Too Stiff

[olblue75]

I’m running a JPSS 32mm rear bar, 1LE front bar, BMR 1 inch drop springs, and 1LE Shocks an struts and my ride is pretty compliant.

[StlRomAniaN]

Originally Posted by olblue75

I’m running a JPSS 32mm rear bar, 1LE front bar, BMR 1 inch drop springs, and 1LE Shocks an struts and my ride is pretty compliant.

I’m running Pedders Xa coilovers with lots of preload due to my ride height along with his 28mm front bar.

The difference between our setups is the stiffness of the springs/coils. Rear tire is lifting in corners making it impossible to put down more than 1/2 throttle in back road carvers.


Sent from my iPhone using Tapatalk

[KillboyPowerhead]

What are your spring rates and tire sizes and wheel specs? Justice Pete always suggested a 5mm bias between front and rear bars (rear 5mm bigger than front) for a square tire and wheel setup. Of course, front and rear spring rates and tire and wheel sizes will be a factor; I'm not sure what springs rates Pete used for testing.

If the rear is sliding before the front then you have some oversteer which isn't a bad thing as long as it's comfortable and controllable for you. Assuming you like your steering bias (oversteer vs understeer) I'd keep the 5mm bias you have now (JPSS front bar is 27mm, not 28) and just go with smaller bars. I'm not sure what sizes the factory bars are offhand, but if you can't get a 5mm bias then try 4 or 6 (the smaller the front is compared to rear the more oversteer you'll get, and vice versa). Also make sure you're comparing apples to apples and get two solid bars, or two hollow bars, not one of each (unless you know the equivalent difference).

[StlRomAniaN]

Originally Posted by KillboyPowerhead

What are your spring rates and tire sizes and wheel specs? Justice Pete always suggested a 5mm bias between front and rear bars (rear 5mm bigger than front) for a square tire and wheel setup. Of course, front and rear spring rates and tire and wheel sizes will be a factor; I'm not sure what springs rates Pete used for testing.

If the rear is sliding before the front then you have some oversteer which isn't a bad thing as long as it's comfortable and controllable for you. Assuming you like your steering bias (oversteer vs understeer) I'd keep the 5mm bias you have now (JPSS front bar is 27mm, not 28) and just go with smaller bars. I'm not sure what sizes the factory bars are offhand, but if you can't get a 5mm bias then try 4 or 6 (the smaller the front is compared to rear the more oversteer you'll get, and vice versa). Also make sure you're comparing apples to apples and get two solid bars, or two hollow bars, not one of each (unless you know the equivalent difference).

I’m unsure of the spring rates used on the Pedders Xa coilovers. Whatever they are, they are very preloaded making them very stiff at the moment. Setting is currently at 0/30 to make them as soft as possible.

Wheels/tires are OEM ZL1 wheels and tires are 285 front and 305 rear.

That’s what I plan to do. I believe the OEM ZL1 bars have a 5mm bias and they may be hollow. Not sure on the last part, but I definitely wasn’t planning on mixing a hollow/solid bar.

I like oversteer vs understeer, but not when my tire lifts off the ground and I lose 25mph on a corner. Not fun. I think the right move would be OEM ZL1 bars, or even OEM SS bars at this point.


Sent from my iPhone using Tapatalk

[KillboyPowerhead]

Finally found a thread with sway bar sizes: https://www.camaro5.com/forums/showthread.php?t=335976

Perhaps a front SS bar (FE4) and rear 1LE/ZL1 bar would be a good start. I believe the Pedders are 8kg front and 10kg rear if I'm not mistaken; compared to factory ZL1 springs (cause you're running ZL1 wheels/tire specs) your front is a fair bit stiffer than rear compared to a factory ZL1, so it makes sense to go with a smaller front bar (assuming you consider a factory ZL1 to be a good reference point - I'm sure those engineers know what they're doing!).

I'd actually like to loosen things up a bit too and see the difference (on BC Racing coilovers which are 8kg/12kg, so pretty stiff), but I have the V6 and the rear brakes get in the way of any bar except the JPSS and maybe Hotchkis bars. Maybe I just need bigger brakes...

[StlRomAniaN]

Originally Posted by KillboyPowerhead

Finally found a thread with sway bar sizes: https://www.camaro5.com/forums/showthread.php?t=335976

Perhaps a front SS bar (FE4) and rear 1LE/ZL1 bar would be a good start. I believe the Pedders are 8kg front and 10kg rear if I'm not mistaken; compared to factory ZL1 springs (cause you're running ZL1 wheels/tire specs) your front is a fair bit stiffer than rear compared to a factory ZL1, so it makes sense to go with a smaller front bar (assuming you consider a factory ZL1 to be a good reference point - I'm sure those engineers know what they're doing!).

I'd actually like to loosen things up a bit too and see the difference (on BC Racing coilovers which are 8kg/12kg, so pretty stiff), but I have the V6 and the rear brakes get in the way of any bar except the JPSS and maybe Hotchkis bars. Maybe I just need bigger brakes...

Thanks for the find. Add the preload of my springs and they're even stiffer. That sounds like the move to make. SS front bar/ZL1 rear bar or ZL1 front/rear bar. That'll be my decision to make.

You can take my OEM Brembos when I upgrade. lol.

[olblue75]

You might wanna try a 1LE rear Bar and either ZL1 or SS bar in the front that should keep the 5mm bias as well but since your running a staggered tire setup the 5mm difference might not work as well. Or maybe a Z28 set up since they use smaller bars with stiffer springs to control roll.

[KillboyPowerhead]

Originally Posted by StlRomAniaN

Thanks for the find. Add the preload of my springs and they're even stiffer. That sounds like the move to make. SS front bar/ZL1 rear bar or ZL1 front/rear bar. That'll be my decision to make.

You can take my OEM Brembos when I upgrade. lol.

What is your preload set at? When I set up my BC's I used the manufacture recommended 4mm (thickness of the adjustment wrench) and everything has been fine; lowered an inch or a bit more in the front, more in the rear to even out the ride height. If I remember correctly Justice Pete has (or had - can't find it) a video on YouTube showing the same thing while setting up the Pedders.

And I will definitely consider the Brembo's - let me know!

[TheFlyingBananaSS]

Love the title...... "too stiff"

That's what she said

[StlRomAniaN]

Originally Posted by KillboyPowerhead

What is your preload set at? When I set up my BC's I used the manufacture recommended 4mm (thickness of the adjustment wrench) and everything has been fine; lowered an inch or a bit more in the front, more in the rear to even out the ride height. If I remember correctly Justice Pete has (or had - can't find it) a video on YouTube showing the same thing while setting up the Pedders.

And I will definitely consider the Brembo's - let me know!

It's pretty much maxed out because I lowered it more than what Pete recommended.

[StlRomAniaN]

Originally Posted by olblue75

You might wanna try a 1LE rear Bar and either ZL1 or SS bar in the front that should keep the 5mm bias as well but since your running a staggered tire setup the 5mm difference might not work as well. Or maybe a Z28 set up since they use smaller bars with stiffer springs to control roll.

I'm going to pull the trigger on one of these set-ups in spring when I buy a new set of tires. It's going to drive so much better. Bald tires and too stiff of a car. Great combination in the cold. lol. I'm just glad I have other cars to drive to extend the life of the tires.

[VR Baron]

Originally Posted by StlRomAniaN

I'm going to pull the trigger on one of these set-ups in spring when I buy a new set of tires. It's going to drive so much better. Bald tires and too stiff of a car. Great combination in the cold. lol. I'm just glad I have other cars to drive to extend the life of the tires.

I think you are right. Bald tires. Stiff bars and springs and being to low is the issue. Your alignment, at least as to camber is fine. I bet bald tires are a large part of it though.
Your pedders springs are 450/560. The bars I feel, are to stiff. If you had stock springs and shocks, they would be what you want. Rule of thumb is stiff springs, soft bars, or the other way around. Here are some combos that may help. These are for street and autocross. Can’t answer for high speed driving.

A friend till lately: be racing coilivers like your pedders, 450/672 springs, DSE hollow bars that best estimate are like 26mm and 30mm solid. Drop is 2” in rear, or 638mm. With at combo, shock setting in middle in front, rears 5 clicks softer, if not the rear slides out on corner exit. That’s with re71 305/30/19s all around.
Now on a tight turn a tire may lift and probably does. I had same issue till I softened the rear bar. On street low speed turn, say onto a on-ramp, any stiff rear bar will lift or loose traction other then stock ss bar it seems.

This weekend at autocross I will run my DSE bars stiff front and soft rear, 4mm ratio at 26/30 and adjust coilivers for turn in and under/oversteer. With rear bar just 1mm stiffer, the rear slid all over. Even with less rear rebound and new tires. Rear bar soft and shocks even all around, I can power through a turn and the rear just sticks. And that’s just around town. My springs are 300/550 on ridetechs, my drop is 651/654. I have more under steer, but I can throw the car into turns and use throttle and power out of turns. And we have coilivers adjustments to compensate, don’t forget about that.

If I were you, raise car to 654 and 660 mm. Preload should only be 10mm as per pedders. Get your new square tire setup and fe4 DSE sways, or BMR bars, which are a tad softer, or the 23mm solid front item and 28mm rear bar .
A note on bars I found anyway. Stiffer bars react quicker and transfer weight faster then softer bars. Even if the mm spread is the same,softer bars, even a mm softer, react slower.
Example, When I did 26/31 car oversteered and slid with rear shocks 4-5 clicks softer then front. With my bars set soft, say 25/30, they reacted a lot slower and I have to run rear shocks several clicks stiffer to dial out under steer. And car never lost rear grip

[StlRomAniaN]

Originally Posted by VR Baron

I think you are right. Bald tires. Stiff bars and springs and being to low is the issue. Your alignment, at least as to camber is fine. I bet bald tires are a large part of it though.
Your pedders springs are 450/560. The bars I feel, are to stiff. If you had stock springs and shocks, they would be what you want. Rule of thumb is stiff springs, soft bars, or the other way around. Here are some combos that may help. These are for street and autocross. Can’t answer for high speed driving.

A friend till lately: be racing coilivers like your pedders, 450/672 springs, DSE hollow bars that best estimate are like 26mm and 30mm solid. Drop is 2” in rear, or 638mm. With at combo, shock setting in middle in front, rears 5 clicks softer, if not the rear slides out on corner exit. That’s with re71 305/30/19s all around.
Now on a tight turn a tire may lift and probably does. I had same issue till I softened the rear bar. On street low speed turn, say onto a on-ramp, any stiff rear bar will lift or loose traction other then stock ss bar it seems.

This weekend at autocross I will run my DSE bars stiff front and soft rear, 4mm ratio at 26/30 and adjust coilivers for turn in and under/oversteer. With rear bar just 1mm stiffer, the rear slid all over. Even with less rear rebound and new tires. Rear bar soft and shocks even all around, I can power through a turn and the rear just sticks. And that’s just around town. My springs are 300/550 on ridetechs, my drop is 651/654. I have more under steer, but I can throw the car into turns and use throttle and power out of turns. And we have coilivers adjustments to compensate, don’t forget about that.

If I were you, raise car to 654 and 660 mm. Preload should only be 10mm as per pedders. Get your new square tire setup and fe4 DSE sways, or BMR bars, which are a tad softer, or the 23mm solid front item and 28mm rear bar .
A note on bars I found anyway. Stiffer bars react quicker and transfer weight faster then softer bars. Even if the mm spread is the same,softer bars, even a mm softer, react slower.
Example, When I did 26/31 car oversteered and slid with rear shocks 4-5 clicks softer then front. With my bars set soft, say 25/30, they reacted a lot slower and I have to run rear shocks several clicks stiffer to dial out under steer. And car never lost rear grip

Appreciate the details there. I’ll be leaving ride height as is. Looks too good and I would never swap out my ZL1 wheel setup for a square setup (although it’s more track-oriented). The ZL1 wheels look too good IMO.

I’m going to look into adding OEM bars. A combination of SS front and ZL1 rear (or similar sized aftermarket rear bar for adjustability) should do the trick.


Sent from my iPhone using Tapatalk

[StlRomAniaN]

I have a question for you all. Was the front endlink for the FE4 suspension upgraded from a 10mm to a 12mm?

If so, that's good because I have those endlinks at home. The only issue is that the mounting point/hole on my Pedders Xa coilovers is 10mm. This may be a dumb question, but what size hole do I need to drill? 12mm bit to enlarge the existing hole? I'd just like to double check prior to mistakenly making the hole too big. I would hate to have a rattle, etc.