The truth about Spec E30 Camber plates.

As we all now know, due to limited shock travel and the soft spring rates of the H&R race springs, spec e30s were often on the bump stops. Now that we have stouter springs the problem is less severe but still not prevented. If you raise the car above the old ride height, shock travel improves but is still limited due to the bump stops. We installed a set of the new coil-overs on the #12, the middle car in the photo above and did the old zip tie trick. The zip ties kept sliding off the tops of the shocks under hard braking. We kept raising the car until they didn't slide off and found that the car had a 4x4 ride height, just like the car on the right.

We didn't like that, so we reached out to GC to see what camber plate options there are for us. They were nice enough to compare the plate thickness of the three different e30 camber plates they sell. The first set is the spec e30 plate designed for stock springs, and the other two plates are designed for coil-overs. (We will ignore the middle plate since it won't provide as much shock travel as the thinner version on the right.)

The GC coil-over plates are designed with a "cupped washer" allowing the actual camber plate slider to rest on the spring hat. The original Spec E30 plates use a zinc plated teepee style insert that sits on the spring hat. This difference between the two is where we gain the most clearance for more shock travel.

The "original "spec e30" camber plate thickness is 52.14mm measured from the bottom of the spring hat to the top of the top plate.

 The slimmest coil-over camber plate measures 37.59 mm measured from the bottom of the spring hat to the top of the top plate. 

That's 14.55 mm of ride height that adjustment that we can gain by using the new camber plates. These measurements were taken with the spring hat in place. Now let's take a look at the "sliders" only without the different top plates or the spring hats. 

The new coil-over slider is on the left side, and the original spec e30 slider is on the right side. Notice the difference in the shoulder height between the two.

The next photo shows both sliders are sitting flat on the same surface that the shock shaft rests on. The difference between the two tops of the sliders is distinct.

The next photo shows them with the steel top plates.

Notice that they are both sitting flat on the surface that the shock shaft will be sitting on, so the distance to the top of the top plate is exactly how much shock travel would be gained when converting from the original design to the new design. How much travel are we gaining with the new design? Take a look below.

 

 

We are gaining 17.44mm (.687 inches). This is even more than we originally thought! 

We installed them before heading to Sebring. We didn't change the coil-over ride height, and the car sat so low after installation that we raised the ride height by one turn on the adjuster for fear of damaging the oil pan. At the track, the #12 was the lowest Spec e30 of the 15 car field.

I had never driven on the new coil-overs before this weekend, and I have to say I absolutely love them. The car feels much more precise at the limit. The weight transition is smooth and predictable. The tires feel like they're working even harder than before. My car still feels very neutral at the limit, and when the back end steps out, you can bring it back easily and controllably (probably due to less weight transition). In turn, 17 at Sebring where I used to feel the front left shock bottoming out with the old suspension, now there's no more bottoming out, although the car tends to hop/bounce a lot more through 17.
Overall, I'm really happy with the new setup and wanted to share our findings with you all.

Three different options for this new camber plate are available here: 

https://www.condorspeedshop.com/collections/e30-parts/products/gc-camber-caster-plate-spec-e30-new-suspension?variant=7671012982830

Option 1. Aluminum Top Plates  - All aluminum camber plates
Option 2. Steel Top Plates - Same camber plates with steel top plates.
Option 3. Conversion Parts - Use your old plates to convert to the new design.


Comments

phastafrican

phastafrican said:

Brilliant post and insightful analysis. Thanks for the effort to gather this much detail. The community will be greatly appreciative of this shared knowledge.

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