I'm trying to figure out if the Whiteline Roll Center Correction Kit is really a necessity or just an additional suspension upgrade. A lot of people talk on the internet but sometimes it's hard to find factual information. I see people saying the roll center kit is a NECESSITY but they don't necessarily say why. Many of them haven't even tried the car with and without the kit to know for themselves if the kit makes a difference.

I've been trying to review the theory behind the kit... and I understand that as the distance between the Center of Gravity and the Roll Center increase there will be larger forces wanting to make the front end roll. But is this actually that noticeable in real life situations? There are a lot of things that theoretically make sense... but in real life it is not that noticeable.

I've been reading some websites where they acknowledge the effect of roll center but then they say the car rolling is actually more affected by the anti-roll bars and the stiffness of the springs... rather than a slight repositioning of the roll center.

I'm considering getting a subtle drop... like maybe an inch in the front. Do you think the roll center correction kit is necessary? Has anybody driven their car with and without the kit to see if it makes a difference?

 

If the car is just your daily driver, it's all personal preference. I am on fortune auto coilovers and a pretty aggressive drop. My car is used as a daily and a few track days a year. There was a noticeable difference before and after. The kit definitely decreased body roll for me, why not correct your suspension after the spring change?

Just search "whiteline roll" in this section of the forum. It's been discussed a good bit


Cheers

Brett

 

If you lower the car,yes it is. Other wise you ruin the suspension geometry.

 

Try researching under bump steer this is what you dont want and what the kit corrects. This will give you the understanding of what you are addressing and the suspension issues. In short, look at the a-arms in relation to the ground from inside to the wheels on level ground. They should look like this / \ in other words slightly higher at the center attach points sloping slightly to the wheels. If they are flat to sloping upwards at the wheels the kit will correct that and the associated issues. If I left something out---sorry, just wanted to give you the short story and what to look for.

 

Actually, the kits include two pairs of parts: ball joints with extended studs for the front LCAs to raise the roll center and tie-rod ends with extended studs to eliminate the bump steer that you would have if only installed the ball joints.

 

The X's factory ride height and handling characteristics have lots of R&D behind it. The car is designed almost to it's fullest given the factory decided specifications for ride height, acceptable understeer, etc.

If you change the ride height (for numerous reasons, but most do it for appearance on a DD), on most cars in the market, you're car might actually handle better, for the X, it's been shown your center of gravity drops a little too low (depending on the springs you choose).

So, like the past posters mentioned, if you're just daily driving. It's likely that on a set of Swifts or non-aggressive drop you'll still enjoy the handling just fine. If you go with Tein's or full on coilovers, you'll probably notice a really nice improvement to your handling if you get the kit in conjunction with your ride height change.

FWIW: a friend rolls his X MR on Swifts and AFAIK he doesn't have the whiteline kit, and has taken his MR to a track day for the road course and Loved the handling. So Swifts + no RC kit, was a thumb up from him. But, every car, and every setup will feel different for every different driver. So I say, if this is your DD, start with your coil/damper choice, then decide on the RC kit. But if you choose to do the RC kit from the start, chances are you won't be disappointed because it would indicate you don't like how the car handles from the start, which seems to be one of the reasons why people buy the Evo to begin with.

 

Necessary? No.
Beneficial? Possibly, depending on a lot of factors such as driving style, track vs. street, etc.

I did not have one on my IX and as of yet I don't on my X either.

 

Nonsense.

The problems have nothing to do with lowering the CG. Lowering the CG is always good. The problems come from lower the roll center.

 

define necessary? Is the car gonna handle terribly if you lower it and dont get it? no - but it will improve the handling if you do

 

 

Yes, I stated this in too much of a hurry to leave for my lunch break here at work. I commonly make the mistake because I tend to "feel" the CG of the car *is* the RC, but I'm a novice driver for the most part, so I just haven't developed the feel between the two clearly enough. So, I stumbled over the two.

By lowering your CG too, the roll center goes too low. Previously someone mentioned how it messes with bump steer, and they were correct as well, because the kit actually adjusts the camber angles while the suspension is under compression creating less roll to the outside of the tire and allowing the camber to move properly and keep the force even across the tire for better stability.

The need for the kit is dependent on how low you shift your CG and how much roll you have while compressing your suspension, because the X, unlike many other cars, can exceed the healthy camber angles because of how tightly the geometry of the strut configuration was designed for factory ride height.

So, yes, I stated it incorrectly, but my suggestion to the OP "Should I buy this product?" I feel is still valid:

--If you lower without them, depending on what you buy and how you drive, you might not see the need

--If you buy the kit, and lower, you're likely to appreciate the kit and probably won't see anything negative about it (other than cost)

--I know someone that rolls Swifts and no kit on his MR, he tracked like that and still had positive things to say about the handling.


I can assume that the springs that are known to really slam the X, people that are set up like that would be more likely to explain there's a need for the Whiteline kit.

for those that thought this was TL: DR
--Sorry I got them mixed up
--This kit helps keep more of the sticky-side of the car down and that's good
--How much of the sticky-side down do you need? Driver preference for use.

 

You need to stop.

The ball-joint part of the RCK does not do anything for bump-camber. It costs you a tiny bit of static camber when you install it, because it swings the LCA down a bit, but you get this back in roll. And it's rather a small amount of change in camber either way.

As to the tie-rod end part of the RCK, this fixes the bump-steer that you would get if you only installed the ball-joints. You see, installing just the ball-joints would make the LCA and the steering arm non-parallel, and it is non-parallel arms that create bump-steer. By installing the second half of the kit, you angle the steering arm down to the same degree as the LCA, bringing the bump-steer back towards zeros.

And absolutely none of the second half of the kits has anything to do with camber. No modification to the steering will ever alter the static camber or the bump-camber curve.

 

if your tracking professionally and if that roll center kit will increase your time attack time or lap time, lateral g and improve your overall performance like night and day....why not. we need some background from you, what do you do, what are your suspension mods?

 

Honestly this car is just a fun daily driver for me. I do go to some track events... but not to compete... I run track days just for fun. So picking up a 10th of a second isn't the most important thing to me.

Right now I have the OEM Bilstein suspension and I am considering buying Swift Sport springs.

 

If you don't track I would say you don't need it. You will not notice the difference on the street or if you only track it a few times a year.