Shock Dyno Thread - Page 2 - LotusTalk - The Lotus Cars Community
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post #21 of 36 (permalink) Old 01-16-2018, 10:46 PM
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Originally Posted by forkmeupscotty View Post
Ok, after dynoing my Nitrons and installing them, I dynoed my Bilstein Track Packs just for the heck of it since all I can gather were mostly anecdotes and no actual data.

I've had these 5 years, 25K miles of 60:40 street/track miles on them.



Few notes:
I've been told all along that it's rebound only adjustable, or on the rare occasions, that it's mostly rebound and some compression adjustable. Welp, I can safely say that it's COMPRESSION ADJUSTABLE.
I know this is an old thread, but it might be the best (only?) source of Elise shock dyno plots out there.

I'm a little confused by your note though. Isn't the top half of that plot rebound, not compression, thus making these mostly Rebound Adjustable?
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post #22 of 36 (permalink) Old 01-16-2018, 11:04 PM Thread Starter
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Most aftermarket damper dyno plots show compression in the upper half and rebound in the lower half. The shape of the curves you quoted agree with this convention.

2006 Lotus Elise
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post #23 of 36 (permalink) Old 01-17-2018, 05:26 AM
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I've never understood why shock dyno plots are given to such high velocity rates. Your shock rates, on track, are going to be not much higher than 1" per second unless you are hitting curbing. Dirt track cars will see rates up to 6" per second when the track is really rough. The other problem that does not show up in these type of plots is the fact that in the real world, the shock is not just seeing a single static velocity. You really need to be able to induce a higher frequency, low amplitude signal on top of your testing velocity. These type of plots will give you a general idea but I believe too much is assumed from these type of plots.

Later,
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post #24 of 36 (permalink) Old 01-17-2018, 09:10 AM Thread Starter
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Originally Posted by eldonz View Post
These type of plots will give you a general idea...
All these plots are meant to do is give you an idea of how the damper behaves. Obviously, inputs due to a road disturbance are not a smooth sine wave. Closed loop position servoing displacement is easily an order of magnitude (or two) greater than a simple dyno test rig... even then, most wouldn't know what to do with that level of fidelity in input disturbance data.

A full time history damping force plot would be difficult to decipher. It would look similar to plotting all of the raw data collected during a PVP damper test. All of the hysteresis would overlap and create data blob around 0 velocity.
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post #25 of 36 (permalink) Old 01-17-2018, 10:35 AM
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Most aftermarket damper dyno plots show compression in the upper half and rebound in the lower half. The shape of the curves you quoted agree with this convention.
You know, I swear those numbers were flipped earlier(ABS values). Thanks for getting me pointed back in the right direction.
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post #26 of 36 (permalink) Old 04-28-2018, 02:47 PM Thread Starter
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Updating this thread... because **** photobucket.

Elise LTS front


Elise LTS Rear


Elise LSS Front


Elise LSS Rear

2006 Lotus Elise
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post #27 of 36 (permalink) Old 04-28-2018, 02:49 PM Thread Starter
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Ohlins LOV "F" front dampers for Elige


Ohlins LOV "F" rear dampers for Elige


The funkiness that occurs at between full stiff and 6 clicks from full stiff in compression:

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post #28 of 36 (permalink) Old 04-28-2018, 02:53 PM Thread Starter
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forkmeupscotty's Nitron street 46mm 1-way dampers

Front


Rear

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post #29 of 36 (permalink) Old 04-28-2018, 03:18 PM Thread Starter
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EVORA DAMPER DYNO PLOT!!

Haven't seen these _anywhere_. I only have the rear tested so far. Front sometime in the future.

Nitrogen force was removed, 73 lbs. Given the shaft area, the gas pressure is ~300psi.

Evora base, rear

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post #30 of 36 (permalink) Old 06-19-2018, 09:12 PM Thread Starter
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Evora front damper plot:


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post #31 of 36 (permalink) Old 07-27-2018, 05:49 AM
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Jake, thanks again for making this thread. As a recent owner/driver of an S240 with the LSS shocks, my ass dyno is once again confirmed to be well calibrated. I swear I could draw plots after just riding in the car. I've never spent any appreciable amount of time on the LSS suspension and now that I have, all I can say is wow. The reason the car crashes over bumps isn't the jounce valving. It's the rebound valving. Once the wheel takes up a sharp bump, the car crashes back down on it's tire since the shock isn't letting the light, non-sprung part of the car follow road imperfections. Totally reminds me of the SSPS valved Koni Yellows. Those are terrible.

600lbs at 9 in/sec!
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post #32 of 36 (permalink) Old 07-27-2018, 08:34 AM Thread Starter
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Originally Posted by glagola1 View Post
The reason the car crashes over bumps isn't the jounce valving. It's the rebound valving. Once the wheel takes up a sharp bump, the car crashes back down on it's tire since the shock isn't letting the light, non-sprung part of the car follow road imperfections. Totally reminds me of the SSPS valved Koni Yellows. Those are terrible.

600lbs at 9 in/sec!
Right?! They're using so much rebound for platform control that they've made the ride considerably worse than just using reasonable damping and stiffer springs.

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post #33 of 36 (permalink) Old 11-17-2018, 03:33 PM
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Quote:
Originally Posted by forkmeupscotty View Post
Ok, after dynoing my Nitrons and installing them, I dynoed my Bilstein Track Packs just for the heck of it since all I can gather were mostly anecdotes and no actual data.

I've had these 5 years, 25K miles of 60:40 street/track miles on them.



Few notes:
I've been told all along that it's rebound only adjustable, or on the rare occasions, that it's mostly rebound and some compression adjustable. Welp, I can safely say that it's COMPRESSION ADJUSTABLE.
The two stiffest settings slightly affect the rebound side, and the two softest settings don't do too much.
Overall build quality and consistency throughout the range is pretty good.
The hysteresis has similar quality to the Bilstein LSS dampers.
Something that isn't apparent on the graph, but according to the guys who dynoed my dampers is that these had fairly high gas pressure, 200~250psi.

Maybe someone more qualified can share their observation.

I also dynoed the springs because I couldn't find a straight answer.
I couldn't measure it the way I wanted to(1 inch preload, measure load every 1/4 or 1/2 inch and divide by displacement to get lbs/in at displacement), but this is what I got.
Ideally, it would've been nice to utilize the damper dyno machine equipped with spring tester to get more precise measurement, but I didn't have access to such setup.

What I have so far is:
FRONT(1 inch preload): 195lbs/in at 2", 200lbs/in at 3", at 4" I'm at full bind and hitting 300lbs/in so it would be somewhere under there, but you'd be hitting the bump stop around then.
REAR(1 inch preload): 270lbs/in at 2", 300lbs/in at 3".
I don't trust the numbers too much, because the the quality of the measurement wasn't as consistent as I like on repeated tests.
However, the numbers is along the lines with the data floating around that the spring rates are either 271/371(unknown progression), or 180~214lbs/in front 266~371lbs/in if you squint your eyes hard enough.

Or maybe I should have used Eibach's own measurement procedure since they are Eibach springs:
Quote:
Determining Spring Rate
All Eibach motorsport springs are tested between 20% and 70% of the spring’s total travel.

Suspension Worksheet | eibach.com/america
It's suggested by the spring dyno operator that these might actually be dual-rate springs since the coil spacing is consistent in the narrow and wide section, achieving similar effect of having tender springs. Progressively wound springs tend to have varying spacing and widths throughout the range.



I want to find better info on the springs some day.

The ID of the spring is 1.88", the spring rates are available up to 400lbs/in 600lbs/in front and rear so replacing them is an option as well as revalving.

==============================

On the side note, I've recently been experiencing some handling issues, which gave me more reason to replace my dampers. The car would gyrate up and down during hard right handed corners.
Dynoing my Bilsteins made the issue apparent, the nitrogen has bypassed the divider piston. It has been corrected since.
It looks like the lower numbers have the highest compression damping. Do the numbers correspond with the numbers on the adjustment knob, or should I read the “1” and “2” as 1 or 2 clicks from full stiff (so 9 or 8 on the adjustment knob)? Trying to make sure I’m reading these plots correctly. Thanks.
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post #34 of 36 (permalink) Old 11-18-2018, 03:24 AM
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Originally Posted by mister2dood View Post
It looks like the lower numbers have the highest compression damping. Do the numbers correspond with the numbers on the adjustment knob, or should I read the 1 and 2 as 1 or 2 clicks from full stiff (so 9 or 8 on the adjustment knob)? Trying to make sure Im reading these plots correctly. Thanks.
Yes, you're correct. The each clicks are "From Full Stiff".

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post #35 of 36 (permalink) Old 03-10-2019, 10:54 AM
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Originally Posted by Lasttoy2 View Post
The main difference I've noticed is at track-out. With the LSS, with enough/correct amount of weight transfer at corner-entry, the balance and the grip feel great, and the front-end grip is absolutely solid at track-out under heavy acceleration. Lotus Sport Ohlins and Nitron DA understeer badly under hard acceleration at track-out as weight transfers to the rear and I lose the front contact patch.
I get understeer on power too (more so than with stock). I wonder if it has to do with front suspension droop?

'05 Lotus Elise: RS134 Monolites, Nitron Singles, Monoballs, V2 arms, RTD2 brace, Innovative motor mounts, V2 tank, GPan, Larini 8", TransCables, LumosHID, GiroDisc, Ferodo DS2500, etc.
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post #36 of 36 (permalink) Old 05-07-2019, 04:34 PM
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ohlins rebound adjsutment

can anyone comment on the Ohlins rebound adjuster. mine is absurdly hard to turn as it gets stiffer. they supposedly have 60 clicks. i get about 10 only before it seems to 'freewheel". i have found this on all 4 of my shocks and i cant believe they all have an identical "fault"
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