As we’ve demonstrated in the past, one of the best things about working with our partners is having the opportunity to tap into their vast bank of knowledge when it comes to their various areas of expertise. For the next edition of Ask the Expert, we’ll be getting together with our friends at SuperPro Suspension Parts to answer your questions about sway bars and bushings, and discuss the effect these parts can have on your car.
Because, as anyone who’s ever gone through their suspension setup knows, both of these things are critical in improving handling.
On the other end of the discussion will be Scott Bennett, SuperPro’s Product Manager, and someone who in addition to being at the company for the past five years, also has 15 years experience of running his own automotive repair shop. Scott will be here to answer any questions you might have about aftermarket sway bars and bushings and how they can impact the way your car drives and handles.
If you have a question for Scott, simply post it below in the comments section. He will then go through and get to as many as he can, before we publish the answers in an upcoming post.
Now, let the curiosity flow…
A few questions:
How do you go about determining a baseline suspension setup?
How does preload effect springs and swaybars?
Can you explain why people say to put a big front bar on my WRX to combat understeer? Doesn't won't making the front end stiffer lead to more understeer?
If we're constantly being told polyurethane bushes are a superior replacement alternative to rubber bushes, then why do all car manufacturers continue to use rubber over poly bushes? Why is it that aftermarket bushes are almost always polyurethane and not, say, a hardened rubber compound instead?
Say you have an OEM sway bar, replace the bushings with polyurethane units, and then use shorter, adjustable end links, is it the same theory as those adjustable sway bars with multiple holes, as in, by shortening the lever arm, rigidity increases?
Could you explain the various optimal sway setups in a racetrack environment for AWD, RWD, and FWD? Its always been a great debate amongst friends on either get the fronts, rears, or both depending on the drivetrain and type of car. We've even been back and forth on the best settings such as medium or full stiff. Thank you!
What would you look for in the cars handling to determine if the poly bushings are creating stiction or binding? Is there a hierarchy of checks to rule other things out (that could potentially be causing handling issues) that you can recommend before pointing the finger at the bushings?
Back in the day, other guys made a big deal about castor loss and dynamic alignment. In other words, what happens when you're cornering is more important than what happens on the shop floor, do you guys take that in to account?
In case we want to change the cars balance to have less understeer or less oversteer, how should the sway bars be upgraded?
If both sway bars are upgraded proportionally, what benefits can feel the driver?
is a SLA setup completely superior to macpherson? how do Porsche and the FR-S get by with it, while cars like the Dodge Charger that have a true SLA setup aren't touted as excellent-handling cars?
can you explain anti ackerman steering geometery as i understand conventional ackerman but cannot get too grip with anti ackerman ? i know its primary aim isnt too achieve true rolling motion but i get confused after this
How can lowering a car effect the pre-load on the sway bar and do you have any suggestions on the best ways to go about correcting/reducing this extra stress? (I have a lowered crossfire and the rear is extra stiff/lively after dropping. I have been playing with sway link length with varrying results, just trying to find a more scientific way to approach the issue.) Thanks
Is it true that Polyurethane bushings can't strech? And is it true that rally cars use a hardend rubber bushing because of this flaw of PU? If so, why so many aftermarket companies offer them?
Greetings from Portugal
Does adding a stiffer anti-roll bar REDUCE that axles grip? I believe that it does, and lowers the "theoretical grip" on that axle, but when approached in the right way, can make the car easier to drive on or close to the limit.
What is the impact of stiffer swaybars on a driftcar? Is it worth the upgrade and how will the car behave afterwards?
As far as sway bars go, what amount of a performance increase can you expect from aftermarket (super pro) sway bars vs. stock on a stock or lightly modified vehicle?Also Is eliminating all body roll the goal or is some okay?
is the spring ratio front to rear fixed?
Ie I want to decrease roll by increasing springrate which atm is 60N/mm front 40N/mm rear do I increase to say 75N/mmfront and 50N/mm rear?
how much is the headroom in a damper before you have to revalve it when changing springrates?
how much R&D goes into your average off the shelf suspension product?
Is adjustable coilover suspension really any good for street use?
Hi, what do you recommend, first replace the front bushings with polyurethane bushings, or replace all of the rear axle bushings first? because when i think about it, when you replace the front first, the steering will be more sharp and the handling improves, but all the bushings on the rear of the car are still stock and allow more movement.
Is the car more likely to oversteer then? (it's about a RWD car) Greetings, David (The Netherlands)
A subject that doesn't get covered often is suspension setups for quick launches in a FWD car. Many suggest stiffening rear springs, but others say that won't help. Can you shed any light on this?
What alignment would you recommend for a BRZ on stock supsension? I've been told that only the toe is adjustable, is that correct?
My car(Scion FR-S) is my daily driver but I also go autocrossing. I was wondering what the best setup would be for my car. I will be using 18x8.5 wheels later with tire size of 235/45 or 245/45...if that info is necessary.
How does your company research and develop your suspension parts,set up and stuff for a specific car?
I love racing car .By browsing this site ,I know how to prepare and repair racing .I' m very appreciated .
I go autocrossing but my car(a Scion FR-S) is also my daily driver. I was wondering what would be a good set up for my car. I am also going to be putting 18x8.5 TSW Nurburgrings on my car. . . if that is important
What is the best way to find out how to set up a car properly? What is your process for tuning suspension?
How do you do fitments on the cars your make products for? Can we see the process to making the bars and test fitting them, then do you do real world testing to the cars before and after? I'd love to see/hear about some processes.
Also the additional force and stress put on the chassis from an AWD drivetrain, does effect how stiff things should be and where
Seems like front Aero will help a car grip the front if you have a stiffer chassis. Same way a rear wing would assist a car with a very stiff rear ie sways, hard tires, and or welded roll cage :)
However the more force put on either end of the car, the more you need to adjust shock rebound and compression to keep from chattering your teeth out. That is why race car teams say that even the most minute change to anything, can mean dramatic effects due to the effects on other parts of the car.
As for WRX, I think all car brands should have bigger sway bars up until they become less effective. Things can be too stiff.
Tires, ALL suspension components, aero, weight, counter balancing...all of these will play a huge factor. If you have the big sway bar and change all other factors you will begin to see what changes work best and worse with a bigger front sway bar.
It takes time to find the perfect balance, but when you do, you will be smiling from ear to ear!
But hey...im not a doctor :)
Remember, getting longer trailing arms in the rear also assist in adding the "stiff" effect to some degree without the springs. Might be a good options too. These guys have a great example here: http://www.kstuned.com/collections/kstuned-products/products/rear-trailing-arm-and-staging-brakes
Both WA race programs, both veryknowledgable :)
@BBones why wont it help? people have put nerf footballs and they got better launches.