912 Rear Shock Absorbers - any difference SWB/LWB?

For you flat four Porsche 912 fanatics

Moderators: Miggs, KS

Post Reply
912Flyer
DDK above all
Posts: 179
Joined: Tue May 07, 2019 2:19 pm

912 Rear Shock Absorbers - any difference SWB/LWB?

Post by 912Flyer »

Hi is there any difference between LWB and SWB rear dampers?

I need a rear set for my 67 912 and wondered whether there was any difference other than the price. SWB £185 each 68 LWB £120!
1967 912
1994 993
2006 987 S
Mini Cooper S
Cooper MK9
Lotus Elan Sprint
Alfa Romeo GTA-R
wildtexas
DDK slapper chatter
Posts: 480
Joined: Thu Apr 20, 2006 1:10 am
Location: N. Ireland

Re: 912 Rear Shock Absorbers - any difference SWB/LWB?

Post by wildtexas »

I believe so. IIRC the long wheel base have different diameter mounting bolts at the bottom. 68 can be weird as it's the one year only thing. I ended up with the koni classic red shocks. Firmer than the 50 year old original boge units, but a very positive feel in road holding.

Matt
User avatar
Knoxy
DDK addict
Posts: 112
Joined: Tue Dec 28, 2010 10:37 pm
Location: S Ayrshire, Scotland
Contact:

Re: 912 Rear Shock Absorbers - any difference SWB/LWB?

Post by Knoxy »

wildtexas wrote: Wed Jun 16, 2021 9:27 pm I believe so. IIRC the long wheel base have different diameter mounting bolts at the bottom. 68 can be weird as it's the one year only thing. I ended up with the koni classic red shocks. Firmer than the 50 year old original boge units, but a very positive feel in road holding.

Matt
Hi Matt, I know this an old post but could I ask what adjustment setting did you go with on the Koni Classics?

I am fitting Koni Classic Red's to the front and rear of my 67 SWB car. Koni recommend the front inserts are set at the softest setting for 912 fitment but I can't find any info for the rears. Off the car, they seem much stiffer than the Boge's that were fitted in 1977. I am looking to try to achieve "standard" ride quality / comfort.

Any thoughts?

Thanks
“Change is easy. Improvement is far more difficult”. - Ferdinand Porsche.

Helga the 912 Light Ivory 1967 (same age as the missus but in considerably better nick)
Ruby the Merc - Mercedes Benz S123 200T Estate
981 Cayman (Sold)
Cayenne - (Sold)
wildtexas
DDK slapper chatter
Posts: 480
Joined: Thu Apr 20, 2006 1:10 am
Location: N. Ireland

Re: 912 Rear Shock Absorbers - any difference SWB/LWB?

Post by wildtexas »

They are stiffer, I can't remember off the top of my head. But it won't be far off the softest setting as my car is stock and the roads here pretty rough country roads.

The rears are easy to remove and adjust.

I'd set them soft and see what you think
Bruce M
Me and DDK sitting in a tree! KISSING
Posts: 2745
Joined: Fri Aug 27, 2004 1:07 pm

Re: 912 Rear Shock Absorbers - any difference SWB/LWB?

Post by Bruce M »

Remember the konis have a fixed compression setting. Only the rebound is adjustable.
User avatar
AndrewSlater
I luv DDK!
Posts: 968
Joined: Wed Nov 30, 2011 3:35 pm

Re: 912 Rear Shock Absorbers - any difference SWB/LWB?

Post by AndrewSlater »

It is also worth checking the size of the bump stops supplied with the Koni classics as the ones that came with mine were incorrect and needed modifying.
My car would crash badly over speed bumps and potholes until I read another post which made me realise the error.
More details here on my earlier post page 11 http://www.ddk-online.com/phpBB2/viewto ... &start=150

Andrew
1966 Porsche 912 Slate Grey, red interior - first owner owned for 41 years
1974 Porsche 911 2.7 (The Manhattan project) viewtopic.php?f=28&t=51455
1973 VW 914 1.7 Olympic Blue - ( gone to a good home )
Nine One One
Put a fork in me, I'm done!
Posts: 1619
Joined: Fri Mar 01, 2013 11:45 am
Location: Kernow - good old Cornwall

Re: 912 Rear Shock Absorbers - any difference SWB/LWB?

Post by Nine One One »

AndrewSlater wrote: Tue Oct 12, 2021 2:47 pm One of the other tasks I undertook whilst awaiting fuel was investigating my shock absorber setup.
I'd watched a video of someone installing Koni Classic shocks to his '67 911 and was surprised when he claimed they were supplied with the incorrect bump stops for the SWB cars. Apparently the rears are supplied with an 9 bump stack but that SWB cars should only have 8 fitted, the later LWB cars take 8.

This made me wonder whether my Koni Classics were correctly installed.
I'd always felt that if I hit a pot hole or speed bump the car would jolt more than I would expect - maybe this could be the reason.

Another thing I had read was that the shocks aren't always supplied with the rebound setting the same.
Must admit, I'd never checked the number of bump stops or how the rebound was set, I'd just fit them as supplied :roll: .

So whilst the carbs were off the and the rear suspension readily accessible I dropped one of the rear shocks.
Bump stops = 9 - bugger!
Rebound setting checked - fully soft - that's good.

Quite a bit of the bump stop rubber had found its way onto the piston of the insert so I am guessing I had hit the bump stop on quite a few occasions.
I find it quite annoy that a set of shocks bought specifically for a SWB car were supplied with no notes suggestion that they need to be modified.

Image

So I hack sawed off a bump stop, and then repeated on the other side.

Now as I have also lowered my car an inch or so from standard height I expect that I had even less play on my bump stops.

Deciding that this was a good find, I decided to check the front rebound setting and bump stop scenario.
At the fronts the standard bump stop was fitted along with the extra one Koni supply.
Now some people suggest removing the extra one when a car is lowered and as its approximately the same height as the extent to which I had lowered the car - I decided to remove that also. Again there was quite a bit of bump stop rubber on the piston of the strut so I suspect it had been hitting quite often.

I also felt that possibly the rebound on the fronts was a little on the low side, so decided to dial in 25% on the fronts.

Needless to say as part of the drive around checking the AFRs the ride seemed a lot more compliant than previously, and when I hit a pothole or two it no longer jolts. Seems a good improvement.

Morale of story: if you are fitting Koni Classics count your bump stops!
User avatar
Knoxy
DDK addict
Posts: 112
Joined: Tue Dec 28, 2010 10:37 pm
Location: S Ayrshire, Scotland
Contact:

Re: 912 Rear Shock Absorbers - any difference SWB/LWB?

Post by Knoxy »

Thanks all, very helpful.
“Change is easy. Improvement is far more difficult”. - Ferdinand Porsche.

Helga the 912 Light Ivory 1967 (same age as the missus but in considerably better nick)
Ruby the Merc - Mercedes Benz S123 200T Estate
981 Cayman (Sold)
Cayenne - (Sold)
GonzoBard
DDK addict
Posts: 114
Joined: Sat Feb 28, 2015 11:38 pm

Re: 912 Rear Shock Absorbers - any difference SWB/LWB?

Post by GonzoBard »

Is it only Koni who supply dampers for early 912s or is there a Bilstein equivalent?
User avatar
Knoxy
DDK addict
Posts: 112
Joined: Tue Dec 28, 2010 10:37 pm
Location: S Ayrshire, Scotland
Contact:

Re: 912 Rear Shock Absorbers - any difference SWB/LWB?

Post by Knoxy »

I believe Bilstien do replacements but have read and watched some feedback that they are a bit too firm for road use on a 912. I’ve always considered the ride quality on my car to be excellent, whilst still giving great handling for a 50+ year old car Ride quality being much better than most modern cars so I am conscious that I don't want to ruin it with new dampers, hence I opted for Konis, Although, I am a big fan of Bilstiens for competition use.
“Change is easy. Improvement is far more difficult”. - Ferdinand Porsche.

Helga the 912 Light Ivory 1967 (same age as the missus but in considerably better nick)
Ruby the Merc - Mercedes Benz S123 200T Estate
981 Cayman (Sold)
Cayenne - (Sold)
GonzoBard
DDK addict
Posts: 114
Joined: Sat Feb 28, 2015 11:38 pm

Re: 912 Rear Shock Absorbers - any difference SWB/LWB?

Post by GonzoBard »

OK, thanks. I too like the ride quality of my car, just the right side of firm, noting that the rear dampers are aged and I plan to replace them. Koni it is, then.
Post Reply