5 replies to this topic

[armegedon667]

Thanks to those who have shared the fitment of Koni Type-R rear shocks as a quality option. I obtained a pair and converted the spring seat to standard 2.5" coilover. On a 12" long progressive 100/300 swift coilover spring this meant a spring retaining clip location at 3.75" from the bottom of the shock. This must be turned on the lathe. Depth is 1/32". Ride height measured out at 25 5/8" or about 3/8" higher than stock.

https://drive.google...?usp=drive_link

Upper spring perches were turned out of 5" round stock on the lathe.

https://drive.google...?usp=drive_link

With the spring seat as low as it is a small notch must be made in the panhard bar for clearance. If you were running an adjustable bar this would not be an issue.

https://drive.google...?usp=drive_link

I went a bit too stiff with swift 100/300's for the streets and my taste. I think I'll move to something a bit softer, this will drop the rear just a bit and should put me right at factory specs.

[CSPCRX]

Nice work on the upper cups.  I have 600s in the rear, now that’s stiff!

[armegedon667]

Well given the rear of these cars is only about 650lbs with the interior in place I'd say that is rather hard!

When I spoke to Swift about their progressive springs they were adamant that they were true progressive winds and not dual rate. I have to say there is no way the profile is a linear progression. The first 40% or so of the travel is soft (where I set the ride height) but it bottoms out the soft portion (springs collapsed) about that position and after that it seems like its in the 300lb zone. I weigh 175 and if I hop up and down on the tail of the car it barley moves. I like the dual rate concept but it would need to be a lower rate for me. QA1 makes what they claim is a true progressive 100-200lb spring. They're relatively inexpensive so I'll try those next.

BTW, I think it your post on the Koni's that lead me on to these, thanks for that.

Did you need to get the Koni's revalved? The stock ITR spring rates on the back were like 150-250 progressive if I recall.

[CSPCRX]

Mine is 853 with full interior but I also have a cage so it adds a lot to the rear.  I ran 350s for years with 27mm torsion bars.  A lot of the track racers went to 30mm front bars and 600# in the rear for a very balanced feel.  Since switching I really like the setup.

 

my friend runs Swift springs and really likes them. There are a few versions of the Koni Yellow ITRs.  I got the race version that is shortened and valved to handle 1000 lb springs so ,y 600s don’t work them too hard.

[armegedon667]

Nice. What are you running up front for struts?

Koni makes a 1.5" OD strut insert for MK1 rabbits 8641-1048SPORT. It has 6" of travel and has an overall length of 20". My thought right now is to make a custom strut housing and throw it in there. Since our knuckles have an opening of about 1.81" I should have no problem getting 1/8" wall thickness out of the housing to support the strut.

[CSPCRX]

I am running a Koni strut that they made long ago.  It’s a shortened, double adjustable unit.  They stopped making them long ago.