Question: Suspension Mod On 40th Anniversary

[threeOh]

At the risk of starting an emotion filled topic, let's just say I believe we're getting close to the day when hanging an engine in back of the the rear wheels is reaching its limit. This car rides ROUGH. That's OK if the handling was commensurate with the ride but its not. Compared to my '87 Carrera w/sport suspension and the little chin spoiler up front (unspoiled in rear) the ride is substantially harsher, the car is less stable at speed and though far more neutral, is also far less communicative. Yes I know DE would help and will begin soon.

Let's start with I have no plans to replace a brand new set of 18's and rosso's with 17's. I'll live with the harshness.

The ROW MO30 appears to be a decent starting place. I don't want to go lower as the underside of my '87 looked like it had completed the Baja when I finally sold it.

My problem is I'm not sure what's in the 40th as its a "varient" (of the US I presume) MO30. If I don't need to replace all shocks and springs its an obvious financial as well as installation advantage.

A simple way to start is knowing what part numbers are in the ROW 40th. And, what part numbers are in the US version of the 40th. The non-40th ROW MO30 is well documented but its dated and I don't know if there have been any changes. Any leads here? However, having asked about the non-40th ROW MO30 I'm not sure a list of part numbers is all that relevant as it ignores any changes Porsche felt were desireable on the ROW version of the 40th.

Front spring replacement is a given. Not sure about the rears. Sways appear to be the same. Shocks may be different but I assume its just the valving. Anyone know if Bilstein's revalving program applies to OEM units. They obviously know the valving they supply Porsche but I don't know if they will revalve OEM units.

Last, anyone with a ROW MO30 played with the sways. I would not do anything until after "stage 1" above. But, I'm inclined to beef up the front a bit or ease up on the rear to make the car more communicative. An alternative is to play with tire pressures. Certainly cheaper. Any experience on an ROW MO30 C2 Coupe here?

[Hank Cohn]

threeOh,

From your post, it sounds like you have some experience with suspension tuning. Do you find the ride of your 40th harsh on normal roads? Porsches, as you are most likely aware, are very sensitive to tire pressure. I am running 34 psi front and 36 psi rear on my ’99 C2 with 18” wheels and stock sized Pirelli Asimmetricos. This combination takes out all of the harshness and gives the car a nice feel for the road. I understand that your car is much newer than mine and a good bit more powerful but tire pressure is an easy place to start.

I have owned several 911s including a GT3-Cup which I raced in Speed World Challenge and I do admit that driving a rear engined car is different than driving a more conventionally configured one, however; I don’t think any of the street versions of the 911 is anywhere near “the limit.” I would exclude cars like the GT-2 and GT-3 only because they may be purchased by people with little driving experience and they offer little in the way of electronic driving aids.

Lastly, I would say that you will only get incremental improvement by exchanging your current suspension for another factory suspension. I wasn’t sure by your post if you are talking about street-only driving or if you are using the car at Drivers Education events. From the posts I’ve read the X74 package sounds like a great Factory alternative. If your car is a street car then I would consider the X74 as an upgrade. If your car is a dual purpose car with a lot of track use, then find some adjustable shocks like the Moton Club Sports and a spring rate that you can live with on the street and have a ball. The only downside that I can see is that you have a beautiful car and it is hard to protect the finish once you start tracking it.

Hank

[threeOh]

Hank,

Thanks for the input. Its street only. The harshness is upfront. The rear feels fine and the less porposing is a welcome change from the '87. If I DE it, its just to get it in a controlled environment and learn its limits. Right now the lack of feel is unsettling. I know the car is nowhere near its limits but some feedback would not hurt.

I would only put factory parts on. No knock against tuners but there are variables on the street that P tests for and tuners don't.

The X74 puts the car down further than I want to go. Therefore the ROW MO30 approach.

Finally ordered a "real" air compressor that came in Saturday. Have to unpack it and can then start to play with air pressure. However, I doubt if its much of an answer at this point -- don't know.

[Hank Cohn]

threeOh,

I think you'll be shocked (no pun intended) at the difference air pressure can make. And, not to be argumentative, but there are several "true" race shops with guys who have been tuning suspensions forever that can make the car do anything you want it to do. The trick is finding one of these guys and then getting them to mess around with a street car. The last element of that recipe is testing. It takes time to dial in an adjustable suspension as in a lot of hours and a lot of new tires! It is very dependent on what the driver wants to feel. The bad news is what feel good one day may not feel so good the next.

Hank

[Jetskied]

Three Oh I think your finding that the stock suspension is just not rihgt since your use to your 87. I know since I had a 84 and own a 78 930. I'm not really sure on that 40th edition, but the US sports had shocks that were way too soft and the spring were as stiff as ROW m030. I currently use the row m030 and love it. It dose not feel harsh at all. When your talking about feedback are you comparing to the 87. The new cars won't ever feel the same. I find the new cars more neutral