I'm trying to install OEM springs on some Function & Form Type 2 coilovers. I have 2 question:

1. Which top hats should I use (OEM or the ones that came with the coilovers)? Do the OEM springs require the "cup" type top hat to not spread out at the ends?

2. The inner diameter of the OEM lower spring perches is too large (see photo with perch sitting on top of coilover). Are there any cheap adapters? Stock perches are about 2.075" and coilovers are 1.687".

Thanks!

 

That seems like a tremendously bad & pointless idea.

Why?

 

To run B Street class in autocross, the car must have stock springs. I'd need to spend thousands to be competitive in STR class, which is where these coilovers currently put me. I bought the car with these coilovers and I like the adjustable damping so I don't want to go back to stock shocks.

 

There aren't really any good/safe ways to do that at a reasonable cost.

This is a very bad idea for so many reasons.

The stock shocks are better than the F&F's. I don't think you will be faster with the F&F dampers.

Maybe use Koni adjustables with the stock springs if you absolutely want adjustable damping?

 

It looks like the stock top hats would work. The lower spring perches on the F&F have cylindrical ledge that keeps the springs centered. I can machine down those ledges to match the diameter of the stock spring perches.

I'm not trying to be difficult, but I'm the type of person who really likes to know why and how... so how would this be bad or unsafe? The springs would be kept in the stock perches, which would be centered via the shaft. I'm guessing that the spring rate would be low for the dampers, but I was hoping they could be adjusted down while still giving me the ability to tighten up the front a little to suit my driving style. I'm not 100% dead set on doing this, I'm just want to exhaust all options before spending money on Konis or replacement stock shocks and perhaps discover something that nobody has tried before.

I'll move up to a class that allows coilovers if I can find some really cheap 9" wide wheels. Anyone got any old beat up wheels?

 

You're not going to discover some magic no one has previously thought of with this.

You can get new 17x9 Tire rack jawns for like $180/wheel.

 

What are the spring rates on the F&F's? How much shock travel is there?

Im assuming the stock springs are MUCH softer.

You'll need to tune the travel of the shock so that you wont be on the bumpstop excessively.

The stock bumpstops are soft/progressive.

The stock shocks also have air springs.

There are quite a few incompatibilities. If you address them, I still doubt the F&F damper works as well as the stock ones.

The physical incompatibilities are also various. Once the spring is mounted, and you try to adjust it...will it jump out of its pigtail "housing" on the stock perch?

Compressing the spring will make it want to rotate. Will it jump out of the lower housing during that cycle? Will the lower housing just rotate? Will it make noise against the shock body? How long will the shock piston seals last if the spring is moving around like that?

Not saying its impossible. Give it a go. But there are lots of reasons why virtually every adjustable coilover comes with FLAT bottom springs.


And...9" wide wheels are what's stopping you??! And that's why youre considering this? Just seems easier to buy 9" wheels....no?

 

Per SCCA street rulebook:

Adjustable spring perches are allowed, but the spring loadbearing surface must be in the same location relative to the hub as on the standard part. Shims may be used to achieve compliance.

The fully extended length must be within ±1” (±25.4 mm) of the dimension of the standard part.

I don't think either as possible with this damper.

 

Dang. Lawyered up.