best suspension under 400
13 December 2014, 10:58 AM
#1
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best suspension under 400
Hi all. I'm looking for new suspension for my wrx.
For 2 reasons. the standard suspension is not to bad but I'd like it a bit stiffer and less rolly.
The front end of the car sits too high. It looks stupid frankly.
Previously on my astra I had ebaci sport springs and bilsten b8 dampers. this gave a nice performance increase and a small drop.
Problem is. The front needs to come down about 40mm. And the back only around 10mm.
Ideally I'd get adjustable coilovers but I Don't think there are any decent ones in that price range. Can I buy spacers to raise the rear once dropped?
For 2 reasons. the standard suspension is not to bad but I'd like it a bit stiffer and less rolly.
The front end of the car sits too high. It looks stupid frankly.
Previously on my astra I had ebaci sport springs and bilsten b8 dampers. this gave a nice performance increase and a small drop.
Problem is. The front needs to come down about 40mm. And the back only around 10mm.
Ideally I'd get adjustable coilovers but I Don't think there are any decent ones in that price range. Can I buy spacers to raise the rear once dropped?
13 December 2014, 03:03 PM
#4
Scooby Regular
Ok. From your requirements it appears you are somewhat lacking in a few basic facts.
The Impreza uses a modern (Mondeo was the first) McPherson strut system. The newer types use more vertical struts and longer lower arms to overcome the camber issues earlier systems had.
The one main issue Mc Ph. systems suffer with is Roll centre based. You judge the roll centre by taking an imaginary line from the 90' point on the top mount through the car till you meet the line extending through the outer and inner lower arm pivots. Then draw back to the tyre contact patch centre and where both sides cross is the roll centre. The Centre of Gravity is above this and the distance between them causes roll torque when a side loading is applied.
On McPherson struts you typically get a 3.5-4:1 ratio of roll centre to ride height. Thus, when you lower 40mm you lower the roll centre 4x40 or 160mm. Think about it. If the roll torque was based on a 80mm distance between CoG and RC, it would now be 240mm so even though you lowered your car 40mm, the roll force is three times larger.
x3.
So you need much stiffer springs to support the car. And/or a stiffer ARB.
For a cheap and effective mod, either quit trying to lower the car or get some Roll correction kit parts, that change the front ball joints and correct your roll centre. With these and a 25mm drop at the front you can get far less roll and a supple ride. By lowering front and not rear the car will tip less into the back corner under cornering, so less under steer.
Cheap? Ok, Roll correction kit, cut half a coil from your front springs and a quarter coil from your rears. Job done.
The Impreza uses a modern (Mondeo was the first) McPherson strut system. The newer types use more vertical struts and longer lower arms to overcome the camber issues earlier systems had.
The one main issue Mc Ph. systems suffer with is Roll centre based. You judge the roll centre by taking an imaginary line from the 90' point on the top mount through the car till you meet the line extending through the outer and inner lower arm pivots. Then draw back to the tyre contact patch centre and where both sides cross is the roll centre. The Centre of Gravity is above this and the distance between them causes roll torque when a side loading is applied.
On McPherson struts you typically get a 3.5-4:1 ratio of roll centre to ride height. Thus, when you lower 40mm you lower the roll centre 4x40 or 160mm. Think about it. If the roll torque was based on a 80mm distance between CoG and RC, it would now be 240mm so even though you lowered your car 40mm, the roll force is three times larger.
x3.
So you need much stiffer springs to support the car. And/or a stiffer ARB.
For a cheap and effective mod, either quit trying to lower the car or get some Roll correction kit parts, that change the front ball joints and correct your roll centre. With these and a 25mm drop at the front you can get far less roll and a supple ride. By lowering front and not rear the car will tip less into the back corner under cornering, so less under steer.
Cheap? Ok, Roll correction kit, cut half a coil from your front springs and a quarter coil from your rears. Job done.
14 December 2014, 01:07 AM
#5
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Ok. From your requirements it appears you are somewhat lacking in a few basic facts.
The Impreza uses a modern (Mondeo was the first) McPherson strut system. The newer types use more vertical struts and longer lower arms to overcome the camber issues earlier systems had.
The one main issue Mc Ph. systems suffer with is Roll centre based. You judge the roll centre by taking an imaginary line from the 90' point on the top mount through the car till you meet the line extending through the outer and inner lower arm pivots. Then draw back to the tyre contact patch centre and where both sides cross is the roll centre. The Centre of Gravity is above this and the distance between them causes roll torque when a side loading is applied.
On McPherson struts you typically get a 3.5-4:1 ratio of roll centre to ride height. Thus, when you lower 40mm you lower the roll centre 4x40 or 160mm. Think about it. If the roll torque was based on a 80mm distance between CoG and RC, it would now be 240mm so even though you lowered your car 40mm, the roll force is three times larger.
x3.
So you need much stiffer springs to support the car. And/or a stiffer ARB.
For a cheap and effective mod, either quit trying to lower the car or get some Roll correction kit parts, that change the front ball joints and correct your roll centre. With these and a 25mm drop at the front you can get far less roll and a supple ride. By lowering front and not rear the car will tip less into the back corner under cornering, so less under steer.
Cheap? Ok, Roll correction kit, cut half a coil from your front springs and a quarter coil from your rears. Job done.
The Impreza uses a modern (Mondeo was the first) McPherson strut system. The newer types use more vertical struts and longer lower arms to overcome the camber issues earlier systems had.
The one main issue Mc Ph. systems suffer with is Roll centre based. You judge the roll centre by taking an imaginary line from the 90' point on the top mount through the car till you meet the line extending through the outer and inner lower arm pivots. Then draw back to the tyre contact patch centre and where both sides cross is the roll centre. The Centre of Gravity is above this and the distance between them causes roll torque when a side loading is applied.
On McPherson struts you typically get a 3.5-4:1 ratio of roll centre to ride height. Thus, when you lower 40mm you lower the roll centre 4x40 or 160mm. Think about it. If the roll torque was based on a 80mm distance between CoG and RC, it would now be 240mm so even though you lowered your car 40mm, the roll force is three times larger.
x3.
So you need much stiffer springs to support the car. And/or a stiffer ARB.
For a cheap and effective mod, either quit trying to lower the car or get some Roll correction kit parts, that change the front ball joints and correct your roll centre. With these and a 25mm drop at the front you can get far less roll and a supple ride. By lowering front and not rear the car will tip less into the back corner under cornering, so less under steer.
Cheap? Ok, Roll correction kit, cut half a coil from your front springs and a quarter coil from your rears. Job done.
i should add the car has ally front lower arms (don't ask me why there there but they are!)
iv also got aluminium rear drop links.
im going to add some caster to the front which will take a little over steer off
im not looking for "hellaflush" lowering. the front end really is to high. it cant be good for handling
ignore the coilvers in this page but this is what im looking for reallly! http://www.superstreetonline.com/how...ar-affordably/
cut springs get a really bad rep but is it actually safe to do on coilovers since the spring cant fall out? its always been a big no no as far as i was concerend
iv been looking at Tein S-Tech springs
they seem to have a good following.
please continue to educate me, which would be better
a. fit lowering springs to only the front
b. fit lowering springs to both the front and back and then uses spacers to raise the back up again
i hate to admit im wrong but i am struggling with this lol
14 December 2014, 04:20 AM
#7
Caster on the front will take away UNDERSTEER not oversteer. A 24mm roll bar on the back will stiffen things up nicely, but probably introduce some oversteer, tyres are a major factor too, I would just look at a set of Prodrive springs, front ALK, droplinks and re-bush everything with super-pro poly bushes, then take it to a Subaru specialist for a geo set up, much better way to spend your £400.
I would also be more concerned with how it handles than how it looks.
I would also be more concerned with how it handles than how it looks.
Last edited by ditchmyster; 14 December 2014 at 04:22 AM.
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14 December 2014, 11:40 AM
#8
Scooby Regular
As Ditch said, you can't have looks and good handling on this car- unless you spend a lot of money and accept a lot of compromises.
OK, a quick story. I used to live in Peterboghorror. The Roundabout above the Nene Parkway at the Moathouse is a large oval that goes over a dual carriageway. If you attack it going up from the lower section to cross over and head into town, the vizability is excellent and you can see if there is traffic coming early enough to set it up for a full on hard throttle single input corner. Utterly satisfying to get right....
Anyway, I had an Escort Mk4, 1986 with RS Turbo suspension (and everything else but the turbo and insurance) back in the day and the LSD would try to pull it into the inside curb on that corner- right at the limit. Later I had a Sierra Sapphire Cossie Rep that was again homebuilt but pure Cossie all the way to the engine (2.0i Ghia base car). Anyway, I would be hanging out of the Recaro on that bend, RE71's squealing and the grin of the Devil. Heaven for a young man don't you think?
Dad then let me drive his Mondeo 2.0 automatic slug. It managed that roundabout 9mph faster than the best my Sierra could do.............WTF! Then I learned about suspension. Semi trailing arms and short arm McPherson had no chance. The Mondeo was a generation apart and that the Vectra was not was why it got panned so badly. (I had one of those for a short while and by heck it would struggle to out-corner a Model T!) The moral?
The Mondeo sat high. was soft and comfortable, yet could corner better than my Sierra, on Cossie suspension and brakes. Why? The Centre of gravity was lower, the roll centre higher and the roll much less. The camber changes with roll were less and the tyres were presented a better chance to grip as a result. Less wear, less drama and loads more lateral "G" available. Hmm.
Your Impreza has similar suspension to that Mondeo. The outside tyre needs to remain nearly vertical under roll conditions. Camber produces side thrust and a slight negative pulls the suspension tight making less complient road manners but more instant bite when you steer. Caster is NOT ADJUSTABLE on the standard parts. This is the lay back of the front and produces camber with steering. (Severe Castor is best seen looking at Mercedes saloons with wheels turned as the front almost falls over). It's a way to give camber thrust without static camber causing wear and tension in the bushes. A GOOD THING.
You Impreza has alloy front arms because as the years go on, WRX gets bits from the STi like this. Alloy lower rear links on later cars too. That's part of the development road for Subaru. Benefits are bolt on rear mount (for CASTOR changes) and outer ball joints (for roll centre correction)
Actually, if you were to raise your car 10mm you'd find it rolled less and cornered better. 10mm rise and 30mm roll centre rise. Engineers work for months to find the very best chassis balance and compromise that is safe and predictable. If it makes the arches look silly, and they find it early enough, they'll change parts to correct in pre-production, either roll centre changes or make new wings with arch shape altered (very very rare!).
The final point is whatever we do to our cars, we move away from the design spec done by Subaru's engineers...professionals who concentrate totally on this. An altered car is a legal nightmare when you sell it on. I'd always recommend keeping original bits and refitting before sale for this reason alone. I can't with mine, but I have O.E. rate springs and will set it to original ride and geo specs before it goes (if I ever have to that is).
As Ditch says, the best value is a 22 or 24mm ARB at the rear. The STi uses a 19mm O.E. Stronger ARB will stop the car rolling into the rear corner and lifting the inside front up causing understeer. I have an adjustable 22mm one and that's enough.
Ditch's rec is for a set of Prodrive springs, these lower the car about 20mm ish but you need the matching Bump stops fitted as well. Front Anti Lift Kit is a new front lower arm rear mount and spacers for your subframe. This gives CASTOR and rotates your lower arm slightly, removing the anti lift and anti dive the Engineers designed in.
Poly bushes will make it all tight but may make the car noisy and increase NVH from poor road surfaces. Not that a Scooby is quiet anyway.... Geo setup is vital for handling.
That is all. You can search for other stuff in the Suspension section.
OK, a quick story. I used to live in Peterboghorror. The Roundabout above the Nene Parkway at the Moathouse is a large oval that goes over a dual carriageway. If you attack it going up from the lower section to cross over and head into town, the vizability is excellent and you can see if there is traffic coming early enough to set it up for a full on hard throttle single input corner. Utterly satisfying to get right....
Anyway, I had an Escort Mk4, 1986 with RS Turbo suspension (and everything else but the turbo and insurance) back in the day and the LSD would try to pull it into the inside curb on that corner- right at the limit. Later I had a Sierra Sapphire Cossie Rep that was again homebuilt but pure Cossie all the way to the engine (2.0i Ghia base car). Anyway, I would be hanging out of the Recaro on that bend, RE71's squealing and the grin of the Devil. Heaven for a young man don't you think?
Dad then let me drive his Mondeo 2.0 automatic slug. It managed that roundabout 9mph faster than the best my Sierra could do.............WTF! Then I learned about suspension. Semi trailing arms and short arm McPherson had no chance. The Mondeo was a generation apart and that the Vectra was not was why it got panned so badly. (I had one of those for a short while and by heck it would struggle to out-corner a Model T!) The moral?
The Mondeo sat high. was soft and comfortable, yet could corner better than my Sierra, on Cossie suspension and brakes. Why? The Centre of gravity was lower, the roll centre higher and the roll much less. The camber changes with roll were less and the tyres were presented a better chance to grip as a result. Less wear, less drama and loads more lateral "G" available. Hmm.
Your Impreza has similar suspension to that Mondeo. The outside tyre needs to remain nearly vertical under roll conditions. Camber produces side thrust and a slight negative pulls the suspension tight making less complient road manners but more instant bite when you steer. Caster is NOT ADJUSTABLE on the standard parts. This is the lay back of the front and produces camber with steering. (Severe Castor is best seen looking at Mercedes saloons with wheels turned as the front almost falls over). It's a way to give camber thrust without static camber causing wear and tension in the bushes. A GOOD THING.
You Impreza has alloy front arms because as the years go on, WRX gets bits from the STi like this. Alloy lower rear links on later cars too. That's part of the development road for Subaru. Benefits are bolt on rear mount (for CASTOR changes) and outer ball joints (for roll centre correction)
Actually, if you were to raise your car 10mm you'd find it rolled less and cornered better. 10mm rise and 30mm roll centre rise. Engineers work for months to find the very best chassis balance and compromise that is safe and predictable. If it makes the arches look silly, and they find it early enough, they'll change parts to correct in pre-production, either roll centre changes or make new wings with arch shape altered (very very rare!).
The final point is whatever we do to our cars, we move away from the design spec done by Subaru's engineers...professionals who concentrate totally on this. An altered car is a legal nightmare when you sell it on. I'd always recommend keeping original bits and refitting before sale for this reason alone. I can't with mine, but I have O.E. rate springs and will set it to original ride and geo specs before it goes (if I ever have to that is).
As Ditch says, the best value is a 22 or 24mm ARB at the rear. The STi uses a 19mm O.E. Stronger ARB will stop the car rolling into the rear corner and lifting the inside front up causing understeer. I have an adjustable 22mm one and that's enough.
Ditch's rec is for a set of Prodrive springs, these lower the car about 20mm ish but you need the matching Bump stops fitted as well. Front Anti Lift Kit is a new front lower arm rear mount and spacers for your subframe. This gives CASTOR and rotates your lower arm slightly, removing the anti lift and anti dive the Engineers designed in.
Poly bushes will make it all tight but may make the car noisy and increase NVH from poor road surfaces. Not that a Scooby is quiet anyway.... Geo setup is vital for handling.
That is all. You can search for other stuff in the Suspension section.
14 December 2014, 04:23 PM
#9
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wow. cheers guys lots off info there sorry i did mean understeer
whats a front ALK? iv got decent tires all round always have and will do.
drop links are ball joints on the front and alloy and PU at the rear already.
thanks for the advice. although rear ARB + prodrive springs +polly bushes + alignment will probably be over 700
ok fortunately caster is something i understand. with the ally lower arms i can take the rear mount off and shim it to bring the lower ball forward
iv been reading reviews
and these seem quite good.
i think ill go with those and then uprate the ARB to counter the lower roll center. if i can aford pollybushes then i will
dose this sound resonable?
A 24mm roll bar on the back will stiffen things up nicely, but probably introduce some oversteer, tyres are a major factor too, I would just look at a set of Prodrive springs, front ALK, droplinks and re-bush everything with super-pro poly bushes, then take it to a Subaru specialist for a geo set up, much better way to spend your £400.
I would also be more concerned with how it handles than how it looks.
I would also be more concerned with how it handles than how it looks.
drop links are ball joints on the front and alloy and PU at the rear already.
thanks for the advice. although rear ARB + prodrive springs +polly bushes + alignment will probably be over 700
As Ditch said, you can't have looks and good handling on this car- unless you spend a lot of money and accept a lot of compromises.
OK, a quick story. I used to live in Peterboghorror. The Roundabout above the Nene Parkway at the Moathouse is a large oval that goes over a dual carriageway. If you attack it going up from the lower section to cross over and head into town, the vizability is excellent and you can see if there is traffic coming early enough to set it up for a full on hard throttle single input corner. Utterly satisfying to get right....
Anyway, I had an Escort Mk4, 1986 with RS Turbo suspension (and everything else but the turbo and insurance) back in the day and the LSD would try to pull it into the inside curb on that corner- right at the limit. Later I had a Sierra Sapphire Cossie Rep that was again homebuilt but pure Cossie all the way to the engine (2.0i Ghia base car). Anyway, I would be hanging out of the Recaro on that bend, RE71's squealing and the grin of the Devil. Heaven for a young man don't you think?
Dad then let me drive his Mondeo 2.0 automatic slug. It managed that roundabout 9mph faster than the best my Sierra could do.............WTF! Then I learned about suspension. Semi trailing arms and short arm McPherson had no chance. The Mondeo was a generation apart and that the Vectra was not was why it got panned so badly. (I had one of those for a short while and by heck it would struggle to out-corner a Model T!) The moral?
The Mondeo sat high. was soft and comfortable, yet could corner better than my Sierra, on Cossie suspension and brakes. Why? The Centre of gravity was lower, the roll centre higher and the roll much less. The camber changes with roll were less and the tyres were presented a better chance to grip as a result. Less wear, less drama and loads more lateral "G" available. Hmm.
Your Impreza has similar suspension to that Mondeo. The outside tyre needs to remain nearly vertical under roll conditions. Camber produces side thrust and a slight negative pulls the suspension tight making less complient road manners but more instant bite when you steer. Caster is NOT ADJUSTABLE on the standard parts. This is the lay back of the front and produces camber with steering. (Severe Castor is best seen looking at Mercedes saloons with wheels turned as the front almost falls over). It's a way to give camber thrust without static camber causing wear and tension in the bushes. A GOOD THING.
You Impreza has alloy front arms because as the years go on, WRX gets bits from the STi like this. Alloy lower rear links on later cars too. That's part of the development road for Subaru. Benefits are bolt on rear mount (for CASTOR changes) and outer ball joints (for roll centre correction)
Actually, if you were to raise your car 10mm you'd find it rolled less and cornered better. 10mm rise and 30mm roll centre rise. Engineers work for months to find the very best chassis balance and compromise that is safe and predictable. If it makes the arches look silly, and they find it early enough, they'll change parts to correct in pre-production, either roll centre changes or make new wings with arch shape altered (very very rare!).
The final point is whatever we do to our cars, we move away from the design spec done by Subaru's engineers...professionals who concentrate totally on this. An altered car is a legal nightmare when you sell it on. I'd always recommend keeping original bits and refitting before sale for this reason alone. I can't with mine, but I have O.E. rate springs and will set it to original ride and geo specs before it goes (if I ever have to that is).
As Ditch says, the best value is a 22 or 24mm ARB at the rear. The STi uses a 19mm O.E. Stronger ARB will stop the car rolling into the rear corner and lifting the inside front up causing understeer. I have an adjustable 22mm one and that's enough.
Ditch's rec is for a set of Prodrive springs, these lower the car about 20mm ish but you need the matching Bump stops fitted as well. Front Anti Lift Kit is a new front lower arm rear mount and spacers for your subframe. This gives CASTOR and rotates your lower arm slightly, removing the anti lift and anti dive the Engineers designed in.
Poly bushes will make it all tight but may make the car noisy and increase NVH from poor road surfaces. Not that a Scooby is quiet anyway.... Geo setup is vital for handling.
That is all. You can search for other stuff in the Suspension section.
OK, a quick story. I used to live in Peterboghorror. The Roundabout above the Nene Parkway at the Moathouse is a large oval that goes over a dual carriageway. If you attack it going up from the lower section to cross over and head into town, the vizability is excellent and you can see if there is traffic coming early enough to set it up for a full on hard throttle single input corner. Utterly satisfying to get right....
Anyway, I had an Escort Mk4, 1986 with RS Turbo suspension (and everything else but the turbo and insurance) back in the day and the LSD would try to pull it into the inside curb on that corner- right at the limit. Later I had a Sierra Sapphire Cossie Rep that was again homebuilt but pure Cossie all the way to the engine (2.0i Ghia base car). Anyway, I would be hanging out of the Recaro on that bend, RE71's squealing and the grin of the Devil. Heaven for a young man don't you think?
Dad then let me drive his Mondeo 2.0 automatic slug. It managed that roundabout 9mph faster than the best my Sierra could do.............WTF! Then I learned about suspension. Semi trailing arms and short arm McPherson had no chance. The Mondeo was a generation apart and that the Vectra was not was why it got panned so badly. (I had one of those for a short while and by heck it would struggle to out-corner a Model T!) The moral?
The Mondeo sat high. was soft and comfortable, yet could corner better than my Sierra, on Cossie suspension and brakes. Why? The Centre of gravity was lower, the roll centre higher and the roll much less. The camber changes with roll were less and the tyres were presented a better chance to grip as a result. Less wear, less drama and loads more lateral "G" available. Hmm.
Your Impreza has similar suspension to that Mondeo. The outside tyre needs to remain nearly vertical under roll conditions. Camber produces side thrust and a slight negative pulls the suspension tight making less complient road manners but more instant bite when you steer. Caster is NOT ADJUSTABLE on the standard parts. This is the lay back of the front and produces camber with steering. (Severe Castor is best seen looking at Mercedes saloons with wheels turned as the front almost falls over). It's a way to give camber thrust without static camber causing wear and tension in the bushes. A GOOD THING.
You Impreza has alloy front arms because as the years go on, WRX gets bits from the STi like this. Alloy lower rear links on later cars too. That's part of the development road for Subaru. Benefits are bolt on rear mount (for CASTOR changes) and outer ball joints (for roll centre correction)
Actually, if you were to raise your car 10mm you'd find it rolled less and cornered better. 10mm rise and 30mm roll centre rise. Engineers work for months to find the very best chassis balance and compromise that is safe and predictable. If it makes the arches look silly, and they find it early enough, they'll change parts to correct in pre-production, either roll centre changes or make new wings with arch shape altered (very very rare!).
The final point is whatever we do to our cars, we move away from the design spec done by Subaru's engineers...professionals who concentrate totally on this. An altered car is a legal nightmare when you sell it on. I'd always recommend keeping original bits and refitting before sale for this reason alone. I can't with mine, but I have O.E. rate springs and will set it to original ride and geo specs before it goes (if I ever have to that is).
As Ditch says, the best value is a 22 or 24mm ARB at the rear. The STi uses a 19mm O.E. Stronger ARB will stop the car rolling into the rear corner and lifting the inside front up causing understeer. I have an adjustable 22mm one and that's enough.
Ditch's rec is for a set of Prodrive springs, these lower the car about 20mm ish but you need the matching Bump stops fitted as well. Front Anti Lift Kit is a new front lower arm rear mount and spacers for your subframe. This gives CASTOR and rotates your lower arm slightly, removing the anti lift and anti dive the Engineers designed in.
Poly bushes will make it all tight but may make the car noisy and increase NVH from poor road surfaces. Not that a Scooby is quiet anyway.... Geo setup is vital for handling.
That is all. You can search for other stuff in the Suspension section.
iv been reading reviews
and these seem quite good.
i think ill go with those and then uprate the ARB to counter the lower roll center. if i can aford pollybushes then i will
dose this sound resonable?
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