filberto

can you give me more details on your getto shock dyno?
where do u get a pentionometer or how ever you say that.
why the colors on the graph, is that a 1,(blue) 2(pink), 3(red) cycle runs?
what software.
thanks man,
Filberto

DavidNJ

I am curious how it is powered. Some low cost units are pneumatically powered. More expensive units have electric motors. What is the linkage moving the arm?

And while a load sensor measures the forces, how is the shock length calculated?

FPV_GTp

Hi , have a look here SportDevices. SHOCK ABSORBER ANALYZER. , Shock Absorber dyno plans.


Shim ReStackor, Finally software to tune a shim stack

cheers

Sofa_King

This would have been awesome when I raced motocross, There was So much track time testing with compression, Rebound, and pre load settings and different spring sets ( Triple rate springs up front, Dual in rear). I can see this set up being worth its weight in gold!!! Good job, Keep it up

DavidNJ

The Sport Devices looks like an interesting design but requires lots of complex machining. It is unclear if some of the pieces can be purchased, but none of the documentation covers it.

They spec a 3kW motor, about 4hp. That's a lot. they talk about spring testing...that's a lot of force.

It seems they are comparing themselves to the top dollar shock dynos.

There are a few that are around $7k-$10k new. For example Intercomp (Intercomp - Shock Dynamometers - Intercomp Racing) and Maxwell (Maxwell Industries). Performance Trends, the home of lots of nifty stuff, has a 1.5hp for $4000, but the temperature sensor and software upgrade add $800 (Performance Trends). The Maxwell has a Scotch yoke, I'm not sure about the others

Performance Trends also has a retrofit kit including 1000# load sensor and position sensor for $1500. That is comparable to the Sport Devices, but more flexible on how it can be used; Sport Devices only works with their complete design.

There are a couple of brands that make pneumatically powered shock dynos for around $2000. There are also a couple that don't have output electronics, instead drawing on a piece of paper, 1970s style.

There is a used Roehrig 3VS on Racing Junk for $5k, a 2VS for $2.2K.

On many of the units portability counts. When a team is tuned into their shocks, they may make changes at the track or want to analyze their shocks to determine if there is a problem. Many of the systems are designed to work in a race trailer. I find the autocross and track day crowd often seem to attack shock issues with springs and anti-roll bars. If it is stiff enough, the shock has a smaller role. With a solid suspension they have no role.

I had seen the Shim Restackor but it would just be a preamble to using a shock dyno...a way to get in the ballpark. However, they have a pretty limited set of pistons and as bar as I can tell no allowance for shaft bleeds, base valves, or reservoirs (which a just another type of base valve). With the base valve or reservoir the shaft diameter becomes relevant; the only fluid passing the base valve or into the reservoir was displaced by the shaft.

The author here had a very non-standard design. It may be an inexpensive design. He had to work out the power source issue but doesn't discuss it. He used Matlab (a $2000 package to start) and LabView (prices start at $1000). but it appears the Performance Trends kit would eliminate the needs for those plus it would include other bits and pieces.

If shock dynos were $500 or $1000 a lot of people would have them. Good coil overs start at $1000. Many of the coil overs run $3000-$4500. Penske 7500s and 8300s, if they are available for your car, are $3300 to $4300, without springs or top hats. At those prices plus rebuilt, revalve, and test prices (plus shipping) a shock dyno could make sense at $2000 or $3000. However, they run over $4000 unless you can make most of it yourself.

FPV_GTp

Hi David , There are many ways to skin a cat but the approach one adopts is purely up to one's individual skills and machinery available at your finger tips.

All depends on how much one can budget for $$$$$ ???? such equipment to be sitting in the shed collecting dust and used once n a blue moon.

I'm sure there are many other commercially available systems around. All depends how much work one is prepared to put in????

Performance Trends shock dyno software and hardware is another good option Performance Trends

PN Description Retail
Price

SDyn-RK Shock Dyno Retro-Fit Kit, includes software, electronics, $1499.00
1000 lb load cell, and 3" length (stroke) sensor.

SDyn-B Base complete Shock Dyno with 1.5 HP 110 VAC motor, $3999.00
2000 lb load cell, 1"/2"/3" strokes, 7/14/21 inch/sec
testing velocities.


Cheers

GravelCivic

Hi
I´m looking into building a similar device. If I understand well, you get pairs of data (F,v) by manually pushing the lever up, right? Is it difficult to get data points to fill out a chart?
If the damper were in the opposite side of the lever, instead of pushing up, you could push down instead of up instead of manually trying to achieve the desired speed hang different weights or the same weights at different distances in order to get better repeatibility of speed? Would that work?

Frank Hanrahan

So in order to see Beanbags photos and graphs, I have to pay $6.00/ month?? I don't get it. Why doesn't old Beanbag just post photos like everyone else?

ross2004

I remember my first day on the internet.

Dilbones

hispanic panic

Photo bucket has fucked everyone. Threads dating back 20 years with great pictures are now invisible cause photobucket is making the authors pay money just to share their photos on the internet. **** photo bucket

jott_1

Would you share your circuit schematic, including the LVDT?

Full_Tilt

This is a 12 year old thread and the OP hasnt logged in for over 2 years. I suggest you search around. With how much things have progressed in recent years I suspect there are probably numerous open-source shock dyno projects floating around.

Also, theres not much to the circuit. If you gotta ask...