UPDATED: Replacing Rear Shocks: Reducing the rear end bounce.

[markboris]

Damn thank you @markboris and others participating and doing God's work in helping us alleviate one of the main sore points in the car! There is a lot of information to parse so would you guys be able to summarize this once the tests are completed (maybe in a different post) or heck even a YouTube video for the layman who doesn't understand a lot of the nuances here? I and I am hoping others can even throw some well deserved $$ on pateron or other channels if it helps!

I have always completed my mods and then started a thread with a write up and photos. This is the first time I started a thread when I started a mod. We are posting as we test. When we find a solution that we are happy with we will post the details. As of right now, on the roads that Anton has issues with, the Koni’s are doing a good job of reducing his “wavy” bounce to nothing. Like I’ve said many times, everyone has different roads and different Mach-E trims so it won’t be the same for everyone but it won’t be worse, that’s for sure.

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[RMoore]

X-Y plot seems to work ok for analyzing the data.

EDIT: On second thought, the slope can change dramatically depending on the parameters, this maybe isn’t the best way. The data seems pretty darn similar just looking at it. I didn’t ride in the car to feel it, but it almost seems like placebo effect? Are we sure the data files are labeled correctly?

Would a power spectrum analysis help here?

 

[Mach1E]

Thanks, this does help. You can start to see some difference with a simple moving average. Here's a SMA on 50 data points (~0.115s).

oem-v-koni-s-10k-20k-50sma:

oem-v-koni-n-10k-20k-50sma:

Blue is oem, orange is koni. You can see that the oems go further than the konis by about 0.01g, sometimes even 0.02g.

Not sure if this will help, but I remember a similar issue years ago when they tried using accelerometers to compare the ride quality in boats.

The objective data and subjective feel didn’t line up.

The reason they figured out had to do with how your body perceived changes on motion.

For example: the bounce you are trying to get rid of will likely make the G forces increase (stiffer shocks). But if the subjective ride “feels better,” then there you go.

Here is a much longer more detailed explanation of the boat ride quality test:

https://www.boatingmag.com/boats/catamaran-versus-v-hull-which-rides-better/

 

[JohnFoxeSheets]

Not sure if this will help, but I remember a similar issue years ago when they tried using accelerometers to compare the ride quality in boats.

The objective data and subjective feel didn’t line up.

The reason they figured out had to do with how your body perceived changes on motion.

For example: the bounce you are trying to get rid of will likely make the G forces increase (stiffer shocks). But if the subjective ride “feels better,” then there you go.

Here is a much longer more detailed explanation of the boat ride quality test:

https://www.boatingmag.com/boats/catamaran-versus-v-hull-which-rides-better/

Leave it to the Floridian to bring boats into the conversation? (though in fairness, someone did mention Cadillacs ?)

 

[Mach1E]

Leave it to the Floridian to bring boats into the conversation? (though in fairness, someone did mention Cadillacs ?)

Haha! Fair.

For the TLDR;
The higher G force boat actually “felt” like it was a smoother ride due to the rate of acceleration.

Bottom line? Measuring G force isn’t going to give you a clear answer. At least not by itself.

 

[JohnFoxeSheets]

Haha! Fair.

For the TLDR;
The higher G force boat actually “felt” like it was a smoother ride due to the rate of acceleration.

Bottom line? Measuring G force isn’t going to give you a clear answer. At least not by itself.

Yeah, that makes total sense. A jittering motion would be annoying, while a rolling motion could be nauseating...

 

[b Mach e]

Leave it to the Floridian to bring boats into the conversation? (though in fairness, someone did mention Cadillacs ?)

Ha!
Just more cush than track.
Don't FFT 's messure frequency strength. Maybe record a runs and compare. Used to be able to stretch out the graphs for detail where there was a shock, to compare

 

[azerik]

I'm putting off getting tires for this testing lol.
I'm going to make a couple videos with my kids phone, pointed towards the back of the car. Maybe that could give a visual representation.
Currently I've only tried graphing the single run I've done, not comparing it to another, yet. I think we can go down the rabbit hole of charts and graphs but numbers mean little more than points on a graph. If we can get a ballpark % improvement I'd be happy with that.

I've put about another 100 miles on my shocks and honestly can't wait for the Vikings to show up.

 

[JohnFoxeSheets]

Ha!
Just more cush than track.
Don't FFT 's messure frequency strength. Maybe record a runs and compare. Used to be able to stretch out the graphs for detail where there was a shock, to compare

Yeah, I think FFTs should do the trick. I've not started looking for apps for this (yet), but I gotta imagine there are a number of them that can generate the comparative data that we want...

 

[markboris]

Besides feeling the wavy bounce in Anton’s car, do you know how he tells the Koni’s are better? When he looks in the rear view mirror, his wife isn’t bouncing up and down like she use to. Not sure if you missed his comment but he said she told him this was the first thing he did that she could feel a difference and she likes it.

 

[markboris]

I've put about another 100 miles on my shocks and honestly can't wait for the Vikings to show up.

They will be there Wednesday all ready for you to install and test. ?

 

[azerik]

Besides feeling the wavy bounce in Anton’s car, do you know how he tells the Koni’s are better? When he looks in the rear view mirror, his wife isn’t bouncing up and down like she use to. Not sure if you missed his comment but he said she told him this was the first thing he did that she could feel a difference and she likes it.

This is the reason I plan on taking video with my kids phone on the center screen shooting out the back window. You can visually see the horizon. As the front pretty much pogo's I think the video (1080p 30 frames) will show reality better than 4k@60 which smoothes out everything. I'll try both but it'd have to be downscaled to be playable anyway.

 

[Dadams]

Do all the testing cars have the Steeda bars? Just wondering how much of a difference that will make, as I don't have them. Wondering if I will have to get those too.

Thank you for all the testing and time you are putting in.

 

[markboris]

Do all the testing cars have the Steeda bars? Just wondering how much of a difference that will make, as I don't have them. Wondering if I will have to get those too.

Thank you for all the testing and time you are putting in.

Mine, Anton‘s and Erik’s do. No you don’t have to get them but if you want to greatly improve the handling I would.

 

[azerik]

The rear bar's lightest setting is 250lbs. The stock bar being 200. It's not a massive difference on paper but in the car it took the side to side wobble out. Shocks would help with that some but not as well as the bar. If you are annoyed by the side to side shake the rear bar will help a ton. If you want it to corner like a sports car (until the tires slide) the front bar will help with that. But these are increasing rigidity. Which can impact ride quality. Mark and Anton have pretty nice streets from what I can tell. I've got a war zone. It's good to have an idea of "this could work well for me because I only have occasional expansion joints" vs "this wouldn't work for me because my streets are like a washboard with moon craters".

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