Ape Factory

iTrader: (3)

Lol, I may take you up on that. I know I can do the swap in about four hours easy assuming no major issues. Plus I'll need to get an alignment either that day or the next morning. I wasn't expecting the journalist until the week after but just got the email to pick her up on Saturday. I really want to see a force damper plot and regular damping curve plot on these.

slartibartfast

iTrader: (7)

I just initiated contact with FatCat Motorsports. Questions I have. First, can the Bilstein progressive springs be replaced with straight-rate springs?

Ape Factory

iTrader: (3)

Sure but the valving would need to be changed. Not sure if you can open up Bilsteins. They run super high internal pressure.

slartibartfast

iTrader: (7)

His business is opening and revalving Bilsteins. Not the crimp tops, though.

Nico-derm

It's too bad Bilstein doesn't just have coils spec'd for the sedan. I talked to a rep in NC and he didn't even have the knowledge/experience with the platform to point me in a direction or advise on necessary changes to adapt the coupe model

Nico-derm

I see that Powertrix (and others) sell Polypropylene Bushings for ~$20 a side... are these the replacements being shredded and is there a better quality solution if so. I'm sure RX8 owners don't replace bushings every 5k lol

Ape Factory

iTrader: (3)

From what I read, the entire bottom cup needs to be replaced as a unit. I haven't kept up with the latest developments but the info is all there on the RX8 board. I heard the replacements were also splitting. Powertrix said they solved the issue but it's a Stance coil over to his specs and colors.

slartibartfast

iTrader: (7)

Some light bathroom reading.
Shock Tech - Compression, Rebound, Twin vs Mono, etc.

Ignore the fact this was written for off-road bicyclists.
Digressive VS. Progressive Damping | DVO Suspension Tech Website

Not so light. This is directed at dirtbikers and descriptions of handling behaviors will seem odd but it is worth the slog.
Shim ReStackor example calculation retuning a shim stack to be three clicks softer

Every little bit of information helps.
TIP Engineering View topic - Damper tuning for Race Applications

Wish I could afford Penske.
http://www.resuspension.com/assets/R...emo%2012.1.pdf

Here's a monotube valve and shows the shim stack.
http://www.fortune-auto.com/technology.htm

Racers find all the problems and learn to compensate.
http://www.ozebiz.com.au/racetech/theory/shocktune.html

Very informative Far North Racing page out of the Autocross to Win series.
http://farnorthracing.com/autocross_secrets18.html

Regarding FatCat, in a brief email exchange, in response to my asking for linear springs instead of the progressives provided with Bilstein PSS, he mentioned machining a collar to allow non-metric springs. I'll ask about true-type in our upcoming "consultation".

Ape Factory

iTrader: (3)

I'm headed over to the shock dyno shop today around 1:30pm. If he has the right upper mount, he'll be able to dyno them today.

Ape Factory

iTrader: (3)

Bad news...he doesn't have anything remotely close to mount these to the dyno. He has machined cups that basically surround the eyelet/bolt hole like on the bottom of the non-X coupe. None of his are wide enough. He also has a yolk style but even his widest one doesn't works with the shock bottom. For the top, he'd also have to machine something that would interface with the top mount and allow you to adjust the shock while it's on the dyno. With the adjustment mechanism in the upper shaft, it has to be something custom.

He mostly tests shocks that have eyelets on both ends. He CAN make fittings for the shocks but it'll run about $275 and take him a day to machine them. Just not worth it. I think if I were really hitting the track hard and racing, I'd go for it. But just for informational piece of mind, I'll pass. Going to try to contact Aragosta directly and see if they can provide a shock dyno plot.

slartibartfast

iTrader: (7)

Man, I want to BREATHE! Don't know how much longer I can hold my breath. Been reading the Far North website while waiting for your graphs.

Ape Factory

iTrader: (3)

I tried. Had pretty high hopes as he was a great guy and willing to help. Hell he was curious as I was. Quick shot just to prove I was there, lol. I showed up and he had left on a bit of an emergency run. Shop was wide open so I carried the big box in until he came back.


What's really disappointing is I could have had these installed today. Now I'll have to wait til next Monday.

Nico-derm

I believe that both points are equally disappointing.... the later only became an issue after discovering the former. Here's to hoping Aragosta pulls through with the requested info!

Nico-derm

I spoke with Charles Park of PowerTrix and he had this to say about their bushing failure

"About 3 years ago we had a manufacturing error where the mixture of rubber was not correct (Mostly isolated to a Mazda RX8 production run). Unfortunately it was blown out of proportion by one biased individual on RX8club.com. It was rectified as soon as it was discovered and owners were sent replacements.
We never had any issue before this isolated incident and it has never resurfaced once we found and corrected the mixture error back to the original formula."

Make of that what you will... you said their replacements were failing as well but that may have been before the issue was found still from the bad production run? I will continue my reading

Ape Factory

iTrader: (3)

I was referring to the Stance repeatedly failing. Powertrix is essentially a stance product. If he's having different bushings made outside of Stance, great. I can't say one way or the other whether it's true.