Strut Differences

[Bret Young]

Hey All,

I could use some assistance/knowledge from you guys regarding front struts. I have been building my '67 912 outlaw project off and on for a few years and starting to get back on it after moving and having a kid.

One thing that I am dealing with is the front struts. I did a full SC front end swap on the car. Everything powdercoated, fully rebuilt, 19mm raised Bilstein struts, turbo tie rods, bump steer kit, PMB brakes, the works.

But what I am running into now (and what I am reading on the forums that others have ran into) is that the control arms with the raised struts are rubbing/grinding on the inside of my wheels. I had some repop 15" fuchs that I sold and just recently put on some Group4 TT wheels and they are also rubbing. Need to get this fixed before they mark up the finish on my new wheels.

My options right now are to take a grinder to the control arms and create some additional clearance between the two parts, or swap back to regular height struts to gain the additional clearance.

So to my question. What is the difference between SC struts and the earlier 69-85 struts?
-Both have the 3.5" spacing for brake calipers
-From what I have heard, the snout of the spindle is the same for both
-From what I have read, they all use the same ball joint and lower control arm?

I have a set of stock Boge struts off a '76 with 3.5" spacing laying around. I know the strut inserts are different, but could I essentially take my hubs/rotors/calipers off the Bilstein struts that I have, swap them over onto the non-raised Boge struts and install them onto the car without issue?

Sorry if that is a lot of information in one post, but trying to determine in interchangability between the struts/hubs/brakes/different years.

Thanks!

[Tyson Schmidt]

They are interchangeable. Just use the spindle nut and washer that goes with the spindle, since there are large and small versions. Early vs late

19mm is definitely too much for 15” wheels. The most I raise them with 15” wheels is 15mm, and even then I usually have the roll the forward lips on the control arms. With some offsets and rim thicknesses, I’ve had to shave the ball joint nut.

Btw the downside to the Boge is the spindles can’t be raised without major fabrication.

[Bret Young]

Originally Posted by Tyson Schmidt

They are interchangeable. Just use the spindle nut and washer that goes with the spindle, since there are large and small versions. Early vs late

19mm is definitely too much for 15” wheels. The most I raise them with 15” wheels is 15mm, and even then I usually have the roll the forward lips on the control arms. With some offsets and rim thicknesses, I’ve had to shave the ball joint nut.

Btw the downside to the Boge is the spindles can’t be raised without major fabrication.

Hi Tyson,

Thanks for chiming in and clarifying. I appreciate it. Sounds like the raised Bilsteins need to go and either find replacement non-raised Bilsteins or just bolt on the earlier Boge struts with the Bilstein compatible inserts.

[Bret Young]

I want to bring this post back up to the top as I have another question. Doing some reading regarding strut inserts and what’s compatible with what year struts and found this thread:

https://forums.pelicanparts.com/porsche-911-technical-forum/446176-strut-housing-interchangeability-question.html

Within that thread was this chart:


The reason I am confused is regarding the interchangeability of the Boge struts. They aren’t on that list. The part number on mine are 911-341-044-00. And I have the same part number on both left and right struts.

I have the hubs/rotors/“A” calipers that are for the74-83 Bilstein strut - just want to make sure the struts that I have are compatible before I tear everything apart and buy replacement inserts.

Maybe I’m just over-analyzing things.

[Bret Young]

Anyone have any input?

[Cairo94507]

I would suggest you give Eric Shea, (Owner) at PMB Performance in Utah a call. He is very knowledgable on brakes, suspension, etc., on Porsches as well as other performance cars. https://pmbperformance.com

[nickelplated5s]

I have 3.5 Boge struts on a 67. 16" rims with 195.50's. Boxster calipers, vented rotors, front and rear with no problem. The caveat is no raised spindles. I know the roll center theory but mine handles flat. Look at the Alfa Brembo thread on Early911s.
BTW, 2.2 motor in it.

[Bret Young]

Originally Posted by Cairo94507

I would suggest you give Eric Shea, (Owner) at PMB Performance in Utah a call. He is very knowledgable on brakes, suspension, etc., on Porsches as well as other performance cars. https://pmbperformance.com

I will give him a call on Monday.