blackvenom

I want to advance the handling on my classic. Its a UK2000 'w' saloon. Without Spending a fortune i am picking bits up now, so i can get it all done in one go and have a 4 wheel alignment

my shopping list includes

Sti carbon top strut brace
lower front H brace
Rear lower Brace
Solid rear droplinks
Front anti roll bar 24mm?
New springs.

Any advice on bits i might have missed or shouldn't bother with? Car wont be tracked or raced so i don't need an extreme set up. Just something to fresh it up when i'm on a empty Dry A or B Road.

Cheers Guys

CREWJ

You won't gain a whole lot from all the bracing. A rear anti roll bar is essential though.

blackvenom

Ok cheers.

Gyver

iTrader: (1)

I would say:

Front strutbrace
Whiteline camber/castor adding front topmounts
STI Group.N rear topmounts
Wishbone polybushes, castor adding rear mount ones
19mm STI front rollbar and STI/Type R oem front droplinks
22mm rear rollbar
Solid rear droplinks
P1 Eibach springs
Polyurethane steering rack bushes

dj219957

camber bolts and someone who knows a good geo setup will make a big difference.

myblackwrx

iTrader: (1)

My Type R has had this done to it

My total suspension upgrade/replacement has been :

Sept 2012
Bilstein (using original springs) £600
Rear droplinks £86 (needed replacing after inspection as the rubber was knackered)
Track control bushes £107 (needed replacing after inspection as rubber was knackered)
Steering rack bushes £27

Today
ALK £137
24mm ARB (rear) £148
Labour time was about 4 hours in total and VAT needs to be added

The ARB and ALK are highly worth it as I've tested the affect of these 2 items today

Personally I would take it to a Subaru specialist get them to have a look over (or under in this case) as to what extra can be done therefore saving labour costs and time.

keljon

iTrader: (10)

Google autospeed wrx handling, they did a 5 part article on handling mods, goes something like
Tyre pressures and alignment
Rear arb and drop links with strengthened mounts optional
Anti lift kit
Front ARB
Rear camber bolts

Also
Shocks and springs are worth doing if not done already
Roll centre adjustment if car is lowered

gary77

iTrader: (1)

Great link there , can someone tell me , is the information in there the same for a classic sti as a wrx, sway bar sizes etc

2pot

iTrader: (3)

Tyre pressures and alignment - critical:
http://www.pcadynamics.com/app/downl...+-+Insider.pdf

Wouldn't bother with the anti anti-lift kit or rear camber bolts (you need reduced rear grip, in relation to the front).

Would add caster: Whiteline kca335 top mounts or lower control arm spacers.
If lowered, would use roll centre kit.

Bars sizes will depend on driving style, spring rates, road surface, bump stops and dampers. Importantly, whether the struts are capable of controlling the combined rate of spring AND bar - underdamping, generates excess heat = loss of performance and increased wear.

gary77

iTrader: (1)

The link made it sound simple now I'm confused again

2pot

iTrader: (3)

What springs and struts are you going to use? And how many miles have the struts done?

gary77

iTrader: (1)

It's got standard struts and springs , they need replacing I think , 105k on them , probably go for the kybs and springs I'm thinking the ones mentioned in a thread of tours I read a while back . I'm open to suggestions but I'm def not thinking about coil overs ,

2pot

iTrader: (3)

KYB excel-g's (£240) - bars 19mm front 20mm rear.
You could use the Eibach P11L springs and matching bump stops, with excel-g's.
KYB AGX's (£505) + P11L's - You might use more rear bar, if the roads are primarily smooth and flat.
If you used the Eibach wr15r/t springs, with AGX's, on b roads, then 19mm front 18mm/19mm rear. If smooth,flat roads then 20mm/21mm rear.

Other struts/inserts may use different combinations.

Track days/stickier tyres, could utilise bigger front bars, with a balancing rear.

A smooth, more experienced, driver, might use a bigger rear bar.
Otherwise, smaller rear bar, ensures the front slides first - much safer on the road, in emergency situations and while learning on track.

Correctly matched bump stops do reduce understeer - without resorting to a big rear bar.

hth

joe v3sti

iTrader: (8)

In relation to 2pot mentioning adding more caster, you should speak with Alyn at AS Performance as he does Hi castor bottom arms. Properly made these, unlike some that people manufacture.

Proper kit!

gary77

iTrader: (1)

Apparently the anti lift kit adds caster , why are other methods better

2pot

iTrader: (3)

The anti, anti-lift kit, intentionally, introduces additional dive/lift - load transfer - under braking and acceleration. The anti, anti-lift kit has to add caster, as well, to make up for what it's doing.

Why not just use the, appropriate, springs rates, camber and bump stops, to maximise the contact patch (or minimise, to taste, at the rear).

Ash Webster

http://scoobyworld.co.uk/catalog/pro...gbo6rpb8qq4us3


will this fit a classic v4 sti?

gary77

iTrader: (1)

I've just read a 7 page thread on nasioc about alk's . Just to better understand what they do exactly , also watched a whiteline video on you tube that explained there purpose ,

So as I understand it , there are 3 things it does , gives 0.5 degree extra caster , has a choice of 3 bushes all being better and gradually firmer than standard , and the lastly the supposed main purpose is they create lift and dive , or more acuratly I'm to believe that the standard setup has anti lift built in by the manufacturer (subaru) , for the supposed purpose that it feels better to drive if the car has less lift and dive and also to stop the front lowering / diving in a crash , but whiteline remove this anti lift with the kit which allows the suspension to do the job it is supposed to ,

I understand the benifit of extra caster and a firmer Bush but I can't see how the anti dive/lift is removed and what causes the anti lift/dive in the first place , it's as if the oe mounting point stops the suspension from working properly or at least that's what I was supposed to believe

2pot

iTrader: (3)

aalk lowers the front lower control arm pivot point by 19mm. In attempting to counter, throttle induced, corner exit undeersteer. But, introducing increased lift and dive, as a result.

gary77

iTrader: (1)

That's not how I understand the purpose of it ,

This is taken from a discussion about alk on nasioc

Quote:
Originally Posted by Gary77
A can't understand why anti anti lift is a good thing ,

Can anyone explain why it's a good thing and how anti lift is manufactured , maybe then I'll understand why it's bad


Quote-
First off. In most cases it is not a good thing for ultimate performance. The main reason it increases lap times is because people are terrible drivers and it gives confidence to them. It's the same reason that most people will be faster in a race car if the engineers soften it up compared to how it would be setup for a professional driver.

Taken from http://www.formula1-dictionary.net/a...antisquat.html
"Anti-dive and Anti-squat are expressed in terms of percentage and refer to the front diving under braking and the rear squatting under acceleration. They can be thought of as the counterparts for braking and acceleration as Roll Center Height is to cornering. The main reason for the difference is due to the different design goals between front and rear suspension, whereas suspension is usually symmetrical between the left and right of the vehicle.

Anti-dive and Anti-squat percentage are always calculated with respect to a vertical plane that intersects the vehicle's Center of Gravity.

Consider Anti-dive. Locate the front Centers of the suspension from the vehicle's side view. Draw a line from the tire contact patch through the Instant Center: this is the tire force vector. Now draw a line straight down from the vehicle's center of gravity. The Anti-dive is the ratio between the height of where the tire force vector crosses the center of gravity plane expressed as a percentage.

An Anti-dive ratio of 50% would mean the force vector under braking crosses half way between the ground and the center of gravity."



It's actually a lot more simple when you can see it than just reading about it. If you know where the center of gravity is then you can guesstimate the anti dive % by looking at the angle of the suspension arms.
On a Macpherson strut suspension you look at the angle of the strut, and the angle of the lower control arm. The most simple way to change the anti-dive is by adjusting the mounting points of the lower control arm. If you have the front control arm mount higher than the rear control arm mount you will decrease anti-dive. If you have the front control arm mount lower than the rear control arm mount you will increase anti-dive.
Most of these 'anti-lift' kits lower the rear control arm mount which decreases anti dive.



Here is a blog from Perrin about their PSRS. It's their version of an anti-lift kit.
A quick blurb from this page. http://blog.perrinperformance.com/wh...-for-your-car/
"I hate the term ALK or Anti-Lift Kit. From the beginning we have battle with this because the other companies Anti-lift kit isn’t keeping the car from lifting under acceleration or decelerating. Its really an Anti-Anti-Lift kit or pro-lift kit. The company that originally came up with the name describes the name as a fix for anti-dive/lift geometry, which has confused tons of customers, and also some of our team as well

OEM’s build “Anti-Lift” geometry into the front suspension help make the car appear more stable. What this does is reduce how much the front end will dive under braking, or raise under acceleration. To most normal customers, this is a good thing making the car appear to be more stable, but this does have some negative effects as it reduces weight transfer from front to back

2pot

iTrader: (3)

"Also, just for the record. The Whiteline anitlift kit was primarily designed to remove the stock anti-lift geometry by relocating the rear of the front lower control arm pivot point down by 19mm. This was its main purpose as we found that the stock geometry promoted power understeer on corner exit."
(Whiteline Automotive, 2006)

gary77

iTrader: (1)

It's just the way you said , ". But, introducing increased lift and dive, as a result."

It makes it sound that it was a bi product of the solution but it was actually the purpose to take away the anti lift that Subaru had manufactured into the setup ,as far as I can tell anti lift is not a good thing in a race car and that is ultimately what we are aiming for by nodding these cars , to a varying amount dependant on use of the car

Sad Weevil

iTrader: (1)

It was precisely this power understeer on corner exit that led me to the Whiteline a-alk, and it does the job very well. My car is strictly for daily driven road use only. I found the standard setup very restricting on corner exit, and with the extra torque of the ppp, rather too exciting, and not in a good way.
For the record, my setup is WR Bilsteins with P11L springs, solid drop links, alk, standard arbs, and very light 16" wheels. This suits my driving style perfectly, and there's nothing I would change. If it was a track car, I'd probably have a very different approach.
YMMV.

2pot

iTrader: (3)

It was a bi-product - Whiteline thought they'd made an anti-lift kit - they hadn't.

https://www.scoobynet.com/suspension...-lift-kit.html

gary77

iTrader: (1)

Thanks for the link , very interesting , good to see Andy f involved .

So although it seems to have all been an accident some people still say that reducing anti lift is a good thing , is that not true ?

2pot

iTrader: (3)

Why introduce additional dive and lift, to the inherently stable platform of a road car? If there are other, available, means to combat corner exit understeer.
Why introduce urethane to a pivot point? Urethane, unless frequently lubricated, will 'grab-release-grab'.

Considering classic road cars:
Rear spring rates (in my investigations, for, primarily, road car usage - B-roads 27.5N/mm or A-roads 35N/mm) and, CRITICALLY, matching bump stops.

http://www.pcadynamics.com/app/downl...10400-TECH.pdf

gary77

iTrader: (1)

From what I understand the anti lift built into production cars helps keep the car feeling more stable but from a performance point of view it should be reduced and the stability should come from the struts and springs instead

Sad Weevil

iTrader: (1)

Interested to know what other means there are to combat power-on corner exit understeer. Surely the problem exists due to the anti-lift properties of the standard suspension: front axle grip is acutely reduced at the time you most need it, because under acceleration the weight transfer is lifting the the entire front of the car, wheels and all. Even more so on uphill corners. This is my experience anyway. In simple terms, the reduction in anti lift keeps the unsprung elements of the suspension on the road more = more grip, with the chassis lifting instead. Certainly, when I fitted mine to my car, it had just the effect I'd expected and made it much more controllable on slippy backroads. I must stress that my car is daily driven, road only, and I need to cover ground fast, so my priorities are to make sure it's as idiot proof as possible, and neutral handling and loads of grip is what I want. I have a rwd track car for the other stuff...

2pot

iTrader: (3)

The aalk is diverting load through the springs, instead of through the bushes and suspension components. That's how it's allowing more pitch in the front suspension.
But, the valving/adjustability of the struts will still dictate the rate of the transfer, and therefore control the level of pitch.

Why not just let the springs/dampers/bump stops do their job.

Anti -lift is only considered detrimental above 30% - which the Impreza doesn't exceed.
Too large a variation in pitch will effect suspension geometry, inducing loss of caster: Something that the Impreza is already deficient in.

Handling-wise, it seems to me, that the aalk is mitigating a sub-optimal selection of spring rates/dampers/bump stops.

Discussion Paper Effect of Whiteline Anti-Lift Kit (ALK)

2pot

iTrader: (3)

You've already got them
Correct spring rates, for the road type.
Additional positive rake
Bilstein dampers
Matching bump stops - assuming you fitted them? To replace the, too soft, 60mm front and rear bump stops that originally came in the wr97/98 Bilsteins.

I'm guessing you fitted the alk before the above?

It's all a bit academic really. I've got an old Plymouth with torsion bar front suspension and leaf spring rear. It originally had drum brakes, front and rear Still makes me happy though.