else.

alessio

iTrader: (3)

Thanks for the input, guys!

Thoughts along the same lines. I have too many variables to play with - shock settings, tyre pressures, ARB settings - and I think starting with the geometry is a good idea, so once I get my engine bits on, that's what I'll do. So what amount of front toe-in are we thinking here? Preferably in mm

There's no need to chase more castor, then, right?

As for the tyres, the 50s weren't in stock and I actually liked the idea of lower and effectively stiffer sidewalls and the gear ration is not an issue since the karting track I'm using lets me get into third a couple of times and that's about it, whereas acceleration out of a corner is a benefit.

The nature of the track in question together with the fact that the guy that gave me suspension advice is used to more powerful cars that can overpower understeer is probably the reason for the toe-out recommendation. That all said, I see absolutely no harm in trying different options as we all learn from experience.

Had some weird experience just driving in the rain today with a lot of understeer through a u-turn. I wasn't pushing at all but with the worn street tyres and little grip due to rain the car understeered a lot, so toe-in at the front it is.

Arnie, you've mentioned somewhere that you do your own alignment? Have you got a string jig made up? I would love some more information on how I can do alignment myself, accurately that is, so that I don't have to drive 50 from and to the track just to test new settings.

Arnie_1

messing with your front toe is worth a try at least. And doing it yourself is super easy at home especially since you have an accurate baseline already.

doing it at home is a piece of cake! Just a little more time consuming than on a rack, but since you don't have to set up the mirrors and such, it be about the same amount of time.


Here's how I set my toe on my cars:

Buy two bookshelf shelves, just those short white ones you can buy at the hardware store for bookshelves. Just make sure they are wide enough to clear the tyre when resting on the ground. So, ca. 50cm wide x 15-25 cm tall.

You place each one against the wheel/tyre on the ground. Make sure you give each a tap with your foot to make sure its truly flush with the tire. Use a jack stand or a sand bag to weight the shelf against the tyre. I use a jackstand and just lean it against the shelf.

The idea is you have two square edges in which to measure the front and rear distances of your wheels.



You have this identical setup on the other side of the car (not pictured)



so you take the tape measure and hold it against the front edge of the board and take a measurement. Then you take the tape and measure the rear distance of each board face. I usually take the little "hook" at the end of the tape measure and hook onto the edge of the board being careful not to tug too hard or you'll move the board/shelf and mess up your measurement. Double check your front and rear shelf measurement. Take the smaller measurement and subtract it from the larger. This is how many mm's of toe in or out you have.




If the rear of the board measurement is larger than the front, then you have toe in. If you have a larger measurement in the front compared to the rear of the shelf, you have toe out.

Make sense?

Once you've measured how much toe in or out your are, then you can decide if you want to try your own alignment! I do my own. I change too much **** on my car so might as well save some bucks and do it myself.

roll your car up onto ramps and adjust your toe. On the Subaru, moving the tie rod facet one position over is equal to about 1mm of movement on the ground/wheel.

Alignments are actually pretty easy, just time consuming because its best to proceed slowly. Do a change, roll your car down and back and forth, remeasure, then raise car and re-adjust.

So, let say you measure your car, front and rear, and you get a measurement of 700 mm front and 696 mm rear. This means you have a total of 4mm toe out. If your car isn't pulling one way or the other and your last alignment was ok, then we can start by assuming that you have 2mm toe out on the left and 2 mm toe out on the right.

If you want zero toe then you need to bring the right wheel in 2mm and the left wheel in 2mm. Get your car up on the ramps (or jack stands depending on what gives you best access to the tie rods. On the Scoob ramps were sufficient. Get a permanent marker or paint marker. Spray lots of some kind or PB Blaster/Rust breaker on the threads/lock nut. Then clean off your tie rod from any dirt or grease first and dry it off. Brake cleaner is good for this. Draw a short, thin line across one of the facets, the lock nut and the threads. This will allow you to gauge where you started in case you mess up and want to start over. It also gives you a place to call your "zero point" where you can count how many facets you've rotated the tie rod.



Sorry, this is the tie rod off my Peugeot. But I think you get the idea.

After marking, the fun part starts, braking/loosening the lock nut. I'm personally not good an reading threads. So I take my two box spanners and try to loosen. If it doesn't work one way, I try the other. Once loosened, you need to figure out which direction to rotate the tie rod to either bring the wheel in or push it out. What I do is unthread the lock nut maybe two turns away from the tie rod adjuster. I then rotate the adjuster and see if it gets closer or farther away from the lock nut. You only need a turn or two to determine this. Once you have this determined, you can start with the real work.

First you need to see where your tie rods are located. Are they behind the wheel? Are they in front? This will determine if you are going to "pull" the wheel in (to reduce toe) or "push" the wheel in to reduce toe. Say your tie rods/steering rack is mounted behind the strut/wheels, you will need to "push" the wheel "out" to get our desired toe in.

So, underneath the car look at your tie rod. You currently have toe out. The tie rod/rack is behind the strut. In order to get the front of the wheel to point inwards (toe in) you'll need to "push" the back of the wheel out ward. You need to extend the tie rod outwards. This will turn the wheel/strut inwards, toe in. Take a good look at your tie rod and see which way you need to rotate the adjuster to get it to extend farther outwards. Remember the lock nut trick? Use that as a guage. On the Scoob, you should just move the the marked facet two positions away from where it was. This will move the wheel 2mm inward. Do the same for the opposite side. Lock the lock nut down. roll car off ramps a few meters, turn your wheel left and right and then roll it forwards to your "measuring spot". I forgot to mention you should be doing this on as level tarmac/concrete as possible.

If you want to be super ****, you can get a long level and place it across the ground in front of you car. You can then see how much you need to "build up" one side to get it to be level. I use vinyl flooring squares. I just stack them up on one side until the level reads "level". I mark this spot on the garage floor. So I always have the same spot where I align my car. To be honest I'm not doing that here at my current home as there is nowhere perfectly level. I just give it a go on the flattest area on the drive.

Anyway, measure the car again, as above with the shelving boards. If you are spot on, you're good to go. If you are off, take note of how far off you were and adjust what you thought were how much each facet moves things. I was off on my Pug. I went with the 1mm idea but it was actually less. So I ended up overshooting my goal. had to go back and forth a bit. till it was zeroed.

Alignment shops lock out the steering wheel when you do an alignment. I don't use a lock. I just make sure the wheel is centered when I start and make sure I do the same amount of adjustment to each side. The wheel will stay centered that way.

you can actually adjust the steering wheel with the tie rods as well if you want.

adjusting a pull is basically more fiddling but perfectly doable too. let me know if you want to know how to do that too.

Basically, you don't need a big buck hunter alignment machine. Most race teams use the strong method for adjusting front and rear (including thrust). And its not too different from what I just described. There's a good alignment thread in the stickies in the suspension forum on NASIOC. On the scoob, I've had the car aligned once properly to make sure my thrust is zero and rear toe is to what I like, say 2mm toe in. Then I just tweak the front. Rear toe hardly changes with ride height or camber changes. So I never touch it to be honest. Ideally I should but I'm too lazy.

I'll try to take pics of the tie rods on my Peugeot to show you how I marked things and set up my shelves.

And as far as caster is concerned... when you get your coilovers, you'll most likely be using camber plates. I would consider setting them up rotated so that you can get more caster as you add camber. Your caster is pretty good, but consider that standard GD Spec C is around 5.5-6 deg. It doesn't have to be a huge priority but if you can add a little bit more just by rotating your camber plates, why not? Or, perhaps look into buying the Vorschlag Camber Plates out of the US. A bit pricey but they have a version that is set up out of the box at a max caster position and all you need to do is adjust camber. Its a very, very nice camber plate.

http://www.vorshlag.com/product_info...roducts_id=259