Coilover Traction Loss

[m0nty]

You shouldn't be driving your car anything like you do on a track regardless. Many members here would be able to help you in setting up your car correctly at the track. My advice would be to meet some of us for a WP test day, get the car set up and then enjoy the occassional spirited drive on the road, but this spirited drive should NEVER reach the same levels you experience at the track.

[tinkerbell]

howcome?

page 6:

http://www.whiteline.com.au/docs/art...sp_02_0213.pdf

[tinkerbell]

a bit more here:

http://www.drifting.com/forums/tech-...abe-u-s-a.html

Stiff suspensions and mountain roads do not mix. Take the bad situations of City and Highway and multiply it by ONE MILLION. Mountain Roads are generally not well maintained, so that 2000 dollar racing suspension is really going to work against you here. The car will be bouncing from the bumps, as the springs will not absorb them. Weight is going to be transferring all over the place, so you’re going to need as much grip as you can get.

Braking under rough road conditions will more than likely cause an understeer condition. Barreling through a turn on a rough road will cause understeer, or oversteer. If you have to brake hard to avoid an animal and the road is rough…you can kiss your Takumi aspirations goodbye as you plow into that Initial Deer.

Remember, a suspension is only as good as the driver. 99% of the time, we are not driving on a track, so finding a good balance for your needs and budget is the key. The best suspension upgrade is upgrading the driver. It’s “how you use it”.

[Type S Tony]

page 6:

http://www.whiteline.com.au/docs/art...sp_02_0213.pdf

a bit more here:

http://www.drifting.com/forums/tech-...abe-u-s-a.html

Tinks come through with Da Goodz!

[ChargeR]

BC Coilovers - BR series
Front Spring Rate : 10kg/mm (558.7lbs/in)
Rear Spring Rate : 12kg/mm (670.4lbs/in)
no other sussy mods
my damping settings would be useless as every coilover is different.
But i had it on "hard to soft" so that could be to blame i think. Ill have to try it with soft settings.

Play around with the damper settings but there is no avoiding that with stiffer spring rates comes less bump compliance. Your spring rates aren't super high so hopefully you can find a happy medium .

How do you find the ride over general day to day bumps with the BC BRs? I only ask because the BCs I have on my daily (V1s) are extremely uncomfortable and I was wondering if it was a common trait of BC dampers. The one shock dyno I have seen of a BC damper showed it to be progressive with a massive amount of high speed damping, not ideal for bump compliance.

[Didz]

hey guys

i have an issue that's been on my mind for awhile.
When i take the car out to national park and have a session of spirited driving, i experience loss of traction around corners when the road get's bumpy. Not only is it annoying its dangerous as well

I have coilovers that's pretty new and no issues with that.

How do i resolve this issue? change spring rates? or is the coilover the problem?

Currently running stockiesd with32psi

Ok after reading other details about ur spring rates and all i can comment on this with my own experience.
Recently i have used 3 different suspension setups on my car. Tein Monoflex, Stock and now DMS 40mm Coilovers.

Tein 10kg front, 12kg rear. Same as yours.
I took my car for a drive around Mt Dandenong (lots of twistie roads) and i have to say i was very nervous as the car felt very bumpy and cornering was not a fun idea. I didnt even want to drive at the speed limit at times.

Stock
No problems of course

DMS.
This is a WHOLE different ball game. The DMS shocks differ in 2 ways to the Teins. The springs are still rated at 10kg front and 12kg rear. However these are progressive spring rates which mean initially they are not so stiff but as they compress, they get stiffer and stiffer. Now it doesnt take a whole lot to get them to stiffen up but there is certainly a higher level of comfort on these roads.
The second major difference is that the DMS have the same level of droop as the stock suspension does (on the front). What does this mean? Well to me, it is a lot safer for daily driving.
Most typical coilover suspension setups have no droop (please forgive me if this is not the right technical term) or very little. What this means is that the wheel will compress but it wont travel out further than the set hight. This is apparent when you go over bumps and ramps and notice a rear wheel off the ground. So all of these bumps are causing the left and right wheels to be off the ground at certain times. Enough to cause an imbalance and upset the driving experience. This is the major reason why most (if not all) coilovers are not road legal in Australia.

My recommendation would be:
1. Dont drive 'spiritedly' on the mountain roads (or any normal roads really) instead, drive this way on a track.

2. Use stock suspension when driving around day to day.
3. Change your spring rates
4. Deal with it and run a higher risk to do some damage.

I am not sure damper adjustments will solve your problem but i am no engineer or suspension expert.

Hope this helps.

[m0nty]

Ok after reading other details about ur spring rates and all i can comment on this with my own experience.
Recently i have used 3 different suspension setups on my car. Tein Monoflex, Stock and now DMS 40mm Coilovers.

Tein 10kg front, 12kg rear. Same as yours.
I took my car for a drive around Mt Dandenong (lots of twistie roads) and i have to say i was very nervous as the car felt very bumpy and cornering was not a fun idea. I didnt even want to drive at the speed limit at times.

Stock
No problems of course

DMS.
This is a WHOLE different ball game. The DMS shocks differ in 2 ways to the Teins. The springs are still rated at 10kg front and 12kg rear. However these are progressive spring rates which mean initially they are not so stiff but as they compress, they get stiffer and stiffer. Now it doesnt take a whole lot to get them to stiffen up but there is certainly a higher level of comfort on these roads.
The second major difference is that the DMS have the same level of droop as the stock suspension does (on the front). What does this mean? Well to me, it is a lot safer for daily driving.
Most typical coilover suspension setups have no droop (please forgive me if this is not the right technical term) or very little. What this means is that the wheel will compress but it wont travel out further than the stock hight. This is apparent when you go over bumps and ramps and notice a rear wheel off the ground. So all of these bumps are causing the left and right wheels to be off the ground at certain times. Enough to cause an imbalance and upset the driving experience. This is the major reason why most (if not all) coilovers are not road legal in Australia.

My recommendation would be:
1. Dont drive 'spiritedly' on the mountain roads (or any normal roads really) instead, drive this way on a track.

2. Use stock suspension when driving around day to day.
3. Change your spring rates
4. Deal with it and run a higher risk to do some damage.

I am not sure damper adjustments will solve your problem but i am no engineer or suspension expert.

Hope this helps.

Bold #1 The issue for performance driving in a DC5 with softer suspension is the drastic change in alignment under compression. Under heavy braking the DC5 front suspension will compress and alter toe settings drastically. For the street it doesn't matter so much.

Bold #2 I wholeheartedly agree.

[ewendc2r]

lol -- mind you, decent suggestion there. I might take my fightex off and only put them on when im going to the track.. saves wear and tear and im sure the OEM would ride much nicer around town. Only takes around 2 hours to change the coilovers and (forgive me if im mistaken) can be installed without really effecting alignment (due to wishbone rather than macpherson installation) ??

[maracer]

Ok after reading other details about ur spring rates and all i can comment on this with my own experience.
Recently i have used 3 different suspension setups on my car. Tein Monoflex, Stock and now DMS 40mm Coilovers.

Tein 10kg front, 12kg rear. Same as yours.
I took my car for a drive around Mt Dandenong (lots of twistie roads) and i have to say i was very nervous as the car felt very bumpy and cornering was not a fun idea. I didnt even want to drive at the speed limit at times.

Stock
No problems of course

DMS.
This is a WHOLE different ball game. The DMS shocks differ in 2 ways to the Teins. The springs are still rated at 10kg front and 12kg rear. However these are progressive spring rates which mean initially they are not so stiff but as they compress, they get stiffer and stiffer. Now it doesnt take a whole lot to get them to stiffen up but there is certainly a higher level of comfort on these roads.
The second major difference is that the DMS have the same level of droop as the stock suspension does (on the front). What does this mean? Well to me, it is a lot safer for daily driving.
Most typical coilover suspension setups have no droop (please forgive me if this is not the right technical term) or very little. What this means is that the wheel will compress but it wont travel out further than the set hight. This is apparent when you go over bumps and ramps and notice a rear wheel off the ground. So all of these bumps are causing the left and right wheels to be off the ground at certain times. Enough to cause an imbalance and upset the driving experience. This is the major reason why most (if not all) coilovers are not road legal in Australia.

My recommendation would be:
1. Dont drive 'spiritedly' on the mountain roads (or any normal roads really) instead, drive this way on a track.

2. Use stock suspension when driving around day to day.
3. Change your spring rates
4. Deal with it and run a higher risk to do some damage.

I am not sure damper adjustments will solve your problem but i am no engineer or suspension expert.

Hope this helps.

I actually understood this, Thanks Justin.


Didn’t think this thread would get such an overwhelming response.
I believe every response has a point or two, which is great
But FARK an LSD would help……………lol…..or maybe not………

[Didz]

I reckon an LSD would help to some degree :P

[tinkerbell]

how is an LSD going to stop the car skipping & losing traction over bumps?

LSD would help on track, where you have a smooth surface... not on bumpy nasho park roads...

[Didz]

how is an LSD going to stop the car skipping & losing traction over bumps?

LSD would help on track, where you have a smooth surface... not on bumpy nasho park roads...

I think it could help in similar ways that a lock diff helps a 4x4. Obviously not to the same degree, but i think it has it's merits.

[ChargeR]

I think it could help in similar ways that a lock diff helps a 4x4. Obviously not to the same degree, but i think it has it's merits.

I am inclined to agree with tinkerbell, if the cause of the lack of grip is the suspension even welding the diff won't make it grip any more. If for example a particularly vicious bump on corner exit upsets the tyres and chassis enough that the inside wheel will start spinning then an LSD would help, but it isn't the underlying issue.

Ok after reading other details about ur spring rates and all i can comment on this with my own experience.
Recently i have used 3 different suspension setups on my car. Tein Monoflex, Stock and now DMS 40mm Coilovers.

Tein 10kg front, 12kg rear. Same as yours.
I took my car for a drive around Mt Dandenong (lots of twistie roads) and i have to say i was very nervous as the car felt very bumpy and cornering was not a fun idea. I didnt even want to drive at the speed limit at times.

Stock
No problems of course

DMS.
This is a WHOLE different ball game. The DMS shocks differ in 2 ways to the Teins. The springs are still rated at 10kg front and 12kg rear. However these are progressive spring rates which mean initially they are not so stiff but as they compress, they get stiffer and stiffer. Now it doesnt take a whole lot to get them to stiffen up but there is certainly a higher level of comfort on these roads.
The second major difference is that the DMS have the same level of droop as the stock suspension does (on the front). What does this mean? Well to me, it is a lot safer for daily driving.
Most typical coilover suspension setups have no droop (please forgive me if this is not the right technical term) or very little. What this means is that the wheel will compress but it wont travel out further than the set hight. This is apparent when you go over bumps and ramps and notice a rear wheel off the ground. So all of these bumps are causing the left and right wheels to be off the ground at certain times. Enough to cause an imbalance and upset the driving experience. This is the major reason why most (if not all) coilovers are not road legal in Australia.

My recommendation would be:
1. Dont drive 'spiritedly' on the mountain roads (or any normal roads really) instead, drive this way on a track.

2. Use stock suspension when driving around day to day.
3. Change your spring rates
4. Deal with it and run a higher risk to do some damage.

I am not sure damper adjustments will solve your problem but i am no engineer or suspension expert.

Hope this helps.

Good post guy. One thing though, your use of the word droop is correct, but the situation I have bolded above is not a good example of damper droop travel limiting suspension movement. When one goes diagonally into a driveway for example, and one of the rear tyres lifts off the ground it is not the damper hitting the limit of it's droop travel that causes this, it is the sway bars and/or mismatch in front to rear roll stiffness. The significant compression experienced at one of the rear wheels in the above situation is transferred to the other rear wheel through the torsion spring that is the rear sway bar and that lifts it off the ground. So a car with swaybars should rarely hit the limit of it's droop travel in roll or over uneven bumps. If you are doing jumps though that is a different story.

However you are correct in my opinion; with the minimal droop travel a normal Japanese/Tiawanese (height adjustable independent of spring preload/damper stroke) coilover will have if the spring is slightly preloaded it seems feasible that in a variety of conditions the damper may top out, which isn't great for traction as you rightly point out. This is part of the reason that I don't run my springs "pre-loaded", if I jack my car up the springs are loose and can rattle around slightly. I am sacrificing a small amount of bump travel by doing this but my bump travel is limited by the tyres running into the chassis anyway. Unfortunately I have no data on this, logging suspension displacement data is on my long list of things to do.

Also on the subject of "preload", it is possibly the most misleading term in the entire internets, or at least the part of the internets dedicated to automotive suspension.

[maracer]

how is an LSD going to stop the car skipping & losing traction over bumps?

LSD would help on track, where you have a smooth surface... not on bumpy nasho park roads...

There is no stopping once the tyre patch leaves the ground..................
Regardless of car/springs/tyres.....bla,bla,bla

[tinkerbell]

Also on the subject of "preload", it is possibly the most misleading term in the entire internets, or at least the part of the internets dedicated to automotive suspension.

despite this truism, maybe we need to check whether the OP can clarify whether his springs are 'preloaded'?

if they were bought and 'bolted-on' - then maybe they have been accidentally installed with the perches compressing the springs.

whilst a slight amount of 'preload' is OK, substantial amounts can be quite unsettling on a cars behaviour...

typesexy - if you jack it up, remove the wheel and grab the spring, does it move about, or is it rock solid?