classic set up :thumb:
25 February 2016, 08:48 AM
#31
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)
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)
I can't find any good clear information on how anti geometry is best set up for a performance point of view .
If staying below 30% anti lift is the optimal then that's made my mind up , have you got any good links about it outside the manufacturers of alk info
25 February 2016, 10:47 AM
#32
http://www.lateral-g.net/forums/showthread.php4?t=42467This is a great read if you want to fully understand how the front suspension works , although I've not got to anti geometry yet ,
25 February 2016, 10:58 AM
#33
I'm thinking that using spacers between the rear control arm mount you could alter the anti lift to whatever is considered optimal and then fit the proper form of caster adjustment to be able to fine tune would be the way to go
Not sure how the bushes would fit though
Not sure how the bushes would fit though
Last edited by gary77; 25 February 2016 at 11:47 AM.
25 February 2016, 12:42 PM
#34
is it not the. Case that anti lift is stopping the struts and springs from doing there job .
I can't find any good clear information on how anti geometry is best set up for a performance point of view .
If staying below 30% anti lift is the optimal then that's made my mind up , have you got any good links about it outside the manufacturers of alk info
I can't find any good clear information on how anti geometry is best set up for a performance point of view .
If staying below 30% anti lift is the optimal then that's made my mind up , have you got any good links about it outside the manufacturers of alk info
If all load transferred through standard rate springs/dampers, you'd be porpoising down the road.
If you change to performance dampers and higher rate springs, with suitable bump stops, and suitable alignment; then I can't foresee corner exit understeer being an issue.
As a final step, should you experience corner exit understeer, after fitting the above, then may be an aalk would suit your particular chassis/driving style.
I'd still be wary about the incremental movement of an un-lubricated urethane pivot bush.
I'd, personally, prefer a group n rubber bush, in that situation.
That 30% figure is one used by Whiteline in their PDF. But, it was taken, by them, from 'Tune to Win' by Carrol Smith.
25 February 2016, 01:03 PM
#35
The best explanation of why an alk might be a good mod ,
in most circumstances, there's nothing horribly wrong with lift or dive (obviously, there's exceptions to this). However, people don't like the way it feels. So the engineers design "anti-" geometry into the suspension. This causes the suspension to move in a particular way in response to longitudinal weight transfer. The net result of this is that the "force" of the weight transfer bypasses the spring and damper and instead runs through the suspension linkages. The effect of this is like having the spring rate shoot through the roof when you have fore/aft weight transfer. In other words, anti geometry makes the suspension very, very stiff any time the car is trying to pitch forwards or backwards.
Installing a properly designed ALK removes the anti geometry and prevents this stiffening of the suspension under pitch. Obviously, as we all know, overly stiff suspensions aren't good for grip on anything other than plate glass. The point of the ALK is to keep the front end in better contact with the road under breaking, acceleration, or bumps that look to the car like pitching (e.g. frost heaves, speed bumps, etc). This gives more front end grip in dynamic situations and allows you to come in harder on the brakes and get on the gas sooner.
in most circumstances, there's nothing horribly wrong with lift or dive (obviously, there's exceptions to this). However, people don't like the way it feels. So the engineers design "anti-" geometry into the suspension. This causes the suspension to move in a particular way in response to longitudinal weight transfer. The net result of this is that the "force" of the weight transfer bypasses the spring and damper and instead runs through the suspension linkages. The effect of this is like having the spring rate shoot through the roof when you have fore/aft weight transfer. In other words, anti geometry makes the suspension very, very stiff any time the car is trying to pitch forwards or backwards.
Installing a properly designed ALK removes the anti geometry and prevents this stiffening of the suspension under pitch. Obviously, as we all know, overly stiff suspensions aren't good for grip on anything other than plate glass. The point of the ALK is to keep the front end in better contact with the road under breaking, acceleration, or bumps that look to the car like pitching (e.g. frost heaves, speed bumps, etc). This gives more front end grip in dynamic situations and allows you to come in harder on the brakes and get on the gas sooner.
25 February 2016, 01:05 PM
#36
I hadn't noticed your reply until after I posted that last link , there is a group n alk , not sure on price though .
Anti lift only comes into play during braking and hard acceleration so not sure if porpoising down the road would be an issue .
Anti lift only comes into play during braking and hard acceleration so not sure if porpoising down the road would be an issue .
Last edited by gary77; 25 February 2016 at 01:09 PM.
25 February 2016, 06:00 PM
#38
The best explanation of why an alk might be a good mod ,
in most circumstances, there's nothing horribly wrong with lift or dive (obviously, there's exceptions to this). However, people don't like the way it feels. So the engineers design "anti-" geometry into the suspension. This causes the suspension to move in a particular way in response to longitudinal weight transfer. The net result of this is that the "force" of the weight transfer bypasses the spring and damper and instead runs through the suspension linkages. The effect of this is like having the spring rate shoot through the roof when you have fore/aft weight transfer. In other words, anti geometry makes the suspension very, very stiff any time the car is trying to pitch forwards or backwards.
Installing a properly designed ALK removes the anti geometry and prevents this stiffening of the suspension under pitch. Obviously, as we all know, overly stiff suspensions aren't good for grip on anything other than plate glass. The point of the ALK is to keep the front end in better contact with the road under breaking, acceleration, or bumps that look to the car like pitching (e.g. frost heaves, speed bumps, etc). This gives more front end grip in dynamic situations and allows you to come in harder on the brakes and get on the gas sooner.
in most circumstances, there's nothing horribly wrong with lift or dive (obviously, there's exceptions to this). However, people don't like the way it feels. So the engineers design "anti-" geometry into the suspension. This causes the suspension to move in a particular way in response to longitudinal weight transfer. The net result of this is that the "force" of the weight transfer bypasses the spring and damper and instead runs through the suspension linkages. The effect of this is like having the spring rate shoot through the roof when you have fore/aft weight transfer. In other words, anti geometry makes the suspension very, very stiff any time the car is trying to pitch forwards or backwards.
Installing a properly designed ALK removes the anti geometry and prevents this stiffening of the suspension under pitch. Obviously, as we all know, overly stiff suspensions aren't good for grip on anything other than plate glass. The point of the ALK is to keep the front end in better contact with the road under breaking, acceleration, or bumps that look to the car like pitching (e.g. frost heaves, speed bumps, etc). This gives more front end grip in dynamic situations and allows you to come in harder on the brakes and get on the gas sooner.
If you want to stop an Impreza understeering look to the bump stops.
The OEM rear stops are intentionally too soft - understeer bias is safer, in an emergency situation
The v5/v6 sti and P1 also have soft rear stops, and rock hard front stops as a form of pitch control. The stiff front stops cause understeer on anything but perfect road surface/conditions. Newage models also suffer these bump stop set-ups.
A stiffer rear stop will achieve what you want. In combination with a shorter, more progressive front stop.
First select your spring/strut combination........
25 February 2016, 06:34 PM
#39
I'd like to hear from someone quilified in setting up car suspension to confirm or rubbish that
What is your background ?
That's not ment to sound condescending,
25 February 2016, 06:37 PM
#40
As previously stated, anti-lift/dive is a device to control the excessive pitch of necessarily soft road springs.
If you want to stop an Impreza understeering look to the bump stops.
The OEM rear stops are intentionally too soft - understeer bias is safer, in an emergency situation
The v5/v6 sti and P1 also have soft rear stops, and rock hard front stops as a form of pitch control. The stiff front stops cause understeer on anything but perfect road surface/conditions. Newage models also suffer these bump stop set-ups.
A stiffer rear stop will achieve what you want. In combination with a shorter, more progressive front stop.
First select your spring/strut combination........
If you want to stop an Impreza understeering look to the bump stops.
The OEM rear stops are intentionally too soft - understeer bias is safer, in an emergency situation
The v5/v6 sti and P1 also have soft rear stops, and rock hard front stops as a form of pitch control. The stiff front stops cause understeer on anything but perfect road surface/conditions. Newage models also suffer these bump stop set-ups.
A stiffer rear stop will achieve what you want. In combination with a shorter, more progressive front stop.
First select your spring/strut combination........
Since anti lift is there for soft springs does that not mean there is a case to say it's not needed with an sti with the correct struts springs and stops
My thought is that anti lift is there because it feels better to the average driver but for outright performance it would be better without it
Last edited by gary77; 25 February 2016 at 06:51 PM.
25 February 2016, 09:44 PM
#41
I plan to follow your advice on all that but I'm still uncertain whether altering the anti lift is good or bad.
Since anti lift is there for soft springs does that not mean there is a case to say it's not needed with an sti with the correct struts springs and stops
My thought is that anti lift is there because it feels better to the average driver but for outright performance it would be better without it
Since anti lift is there for soft springs does that not mean there is a case to say it's not needed with an sti with the correct struts springs and stops
My thought is that anti lift is there because it feels better to the average driver but for outright performance it would be better without it
Whether there is a ever a spring/damping rate, on an awd, MacPherson strut suspension, that makes anti-lift/dive irrelevant? - pass.
I'd guess the spring and damping rates would have to be substantially higher, than an acceptable road spring though (ie beyond a spring rate that allows a tyre to follow typical road imperfections).
Anti-lift/dive is there because road spring rates need it. It gives limits to lift and dive. Which, I would imagine, contains the suspension geometry. within prescribed limits.
I'd suspect, it would be very weird to drive a softly suspended road car, without those limits.
26 February 2016, 09:56 AM
#42
True but softer front springs means more grip , I've read comments about the anti lift kit making the front springs softer but that I think is in relation to them feeling much harder as a result of anti lift , not necessarily softer than there state while not braking accelarating ,
I'd like to hear from someone quilified in setting up car suspension to confirm or rubbish that
What is your background ?
That's not ment to sound condescending,
I'd like to hear from someone quilified in setting up car suspension to confirm or rubbish that
What is your background ?
That's not ment to sound condescending,
Accounting for:
Rake - a, relatively, higher rear ride height, moves the roll centre rearward, increasing rear roll resistance. That, in turn, makes the front end roll more - helping turn-in response and reducing understeer.
Spring rates - linear in their operation range - Not too stiff!!!!!!!
What's The Best Suspension - Soft or Stiff Springs? - YouTube
The available dampers.
You'd normally make the springs, first, to get the rate and ride heights you want - then sort out the damping to match.
But we have the new dampers:
KYB excel-g £240
KYB agx £505
Koni inserts £650 + renovating/cutting the existing housings
KYB inverted £750 -£1000
So, it was a case of measuring them on a dyno, first.
11 March 2016, 08:22 PM
#46
Whiteline used to make a 20mm rear 3-way adjustable bar bsr20z. Try as performance.
Front bars:
Std front turbo bar was 19mm - 20410AC000
Bug wagon turbo front bar was 20mm - 20401FE010
Eibach are currently designing me a prototype 2-way 19/20mm front.
And a 3-way 19/20/21 rear.
Front bars:
Std front turbo bar was 19mm - 20410AC000
Bug wagon turbo front bar was 20mm - 20401FE010
Eibach are currently designing me a prototype 2-way 19/20mm front.
And a 3-way 19/20/21 rear.
11 March 2016, 10:43 PM
#47
i should have known you'd be on it, but i hate to say it, i would of gone 20,21,22 rear are people likely to go smaller than oe on the rear ?
i hope we are talking weeks not years for this
i cant bare to trawl through the spring thread again , what is the differance between the sti standard spring on the my00 and the p11 and wr15. a picture of all three together would be great, whats the ride hight differance and are they all the same style ,as in behave the same way ? is it just the rate thats different.
i hope we are talking weeks not years for this
i cant bare to trawl through the spring thread again , what is the differance between the sti standard spring on the my00 and the p11 and wr15. a picture of all three together would be great, whats the ride hight differance and are they all the same style ,as in behave the same way ? is it just the rate thats different.
Last edited by gary77; 11 March 2016 at 10:52 PM.
11 March 2016, 10:52 PM
#48
Stiffer rear bump stops come with the P11's and wr15's. So you may need less rear bar to maintain your favoured balance.
The wr15's, on undulating, uneven roads, would certainly need less bar. As Prodrive did with the wr99 kit - reduced rear bar to 18mm.
I can't think why McLaren keep getting the priority, over me.
The wr15's, on undulating, uneven roads, would certainly need less bar. As Prodrive did with the wr99 kit - reduced rear bar to 18mm.
I can't think why McLaren keep getting the priority, over me.
Last edited by 2pot; 11 March 2016 at 10:58 PM.
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