What Motorsports teach us on Daily Driven Evo's (Handling)

[Exyia]

Part 3 - Swaybars

This area of the suspension took me a while to open my eyes and understand. Thanks a ton to Andrew (again ) on guiding me through it.

First...
Swaybars/settings are NOT black and white!

Everytime I read someone say
"oh, stiffer front will add understeer; stiffer rear will add oversteer"
I want to throw a Playstation4 at them.

This isn't Gran Turismo. Please quit throwing misleading information out just because you do it in a video game.

I don't feel like going into an explanation of what swaybars are and how they work. I feel like many already have an idea. I want to bring up what people mis-understand about sway bars here.

Upgraded sway bars simply reduce body roll. The sway bar connects two ends of the car. Body roll occurs when one side goes down, and one side goes up. Since the sway bar is physically holding the two ends of the car, the car MUST twist this bar to roll. Upgrading sway bars is done to demand a higher force from the car in order to twist said bar.

Our heavy cars on a macpherson strut system means body roll causes positive camber gain on the front tires. Obviously, we're losing contact patch and losing grip. A stiffer front bar would reduce body roll up here and combat the positive camber gain.



"But Exyia, everyone tells me a front bar would increase understeer and to just get a rear bar and be done"
A sway bar increases the speed/load it transfers to the tire/wheel. Since the body is rolling less, that force is being absorbed and loaded directly on the suspension instead. So yes, you will understeer more - because the tire will reach it's load capacity sooner.

But for most people, especially daily driven cars, you won't reach that (although I guess if you didn't pay attention to Part 2 and got weak tires it would). You WILL feel the reduced body roll in the form of obvious driver confidence, and more importantly, less positive camber gain. Remember, we are driving heavy cars - any understanding we know of suspension, apply 120%. The Evo X has the terrible traits of having spring rates WAY too soft (because rallycar!) and heavy weight up front. Combine the two and positive camber gain is probably the #1 thing combating your grip level. This is the reason that I recommend the front sway bar to everyone.

Yes, I know the install sucks. But don't let that tell you it's not worth upgrading.

As for the rear, this is another topic I can't agree with many on. I think the Evo X works worst with the rear sway on fully stiff. I won't go as far as to say it should be on fully soft - as that can depend on your individual setup - but I highly disagree with stiff rear ends.

A rear end too stiff (like having your rear sway bar at the full stiff setting) easily causes tail-sliding behavior - especially if you didn't upgrade your front bar. Obviously, I find this bad/dangerous for street driving - or very annoyingly ASC prone.

Evo X's do two things really well: make a lot of power (even on stock turbo), and put most of said power down most of the time with it's AWC/AYC. Because of it's ability to utilize so much power mid-turn, my experience found that the rear tires undergo large amounts of load from the AWC/AYC alone. Overloading the tires too much causes RWD-like oversteer, where the tires simply spin. Loaded just right however, the Evo X seems to pull these amazing turning angles WITHOUT ANY wheel spin or loss of rear traction. At full throttle, the AYC just seems to fully understand and attempts to glide rally-style while still powering forward (provided the tire grip is there)

Take the most beautiful smoke-creating tail-slide you can imagine, and the Evo X can do the same angle without burning rubber. Take the most radical rally car, gliding across a gravel turn sideways, and the Evo X can still do that on tarmac.

I think it's a very un-recognized talent in the AWC/AYC. It's a very weird experience at first, and responding to corners with more throttle rather than tapping the brakes feels un-natural at first. But when setup correctly, the AWC/AYC system will do all the work - and god damn it works beautifully.



This balance gets harder to achieve the more power you make - something I'm tinkering with right now and I'm very OCD about. I don't like the power-sliding shenanigans that other are used to. I like to achieve oversteer without/with more rear traction, something this car has great potential doing compared to a RWD car.

Things to keep in mind when choosing/adjusting sway bars. Sort of a rant, but that's my opinion on setting up balance. Feel free to discuss

I might expand on this later

[HappyMint]

Good post man. I currently run medium stiffness up front and in the rear and I like it quite well. Front sway bar is one of my favorite mods and I agree 100% with your sentiment on it. The FSB massively improves the "sharpness" feel of the car. Turn in is dramatically improved, and lane change maneuvers (slaloms particularly) can be taken quite a bit faster in my experience.

[HPEVOX]

I think driving style comes into play here to with how you want the car to behave for which event you are running. I agree to an extent on the turn in being awesome with a balanced setup, but I am a "full stiff rear" kind of guy lol. I run 7k front and 10k rear on Ohlins with whiteline rsb on full stiff and it oversteers nicely for me, which is what I want on an autox course. I would NOT want this setup on a road course, as I would be sideways around any corner that carries decent speed. It's hard to get the car to rotate and avoid understeering at some of the low speed turns with autocrossing, so I encourage oversteer as much as possible to gain that "pointing" at lower speeds. I'm sure you know how it is more prone to understeer at low speeds, just like most vehicles. I say again though, I only prefer this because my only use it autox. I would run a more balanced setup on a road course. Seems like most prefer 10k/10k with fsb soft and rsb mid for road race setups from what I have read.

[McCoy]

Wait a second...

Simple rules do apply here, if you stiffen up the front of an Evo X it'll push on the nose. Stiffen up the rear and you'll have the opposite. Thing is, it's not quite as simple as that either as most people are going to have:

A. Different Spring Rates - Front and Rear
B. Different Ride Heights
C. Different Bump Compression
D. Different Rebound Compression
C. Different Anti-Roll bars

ALL of those differences will make very big changes to how a car handles. Added to that, understeer on entry of a corner is different to mid corner push and exit. You'll do different things to combat understeer dependent on where the understeer is during a corner, is it at entry? Is it more prevelent mid corner and exit?

As an example, softer bump compression will help with reducing understeer on entry of the corner, where as harder bump compression will help with mid corner and exit push. So something as simple as bump compression can make a difference one way or the other dependent on WHAT part of the corner you are attacking. Everyone on here has for the most part different setups. Wether it be different allignments, tyres, suspension, ride height etc etc. So Blanket statements dont always cover everything and everyone.

When we run our Evo X Time Attack race car at an event I sit down with the driver and go through each corner around the circuit with him. I ask the driver to rate out of 10 how the cars feels around the corner, then we disect that up into each part of the corner so each part has a 10/10 rating attached to it. We do this as small changes can be made once we see a pattern developing on one particular part of multiple corners, of course this changes from track to track as each race track will have different surfaces, corners, grip levels, elevation changes. So there isn't one perfect setting to use everywhere, it simply doesnt work like that.

No I know you are talking about autocross and a D/D car but for the most part, yes an anti-roll bar on the rear as a blanket statement (which I've shown can not always be true due to many factors) will on the whole make an Evo X exhibit more understeer.

Not trying to take anything away from the thread, I reckon it's a great idea and will assist alot of people, I'm just trying to add some more content so people can think about the changes they are making and what effects they will net because of those changes. Also, what works for one car and driver, won't neccessarily work for another. From there you have driving styles and sweet jesus that is a whole other ball game.

[dylphill85]

Subd

[Exyia]

I enjoy your posts/experience as much as anyone else, but we're trying to keep it simple here McCoy

I mainly wanted to clear up misconceptions about sway bars. I am sick of reading
"Springs and rear sway bar are perfect, front isn't needed"
"front will add understeer, big nono"
"I added just a rear bar and put it on full stiff and it's perfectly balanced now"

I don't disagree with any of your points, I just wanted to stay condensed, simple, and to the topic

Originally Posted by HPEVOX

I think driving style comes into play here to with how you want the car to behave for which event you are running. I agree to an extent on the turn in being awesome with a balanced setup, but I am a "full stiff rear" kind of guy lol. I run 7k front and 10k rear on Ohlins with whiteline rsb on full stiff and it oversteers nicely for me, which is what I want on an autox course. I would NOT want this setup on a road course, as I would be sideways around any corner that carries decent speed. It's hard to get the car to rotate and avoid understeering at some of the low speed turns with autocrossing, so I encourage oversteer as much as possible to gain that "pointing" at lower speeds. I'm sure you know how it is more prone to understeer at low speeds, just like most vehicles. I say again though, I only prefer this because my only use it autox. I would run a more balanced setup on a road course. Seems like most prefer 10k/10k with fsb soft and rsb mid for road race setups from what I have read.

See I just completely disagree with that, but to each his own as far as setups go

but more direct to the point of the readers "I just DD my car, is this relevant?" - I think people should understand that to NEVER discount either sway bar upgrade, nor to blindly assume stiff is always best. In suspension, more stiff does NOT equal more racecar

[McCoy]

I was keeping it simple...

heheh

[HPEVOX]

Originally Posted by Exyia

See I just completely disagree with that, but to each his own as far as setups go

but more direct to the point of the readers "I just DD my car, is this relevant?" - I think people should understand that to NEVER discount either sway bar upgrade, nor to blindly assume stiff is always best. In suspension, more stiff does NOT equal more racecar

I think it's like McCoy said too though with what setting I have the damping set on the shocks (only 1 click stiffer in the rear so you'd like that lol), vs spring rates vs if you have correct roll center, ride height, tires, pressures etc. It all works together. Like I said though, it's for autox only to get that oversteer when I want it at low speeds. It works for me anyways. I have tried other settings, but this suits me best for my setup on my car. Driver preference is a huge part of any setup I believe. That's why the professional drivers are always communicating with the engineers and crew chiefs to dial in their setup just the way they want it. I doubt you could find any 2 indy cars, f1 cars or nascar..s lol setup exactly the same. Not being a dick either i understand you're just getting some basic info for the mis-informed out there and I think it's great. I'll try not to derail it anymore.

[EVOL ME]

I for one appreciate the back and forth. The differences in opinion and the stated reasoning will at least give "noobs" as myself multiple avenues of research to personalize our own style. Please continue.


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[AdhesiveTeflon]

Shit....now I feel like I'm learning math all over again