I have a pair of 72-73 911 "Koni only" struts with 3.5" SC calipers. The only Koni inserts I can find for them are sefl-leveling "reds". I am thinking of installing these on my track car that will be used for DE events for the foreseeable future. What is this "self-leveling" system these shocks use? I take it they are not adjustable shocks.

Will these shocks give me acceptable performance when pushed hard on my 1970 teener with 2.2 six semi-race engine? Koni "reds" will also be in the rear. Thanks.

I can't speak to the self leveling stuff, but (assuming we are talking about the same strut) you can use regular Koni "yellow" sport inserts in those struts. When you buy the Koni yellow they sort of assume you are installing them in Boge struts, so they come with a centering ring and Boge specific gland nut. If you use them in the OEM Koni strut, you just need the special gland nut that matches the OEM Koni strut.

I have OEM Koni struts (91134104110 and 91134104210) that I am rebuilding. The gland nut you need is Koni part number 73.25.01.0111.1. I got mine from Paragon Products.

See here for photos of my rebuild...

http://motorsport.zyyz.com/project_914_03_25.htm

I need to powder coat a few more things and then rebuild my calipers and then I am going to put it all back together again.

This was not the case with the Koni struts I had (73/74? 911 S struts w/ 3.5" brake spacing). The inside diameter of the strut at the bottom (where the spindle is attached) was too small for the Yellow Koni insert to fit. The top of the strut tube was larger in diameter but the bottom was smaller.
Koni used to offer a standard hydraulic replacement insert, not a sport or gas insert for these struts.
I stuck with the 911 T struts w/ 3" brakes and Koni Yellow Sport inserts.
It was a number of years ago that I looked into this and availability may have changed and I may have had different struts.

There was a pneumatic front suspension used on some 911s. They used no torsion bars and were not considered (by some) a good or even safe option for track use.

Good Luck
Jim

One reason I listed my part numbers on my struts is because I think they are newer (74-77?) and may be a different part number than the earlier struts the OP has.

At the bottom on the struts, there is a section where it necks down to a smaller diameter. I may be making this up. But I "think" I remember something about how some of the Koni inserts didn't fit due where the neck is located. That to make this fit some shaving of the insert was done, but that this weakended the insert and was no longer recommended. And that later inserts have a different design to deal with the neck location. For example it's my understanding that the 914 specific insert will not fit into my strut due to this, but that the "newer" 911 insert (which I have) does fit. Or I may be confusing the issue I remember with the one you are describing.

Persoally if it turned out that this particular strut only allows a Koni Red, I would probably not use it and get either a Boge (which allows more insert options) or maybe a newer Koni strut like I have.

I would call either Koni directly (they have a Tech line in which I have had good experience with questions like this) and/or Jason at Paragon Products to determine what really fits into that particular strut.

All Koni's are adjustable. I've never heard of a self-leveling Koni but... first time for everything.

The part number for the pass side strut is 90134108410.

Below is a website that lists the inserts for the Koni only struts I have .. I think. I believe the Porcshe parts manual lists this as a 72-73 911 w/S calipers, however, the websites lists 72-74, not 72-73.

The AutoCarParts.com website info is listed below. I'm only using the site for reference, but seems to be consistent with other parts suppliers. Notice the reference excluding the self-leveling front units?

link http://www.autocarparts.com/c_Porsche_911_..._Shocks_m_Koni/

72 - 74 Koni Shocks & Struts for Cars, Porsche 911 Carrera
Porsche, 911, Carrera Front Pair - RED
Exc. Self Leveling Front Units
Models w/Koni 86 1638 $428.00 $321.00

72 - 74 Koni Shocks & Struts for Cars, Porsche 911 912
Porsche, 911, 912 Front Pair - RED
Exc. Self Leveling Front Units
Models w/Koni 86 1638 $428.00 $321.00

They are excluding the "Hydronumatic" struts made by Porsche. Basically stating, they do not make inserts for that strut.

Mike, I think you are right regarding the "Red" (86 1638) as being the one that Koni says fits. I also agree with Eric that they are just saying "this does not work with the hydronumatic" strut.

To address your original question, it's my understanding that the "Red" are just not aggressively valved as the "Yellow". Also most of they yellow are adjustable via the "knob" on the top. While I think the adjustability of the Red is done some other way?

I would still call someone such as Jason at Paragon or Koni because I believe there are other combinations that will work than what is listed on the Koni fitment guide. I think some of the fitment guide is also based upon valving. For example if Koni has an insert with what they think is optimal valving for your application, they will list that particular insert. But if there is also another insert that will fit into the strut they will not list it. So I think they may have a "red" that is perfect, but there may be a "yellow" that might work. I think you can even get the "red" body revalved if it's not aggressive enough for you as is.

Thanks for recommending Paragon. Apparently a "Yellow" 8641-1039 sport with a different gland nut will work. They're not cheap, but that's what I'm going with. Now for the rears ......... yellows also. Thanks all.

If they're new, they all come with the top knob adjustment now. It's possible the vintage ones may not.

Richard is correct, you can get them revalved. You can even get a new center rod installed with the knob adjustment.

Jason know his Konis' Sounds like you're on your way.

Old Reds = "collapse to adjust" -