Shock Dyno Data Anyone?

[Jayrdee]

So, I'm sitting here bullsh*tting at work and just thought of something that would be kind of cool, if anyone here is a nerd like I am. Would there be any interest in measuring various aftermarket shocks and comparing their compression/rebound data?

I'm a Production Engineer at Hitachi Automotive Systems building monotube shocks. The plant I work at used to be Tokico. My "section" is shock assembly, so basically we get all the components (tubes, rods, free piston, piston valve, etc) and assemble the shocks before they get moduled and sent to the customer. The majority of shocks I produce are for Ford. Like the Ford F150, Mustang, Ranger, etc.

With that being said ... I have access to "Damping Force Tester" machines which measure a shocks compression, rebound, and gas reaction specs. We also use them to verify a correct piston valve stackup is being used. All my lines have them. And the QC labs have them. Theoretically I can put any shock I want to in there, run the machine, and it will spit out its compression/rebound and gas reaction data. For example the fancy graph Fortune Auto advertises on their website for their 500 series coilovers:



I stare at these type of graphs all day/everyday.

I think it'd be cool to gather various aftermarket shocks like TRD Blues, Bilsteins, KYBs, Annex, Fortune Auto, etc. and run them all against eachother, compare the data, and see how they differ. What do you all think?

Now i just need shocks ....

[totta crolla]

I have some TRD blue front AE86 dampers that on setting 3 seem almost perfect (for the springs used) I'd really like to know what the actual rates are! Also have AE86 Bilstein B6's Problem is... I'm in the U.K

[Jayrdee]

I have some TRD blue front AE86 dampers that on setting 3 seem almost perfect (for the springs used) I'd really like to know what the actual rates are! Also have AE86 Bilstein B6's Problem is... I'm in the U.K

I'm sure we can work something out!

[davew7]

I would bet that the Hitachi Automotive Systems corporate office already has hundreds of benchmarking studies on file, for all major shock suppliers. See if they are willing to share the info. That would narrow the field for any additional testing. davew7

[Jayrdee]

I would bet that the Hitachi Automotive Systems corporate office already has hundreds of benchmarking studies on file, for all major shock suppliers. See if they are willing to share the info. That would narrow the field for any additional testing. davew7

I'm sure they do, but unfortunately I'm just a level 1 engineer, still at the bottom of the totem pole Lol.

[jondee86]

Collecting the information is one thing... knowing what to do with it is another I used to think that
if you were clever enough you could do some calculations based on loads and speeds and phases of the
moon and then go and select shocks from a catalog that would be perfect for your car. I have since
discovered that the calculations are complex and frequently require assumptions about hard to measure
operating parameters. So ordinary folks rely on clever factory engineers and honest marketing people
to do the calculations and product testing to come up with the "best shocks for your car".

This is fine in theory, but because of the aforementioned assumptions, the shocks are tuned for one
specific performance situation e.g. fast road. When asked to perform in the same car on a racetrack
the result will be unsatisfactory. The quick fix answer is to put a knob on top to adjust the rebound
damping rate. So providing the shock is used solely for the design application and has some adjustment
(preferably compression and rebound) it will provide decent performance at a reasonable price.



More recently I have discovered that even the experts having done the calculations for a particular
model of car used for a specific type of driving, build prototypes and test them extensively on the road
under their design conditions. Feedback from these tests allow the shocks to be fine tuned for the best
handling. Testing may also involve matching shocks to springs for competition vehicles.

Which brings me to the point of this post The magic is in the tuning of the shim stacks and is the
reason high end coilovers are supplied as a unit with carefully matched shocks and springs. Changing
from the manufacturers recommended spring rate will negatively affect the performance of the shocks.
Winding the damping up to compensate for springs that are too soft is no substitute for fitting stiffer
springs. Race cars will have multiple sets of coilovers and will change them out to get the ride height,
spring rate and damping that they require for each circuit or event.

Add to this the driver with his/her own preference as to how the car should feel and handle. There are
a lot of variables at work in suspension design. Simply knowing the shock dyno data does not mean that
it will work in a particular application... UNLESS... you have prior knowledge from actual on the road
testing of the values proven to suit that application.

So by all means add to the knowledge base. Maybe if someone can collate information on what shock and
spring combinations have been found to work "great" by a good selection of drivers, we could eliminate
some of the "wasted my money" selections and highlight some of the "better than average" selections.

Cheers... jondee86

PS: The current lockdown situation makes for spare time to write stuff like this

[Jayrdee]

Jondee, yes you're totally right. Trust me, having the data and knowing how to read it are two totally different things. I deal with that first-hand everyday haha

I like that picture you posted because that shows where all the magic happens; the piston valve stack-up. For example, one particular model shock may have 10-20 different part numbers, which are all the same shock but with different "valve codes" (what we call the piston valve stackup). A truck going to a mountainous area, or an off-road trim level, will have a different valve code than a base model or one going somewhere flat or whatever. The valve stack up is where all the time and research go.

The shims get as small as 0.15mm in thickness, so its super easy to get the stackup wrong, or load the wrong trays in the machines because they all look the same haha.

With that being said, thats why I think it'd be interesting to put different shocks against each other.

[jondee86]

The valve stack up is where all the time and research go.

And this is the reason why it is so difficult to get shock dyno data from manufacturers. They
have invested time and money in developing shocks that work for specific applications, and
they don't want to give that information away. Usually, high end manufacturers will be able
to re-valve their shocks to suit your application if you provide them with the vehicle model
and how it is going to be used.

As an example, a few years ago when I was looking at upgrading shocks on my AE86 to "fast
road and occasional track" specs, I asked the local Bilstein agent for a recommendation and
he gave me this when I asked...



It was said to be the dyno of a shock with a shim stack that had been proven to work well
with the AE86 in similar applications to mine. However, for a variety of reasons I ended up
going with standard Koni shocks re-purposed from other vehicles. So I never got to find out
how much better a custom valved shock could be in comparison.

Cheers... jondee86

[Jayrdee]

Anyone here wanna send me some shocks to do some tests? I'll pay for shipping!

[totta crolla]

I'm very tempted to send you one of the TRD blues. It would be interesting to see the graphs and to see what adjusting them does. For the roads in the U.K most performance dampers feel too stiff in high speed bump, wheels hopping etc. and using softer springs has little or no effect on this behaviour. At a guess I would say that the Bilstein graph above is probably a B6 AE86 standard setting. I always felt that mine were too stiff in bump and they struggled to control the rebound from a 200lb spring. Jayrdee will put me right but l would say that they were designed to work with standard springs. Does anyone have any data on stock AE86 damper rates? Toyota will have spent Months perfecting the rates and they would be the ideal baseline to work from.

[jondee86]

These are the oldest TRD shock listings that I have. There seems to be some damping
rate information that might be useful...

https://imgur.com/9FpTDK6

Pic is a bit large but it is a scan from a not very good photocopy so I left it a bit big
to make it easier to read

Cheers... jondee86

[totta crolla]

Some useful information there Jondee, thanks.
My TRD's are 48511-AE881 1127/588N 4-stage adjustable rate Cartridge type
I wonder, should we assume the figures on the far left of the image 'GTV' etc are the standard damper rates?
Piston test speeds would need to be confirmed and possibly converted. It shows 0.3 m/s for the assumed standard dampers.

[jondee86]

Here is a scan of the same page from a later TRD price list...

https://imgur.com/yAg4mIK

It adds a bit more information in the way of OEM spring rates. I have always assumed
that the GTV rates apply to those JDM AE86 models (Levin, Trueno etc) fitted with the
4AGE and 5-speed transmission. I imagine that the other rates apply to models fitted
with lesser engines where "sports" suspension was not required.

Cheers... jondee86

[Jayrdee]

Ha, very interesting to see the standard speed setting is 0.3 m/s. While our Quality/Prototype labs run shocks at various speeds, on the assembly lines we run them only at 0.3 m/s and 0.6 m/s since those are the speeds required by the customer.

I'm very tempted to send you one of the TRD blues. It would be interesting to see the graphs and to see what adjusting them does. For the roads in the U.K most performance dampers feel too stiff in high speed bump, wheels hopping etc. and using softer springs has little or no effect on this behaviour. At a guess I would say that the Bilstein graph above is probably a B6 AE86 standard setting. I always felt that mine were too stiff in bump and they struggled to control the rebound from a 200lb spring. Jayrdee will put me right but l would say that they were designed to work with standard springs. Does anyone have any data on stock AE86 damper rates? Toyota will have spent Months perfecting the rates and they would be the ideal baseline to work from.

Shoot me a message dude! We can make it happen!
What would be really cool is if I can get your shocks, run them, and see if they match Jondee's scans!

[jinx]

you measuring used shocks ?
what good is the raw data, when there are so many other variables in real world application
Heck, if I had access to making shocks, it seems like there is a market for shorter inserts for many older cars
I'd think slightly stiffer valved for more performance oriented
Some ebay vender offered such, with mixed results. Good idea, but execution was off
They were low priced, so that probably compromised materials, etc

[jinx]

LoTek for example catered to this market for a few applications.
We AE86 just go with shorter appl cartridges/mod housing + shorter rear shocks
stock length cartridges kill travel and die even quicker with more aggressive spring rates

[Jayrdee]

I would prefer new shocks, but then again I doubt anywhere/anyone will send me new stuff just to test Lmao. The purpose of this little experiment is just for fun (because I'm a big nerd).

You can still infer some good information from the raw data though. For example TRD Blue shocks are a twin tube design, while the Fortune Auto 500s like I have are mono-tube. It'd be interesting to see how/if the compression/rebound characteristics differ between the two.

Side note, I reached out to our design group to see if there's any archived data from the aftermarket Tokico shocks. (HTS, Super Sport, Illumina, etc.)

[totta crolla]

Jayrdee, yep sent you some details. Whilst I understand that used dampers will give a slightly different result to new ones my TRD's seem about as good as I want for my application. If they have worn to this setting then all the better for getting the data now!

[Jayrdee]

Jayrdee, yep sent you some details. Whilst I understand that used dampers will give a slightly different result to new ones my TRD's seem about as good as I want for my application. If they have worn to this setting then all the better for getting the data now!

Yepp! Check your emails, I think my response went to your email inbox vs club4ag.


Someone correct me if I'm wrong, but Tokico manufactured all the TRD AE86 shocks, right? I wonder if I can find some old archived data about those too ...

[totta crolla]

l think my e-mail address attached to this site is defunct. Can you try via PM please Jayrdee?

[Jayrdee]

l think my e-mail address attached to this site is defunct. Can you try via PM please Jayrdee?

PM'd you!

[oldeskewltoy]

didn't see this until now for some reason.......... HTS 112s

[Jayrdee]

Hmmm.. now this is interesting.

So, totta crolla might be sending me a 48511-AE881 front shock, so lets compare that to the HTS 112 front.

HTS 112 front at full soft:
Rebound = ~0.5 kN @ 0.3 m/s
Compression = ~0.5 kN @ 0.3 m/s

According to the scan that Jondee posted, the 48511-AE881 front (im assuming these were all tested at full soft):
Rebound = 1.519 kN @ 0.3 m/s
Compression = 0.588 kN @ 0.3 m/s

So the TRD shock obviously has way more damping force on rebound vs the HTS. But whats even more interesting to me is that the GTV specs are 1.078 / .363 kN

So does that mean that the stock GTV shocks have more damping force on rebound than the HTS at full soft? Rebound is usually whats affected whenever you have shocks with dampening adjustment, and the HTS at 4 turns is a little under 1 kN, which is still not as much as stock GTV shocks. So in theory the HTS shocks would feel "softer". I wonder the reasoning behind that.

This is just going off scanned data too. This is why I want to get my hands on the real thing and test them!

[jondee86]

The HTS112 were the "long stroke" version for use with cars at the stock height.
The HTS102 were the "short stroke" version aimed at drift and race applications.



I would expect (but have no figures) that the two versions would be valved differently
as the HTS102 would likely have to deal with stiffer springs than the HTS112. The 102
was basically a size for size replacement for the TRD RACE series shocks and reputedly
had a wider range of adjustment.

Cheers... jondee86

[Jayrdee]

Ahh okay that makes sense. So you could imagine the 112 being a sort of OEM replacement.

[jondee86]

OEM replacement in terms of physical size, but with up-rated valving to handle modest
lowering and "sporting" spring rates. I believe that OST used 112's and found that he had
to be inventive in keeping 4.4 (?) kg/mm springs captive.

Cheers... jondee86

[oldeskewltoy]

OEM replacement in terms of physical size, but with up-rated valving to handle modest
lowering and "sporting" spring rates. I believe that OST used 112's and found that he had
to be inventive in keeping 4.4 (?) kg/mm springs captive.

Cheers... jondee86

That was in my AE86... but that was not the HTS112, that was the Illuminas. I used a tow strap to keep everything together - it worked perfectly until I sold my AE86






Surreptitious has the HTS112's, and they are fully captured - using spacers at both end




Both are Tokico.....(HTS, and Illuminas)