What will poly / race bushes do?
#1
What will poly / race bushes do?
NOT ON A SCOOB but in general terms what will they do.
I was assuming / hoping that they would reduce body roll and therefore improve turn in and general handling (on track) whilst making it a stiffer and less user friendly on the road.
What say you? anyone got experience of these and what was the result from the change?
These are being used in conjunction with a decent Koni suspension set up.
cheers
Gary
I was assuming / hoping that they would reduce body roll and therefore improve turn in and general handling (on track) whilst making it a stiffer and less user friendly on the road.
What say you? anyone got experience of these and what was the result from the change?
These are being used in conjunction with a decent Koni suspension set up.
cheers
Gary
#2
Difficult to see why they would reduce body roll.
They will reduce the wheel deflections in the sideways and fore-and-aft directions, which will keep the geometry more consistant, and possible prevent the fronts from rolling out on to their shoulders so much, so you may be able to run with less static camber, whilst keeping the same dynamic camber under load. Basically you are just taking a source of softness and slop out of the car, so it should feel more direct and responsive, and it will be easier to get the geometry set acurately and you will get less unwanted wheel deflection under cornering loads.
The ride and NVH will go out the window though as the ability of the wheels to move fore-and-aft to absorb sharp edged bumps makes a massive difference to the ride quality, if you watch cars driving through a pot hole at a reasonable speed, you can see the wheels moving fore-and-aft as well as up and down.
They will reduce the wheel deflections in the sideways and fore-and-aft directions, which will keep the geometry more consistant, and possible prevent the fronts from rolling out on to their shoulders so much, so you may be able to run with less static camber, whilst keeping the same dynamic camber under load. Basically you are just taking a source of softness and slop out of the car, so it should feel more direct and responsive, and it will be easier to get the geometry set acurately and you will get less unwanted wheel deflection under cornering loads.
The ride and NVH will go out the window though as the ability of the wheels to move fore-and-aft to absorb sharp edged bumps makes a massive difference to the ride quality, if you watch cars driving through a pot hole at a reasonable speed, you can see the wheels moving fore-and-aft as well as up and down.
#3
Scooby Regular
Graham (911)'s your man. He's replaced them all on his Impreza, so can give you real-life experience albeit you're not talking specifically about an Impreza.
They basically take out more of the movement from OE bushes, so should tighten everything up. As said already this will lead inevitably to more noise and a decrease in ride quality.
Just 'how' much depends on what bushes are replaced e.g. replace every single one of them and the difference may be noticeable.
Stefan
They basically take out more of the movement from OE bushes, so should tighten everything up. As said already this will lead inevitably to more noise and a decrease in ride quality.
Just 'how' much depends on what bushes are replaced e.g. replace every single one of them and the difference may be noticeable.
Stefan
#4
I love that saying .....''it tightens everything up'' ......... I have used that when im not convinced what im talking about sorry if that isnt the case.
I have a full set of ARB / drop link / rear bump stop bushes coming for my 205. I guess the simpy way to find out the answer is change them over and report back.
thanks for the comments all the same........
Gary
I have a full set of ARB / drop link / rear bump stop bushes coming for my 205. I guess the simpy way to find out the answer is change them over and report back.
thanks for the comments all the same........
Gary
#5
Originally Posted by AvalancheS8
Difficult to see why they would reduce body roll.
They will reduce the wheel deflections in the sideways and fore-and-aft directions, which will keep the geometry more consistant, and possible prevent the fronts from rolling out on to their shoulders so much, so you may be able to run with less static camber, whilst keeping the same dynamic camber under load. Basically you are just taking a source of softness and slop out of the car, so it should feel more direct and responsive, and it will be easier to get the geometry set acurately and you will get less unwanted wheel deflection under cornering loads.
The ride and NVH will go out the window though as the ability of the wheels to move fore-and-aft to absorb sharp edged bumps makes a massive difference to the ride quality, if you watch cars driving through a pot hole at a reasonable speed, you can see the wheels moving fore-and-aft as well as up and down.
They will reduce the wheel deflections in the sideways and fore-and-aft directions, which will keep the geometry more consistant, and possible prevent the fronts from rolling out on to their shoulders so much, so you may be able to run with less static camber, whilst keeping the same dynamic camber under load. Basically you are just taking a source of softness and slop out of the car, so it should feel more direct and responsive, and it will be easier to get the geometry set acurately and you will get less unwanted wheel deflection under cornering loads.
The ride and NVH will go out the window though as the ability of the wheels to move fore-and-aft to absorb sharp edged bumps makes a massive difference to the ride quality, if you watch cars driving through a pot hole at a reasonable speed, you can see the wheels moving fore-and-aft as well as up and down.
The car will be 95% a track car this year so everything you have said points in the right direction for me.
Thank you
gary
#6
If your car is essentially a track day car and a bit on the road, then the bushes are great.
Pig of a job to fit them totally to any chassis though, and in time they will groan and moan when driving off especially if the car has stood for a while (ie a few days or more)
After a few miles they will loosen-up and all is well.
I must admit that I really doubt that you will see a huge improvement, but things will tighten-up ( ), behave sharper etc etc .
A further more tangible benefit (on my Sti v3) is the control of the chassis under very hard accelleration and braking as the suspension is so much better controlled under heavy loads; no torque steer, squirming etc so the car feels 'tighter' ( )
Would I fit them again?
Yes, as they do provide that bit extra control, and they do not control body roll except where used in the anti roll bar pivots/drop links.
My 2 penneth!
911
Pig of a job to fit them totally to any chassis though, and in time they will groan and moan when driving off especially if the car has stood for a while (ie a few days or more)
After a few miles they will loosen-up and all is well.
I must admit that I really doubt that you will see a huge improvement, but things will tighten-up ( ), behave sharper etc etc .
A further more tangible benefit (on my Sti v3) is the control of the chassis under very hard accelleration and braking as the suspension is so much better controlled under heavy loads; no torque steer, squirming etc so the car feels 'tighter' ( )
Would I fit them again?
Yes, as they do provide that bit extra control, and they do not control body roll except where used in the anti roll bar pivots/drop links.
My 2 penneth!
911
#7
Scooby Regular
personally have always used 'powerflex' bushes on most of my track & fast road cars..............never had any issues with NVH or ride quality and used to use a hillclimb spec car for the daily commute..............
think it depends on the quality of the parts you buy............
alyn
think it depends on the quality of the parts you buy............
alyn
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#8
Scooby Regular
LOL. Well logically if an OE bush flexes more than a stiffer 3rd-party poly one then replacing them with such items there won't be as much movement between components i.e. you could say the joint is tighter
#9
Moderator
iTrader: (1)
NOT ON A SCOOB
Now, some cars...especially large cars with complex multi link suspension actually depend on some movement in suspension and steering mountings to help with the general handling and ride dynamics of the car, in the road use sense at the least.
Polybushes, if they are too stiff can ruin the driveability of the car on a rough road. Generally making it feel edgy and unsettled.
Without being specific on any car - in general, on some cars they can be an improvement, and on some cars they are not and are worse. And on some they don't make the blindest bit of difference - as the original mounting rubber was of equal stiffness anyway.
Best to get owners opinions on the particualr make and model of car before investing...but take note of what other suspension and wheel/tyre mods they did at the same time (such as bigger wheels, shocks, springs and ARBs).
#10
Thanks for the comments chaps it made for some interesting reading.
The car in question is my trusty 205 gti.
The bushes were very cheap (friend in the trade etc). I will give them a try and if I dont like the outcome then I will go back to standard parts again. If nothing else the car will have new bushes, which can't be a bad thing.
Gary
Oh and other owners comments range from ........ ''it made the car feel stiffer PMSL, to very hard on normal roads, to couldnt really feel the difference.
The car in question is my trusty 205 gti.
The bushes were very cheap (friend in the trade etc). I will give them a try and if I dont like the outcome then I will go back to standard parts again. If nothing else the car will have new bushes, which can't be a bad thing.
Gary
Oh and other owners comments range from ........ ''it made the car feel stiffer PMSL, to very hard on normal roads, to couldnt really feel the difference.
#13
Bushes have turned up .... they are harder than a hard thing ........ They feel as if they will really ''tighten things up'' ... PMSL
Will let you know how I get on after the weekend. Thanks for the discussion though fella's. Much more interesting than the usual dribble in the general section.
Gary
Will let you know how I get on after the weekend. Thanks for the discussion though fella's. Much more interesting than the usual dribble in the general section.
Gary
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