Project '99 Miata Sport

[Mike]

yep, a manly looking miata. i dig.

[Steve85]

Daaamn...

[.RJ]

[Evan]

dammit those wheels give me a boner

[Nis01]

I'm potentially going to change around some suspension pieces and I want somebody to learn me on ability to control Rebound / Compression on a SINGLE adjustable shock. In talking to the owner of a company who does custom design / revalving of shocks and I got some good information from him but I'm still a bit hazy. I know some shocks such as my twin-tube design TEIN Flex have a constant compression and the 'knob' adjusts rebound only. Now, on a certain monotube setup I see that Compression / Rebound are both adjusted together with the 'knob', is this true in all cases or am I missing something? What are the advantages / disadvantages? The owner told me that rebound is adjusted considerably more than compression with each adjustment which allows the valving to remain proportional (I could see where that would be beneficial if I understood this correctly). I'm not concerned with the twin-tube vs. mono-tube debate, I have a pretty good understanding of the differences.

I would like to stay Single adjustable mono-tube based on price, ease of adjustment and minimal TT points but may want to upgrade to a DA in the future and would like a better understanding. The main reason I want to upgrade is to run a stiffer spring rate without totally ruining DD capabilities. I believe a custom revalved Bilstein could help me reach this goal based on the reviews and research I've done and they are very cost effective. As a note, the fastest miata time at my last autocross was set by this setup with RA-1s on a very slick course. I was only 0.70 of a second behind him on a wider street tire but I believe his suspension to be the major difference in performance, his car consistently runs top times against some fairly tough competition.

In my observations the TEIN Flex are a pretty solid and consistent coilover setup, but I have found some shortcomings that I knew would be inevitable with a mid-level off the shelf shock. They are said to have very high rebound from the company and this is quite noticeable on the street with any large inconsistencies in the pavement. I notice small bumps are no problem but any significant drop / dip causes a large reaction from the shock. Also, anything that requires quick reaction like rapid ripples in the pavement or roads with lots of uneven portions make for a pretty unsettled ride. I'd assume its the 'lag' or hysteria involved with the twin-tube design that would account for this reaction. At the same time I also have to give them their praises as I have consistently been able to drive the crap out of them on an autocross course and even on street tires the car is neutral and pretty damn fast considering my minimal seat time in the car.

I know there is a lot of experience on this forum with Koni setups, and I would consider some of the newer monotube alternatives but they may or may not be cost prohibitive. I know there are better and more expensive setups out there (Ohlin, Moton, JRZ, etc... ) but I'd like to continue to keep this a low cost, best bang for the buck project. All information is welcome and please correct me if anything above is inaccurate. Thanks in advance, forgive my novel of a question.

[.RJ]

IMO, you want separate compression and rebound adjustments - this is critical. The problem with cheaper shocks is the adjustment mechanism, they use a needle valve and it can be hard to get precise control of your adjustments and if you are paring up both bump and rebound on the same adjuster you can really run into trouble.

Also, having compression adjustment is not necessary most of the time - most of the time it creates more problems than it solves and often once its set, there isnt a whole lot to change - compression controls the sprung weight of the car and it would take a pretty drastic change to need different compression adjustments. I do know that some racers will soften up compression for wet tracks.

I've never used the Tein stuff and dont know much about them - they may be ok - I dont know - but I've always been partial to the Koni stuff. They sell a 'race' valved version aimed at track/autox use that may be worth looking into. Dont get hung up on monotube either - its a good design but a twin tube shock can perform just as well.

[Mike]

I would also go Koni if I were buying again.

[D_Eclipse9916]

Read this especially, but I would definitely recommend reading the entire article. Has some very good information as he actually dynoed shocks and competed on a national level. I also have been talking with some very successful time trialers and mono-tube vs twin tube is nothing compared to getting a shock that is properly matched to a setup.

<!-- m --><a class="postlink" href="http://farnorthracing.com/autocross_secrets6.html">http://farnorthracing.com/autocross_secrets6.html</a><!-- m -->

[.RJ]

Pretty good article - what he says about the Konis being non-linear - they built a lot of 'low speed' damping force to control the chassis without building a lot of 'high speed' force at the same time so the car doesnt get upset over bumps when you increase the damping.

Penske is indeed bling - I've had 3 on my motorbikes but I dont think they make much in the way of off the shelf stuff for cars.

I wish I knew how the shock on my mountain bike worked :lol:

[D_Eclipse9916]

Rj, check out the other pages, such as setting up suspension, or the page for setting up natural frequency and spring rates...That calculator is fucking redonculous!!!! My next autocross/road race car is gonna be a LOT of time researching and measuring suspension., ive had my power fix, now im ready to blow away people in the corners too, then I just have to learn to drive without sucking.

[D_Eclipse9916]

Good read to help you figure out what is going on within a shock...<!-- m --><a class="postlink" href="http://www.penskeshocks.co.uk/downloads/AdjustableTechManual.pdf">http://www.penskeshocks.co.uk/downloads ... Manual.pdf</a><!-- m -->

[.RJ]

Rj, check out the other pages, such as setting up suspension, or the page for setting up natural frequency and spring rates...

Never tried that - wonder if its sound theory? I just go with what other people use :lol: Lots of different ways to set up a car or bike though...

[Nis01]

I've read that article before. Good read for sure. I have used spreadsheets to calculate FRC for this car and I have what should be a pretty neutral setting. Reading that article again reminds me why I like the plug and play Bilstein setup. There is also an AST setup that is being designed which has had amazing results on different platforms, not really sure if I want to wait or pay the extra money for a more bling setup. Keep the information coming guys.

[.RJ]

There is also an AST setup that is being designed which has had amazing results on different platforms

Results in competition?

I've never heard of them...

[Nis01]

Vorshlag is the US development and supplier for the ASTs. Their new shocks are the 5100s which are a single adjustable, aluminum, monotube setup that are fully upgradeable to double and triple adjustable with remote resevoirs. They are not cheap but they have been quite competitive in autocross and roadcourse time trials.

Link: http://www.vorshlag.com/forums/forumdisplay.php?f=36

Performance wise I think they are right on par or superior to the custom revalved Bilsteins but I have a feeling they aren't quite as street capable or durable (not to mention a good bit more expensive). I do love the lightweight aluminum monotube design and use of 2.25" hyperco springs (bigger tire clearances). Definitely some top notch equipment but I really don't know that I need the extra bling. Interestingly enough AST designed a custom shock just for a E-Stock miata customer which was beat by a revalved Bilstein at nationals. Either system allows me upgrade to remote resevoir and dual adjustment but I really don't need / want either of those options at this time.

Another plus for me is that the revalved Bilstein is available NOW, whereas the ASTs are still finishing up development for the miata chassis with a west coast supplier / tester and I really don't have a definite time frame for when they will be in production. They just might be worth the wait though....

[Goodspeed]

Koni adjustables. They'll save you two pounds, and give you better traction for the holeshot.

[Nis01]

Perfect quote especially since I'm watching it on tv right now. :lol:

[.RJ]

AST designed a custom shock just for a E-Stock miata customer which was beat by a revalved Bilstein at nationals.

A shock like that is only as good as who tuned it, and more importantly, who is driving it and the kind of feedback they are giving. Take competition results for what their worth - the fastest guys are going to be better at setting up cars and getting the most out of them, even a 'stock' class car can have a lot of options. A triple adjustable remote reservoir shock can have you going in circles where as a single adjustable with the 'correct' damping will be easier to tune and ultimately faster for most of us. I always used singles on my Integras, all 4? of them and never felt like I needed more knobs. I rarely touched them unless it rained, but then again setting up a dancing elephant is to lock out the rear suspension :lol:

[xvxax]

You should be at MIT or something.

[Nis01]

Yea, I figured this much as far as comparison of suspensions when there are so many extra variables... figured it was just an interesting note to throw out there (simpler can be better). Your reasons are exactly why I want to stick with single adjustment for the time being, my only real reason for any adjustment is the ability to keep the ride somewhat comfortable for street driving and like you said slight situational changes. Anymore input? Additional reading?