Suspension Upgrade 1989 3.2

[ianmorrow]

Gary what Bilsteins have you got?

[Gary71]

Hi Ian, Mine are B6 front and rear.
Let’s be honest it’s no limo, but it’s not overly harsh considering the rest of the suspension has minimal compliance at best even on stock bushes.

[hot66]

personally I'd go with Tuthills recomendation as they do know what they're talking about when it comes to suspension for UK roads although you will have to see what they actually mean by 'Sprint' .. I still find the rear of my car with stock torsion bars and 'yellow' street sport shocks quite compliant and really comfy ... especially if I compare it to the ride of my 964 on Bilstein coil overs. Just be aware though there are quite a few rear bilsteins all with different valving :

https://www.fvd.net/us-en/shop?&term=&s ... %5B%5D=158

green 196/133
street sport 336/164 ( B46-0975 ?)
Rally 285/140
clubsport 220/180
clubsport 400/200

i think the new numbering for street sports is this : ???

https://www.fvd.net/us-en/115975/shock- ... 6-164.html

[ianmorrow]

Yes I think it’s either B6s all round or a slightly stiffer rear and to understand the difference between Sprint and Street Sport is important. It’s not just the purchase of the units which is not too bad given Design911 s discount £118 front and £101 rear it’s the installation cost and the subsequent risk that’s it’s all uncomfortable. Thanks all for the benefit of your experience.

[Chris_911]

Yes I think it’s either B6s all round or a slightly stiffer rear and to understand the difference between Sprint and Street Sport is important. It’s not just the purchase of the units which is not too bad given Design911 s discount £118 front and £101 rear it’s the installation cost and the subsequent risk that’s it’s all uncomfortable. Thanks all for the benefit of your experience.

Installation of the rears is very simple.
Fronts less so but still within the scope of a home garage.
No need for any geometry setting afterwards.
As I think Nige said you can buy a Bilstein insert for a Boge front strut - this is what I have on my car.

[Northy]

You might find changing from Boge to Bilstein increases your right height. So factor in resetting that and the geo.

[Chris_911]

You might find changing from Boge to Bilstein increases your right height. So factor in resetting that and the geo.

I didn't find that Lewis.

When I did mine it was a straight swap from Boge Sport to Bilstein. The rears just bolt on and the fronts were a sealed Bilstein unit which dropped into the Boge strut.
Ride height didn't change and there was no movement of any of the damper mounting points so no geometry change.

I would advise putting a quantity of gear oil in the front strut before you insert the cartridge.

[jwhillracer]

When I changed the dampers on our Hillclimb car from Koni to Bilstein, it raised the ride height by over 15mm, so it's as well to be aware that it might happen ……….

JW

[Chris_911]

When I changed the dampers on our Hillclimb car from Koni to Bilstein, it raised the ride height by over 15mm, so it's as well to be aware that it might happen ……….

JW

Interesting.
Guess it must be a higher gas pressure in the damper.

[RoscoP]

Hi Ian,
Don't know if it's of interest but I'm in the process of converting the suspension on my rsr tribute to coil overs. As a result I'll have a full set of torsion bar suspension for sale - fronts with Bilstein sport insets and rears are yellow billy sports v. low mileage only went to classic le mans once...will also have stiff FVD torsion bars for sale 22mm fronts and 29mm rears though probably too stiff for what you need!
Also have a v. nice set of dage fuchs split rims with tyres 9s front and 11s rear btw!
Cheers
Ross

Thank you for listening.

[ianmorrow]

Hi Ross and everyone
Thank you so much for all your help. Experience is everything. I have ordered new Boge as it was good enough for Porsche in the 80s and comfortable for me and it keeps the car original. Although the local Porsche specialist said he would leave all well alone.
This brings me on to the next problem. I think it was president Kennedy who said “ if it’s not broke don’t fix it” well
More beginner errors though
1. I wanted the arches brought back to the original colour and the fuel pipes were coated in some lack tar stuff and the braided pipes that led to the oil cooler hadn’t been changed in 30 years so I got my local very good mechanic to remove the pipes and the cooler and I got the pipes beaded back to original bought new opc braided pipes and the cooler resprayed . My man was concerned re the entire operation but I saw no problem. Yes everything came apart ok but joints leaking when replaced. So tomorrow I’m off to a local radiator specialist as bill for all replacements from OPC is 2500£. 911 design 1200£
2. My man has the rear new Boge in but I am now hugely nervous at what else will occur
Lesson “ if it’s not broke don’t fix it”
Will report on progress as it’s important that others don’t follow a “ fools progress “

[911hillclimber]

This has been an excellent thread, lots of real world experiences.

My car (73T) is on a mix of custom Bils Fr and Koni sport Rr and as the car is now a weekend tour classic and not the hill climb car it was, I am progressively 'tuning' back to comfort mode.

Boge is an interesting move and imho you are on the right track.
Do Boge do an insert to match the Bils front uprights, or, indeed, do Bils do a Boge 'rate' insert?

[ianmorrow]

Yes it certainly has been a real world experience for me. Monday will tell whether the pipes and joints can be sorted so that they join unleaking and will come apart again in the future.
Can anyone help with this one? After I bought the car I took it to my Porsche specialist for an opinion. Yes I know it’s the wrong way round but we were where we were . He declared it a good car . There was a little movement in the inner steering arms and he recommended changing to the turbo units as an upgrade. The bushes were also changed at this time. I noticed that the tyres then rubbed on full lock on reversing against the inner wings to the extent that the paint was through to the metal. On questioning he said that was usual and a spacer kit was the way to sort. It happened on driver side more than other.
Any views please.

[ianmorrow]

I drove the car back from the shop and a bit further and the new Boge are really comfortable on my country roads. I feel they were a good choice for me who wants road tours and a trip to the local pub.
The Bilstein 6s are hard I know but how thy compare with B 4s I’m not sure . Any thoughts?

[gridgway]

I thought that B6s all round worked well. Also don't forget that the torsion bars play a much bigger part in how stiff a car feels that the dampers.
Graham