Hey Everyone,

I've done a fair amount of research on this subject this morning, however I am not finding the required information.

Upon doing a bit of research I am not actually sure if I need shocks/struts. Someone I know suggested that I need new struts. This was because when I go over bumps there will occasionally be a bang from the rear, but nothing that I really notice.

I thought my ride quality might have degraded since I bought the car, so I considered the struts being shot as a possibility. However upon researching it seems like the main symptom of shot struts is a bouncy ride. The only thing I have noticed is that bumps feel harsh, however it may have been like that from the factory as 997 911's feel way bumpier.

My car is at approximately 65,000 miles, and has never had the suspension replaced.

If anyone feels I may need to replace something based off of anything in this report, or has any ideas please let me know. Stillen is having a black friday sale on suspension today so now would be a great time to know!

Thanks,
Tony

P.S. If new suspension is necessary I would love to upgrade.The only aspects I care about is the performance, reliability and whether or not they can be used throughout winter. The ride height, and quality of the ride in the city is of little concern to me.

 

Check you shocks for leaks, that is a sure sign you need to replace them. I would recommend Tokico Blues or really Tokico d-spec adjustable. They have a lifetime warrantee

 

Hey,

I have been doing some more research and I read a post that got me thinking about my recent stillen sway bar purchase.

The post read: "Rather than waste money on lowering just install a 40-60% stiffer ADJUSTABLE rear sway bar and leave the rest alone [don't mess with front]. That will increase the sum of rear spring and bar stiffness by ~~ 20-25% which will shift the [46/54=0.85/2=0.43 x 20-25%%=] {stiffness ratio} 8.5%-10.75% [understeer ratio shift more rearward towards neutrality]."

Would you guys suggest only installing the rear bar?
Or installing both but the rear much stiffer?

Thanks

 

I installed Hotchkis sways front and back. I set the front to the middle holes and the back in the front holes (full stiff). Night and day difference. I would say, yes, you could only instal the back bar and set it full stiff and get some of the benefits...


But not all.

 

I think it depends a lot on how much driving experience you have.

Do you have an issue with under-rotation at corner entry? do you have an issue with power-over? do you have a problem with understeer mid corner under maintenance throttle?

Another thing is are you planning on always driving with VDC on? If not how comfortable are you with controlling over-rotation? How confident are you on your throttle application during over-rotation? Are you confident you will never lift?

edit: Say for example, you misjudge the speed at corner entry, and when you turn in, you car starts to over-rotate because you got stiff rear-sway bars, but you are still going too fast, do you know what you are going to do?

What are you looking for out of your car? what do you mean by performance? are you tracking your car?

On the other side, looking from performance alone, it is also not a straight forward answer. Usually the process goes: determine tires (which determines peak lateral g) -> determine ride height -> chose spring rate -> calculate peak roll angle -> then use roll bars to adjust peak roll angle to desired and adjust balance of car.

I'm also not quite sure of the analysis posted. Is the movement ratio or whatever they call it of the anti-roll bars the same? (distance from axis of rotation to attachment point of bar)

anyway, the roll angles under cornering and overall balance of the car aren't just determined by anti-roll bar rate. The weight shift and corner weights and spring rates play a roll (wheel frequencies on front and back are different).

 

Thanks for the reply. My knowledge of this subject is still very vague, although this did help fill in quite a few of the blanks.

Under rotation at corner entry? Yes

Do you have an issue with power-over? No. I would like to be able to induce oversteer with less effort

Do you have a problem with understeer mid corner under maintenance throttle? I don't think so, but I generally dont add too much throttle until a little after the apex. Only notice understeer on corner entry

Another thing is are you planning on always driving with VDC on? If not how comfortable are you with controlling over-rotation? Very comfortable

-How confident are you on your throttle application during over-rotation? Are you confident you will never lift? Lol I was confident with my throttle application prior to reading this question. By lift do you mean start to roll? I have never began to experience lift off if that's the case.

What are you looking for out of your car? What do you mean by performance? I'm mostly hoping to eliminate understeer, but I also would like the car to corner tighter and to feel the road more

Usually the process goes: determine tires (which determines peak lateral g) -> determine ride height -> chose spring rate -> calculate peak roll angle -> then use roll bars to adjust peak roll angle to desired and adjust balance of car. Well unfortunately I wont be going to this extent. On stock suspension and crappy tires, what would be a good starting point to set the sway bars at for front and rear?

Thanks again. I really appreciate the lesson on suspension, it helps a lot.

 

One issue with having neutral oversteer is that it is hard to recover if you over-speed into a turn. Say you misjudge your turn, or you have cold tires, or there is dirt/leaves/water on the road. With understeer you can scrub off speed. with oversteer you are kind of out of luck.

lifting is when you lift your foot off the gas pedal. Power over is easier to control because your foot is already on the gas. When the car starts to oversteer mid corner, the natural instinct is to lift off the gas, which is just about the worst thing you can do.

anti-roll bars don't increase the amount of traction your car has, it just moves it around. For feel, that is subjective. All in all, for the price, they aren't too bad of an idea. I would caution you on adjusting the balance of the car is all.

 

At first I thought I disagreed with this, but you are correct. It keeps all four tires in better contact with the road for better (not more) traction. It really distributes the weight of the car to all four wheels better.

 

With 65K miles on your G I can guarantee you need more than shocks! The noises you're hearing are probably coming from worn parts. Find a brake/alignment shop in your area that deals with suspensions, they'll get it on a rack and find and replace what needs to be. That kinda mileage you need shocks, Tokico D specs are a great choice. Once your suspension is tight you can think about upgrades like sway bars and end links, first spend your $$ where it's needed!
Gary

 

Thanks as always Gary! Your opinion has played some part in every modification have done to my car.

I think I'm going to take your advice and focus on other areas of my suspension first. sway bars were supposed to be a $300 way too easily boost my handling, however now I'm discovering that with after shipping and end links by total will be around $800 before install.

 

Focus on shocks (I like D-specs as well), shock bushings, and front suspension bushings, namely the inner and outer LCA bushings, upper a-arm bushings and compression rod bushings. Those will take you a long way towards improving handling and ride and you may find you don't need anything else. I still think a rear sway bar is a nice upgrade for the street w/o compromising ride height (for winter, etc.) but that's a decision that can wait till after the other stuff.

 

Just the advice I needed! I was curious as to whether I should just focus on the shocks for now. Those bushings look times consuming. I guess it won't be so bad if doing the shocks at the same time though.