Anyone else remove the rear sway bar?

[Johnvu]

I deleted my rear sway bar after using the Flatride calculator whenever I first got my coilover setup to really dial in the FRC. I have since upgraded the front sway bar to a turner one, which allowed me to put the OEM rear bar back on. I have to say that the car feels a lot more stable around turns but I haven't taken it to the track so I cannot compare apples to apples yet.

[D-O]

To point out the obvious, just removing a sway bar, without changing the spring rates to match, will results in a huge change to FRC (oversteer/understeer ratio).

Removal of the rear bar would result in more rear grip? If the car was loose this would likely bring it closer to neutral?

[Obioban]

Removal of the rear bar would result in more rear grip? If the car was loose this would likely bring it closer to neutral?

Whatever it was, it’ll make it (significantly) more understeer biased.

[Tbonem3]

Is anyone taking rear wheel/tire width into consideration. Like, removing the rear bar might work better with a 265 on 9.5", but understeer too much with 275 on 10"?

cobra - what is your wheel width and tires? I don't understand how your rear spring rate can be so low AND you are happy without the rear bar - are you on 9" 255s? Stock rear spring goes up to like 680lbs or something, but you're in the 400s?

Spring rate increasing will limit roll, but it also increases compression. Sway bar tuning will affect roll, but not L+R spring/shock travel action. So, I thought you go stiffer springs, less travel needed, lower height/lower COG, but then you delete the rear bar in order to maintain some roll/grip and not so much oversteer?

[cobra]

Is anyone taking rear wheel/tire width into consideration. Like, removing the rear bar might work better with a 265 on 9.5", but understeer too much with 275 on 10"?

cobra - what is your wheel width and tires? I don't understand how your rear spring rate can be so low AND you are happy without the rear bar - are you on 9" 255s? Stock rear spring goes up to like 680lbs or something, but you're in the 400s?

Spring rate increasing will limit roll, but it also increases compression. Sway bar tuning will affect roll, but not L+R spring/shock travel action. So, I thought you go stiffer springs, less travel needed, lower height/lower COG, but then you delete the rear bar in order to maintain some roll/grip and not so much oversteer?

I am on 245/275 Front/Rear Michelin PS4S on 8.5/10 - 18 wheels.

Stock rear springs are ultra progressive - starting out at 360lb/in for the first 3 inches, then going up to 550 for the next inch, and then ramping up to 700 beyond that, in order to account for passengers and filling the trunk with weight. For a single driver with 0-1 passenger, a 475lb/in linear spring rate is pretty reasonable and predictable.

I think you're on the right track with the thinking. There is no set spring rate threshold where rear swaybars are needed or not needed, maybe it comes down to driver preference. I prefer a soft linear setup overall, as the car is more predictable and compliant. It does not feel like a go-kart, but it still stays pretty flat and isn't like a stadium truck or anything 😄. I am still tweaking with setup but the sway bar seemed to make a change in the right direction!

[Tbonem3]

Yes, we're all starting move towards "compliant is fast"

I think there's still a sweet spot where you can get the desired roll and compliance for grip, but have enough compression to match (shorter) travel for most of us who are lowered a half inch to an inch from stock.

I welcome greater delineation between what a track car with aero needs and what a street car needs.

With your 10" 275, no rear sway, and relatively light spring rate of 475, you don't think you've got too much oversteer? I don't mean to pick on you, I promise, I just have only ever seen the rear sway delete helping with grip and understeer when the car has much higher rear spring rate.

It's also an undoing of decades of "modding" paradigm that says to throw bigger sway bars on the car, and the resulting "sporty" feeling from doing so.

Personally, now that I'm up to 400lb front springs and dampers with more compression, I wonder if I should back down my Hotchkis from medium setting to softer (which is still stiffer than stock bar). I do love expirimenting!

[cobra]

Yes, we're all starting move towards "compliant is fast"

I think there's still a sweet spot where you can get the desired roll and compliance for grip, but have enough compression to match (shorter) travel for most of us who are lowered a half inch to an inch from stock.

I welcome greater delineation between what a track car with aero needs and what a street car needs.

With your 10" 275, no rear sway, and relatively light spring rate of 475, you don't think you've got too much oversteer? I don't mean to pick on you, I promise, I just have only ever seen the rear sway delete helping with grip and understeer when the car has much higher rear spring rate.

It's also an undoing of decades of "modding" paradigm that says to throw bigger sway bars on the car, and the resulting "sporty" feeling from doing so.

Personally, now that I'm up to 400lb front springs and dampers with more compression, I wonder if I should back down my Hotchkis from medium setting to softer (which is still stiffer than stock bar). I do love expirimenting!

Right now the car feels more balanced than it did before I took the bar off. It was tending to oversteer more easily before as it felt like it was picking up the rear inside tire.

[bigjae46]

To point out the obvious, just removing a sway bar, without changing the spring rates to match, will results in a huge change to FRC (oversteer/understeer ratio).

You do get more understeer especially when threshold braking and do the normal late turn in. The advantage is you can brake a little less, turn in a little earlier and give it a lot more throttle which will help turn the car. In most mid speed and faster corners, the car in front is still on the brakes and I'm already back on the throttle.

Could be a driver improvement but I get far more responsive rotation when trail braking.

[cobra]

Is anyone taking rear wheel/tire width into consideration. Like, removing the rear bar might work better with a 265 on 9.5", but understeer too much with 275 on 10"?

cobra - what is your wheel width and tires? I don't understand how your rear spring rate can be so low AND you are happy without the rear bar - are you on 9" 255s? Stock rear spring goes up to like 680lbs or something, but you're in the 400s?

Spring rate increasing will limit roll, but it also increases compression. Sway bar tuning will affect roll, but not L+R spring/shock travel action. So, I thought you go stiffer springs, less travel needed, lower height/lower COG, but then you delete the rear bar in order to maintain some roll/grip and not so much oversteer?

Update - you were on the right track. The springs I was using were too soft to enable removing the rear bar. Not so much from a driving perspective necessarily, it felt pretty damn good, but was rolling a lot and bottoming out the rear shocks if I encountered a bump while cornering. I've since switched to 650lb rear springs and it's much better matched to rear bar removal.

[Tbonem3]

Oh wow you made a big jump up. I don't know if the goal should be rear bar removal necessarily, though it might be for a track car with aero running 900lb springs IDK. I'd like to think I found a nice spot with the stock bar and 550lb springs, though I'm lighter than most.

[bigjae46]

One side effect from no rear bar is I get more inside front tire lift. It looks cool! I definitely lift the inside tire more. Not sure how detrimental lifting the tire is, I'm sure there is a loss of overall grip.

Here I'm on the throttle. This is a common place for photographers to shoot. I've never seen the left front tire lift before removing the rear sway bar.

[eacmen]

One side effect from no rear bar is I get more inside front tire lift. It looks cool! I definitely lift the inside tire more. Not sure how detrimental lifting the tire is, I'm sure there is a loss of overall grip.

Here I'm on the throttle. This is a common place for photographers to shoot. I've never seen the left front tire lift before removing the rear sway bar.

Interesting. I would think this should cause corner exit understeer?

Might need more rebound or droop travel?

With big wang and being on throttle might need more front down force?


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[stash1]

With big wang and being on throttle might need more front down force?
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Is there more between you two that you're not sharing?😉

[bigjae46]

Interesting. I would think this should cause corner exit understeer?

Might need more rebound or droop travel?

With big wang and being on throttle might need more front down force?

I have more issues with not enough rear down force. I have a large 6" front carbon splitter that I made and an NRG wing that I got from Amazon using Hilton Honors points. The carbon splitter has changed the balance towards oversteer. I made some larger endplates and taped on a gurney flap to improve rear downforce.

I was thinking more droop travel? I can't remember having understeer at exit. Not sure if I'm driving around it?

There was a discussion about correcting suspension geometry. I wonder whether this indicates sub-optimal geometry?

[eacmen]

I have more issues with not enough rear down force. I have a large 6" front carbon splitter that I made and an NRG wing that I got from Amazon using Hilton Honors points. The carbon splitter has changed the balance towards oversteer. I made some larger endplates and taped on a gurney flap to improve rear downforce.

I was thinking more droop travel? I can't remember having understeer at exit. Not sure if I'm driving around it?

There was a discussion about correcting suspension geometry. I wonder whether this indicates sub-optimal geometry?

Lifting one wheel looks good on photos but means you’re not getting optimal front grip. The inside wheel isn’t doing much so it’s not 50/50 grip wise but I would expect that if you can find a way to keep the inside front contact patch you should be able to track out with less understeer.


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