Hi I'm Shaikh Jalal from Fat Cat Motorsports and I wanted to give a follow-up video to the 'What is Flat Ride and why should you care?' and this is a really cool story that was the whole thing unfolded because a not yet customer but soon to be customer Greg down in LA who has an Audi S4 Avant contacted me and said
watched some of your videos and I watched your flat ride video and I have this S4 Avant wagon that has Ohlins suspension on it right now from Stasis who's no longer in business and we converted it to airbags and we've been you know I've been using it for a while but I had some issues with the Ohlins they you know they leaked or they I think that's what he was essentially indicating that they just weren't behaving properly he sent them back once they worked for a while and
Then like a year later or so, he had to send him in again.
And he uses the car for kind of fun street driving, canyon driving on the weekends, and also to go to snow country, which is why having the adjustable height in terms of the airbag, it was convenient for him and useful.
And so he said, but I've been hearing about, you know, read about what you're doing, see your videos, a flat-ride video.
I tried that.

I played with the ride heights to try to kind of get the rear suspension to be a little...
more firm than the front and he said I could feel it working and like the car wanted to turn more eagerly and it actually seemed like it rode better too and so but now I feel like the damping like it's just like the front is just way too firm and the rear just feels like there's just not enough control back there and so like what can you do and so I said well we've got a lot of tools at our disposal but I don't know what your spring rates are I don't know what your frequencies are
I can look up the information for your car, for the weights, get the motion ratios.
We've already done an Audi A4 B5 chassis, so it's essentially the same, more or less, than what he's using.
But I really want to know what the effective spring rate is or what the bounce frequency is to make sure you do have Flat Ride and that we know how much Flat Ride, essentially how stiff you're running right now.
And so I said, well, let's take this step by step.

So we got some Bilsteins and just some Bilstein struts, shocks in his case.
It's multi-link front or double wishbone front and multi-link rear.
And so I said, well, Greg, here's what I really propose is that if you had coil springs, we could just get the reading off the coil spring or measure it and get that spring right and figure out the frequency.
we don't know from the airbag.
There's no gauge.

There's no way to really tell exactly what the spring rate is.
So it's based on air pressure and the bag's parameters.
And I had not worked with an airbag before.
This is my first time.

And so he already kind of came to me in a way.
I was pre-qualified because he'd already tried something I had suggested and it was already effective for him.
He wanted to go to the next level.
So I said, so let's actually bounce your car.

And the right way to do this is to have shocks that have no damping in them whatsoever 
and we bounce the front and bounce the rear and get our cycles per second our counts for the frequency 
and so he's like okay well you know yeah we can do that and so you know we had a lot of consulting time I mean he definitely invested some time and money in getting my feedback and having him set things up and this is where having
You know, not everything is as cut and dry as, like, okay, I have a 95 Miata or I have a 2003 BMW M3, and what can you do?
It's like, well, we know the application.

We can already dial this in.
So minimal consulting time needed, you know, maybe half an hour.
Greg had worked with me for several hours, and we were doing lots of, you know, kind of nailing down the details.
And so I got the Bilstein from him, took them apart, drained them, took out all the gas, there's no fluid, and just 
sent it back to his shop that he was working with and said, okay, just install these with the airbag, and actually the airbag 
vendor had to make a custom adapter to get the bag to fit on the Bilsteins versus the Ohlins, slightly different body.
In fact, the Ohlins were inverted, so there were some issues with the bag clearance anyway, so this was one of those times where 
a non-inverted shock was actually better because you had more clearance between the bag and the tire and the hub and everything.
So they got that all sorted out, and then I happened to be in the area.
In fact, I kind of planned to be in the area, and I was actually going down to San Diego to meet up with Eric SMG, who's on the M3 Forum.
And so we had our own good full day of driving his car and my car and talking and all that good stuff, which is kind of another video we can talk about.
But on the way back, I made plans to meet up with Greg at Antidote Performance.
The good guys over there, Jake and Tariq, and they have a new technician, Andrew, I believe, there now, too, like an engineering-level technician.
And so we went for a ride in Greg's car.
I said, why don't we go for a ride?
So they had already bounced the car.
They got frequencies.
It was like 1.7 front and about 2.0 rear.
In Hertz. 

And so I'm like, perfect, Flat Ride. We got it.

And he got the height was kind of in the middle of the range.
It was a little on the lower side for what he was looking.
And we...  So then we went on the road.
Actually, they had balanced it at several different heights in the rear, and it changed rather dramatically.
He had made the rear airbag stiffer intentionally, basically shortened the rear airbag so that you could get a higher frequency to get this Flat Ride behavior.
And so, mind you, there's no damping in these shocks.
And I said, well, why don't we go for a drive and just see how it feels?
He's like, really?
He's like, there's no damping.
Isn't it going to be scary and dangerous?
I'm like, hmm.
I don't think so.

I think it's going to be kind of surprisingly, I'd like to believe it's going to be, let's not go nuts, but I have a feeling it's going to be more controlled than you might think.
And I was sure that it was going to be reasonable to drive.
Maybe not that you want to go leave it that way forever, but that would be an interesting experience.
So I said, let's do it.
So we went out.
And the area of L.A., it's kind of the Fullerton area.
And so there's some really nasty, you know, road potholes.
And it was an industrial zone that we were driving through, and there was construction.
So there were some really nice spots to exercise the suspension, railroad tracks.

And so Greg's driving, and we just went down the road straight first and didn't really do anything aggressive.
And he was like, okay, well, this is – you can feel the firmness and –
But you don't feel harshness, and this is another reason why the idea of where harshness comes from is from the damping, really.
You get bounciness from the springs.
That's just an oscillation.
But the harshness where you're actually getting these sudden accelerations, whether it's up or down or kind of both, is from the damping, where the acceleration that's being induced by the shock, either upward or downward.
is what's jarring your body and that's what's harsh not the oscillation itself and when you actually have that the front softer and the rear firmer and you're doing you know so i can like yeah so this is stiff and this is soft so you know you're getting that that stiffer rear and you get that control so the rear is like control control you're going to the turn the rear's yeah i got this i'm moving this like i kind of demonstrated in the previous video and this is the first time i got a chance to really be in a car that had
Flat Ride spring rates and no damping.
I mean, other than whatever friction was there from the shock moving through the rod guide.
I mean, it was basically minimal damping.
There was no fluid, no nitrogen, nothing in the shock.
And so then he did a couple of slaloms and the car actually felt really nice.

It was controlled.
It was, I mean, the slaloms, it responded really well.

I mean, it really responded well, which was like, wow, this is really cool.
This is even more along that direction of here's that rear,
kind of guiding the front.
And then it just, you know, had this comfortable, like you could just slalom it back and forth all day and it just would, it was stable.
And that was really exciting.

It's like, okay, this is where the idea of using only as much damping as you need and not too much was already demonstrated.
You know, like this, the frequencies were inducing this to be this kind of the rear oriented behavior.
And then we went over some bigger bumps, you know, and he was only like 30 and then 30 to 40 miles an hour.
And you could feel though, this is where you could feel like the rear would be like you'd have like three oscillations, you know, and then it would settle down.
So it's like, yeah, you don't want to live with that on a daily basis.
You know, that's where you definitely need some damping.

And that's where the rear, because it was also higher frequency, we kind of decided when I did the ultimate valving and he got KBO, 
I decided I was going to use more of a, initially a linear rebound curve where the compression kind of rose and then did its blow off behavior 
and But the rebound was initially it had a longer Delayed knee the knee was actually more to like seven or eight inches per second Kind of via 
some valving tricks that I had not really used before so that was where it looked like it was a linear damper but then it did blow off and go digressive above that that speed and
And essentially what ended up happening with that combination is that when I looked at the Ohlins graphs, like the Ohlins were a linear piston and it was very linear rebound, like really just kind of just kept going and going and going and the same slope on rebound and the compression was also linear, but it was rather soft.
So with the KBO, we could add a little bit more low speed compression versus what the Ohlins had.
And then we could get a little bit better body control.

But then on the rebound, it was similar rebound to what was there.
In fact, I think it was actually a little bit softer initial rebound, but then it kind of had this nice progressive curve where it was softer initially, again, to kind of give that compression a little bit more room to sort of stabilize the chassis, and then the rebound to let the tire, you know, extend a little bit more easily.
And then it built up, and then it blew off.
So it had this kind of nice progressive curve.
And I really liked it.

When I saw it, I'm like, God, that's beautiful.
I'll probably, I could probably post a link to it in the comment section.
So, like, note to self, do that.
So we were driving, though, with no damping, and I could feel that bounciness.
I'm like, okay, I know obviously the rear, but the front felt really quite stable, and it could definitely use some more damping, but the rear was obviously the one that needed more control based on its higher frequency, but still not like 60% or 70% of critical damping or something like that, and I think I'm not even using that much.
I think it's in like the...30s to 40s, if I remember correctly, like mid-30s or so, and it's kind of a very overall because the 
compression builds up more and then it blows off and the rebound has more of a delay blow-off.
The overall damping ratio has a very linear type of a build-up.
And so, yeah, that was pretty illuminating.
And as I told Greg when we were finishing this test drive and we were coming back and he started to feel more confident, so he kind of took some turns pretty aggressively.
Again, no damping in the shock whatsoever.

And I said, Greg, this is as good as it's going to get in terms of comfort, in terms of your car's ability to track the road and not get abused by it.
Because now you can really see what you had before with the Ohlins, where you had the firmness in the front and kind of the soft and uncontrolledness in the rear, the way that they had valved it.
that that was more the fault of the dampers, not necessarily the springs.
Although now you've got these Flat Ride, definite Flat Ride.
You may have had it before, you weren't sure, but now that you've bounced it and you've adjusted the rear airbag, so now you know you have it.

And then what we're gonna do with the KVO is to make sure that you get enough low speed damping for the control, enough mid speed, especially rebound and also compression, but in this case, more rebound in the rear,
versus the front, to give you the bump control so that when you go over the bumps, you get a smooth settling response.
But then definitely digressing, blowing off both rebound and compression.
And in the case of compression, where instead of having kind of a linear blow-off, or sorry, a digressive blow-off, which is still a straight line, but it's not the same slope as a linear, it's up and then rolls off, KBO goes up and then essentially goes flat.
So then you get that bump compliance so that you can go over the railroad tracks.

You can go through those speed bumps and the dips without the car kind of launching and kicking back on you or going over a bump and having the car launch going over it.
Or to pack down where if there's too much rebound, it'll clear the bump on the initial part, but then it's going to, boom, really smack down afterward.
So this is, as I said, the best you're going to get is really with no damping in terms of ride comfort.

And then we're adding our... our tricks, our elite valving to take that Flat Ride that's been designed now and to optimize it and give you the ride control and the roll control that you need while still giving you the best ride quality that we can.
And so he actually still had, there were some issues with the, so fast forward like a month and a half, you know, we did the valve, got them over to him and he
I've been waiting for him to give me some feedback, and he had some airbag controller issues and things like that that should be resolved hopefully soon.
And he said, based on the test that he's been able to do, he says it feels really good.
He says, I can feel that the shocks are doing really well.
I just have to address these other kind of peripheral issues to be able to really say for certain.
So I might make another video, you know, after that.

In fact, if I can, I'll even take the camera down with me and just, you know, kind of interview Greg because it will be really cool to get his, he's really spent a lot of time, a lot of money to kind of create this really ultimate city car, canyon carver, and then like this, you know, weekend or snow country, you know, pleasure touring machine that can haul his family and their gear around, so.
he's definitely had a real vision for the car and I really respect that and it's exciting to see that the test of no damping and how that the idea then of just like adding the ingredients you need on top of that good baseline without having you know pitch you know whacking you in the back of the head you know with the front being too stiff and the rear too soft it's like it was like this really cool validation of like yes this makes sense this is why
when I talk about Flat Ride, like here's the physical proof of it.

And I mean, there's a theoretical understanding that's legitimate.
And then here's the physical test, you know, like putting my money where my mouth is like, yeah, let's go for a drive with no damping and see how it is.
And, you know, and then even checking them, my feeling of like, oh my God, isn't that crazy?

It's like, no, it's not crazy.
It's just awesome.
So.There's the follow-up to the why is Flat Ride important, why does Flat Ride matter, and why should you care.
So there's some first-hand experience, and I hope to get Greg's feedback, too, so that you can get another person's assessment of that.
So, thanks.