Rear bouncing so much... help?

  • Thread starter Ceolix
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Ceolix

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Portugal
Ceolix
Guys i'm using corvette z06 (c5) on nurbrugring
and i'm using soft springs, on front and rear

1,00 front toe in
0,30 toe out

2 front compression dampers
2 front extend dampers

3 rear compression dampers
3 rear extend dampers

95<- front ride height
105 <- rear ride height.


How can i make it more stable?
 
You didn't post your spring rates...but isn't it your toe settings causing the problem.
I would set toe to 00 / +0.50 as a new baseline/starting point.
Good Luck ! :)
 
jules283
You didn't post your spring rates...but isn't it your toe settings causing the problem.
I would set toe to 00 / +0.50 as a new baseline/starting point.
Good Luck ! :)
Click to expand...

why would you 00 on toe
it gives understeer.
toe in better grip i think
 
He did say his on soft springs so that could be a problem?

When ever I race on tracks I normally stiffen my suspension springs. (I'm no good at track/drift car) but I dont see any point on soft springs.
 
irabbiT
He did say his on soft springs so that could be a problem?

When ever I race on tracks I normally stiffen my suspension springs. (I'm no good at track/drift car) but I dont see any point on soft springs.
Click to expand...

Soft springs have many uses .... all depends on what you want from them and what your objective is
 
irabbiT
So soft springs are good for track? :$ never knew, thanks!
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Can be ... Like i said depends on what you looking to do with them , i personally look at it like this there is no good or not good way of setting certain things up but rather how you tie them all together for the final result.

Try soft springs with slightly stiff ARB's or maybe with stiff dampers ect ect ect.

You never know them soft spring trials may open up a few more advanced lines or more ideas for when tuning for specific sections of specific tracks =)
 
To calm the bouncing, set you damper extension to 5. Basically at 2/3 you are soaking up the bumps but not returning the tire to the ground very fast. You also might make the front stiffer than the rear to keep the engine from transferring weight all over the place. So a 4/3 compression and a 6/5 extension with 4/3 arb's would be a good base setting To start from.
 
ImToLegitToQuit
To calm the bouncing, set you damper extension to 5. Basically at 2/3 you are soaking up the bumps but not returning the tire to the ground very fast. You also might make the front stiffer than the rear to keep the engine from transferring weight all over the place. So a 4/3 compression and a 6/5 extension with 4/3 arb's would be a good base setting To start from.
Click to expand...


I never understood the dampers extension
the compression, 1 compress very fast
and you will oversteer or understeer faster

Whats up with the extend dampers?
 
Ceolix
I never understood the dampers extension
the compression, 1 compress very fast
and you will oversteer or understeer faster

Whats up with the extend dampers?
Click to expand...
Use the numbers as the amount of resistance.this is just a vague example but imagine that 1 would be similar to a Cadillac in that it would be very easy to push the wheel up and allow for a soft supple ride. 10 would be like a cement truck designed to carry a lot of weight.

For extension it is how hard the suspension pushes back. So a higher extension would push the wheel back to the ground faster which keeps you from bouncing around so much. Go too stiff though and it is bad. It would be like your car had spring shoes on and would launch off of bumps.

That's a simple explanation. @Motor City Hami has a in depth tuning guide that would help as well.
 
Ceolix
lol, what you mean?
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Check the toe settings on various tunes posted within this forum. Not many tuners will use as much toe-in at the front ( as you have ).
Too much toe-in will create stability or resistance to change direction, but initial response may be good.
Too much rear toe-out goes the other way. Easy direction change and possible stability problems. If taken too far the car will not hold tight to a line because the rear wheels are steering out/away from the turn.
Front and rear toe are relative. They should be matched so as to compliment each other.
So I believe your front and rear toe settings are fighting each other.
Lots of resistance to direction change up front combined with a rear that wants to swing around has similarities to the fixed front wheels/castered rear wheels of a typical supermarket shopping trolley.
Like I said, check out tunes within this forum for reference.
Again, good luck.
 
jules283
Check the toe settings on various tunes posted within this forum. Not many tuners will use as much toe-in at the front ( as you have ).
Too much toe-in will create stability or resistance to change direction, but initial response may be good.
Too much rear toe-out goes the other way. Easy direction change and possible stability problems. If taken too far the car will not hold tight to a line because the rear wheels are steering out/away from the turn.
Front and rear toe are relative. They should be matched so as to compliment each other.
So I believe your front and rear toe settings are fighting each other.
Lots of resistance to direction change up front combined with a rear that wants to swing around has similarities to the fixed front wheels/castered rear wheels of a typical supermarket shopping trolley.
Like I said, check out tunes within this forum for reference.
Again, good luck.
Click to expand...

i thought rear toe-in would increase stability?
i am using toe in in rear and if i touch 3cm on the grass my car
spins a lot, and it feels like the grass is pushing my car.
 
Ceolix
i thought rear toe-in would increase stability?
i am using toe in in rear and if i touch 3cm on the grass my car
spins a lot, and it feels like the grass is pushing my car.
Click to expand...

Your original post suggests you are using toe-out at rear ?
 
I normally use toe-in on the rear and toe-out in front. The toe-in on the rear tires allows for the power to be put down without as much instability. The toe-out on the front counteracts the understeer that goes with the toe-in at the rear. That's just a generic formula though-- you still have to make fine adjustments for each car and track.

Also, switch to the fully adjustable suspension if you haven't already and play around with stiffer setups on the compression and extension values. Higher values= less weight shift and a car that is usually easier to control.
 
ImToLegitToQuit
Use the numbers as the amount of resistance.this is just a vague example but imagine that 1 would be similar to a Cadillac in that it would be very easy to push the wheel up and allow for a soft supple ride. 10 would be like a cement truck designed to carry a lot of weight.

For extension it is how hard the suspension pushes back. So a higher extension would push the wheel back to the ground faster which keeps you from bouncing around so much. Go too stiff though and it is bad. It would be like your car had spring shoes on and would launch off of bumps.

That's a simple explanation. @Motor City Hami has a in depth tuning guide that would help as well.
Click to expand...
I agree with you for the most part, and I think higher dampers may help, especially with soft springs.

But it is my understanding that more resistance from the higher damper setting slows down the motion of the springs meaning it would return slower to the pavement, not quicker!?
 
Last edited:
Thorin Cain
I agree with you for the most part, and I think higher dampers may help, especially with soft springs.

But it is my understanding that more resistance from the higher damper setting slows down the motion of the springs meaning it would return slower to the pavement, not quicker!?
Click to expand...
You could be right. It was my understanding that the dampers limit/control the movement of the springs. For example, a soft spring setup would benefit from high damper settings. That way you'd have the weight moving more for a more loose back end while braking but the high dampers would return the weight to normal quickly. I'd never find the thread again but I saw a diagram here that put it in visual form for the slower people like myself. I could have read it wrong though. I personally use the springs to control the weight balance and movement and the dampers to control how the weight is returned to neutral after braking or throttle input.
 
ImToLegitToQuit
You could be right. It was my understanding that the dampers limit/control the movement of the springs. For example, a soft spring setup would benefit from high damper settings. That way you'd have the weight moving more for a more loose back end while braking but the high dampers would return the weight to normal quickly. I'd never find the thread again but I saw a diagram here that put it in visual form for the slower people like myself. I could have read it wrong though. I personally use the springs to control the weight balance and movement and the dampers to control how the weight is returned to neutral after braking or throttle input.
Click to expand...
The way I've seen it described best is...

Springs control how much weight transfer you get. Dampers control how quickly it transfers.

Soft dampers provide less resistance, which allows the springs to work faster. Set too low and the springs will keep compresssing and extending until the energy in the spring dissipates. This will feel like the car floats around a bit on the bumps.

Hard dampers offer more resistance, which slows down the compression/ extension of the spring. Set too high and you can limit the amount of travel of the springs. This will feel like the car skips over the bumps, as the springs may not be able to move freely enough to absorb the bumps.

For example:A car with 50:50 weight distribution has springs set the same front and back. If you set the front damper at comp 3 and ext 4 and set the rear with comp 4 and ext 3. You should find that the weight will transfer forward quicker under braking but will return to neutral a bit slower and will also be slower moving the weight to the rear during acceleration.

l would by no means consider myself an expert but this is how I understand dampers work.
 
Last edited:
jules283
Your original post suggests you are using toe-out at rear ?
Click to expand...

my mistake then
i use toe-in at rear to increase stability
but like i said, when i go near grass
i feel like my car is pushed and then i spin off the track
is this due to the maximum toe in at front wheels?
I don't know what toe-out front wheels can do
 
Thorin Cain
The way I've seen it described best is...

Springs control how much weight transfer you get. Dampers control how quickly it transfers.

Soft dampers provide less resistance, which allows the springs to work faster. Set too low and the springs will keep compresssing and extending until the energy in the spring dissipates. This will feel like the car floats around a bit on the bumps.

Hard dampers offer more resistance, which slows down the compression/ extension of the spring. Set too high and you can limit the amount of travel of the springs. This will feel like the car skips over the bumps, as the springs may not be able to move freely enough to absorb the bumps.

For example:A car with 50:50 weight distribution has springs set the same front and back. If you set the front damper at comp 3 and ext 4 and set the rear with comp 4 and ext 3. You should find that the weight will transfer forward quicker under braking but will return to neutral a bit slower and will also be slower moving the weight to the rear during acceleration.

l would by no means consider myself an expert but this is how I understand dampers work.
Click to expand...
I think we are basically agreeing, we may just use dampers differently. If I had a 50/50 car I would be 3/3 comp and 4/4 ext instead of flipping the rear.
 
You don't say what your diff settings are, but with that much toe you'll struggle to feel much of anything else.

First things first - any powerful RWD car will oversteer if you go on the grass... you don't need a settings adjustment (well, maybe fit dirt tyres ;)), you need to stay off the green bits!!

As for the set up, remove the front toe and set the rear to around +0.20.

After that, your problem is not the car.
 
Ceolix
my mistake then
i use toe-in at rear to increase stability
but like i said, when i go near grass
i feel like my car is pushed and then i spin off the track
is this due to the maximum toe in at front wheels?
I don't know what toe-out front wheels can do
Click to expand...

As Stotty says, set front toe to 0.00 and rear toe to +0.20 and check for improvement.
 
It feels like you're being pushed because you're losing grip over the grass. Grass ≠ tarmac. Just avoid the grass and it'll solve all your spinning problems...
 
ImToLegitToQuit
Use the numbers as the amount of resistance.this is just a vague example but imagine that 1 would be similar to a Cadillac in that it would be very easy to push the wheel up and allow for a soft supple ride. 10 would be like a cement truck designed to carry a lot of weight.

For extension it is how hard the suspension pushes back. So a higher extension would push the wheel back to the ground faster which keeps you from bouncing around so much. Go too stiff though and it is bad. It would be like your car had spring shoes on and would launch off of bumps.

That's a simple explanation. @Motor City Hami has a in depth tuning guide that would help as well.
Click to expand...
Agreed extension controls actual weight of car and compression control unsparing weight which are calipers etc.If compressions are to soft, the you lessen stability, grip, and have weight transfer issues...
 

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