78. But for an inch …

The factory kits include (at the time I purchased my car) 7″ 850# springs for the rear dampers.  Many builders going with an aluminum block based LS motor and Graz will find themselves running the spring adjustment collars almost all the way just to get a reasonable ride height.  In my case, I’m running a 5″ rear ride height as measured from the engine frame rail to the ground, located along the spindle centerline (or thereabouts).  I’ve been running the car in this way since I originally completed it.  I figured I’d need to go to a different spring rate but I wanted to drive the car as-is for a while before going with a new spring.  Turns out, after a few thousand miles, that I like this spring rate just fine.  I feel the rear is planted well enough and it doesn’t feel squishy or bottoms out while I’m tooling around at my pedestrian canyon pace.  Some searching on GT40s led me to a thread discussing alternate spring rates and lengths and here’s where I learned that you can install an 8″ spring relatively easily, but anything longer and you’re likely to need a spring compressor to get the collars started.

I ordered a set of HyperCo springs, PN 188B0850 from Amazon.

New spring on the left; factory supplied spring is a QA1 7″ 850-lb spring (this has changed over time).

Adjusting the ride height on these coilovers is a real PITA, especially if you have the wrong-sized spanner wrench (which is what I’ve been using since I started working on the car).  I had a set of wrenches from my Audi’s suspension so I was making due with those – mistake; the incorrect sizing led me to marring my collars.  I figured at some point I was going to rebuild these shocks and I’d replace the collars at that time.  I’ve since gotten cheaper and lazier so when I discovered a new set of collars cost $30 per corner, I decided to skip this part of my to-do list.  However, I decided I’d finally spend a few bucks to get the correct spanner wrenches – PN T115W, also from Amazon.


The new wrench fits much more tightly against the collar than my last set of wrenches. I also like that these are stubby wrenches so you can put a socket wrench on the end of these.

The last bit of updating I wanted to do to the rear shocks while I had everything apart was to install a set of bearing thrust washers between the inner collar and spring seat.  Adjusting the collars when you’re nearing your final setting takes a good bit of torque on the spanner wrench – even if you’ve gobbed on a bunch of anti-seize, which is required if you want to maintain your warranty from QA1.  The addition of washer kit PN 7888109 makes this a low friction, low drama affair.  One set of thrust washers will service 2 corners.  These were also purchased from Amazon.

Damn, Amazon really is A-to-Z.

The thrust washer kit comes with enough parts to service 2 corners.  The flat washers appear to be identical to the washers included with the standard shock.  The middle thrust washer is comprised of a series of needle bearings to help reduce the effort required to turn the adjustment collars when setting ride height.
The stack assembled; I used a good amount of anti-seize between the various washer components to keep things moving freely once under load.
Here’s what the rear spring looks like on my car, YMMV.  At a rear ride height of 5″ the adjustment collars appear to be on the very last threads of the shock body.
A closer look reveals there’s a few threads left – not much, but a few.  I had initially set my car up with a 5.5″ rear ride height and this put the collars down to their lowest possible position on the shock body.
If you planned your build well – or just got plain lucky like I did – you’ve left enough room between your rear shocks and mufflers to be able to service the shocks without having to disassemble your exhaust system.  Backing the collars down and releasing the load on the springs gives you the ability to disconnect the shock at the aft end.
When installing the new 8″ spring, there is *just* enough room to squeeze the spring on without the need for a spring compressor tool.  You’ll need to back the collars down to their uppermost positions before you’re able to install the thrust washer stack, the spring, and the top mount.  Again, YMMV here.
This upper mount required some delicate shoving to get into place.
Here’s what the new setup looks like; I’m currently running a rear ride height that is higher than my normal 5″ as I’m going to give these a few miles of driving to settle before I get them set to my final ride height.

The before and after in a side-by-side; use the slider to see the difference.  It’s subtle but helps keep my OCD in check.  Worth the trouble and expense?  Yeah, I think so.

Move the slider left/right to see the difference!

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