When to replace shocks

[Karl Owen]

Hello, 2007 997.1 C4S here, Arizona daily driver with ~80,000 miles. Took it for a few autocross and track days a 6-7 years ago, but not much recently, other than I enjoy spirited street driving and cornering. 

 

When should I replace the shocks? I assume they get tired with age and miles.  By the way, the two hood and one engine compartment lid hydraulic supports gave out within a year of each other. I realize the suspension shock are different, nonetheless I was just wondering if there is a natural life to them?

 

I would be looking for Bilstein B4's (I have PASM), but was wondering what is the difference between the B4 and the B6?

 

Many thanks.

[jchapura]

Howdy Koenbro,

 

I have a 2005 C2S. I noticed some drive-ability problems when there was ponding on the road (and maybe some dry weather "bouncy-ness"). I took it to a well known independent and he put it up in the air. Tire wear wasn't bad because I took most of the camber out about a year earlier but he said it probably had excessive toe-in and that should be eliminated and the camber put back. (You'll never get the same wear life out of the rears compared to the fronts). But...the most important thing was the rear shocks - he said he could lift the wheel assembly a few inches and if the setup was new/not worn, he should not be able to (by hand). I swear I had tried the four corner "bounce" test and the body settled in what I thought was a normal amount of rebounds. I guess the hand bounce test just doesn't cut it. So, I thought about Bilsteins to retain the PASM. I'm going with Ohlins R&Ts (Mostly because there was an availability problem with almost all Bilsteins for my car). I'll "code out" the PASM. I'm in the middle of the retrofit.

 

Shocks do wear out. Some say they're either good or bad. And they are only bad when they are leaking. Good or bad (binary) - has just not been my experience with any car I've owned (and my C2S's were not leaking). Even Ohlins recommends a rebuild after 20-30k miles on the top notch shocks. These things wear out. Especially things sliding past one another. Some say 50k miles is at the upper end of the useful life for a shock.

 

I think you could probably adjust/stiffen your existing PASM shocks with the DSC Sport Controller module. That's another option to consider.

 

John

 

 

[Karl Owen]

I like PASM, and don't want the baseline feel of the shocks to be any stiffer than stock, yet it's nice to tighten the feel at the press of a button. Also I keep my car as stock as possible, the only main change has been the BT system,  installed behind the factory stereo, and looped in to replace the disc changer.

 

Are the Ohlins compatible with PASM, ie do they have the electric wire?

 

[jchapura]

They are not electrically controlled shocks. No wire. With the Ohlins, one can buy a black box that simulates the PASM part of the shock rather than having it coded out. It's just to fake-out the computer.

 

[Karl Owen]

They are not electrically controlled shocks. No wire. With the Ohlins, one can buy a black box that simulates the PASM part of the shock rather than having it coded out. It's just to fake-out the computer.
 

I see. I think I will stick to Bilsteins. Only question is B4 or B6?


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[Captain Lockheed]

Don't forget that mounts wear out too, new engine and gearbox mounts will make the car feel better.

New top mounts as well.

[Karl Owen]

Funny you should mention that. I have just replaced the engine mounts last night.  I am not even that skilled, yet it was very easy. The new one is in the middle with normal stick-out. The old ones are clearly shot. The exhaust tips were 27-29 mm under the bumper, but once I torqued the nuts to spec, they are seated 14mm below with the new mounts. Highly recommended maintenance.

Edited May 17, 2019 by Koenbro

[Karl Owen]

1 hour ago, Captain Lockheed said:

New top mounts as well.

 

 

 

What is a top mount btw?

Edited May 17, 2019 by Koenbro

[jpr993]

What do you need to replace the engine mounts?  I am going through the same "maintenance" on my 06 C4S and am looking at all perishable parts....

 

Thanks,

Jon

[Karl Owen]

What do you need to replace the engine mounts?  I am going through the same "maintenance" on my 06 C4S and am looking at all perishable parts....

 

Thanks,

Jon

 

Nothing special, jack, stands, torque wrench, 18 and 13 mm sockets, locktite. I supported the engine by jacking up the engine carrier while swapping out the mounts.

 

 

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[Captain Lockheed]

On 5/17/2019 at 4:53 PM, Koenbro said:

 

 

 

What is a top mount btw?

Top shock mounts, front and rear they degrade over time too.

Sorry should have explained better.