voted yes. any idea of a price yet? or even a ball park?

I think we were discussing a $300 price range. Don't quote me yet though that may change. I do know that we were looking at a higher price range than then the average Street Spring only because of the limited application range.

thanks, no i won't its just nice to know a ballpark.
how much is the drop going to be on the street springs compared to the track?

bump?

i know most of you are autocrossing but i track. I am ready to buy and voted. This may be my low ball answer to my current problems. i have the yellows koni and the tein h spring.---not enough spring for me now. I do like my drop.
Will be a hell of a lot cheaper than coilovers.
olddrager

The almost exact target I wanted to do, Koni Yellows and these springs to avoid having to go to a worthy track coil-over...


I will call progress this week and discuss where he is at and keep you guys posted.

Thanks Fluid! :)

Thanks again Fluid.


They say patience is a virtue... I guess I need to be more virtuous :lol:

Bump for an update! :D:

Hey man any news? BUMP!

Awaiting a phone call from Progress today about delivery of a prototype.

I am looking for one test subject, unfortunately since I have been burned in the past so much I will be charging close to retail on the set.

One Person that has aftermarket Koni/Tokico D-Spec's and is interested in the spring rates/drop discussed.

$300 shipped within the states.

This is not to say that $300 is the MSRP or what the price they are going to be sold at but is a good indication of price range.

All feedback provided from test subject will be directly forwarded onto Progress.

Any revisions or changes made therein test subject will receive a new set if desired for exchange of original set.

If price of the Springs change test subject will be reimbursed accordingly.

Buying this one Prototype Spring is not cheap at all, but I am pushing it through to see it available for you guys.

I have some people in mind please PM me for those that are interested in participating.

Once I have a finalized timeline I will discuss further.

Thanks for the update Fluid. Hopefully someone can step up to be a tester asap. I would if I wasn't running B-stock this season. Once the production springs are ready though I will buy a set!

Depending on how the RX-8 prototype springs work out, do update this thread with any info on possible MX-5 fitment.

private track day. july 25th.

:)

beers :beer:

So are you the prototype "hamster" Swoope? If so, please post pics!

dont know yet.

beers :beer:

I will offer to be the reviewer and tester of the springs I think. I have been debating the whole coilover thing for some time, but know once I am happy with the height and corner weights, I will leave it there and fine tune other things anyway.

I would like to understand the final choices on drop and rate. But I think this is something I will do.

Thanks. Contact me if you are interested.

Wouldn't the Koni yellows have to be revalved to properly handle those spring rates?

no
olddrager

I checked with Koni USA directly and these Progress Spring rates (~450/300) are within the range of the ots konis.

Still waiting for a call from Progress... *sighs*

Brice,
Count me out on these springs. Just picked up a set of HKS Hipermax RS coilovers. Sorry, deal was to good to pass up.

so what is the final spring rate & drop, I got Koni shocks, how many turns on the rear you think it need. When are you going to get the prototype, I try it out for you if no one want to.

Spring Rates and Drop
 

If final numbers have not been determined....I vote for this.

Drop: .8-1.1" drop. Would prefer no lower for geometry reasons.

Rates:
Front: 420
Rear: 280

Anything in this range works for me.

These were some earlier posts from Fluid on this subject:

On spring rates...
On lowering/drop...

If Progress is offering such a stiff racing spring, wouldn't the initial part of the spring have to be extremely progressive? I ask because our stock dampers and the Koni yellows have a set extended length and distance between the top and bottom perch. If the rate is so high, you either need to make a shorter spring or make the initial part progressive to get the car to sit at an acceptable ride height. You can't really make the spring that much shorter though, since doing so will mean that if the damper is fully extended, the spring will unseat. Therefore, the only way I can see of making such a stiff spring while still having a good ride height is to make it very progressive.