Bilstein HD or SP for daily driver?

[mthomas58]

What is recommended for daily drivers?

How much different is the ride between the two and how do they compare to stock Boge's? Why do some put SP's on the rear and HD's on the front?

As always, Thanks!

[Quicksilver]

The sports are a firmer valving then the HDs so they really do some good in sticking the rear. The consensus on the front is that the extra firmness only makes the ride harsher and doesn't improve grip.

Do a search for one of Steve Weiner's explanations. (Steve@Rennsport) He is one of the real gurus on getting the most out of the 911s suspension and he has explained this pretty clearly.

[KTL]

Many of the shop owners around here recommend the HD and Sport, front vs. rear. The sports up front are said to make the ride a bit more harsh because you can feel it in your hands through the steering wheel.

For street use i'd go with the HD all around. I imagine these are more closely matched to the stock torsion bar rates than would be the sport shocks.

As far as comparison to the stock Boges? I can't answer because i've only seen the difference between tired '87 original Boges vs. new Bilstein (HD front, Sport rear in my case with larger 22/29 torsion bars) installed in 2001, so there was a significant difference in feel in my case. My front shocks were very soft with only mid-60K miles on them. Rears were very soft too. New ones are going to be much stiffer no matter which you choose.

If I was to install new shocks on a car that is completely street driven? I'd chose the Boge. Why? Because they're cheaper, good quality and what difference are you really going to gain in street driving by going with the Bilstein other, than being able to say they're Bilstein???? That's just me though. I'm kinda cheap sometimes.

[livi]

I went standard (HD) all around for primarily street use. Very happy. Particularly when compared to the very tired 20+ years old Boge. A set of new Boge is probably not bad either, but many owners go with Bilstein.

Either way, you will be amazed what new shocks do to the ride of the 911.

[mthomas58]

Thanks for the thoughtful responses guys! Certainly gives me something to chew on.

[arbita1]

Originally posted by KTL
(HD front, Sport rear in my case with larger 22/29 torsion bars) installed in 2001, so there was a significant difference in feel in my case.

I'm looking to do the same torsion bar set up. My original plan was to have a set of Bilsteins revalved to match the torsion bars. But now finances are making me think otherwise.

Do you not find the HD's in the front too soft for the 22mm torsion bars?

[defcon65]

I went with HDs front and rear. The difference was night and day from the old Boges. It's plenty firm and sticks great.

[MuffinMan]

If you are using the stock torsion bars, the recommendation from the gurus is that the valving in the HDs is a better match than the Sports. If you increase the size/stiffness of your torsion bars, then it's a different story based on what you choose.

[MysticAlpaca]

I ended up with Sport front and rear but I also have 22 front and 30 rear Tbars. Feels pretty good to me but I am curious what a custom valved front shock would feel like.

[arbita1]

It's not that expensive to do. If you send them to Bilstein it's around $65 - 75 per shock.

[glenncof]

1985 Cab.

I called Bilstein tech and discussed HD vs SP.

He said use HD unless car is lowered (I even argued the Cab is heavier. He was insistent.) I assume Bilstein knows better than me ! I think he said something about operating range.

I replaced the rears on mine >>100K miles. I had planned to do the struts at the same time but after replacing rears, no need. Very flat stops. I find the Boge struts still going strong at 176K miles.

The rears had to go due to car 'dancing' at highway speeds after a tweak of the steering wheel.

[RickM]

Originally posted by glenncof


He said use HD unless car is lowered

Is this because HDs are not "stiff" enough to keep from bottoming out?

[mthomas58]

Based on my knowledge of PO's, I seriously doubt my car has ever been intentionally lowered. That said, my right hight is 25 1/4" front and 25" rear......close to euro height based on what I read here.

[Greek55]

I have sports all the way around as suggested by Bilstein. I like the steering feedback. It is not too stiff for daily use and it handles great when i do DE's. I also lowered the car to Euro height.

[KTL]

Originally posted by arbita1
I'm looking to do the same torsion bar set up. My original plan was to have a set of Bilsteins revalved to match the torsion bars. But now finances are making me think otherwise.

Do you not find the HD's in the front too soft for the 22mm torsion bars?

I find it too soft all around.

My point being bigger torsion bars are not all they're cracked up to be. Look at the other pictures on page 1 of the gallery and you'll see the blue, silver 911's with stock suspension are leaning as much as me with "upgraded" suspension.

I understand that sway bars compensate for body roll, but to a point of tuning. They're not supposed to be used to eliminate roll altogether. Just proves that stiffer sway bars are a big compensator for lack of spring rate in torsion bar 911s. Even the biggest torsion bars don't have the rates you can get from coils to REALLY stiffen things up.

edit............ oops, bad link i'll repost below

[KTL]

http://autobahnevents.exposuremanager.com/g/porsche_club_michigan_region_june_7th2006&gallery_page=&gallery_all=&view=1&photo_page=1

[Greek55]

I agree with Kevin. I kept stock torsion bars and added adjustable sway bars so I could fine tune.

[edward993]

Originally posted by glenncof
1985 Cab.

I called Bilstein tech and discussed HD vs SP.
He said use HD unless car is lowered (I even argued the Cab is heavier. He was insistent.) ....

Originally posted by RickM
Is this because HDs are not "stiff" enough to keep from bottoming out?

IIRC, the Sports when fully compressed are shorter than the HDs fully compressed, thus offering more shock travel than an HD would, making the Sports the more suitible shock for a lowered car ...especially a dramatically lowered car.

Edward

[KTL]

The one downside though is that since stock torsion bars lack spring rate, the sways do more than their fair share of work. So what? Well that's why sway bar mounts are notorious for breaking.

I'm not complaining here. Just saying that shocks and springs are capable in stock form, since "upgrading" doesn't gain as much as you think- in terms of increased spring rate.

But there is something to be said for the feel of the upgrade. Fresh shocks on a 911 make a world of difference, as others have already said. The same can be said of most any car, but I think the 911 is a bit different due to it's weight distribution and manual steering.

[Greek55]

True Kevin. We have over reinforced the mounts on my car, I hope. So far it has lasted 2 years.