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Old 06-11-2012, 11:25 PM   #21
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I think it is time to get some linear pots. We are spending lots of time in qualitative arguments and not enough on quantitative ones. I am saving money for pots...
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Old 06-11-2012, 11:40 PM   #22
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Originally Posted by EO2K View Post
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I had lunch with Shaikh @ MRLS back in April and had a great conversation regarding my suspension. I "erred of the side of caution" and went with 400/300 (maybe 275? derp) for dual use but I now see that I could go A LOT higher and still be comfortable on the street. We discussed this and he was willing to do a revalve for me on my current shocks, but that may be because I'm a current customer. He's a nice guy, but super busy. It can't hurt to ask.

What are you using for a seat? My Sparco makes the car feel a lot different than the foamectomied seat I was using before
My 700/325 with SDs were quite comfortable on most roads. Yes, it is how a damper manages the energy from a spring that translates into a "good" ride. Now I am on 450/275 and the ride is not that different (I have asked Bernie for something else so there is a bit of a difference but not in a bad way, but a good way) but I have different goals for the car this year. Next year if funds allow I will try yet another set-up providing I switch tires.
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Old 06-12-2012, 01:25 AM   #23
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Originally Posted by danny2747 View Post
I think it is time to get some linear pots. We are spending lots of time in qualitative arguments and not enough on quantitative ones. I am saving money for pots...
FCM has 'em, and I've seen the data.
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Old 06-12-2012, 03:18 AM   #24
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Jason, "a bit underdamped" in the front, does that mean ok? At this point I will take "OK" over "screwed".
Less than optimal. If you need the front to be softer to not be underdamped, you may need to make the rear softer to balance the car.
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Old 06-12-2012, 08:34 AM   #25
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I will take less than optimal over screwed at this point. It is very true what mgeoffriau is saying about the bad taste of the SD experience. It has taken me a year to get over most of it and still get pissed at times. I do not have money for anything right now and spent enough to buy some XIDA's. I am at the point that I can deal with it and long as I can have confidence that Bernie did not deliver me a crap tune, just to get the shocks out of his shop. I am not a full time racer with a degree in shock tuning and was hoping to rely on his expertise to magically provide me with the set of shocks that would be comfortable on the street and do awesome things on my track days. Communication was lacking and caused all the BS. I was at fault for running springs that ended up binding and that appeared to cause a large amount of issues.

Sunday I removed all 4 shocks to check everything. I found all 4 lower shock bushings had taken a beating again. I knew I had messed the original shock bushings up and had to get them replaced by Bernie. At the time he blamed everything on running the car at too low ride heights, but even after raising the ride height to at or above OEM I still had the same issues. I finally figuired out the 7" 250lb/in rear springs were binding back in December. I went to a 9" 300 lb/in spring in the rear which made a huge improvement. The fronts looked fine, but after pulling them off the car I noted fine lines on the top and bottom of each coil that I did not see when I found the rear ones binding. The fronts are 7" 400lb/in QA1 springs, which I thought is the lenght everyone uses in the front. They must have been binding all this time too. So who knows how that messed everything up.

Luckily I had bought a set of shock bushings and had another 550lb/in 7" spring to try in the front. My brother helped me swap out the bushings and springs.

After my 70 mile round trip to work yesterday I got the car up on the ramps and scales to check alignments and cornerweights. I was impressed that my eyeball height adjustment got the corner weights to 50.2%, I spent more time chasing my tail to get to 50.0% than what was needed and should have left it there to begin with. I checked all the springs for coil bind where I had placed some paint marker on the top surfaces of a few coils. Everything looked clean with no indication of binding. The FR wheel did hit a pretty good pothole that was hidden in a puddle of water so I pulled the wheel to check the bushing and it seemed ok too. At this point I am very confident that I have addressed the coil bind issues.

The blown bushings must throw everything off due to the resulting suspension travel that would not be controlled by the shock or spring. I understand now why Bernie made such a big deal about the bushings causing all the issues (well most). I am still feeling more vertical accelerations than I was hoping for, but I believe it is acceptable. Having three slipped disks and a fractured vertebrae, just doesn’t help at all. To get another data point I drove my dad’s 99 to work today. He has Koni sports at pretty much full stiff on factory springs with RB tubular front swaybar and RB solid rear bar. His setup has always been very comfortable (acceptable) on the street and is still fun to drive. I took it out on track two weeks ago during some fun runs during lunch and my only complaint was that it had a little too much body roll for my likeing. Still had lots of grip though. Ok, back on topic. I drove it to work this morning along my usual route. Even this setup is transmitting very similar vertical accelerations that are driving me nuts, not quite at the same amplitudes though. I know this setup is not perfectly tuned or the best out there at all, but it is at least calming my concerns that something is way off with my SD valving. If the much lower OEM spring rates on this setup doesn’t make that big a difference I might just stay at the 550/300 for a while and not worry about dropping to 300/200 rates, at least not right now. I will just save the money for chiropractor visits. I love driving my old crap car to work, sure my Jetta rides like a chariot in comparison, but it is not 10% as much fun. That’s why I got so upset about the whole SD experience, because it made me love my car less and even not want to drive it at times. That’s just dumb!

I was thinking about coming up with some way of measuring suspension travel, velocities and accelerations. It would be so much easier to just look at data instead of “feel”. Like I have mentioned before, these SD shocks handle awesome and are not harsh by any means. Even the vertical accelerations I am talking about are still smooth and controlled, it’s just more than I had expected. I need to find some cheap acceleration sensors or really cheap lvdt’s and make my own application either with my Motorola development board or even a PIC just to capture the raw data. That would be another great project I do not have time for.

“When you are in your teen years, you have time and energy but no money, as an adult you have money and energy, but no time and as a elderly you have time and money, but no energy”!!!

Last edited by Braineack; 06-12-2012 at 09:41 AM.
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Old 06-12-2012, 10:11 AM   #26
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I was running 550/300 and upped the rear rates to 350. That seems to have improved ride quality for me-it has to do with bounce frequencies. I'm using 7 inch springs front and rear.

Last edited by wannafbody; 06-12-2012 at 11:42 AM.
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Old 06-12-2012, 01:03 PM   #27
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Quote:
Originally Posted by relte View Post
I need to find some cheap acceleration sensors or really cheap lvdt’s and make my own application either with my Motorola development board or even a PIC just to capture the raw data. That would be another great project I do not have time for.
BTDT.

I use this 4 channel datalogger:
http://www.dataq.com/products/startkit/di145.html

and this 3 axis accelerometer:
http://www.sparkfun.com/products/9269

I don't have linear pots, but you can get a ride height sensor out of an E39 BMW.

No construction needed. I used the data I gathered to create various road models that I use in my simple suspension simulation.

Last edited by JasonC SBB; 06-12-2012 at 01:14 PM.
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Old 06-12-2012, 01:11 PM   #28
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Your rear shock dyno isn't much different than the NA miata R package:

http://www.cardomain.com/ride/742393...e-5#7423930048

100 mm/sec is 4 ips
1250 N is 280 lbf.

Vanishingly small bump damping.

Your complaints are the same as folks with said NA R package.

Big rebound, vanishingly small bump damping. This formula is used for cars with tall ride heights and soft springs, to get them to dynamically lower during slalom type maneuvers. It is also used in racing series' with a required static "ride height" ("must clear this piece of wood"), but with downforce. The soft springs, weak bump, strong rebound, and downforce, lower the car at speed. Such as NASCAR. Perhaps this is where Bernie's "this works great in racing" experience comes from. Horses for courses.
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Old 06-12-2012, 08:08 PM   #29
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So, when I call a shock builder and say something like I want the car to handle well on aggressive driving on the streets and maybe a few autocross or track days, what should the final result look like? I am thinking that we need to do some pentagram type plots like the Tire Rack: can we do this in any reasonable fashion? Cost/logistics wise? I have a DL1 logger but linear pots would run me about 300 a piece. I can try to set up the DL1 vertically at various points in the car. Any other ideas? I am not ready to start another thread, but I would like us somehow to get FCM, SD, Emilio, whomever to develop some killer combos a la carte so the Miatae can always be the best handling cars out there.

If thread drift, let me know and I'll start a new thread.
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Old 06-12-2012, 09:01 PM   #30
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If someone wants to send me some FCM or Xidas I'll do some street comparisons.
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Old 06-12-2012, 09:11 PM   #31
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danny2747,

FCM's formulae for determining the target shock dyno curves based on desired characteristics, usage, car weight, and spring rates, are the result of years of testing and customer feedback. And if you ask different shock vendors, you will get different answers. Some may work better for some customers, others, not so well. As you can see, the formula that SD has used, has produced some serious negative feedback for street miata applications.

Because I had worked closely with FCM, I may be a bit biased; and, I can't divulge his trade secrets. I can only give general opinions, and technical reasoning.

One thing I can say - when someone says "Brand X/S/F/A/K/T is the best", and they haven't driven or owned a competing brand, take it with a grain of salt. Also, when you look at comparos of different valving/coilovers wrt ride qual and grip on bumps, remember there are many confounding variables: ride height, bumpstops, chassis stiffening, tires, and most especially, the butt-o-meter. There are probably even more variables if you look at track times or subjective handling.

I've seen guys gush "it's firm but not harsh", and then when I rode/drove it, it was utter crap.
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Old 06-12-2012, 10:24 PM   #32
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One thing I will say was my biggest mistake is that I read all the reviews for custom re-valves, that pretty much just covered FCM and SD. What I took away from all the write-ups at the time was tha they both provided a shock that was tune for optimal performance for a set of parameters. If you can give the two of them the same parameters and end up with two different resulst, I would be pretty sure that at least one of them is not truely "optimal". Based on the assumption that they produced the same (or at least similar results) my cheap *** decided to save a hundred or two by going SD. Looking back now I can say that all the reviews that emphasize the great street manners that can be had with tons of grip are all by FCM users. Oh well, my mistake.

I would love to find a way to collect data and quantify the accellerations and find data that would allow us to compare the different re-valves on paper. Just like Jason mentioned even the slightest change in combination of spring, bumpstop, ride height and other parameters can generate a completely different experience that can be perceived very differently.

Ultimately though, it would be impossible to compare apples to apples unless you use the same car on the same track or stretch of road. This would be similar to the issues Emelio pointed out in a recent shock hirarchy thread. Sure would be nice if you could point to a spot on the performance vs. comfort curve and say Mr. shock builder here is my car specs, please tune the shocks to perform this way. From my experience and what I am hearing from others it seems like FCM has improved and tailored his product for the Miata customer base where Bernie has decided that he knows what he is doing because he is king and that is what we will get. I know I am not the shock master, but when I ask intelligent questions to try and understand and get treated like a DA, that really gives me confidence that someone knows what they are doing. Damn, there I go again, this crap sure has made me a bitter bastard!

Thread jack all you want. I am looking for sollutions, how we get there is less important. Oh, and if Shaikh would find it in his great old heart to send me a set to compare to the SD's, I would gladly do so with the most honest review possible!
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Old 06-12-2012, 10:56 PM   #33
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Maybe we wouldn't all be armchair quarterbacking if Shaikh posted some dyno charts of his revalves but he refuses to given them even to his customers. One guy on this forum has both FCM and SD shocks and likes each but each are for slightly different combinations.
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Old 06-13-2012, 02:25 AM   #34
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Shaikh now considers his dyno plots a trade secret, and it's his choice whether to show them or not, just as it's your choice whether to buy his shocks or not.

However, I can say, and I've been saying this from the start, that SD's very weak bump damping, is just not a good thing.
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Old 06-13-2012, 10:22 AM   #35
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BUT F=PROD. SPEC MIATA!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! OMFGMFGL<MFLKfdakjfsaj
kfd
lca
cla,cdsacdsac
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Old 06-15-2012, 10:33 AM   #36
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???
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Old 06-15-2012, 11:04 AM   #37
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Just trying to remember anythign good that's come form spec miata and trickled down to us joe schmoes....seems like it's always the other way around.

Everytime I talk to a spec miata guy, I cringe with the lack of innovation and understanding.
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Old 06-15-2012, 03:53 PM   #38
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I had a spec miata guy tell me to just get the spec suspension kit and it would handle great. I can't imagine how bad the ride quality would be with 700/500 rates and the off the shelv valving.
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Old 06-15-2012, 04:14 PM   #39
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You are correct. On the street, its a ------- nightmare.
When I was a noob I took my car to a local shop for a clutch job. The owner said he had a Spec Miata so I figured he knew what he was doing. He offered me a ride around the block (to show off his impressive 90HP no interior pogo stick) so I took it. Ungh... that's how I figured out what I didn't want. Spec cars may handle well but they are just plain uncomfortable on the street IMO.
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Old 06-25-2012, 09:53 PM   #40
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Not providing dyno plots? That seems kokey to me. I can get dyno plots from AST. Or Motons or Penskes.
I may have to buy a set of used FCMs and have them dynoed.
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