Mr. D

I've got an Roush Supercharged '08 Mustang. I love the car, but would like improve the ride particularly of the rear axle. I don't want to stiffen up the suspension as I only drive it hard on straight roads. I'm not concerned with improving handling in curves or for road racing... I want to improve the ride especially in the rear end as my back isn't too good! Anybody know shocks well enough to give me a recommendation. I've used Bilstein's on other cars, but as I said I want to eliminate feeling the road bumps in the rear axle! Recommendations....

Mr. D

Derf00

Not sure of the ride quality you are after since shocks is only one part of the equation. A live rear axle is not the best setup for a 'cushy' ride.

If your car was built by roush (roush suspension components) you would want to swap those for OEM type. OEM uses Rubber which is much softer (mushy) that the Polyurethane aftermarket uses.

Also when you start going for cushy, be prepared for wheel hop. That's where the rear wheels start jumping very rapidly under heavy acceleration or due to street surface imperfections and NVH.

Jazzer The Cat

Boy, you can run some softer springs/shocks, but have to ask why you purchased a Roush? Your car is a high HP ride and designed to take corners well, so you will probably need to soften the springs/struts/shocks all around to get the ride you are looking to find.

Softening up only the rears, will likely introduce some front/rear balance issues and introduce an understeer issue. Although, if you don't drive corners hard, it probably wouldn't make a whole lot of difference, based on what you have said above.

Jazzer

Mr. D

Thanks for the responses! You're right in that I don't drive curves hard mainly because it is unsafe unless in area designed for that purpose. I keep it to straight line acceleration in conditions where I don't endanger other people. Road racing on curves risks other people's lives! I stopped doing that, as well as street racing, when I was 18... after a few close calls! I guess that's called growing up!

I'm runnning stock Mustang suspension. I have a Roush blower, but not Roush suspension just because I don't want the ride that goes with it. The reason I'm discussing shocks is because the right shock will allow the wheel to move & absorb some of the shock of a bump or rut. Too stiff a shock designed for competition can transfer most of the impact of a bump to the body & you. I'm looking for a shock that will allow the wheel to move enough to absorb shock, but yet not be so soft that control is sacrificed too much. Some of my "partners in crime" think Bilstein shocks do that well. On plain, old pickups the inexpensive Monroe Sensitrac shock allows enough "initial" wheel/shock travel to reduce the hop on older concrete block highways that shakes your teeth. Allowing a little shock travel before the shock stiffens up can improve the ride especially on a solid axle car. I work with C1 "solid axle" 53 to 62 Corvettes also! Bilsteins help their ride allot.

Any suggestions?

Jazzer The Cat

I didn't read your opening post close enough to realize that you didn't buy a Roush, just added the charger

I am gonna let Norm chime in at this point. He is FAR better versed on shocks/strut/spring combo than I and would have some good suggestions for you. Keep in mind, that having a serious increase in HP/T means you should have a suspension capable of maintaing control of your car during even a moddest turn.

At the very least, I would recommend a really nice set of tires that offer grip suited for your seasonal driving needs. Actually, I always recommend this... lol, but if you soften up the suspension, you should at least compensate to a degree with premium grip of the road.

Jazzer

Mr. D

In terms of the suspension as related to my driving style, I find in turns that I run out of "Juevos Rancheros" before I run out of suspension & tire grip! I'm a straight ahead old muscle car type driver! One of the problems with having the best tire grip & suspension is when you push until it lets go... you in big, big... big trouble!

Jazzer The Cat

^ this is not necessarily true, but I understand what you mean

A good suspension will be forgiving, but not if you ask for it at 110 MPH while in a 4-wheel drift condition a split-second from lateral contact to the cement support structure of that highway overpass you see out your passenger window

The point at which your car looses its grip, it would idealy not completely let go, but should actually pass "beyond" its limit in much the same way it was reached. Tires, as the most important of all suspension components, are a big part of this equasion and should have a nice release-curve (cannot think of the correct phrase, at the moment) to be predictable once this line is crossed. The S197 cars have avoided a particular suspension design, the un-rivaled 4-link or "quadra-bind" rear suspension, so as to not have this as big an issue from the factory.

A well designed suspension will be VERY helpful to reduce those "big trouble" situations

Jazzer

Norm Peterson

Your first line of defense is your tires . . . and the pressure that you inflate them to. As long as you aren't toting heavy trunk loads or a full passenger load, feel free to take 2 or 3 psi out of the rear tires even if they're an OE size. That's the first thing I did on my '08 - the back end was just too harsh with the 235/50-18's at 32 psi per the sticker. You could probably run 255/45's at 27 or 28 psi, at some risk of triggering the TPMS lamp occasionally. Keep the fronts up at 32.

Shocks are the next step, and while I don't have any experience with Bilsteins on an S197, I found them noticeably better riding than KYB Gas-A-Justs on another front engine/rwd stick axle car - without giving up handling (I autocrossed that car with them - there should be a picture in one of my albums). That makes at least two different platforms that the Bils provide good ride quality with.

Harshness is a high shock piston speed event, and some shocks are better valved than others as far as taking the sting out of sharp bumps. Actually, even the Koni sports that I have on my '08 are slightly better than the OE shocks if I leave them full soft.

What you DON'T want to get even if Tokico was to make them is Illuminas. Those things are HARSH (with three exclamation points) over precisely the road disturbances that you mention.

Sensa-tracs work differently, and the softer riding portion is only around the stock ride height. If your car is not stock height for any reason, they won't work as well as the ads suggest. If your car is at stock ride height, they won't control the squat the car takes when you hit the gas in a lower gear, and the tail will rise faster under hard braking. There are very few instances where I'd suggest them, and they'd be to people with worse back trouble than I think either of us have, maybe worse than both of us combined (just so you know, I'm wearing a weight lifter's belt to keep my own back from acting up from leaning over as I type this).


Norm

Mr. D

Norm & Jazzer,

First of all, thank you so much for taking the time to respond to my question. I found Jazzer's comments on losing traction interesting. I guess, not having the situation occur with my Mustang, I assumed that losing traction in a hard curve might be total loss of traction rather than gradual loss.

(1.) What do you two guys recommend in a reasonally priced "better" tire to replace OEM quality?

(2.) Based on what Norm said, I think I will reduce air pressure in the rear about 3 PSI on my '08 Mustang (DUH!) & put on some Bilstein shocks! I've had good results with them on solid axle C1 Corvettes ('53 -'62) Sorry... I love them too! Modern Mustangs are a recent find!

For those reading wondering why I didn't get a complete Roush package... one part of the answer is easy! (1.) I have the 460 HP Mustang you see on my Avatar for a total investment "including buying the car new" of $32K. (2.) Not driving curves too aggressively, I didn't want to give up any ride comfort. The stock Mustang GT handles pretty well for my taste. As I said, I rarely put my foot in it unless I have clear, straight road ahead... and then.. I still run out of space in a hurry! Shifting out of 2nd at 80 MPH will do that! Those that have Roush Supercharged 4.6's know that 0-60 is pretty quick! I'm glad they haven't approved the 5.0 with a Supercharger in Calif.... because it might cost me some money! In any case... being an old timer ... I prefer the more classic '08 body style!

Any other ideas....? Thanx again, guys!

Mr. D "A retired teacher that never could follow rules too well!"

Jazzer The Cat

Norm gave some good info there, so certainly try lowering tire pressure a bit PRIOR to going after new shocks. Do this for two reasons and the first being a very quick and easy way to see if this is the best direction for you. The second, being pretty darn cheap to just let a bit of air from the tires

If you should decide to replace them, be sure to consider a couple things. You want a nice ride, but most nice riding tires are not going to offer a whole lot of grip. Whether (actually the correct spelling here.... I looked it up!) it be for off-the-line or lateral grip, this needs your consideration. This is because you NEED some nice grip to get that 0-60 rush on those occasions and secondly, because you must slow down at some point too. Putting that power to the ground generally requires a certain amount of acceptance to a harsher ride.

An bit of an exception to this, would be something along the lines of an M/T Street Radial. This is a VERY grippy tire for off-the-line, but is going to offer less of it in a lateral sense, so not soo great for corners. The sidewalls are somewhat tall, for a nice "slingshot" off the line, but will absorb bumps in the road probably better than your current tires. Now... these tires are NOT GOOD IN THE WET, so this must be taken into consideration, beyond if you even think they are good for you otherwise. A very big part of what can help to improve the ride quality is profile height. Not to say a taller sidewall will automatically be a nicer ride, but comparing the same make/model of tire with this being the only difference.... yes. Don't know if you are running a 17" or 18" wheel, but the overall diameter of your OEM tires is 27.2" (+/- a small amount) So long as you maintain this diameter tire, you will not effect your speedometer/ODO accuracy and your fender clearance/ride height will remain unchanged.

There is more to the subject than what I have said here, but gives you an idea of a direction you may consider. For more info on the subject, head over to my other little corner of the interwebz.... Wheels & Tires and maybe peep Choosing a new tire thread as well

Jazzer... keepin' it real for the teach

EDIT: If you REALLY want to improve your ride quality AND your off-the-line grip... consider a set of smaller wheels out back. You may be able to go with a set of 15" wheels, but need to confirm they would clear your brakes first! If they do, than this can add 2 or 3 inches to your existing profile height and allow a taller sidewall for a double-bonus