- We'll see how our ride height is,
just kinda took a guess in the dark so,
let's find out.
Oh (bleep)
Coilovers, it's like buying a new
better set of legs for your car.
I don't think there's anything out there
that can improve your car's handling, looks,
and just your general smiles per gallon
as much as a new good set of coilovers.
Today I'm gonna go over what coilovers actually are,
how they work, all the vocab associated with em,
how to pick the right ones,
I'll show you how to install 'em on the Miata,
and then we'll 'em for a test drive.
I'm Zach, this is Money Pit, let's do it.
(upbeat music)
So the job of the suspension of a car
is to absorb bumps and potholes
and make driving comfortable.
The problem is that auto manufacturers
usually make cars too comfortable,
and cars end up being really squishy and soft.
Take a look at all the body roll on the Miata.
On the stock soft suspension,
the forces of the weight of the vehicle in the corner
just squash the outside suspension,
allowing the inside suspension to stand up.
(upbeat music)
So this week we're gonna replace that suspension
with these coilovers.
But before we do that,
we need to understand what a coilover really is,
and how it works, so let's talk about it.
There are two major components here,
a coil spring over a shock absorber.
First let's look at the spring,
this is a coil spring,
or a big old piece of steel
wrapped up in coils.
So it looks like this, or like this, or like this,
or like this, or like that,
and its job is to store energy
so that when its compressed
it always wants to return to its original shape.
That's why your car always returns to the same ride height
after hitting potholes or speed bumps
or whatever the hell the kids are hitting
on the streets these days.
Let's forget about the spring for a minute
and just look at the shock absorber.
It's kind of really he hero of the whole setup here
because it's responsible for absorbing and damping
all the shocks, bumps, and potholes, et cetera.
So what do we mean when we say damping?
Well what we really mean is slowing down
the natural motion of spring oscillation,
or up and down bouncing.
So using this little spring,
if I just push it down and immediately move my hand,
it just kind of jumps.
But if I push it down and dampen its return to normal,
it's very controlled,
because I've controlled it.
So that's kind of what your shock absorber is doing.
I know you've seen a car
with a blown shock absorber on the street.
That's what it looks like,
that is a shock absorber not doing anything
and just letting your spring oscillate.
So how does your shocks do it, huh?
Well it's called hydraulic resistance baby,
and it's really pretty simple.
In here there are a couple of chambers,
there's a hydraulic fluid chamber,
there's a high pressure gas chamber,
they're separated by a floating piston,
and then at the end of this rod
is a piston which lives in that hydraulic fluid.
So that piston is forced up and down
with bumps in the road,
which forces that hydraulic fluid that it lives in
through tiny little holes or orifices in that piston,
and that's what dampens oscillation,
thanks to the resistance of the hydraulic fluid
to flowing through those tiny holes.
The bigger the bump, the harder the fluid is pushed,
and the more hydraulic resistance, and heat, we get.
But what about that gas chamber, huh?
Why is that there?
It doesn't sound necessary.
Well it kind of is, many shock absorbers
also contain high pressure nitrogen gas
to keep pressure on the hydraulic fluid,
and that's important because of something called cavitation
which doesn't have anything to do with your dentist.
Cavitation is when the hydraulic fluid
begins to foam up due to repeated rapid shocks,
and then once that fluid foams up, or cavitates,
the shock is rendered completely ineffective.
Think of it this way,
you have a can of soda, you shake it up,
nothing happens because
while it's still closed it's under pressure,
so it's not foaming up.
It only foams up when you remove the pressure by opening it,
and that's basically what's going on
inside a high pressure gas shock.
You're shaking the hell out of it,
but thanks to that pressure,
it stays unfoamy and super effective.
(upbeat music)
Okay, so this is a setup change.
- [Man Behind Camera] Is it?
- I think so.
All right, so now that we've got a basic understanding
of what's going on in there,
let's get back to talking about coilovers.
Let's do a little vocab lesson.
Threaded body, adjustable damping,
pillow ball, ride height, external reservoir,
spring rake, pressure, rebound,
what does any of that mean?
Fear not, it's just car parts baby.
So let's break it down, talk about some
of the different parts and features
that you'll come across on the hunt
for a set of coil overs for yourself.
Pretty much all performance oriented coilovers
are gonna have a threaded body,
which means what it says.
The body of the coilover is threaded.
So that allows you to adjust the height
of the lower mounting bracketry,
which in turn adjusts the ride height of the car.
So the threaded body also generally
allows coilovers to use a threaded spring perch
which separates ride height adjustment and the spring seat,
which I think needs some explaining.
You see, on some coilovers
you adjust the ride height by adjusting the spring perch,
which if you're lowering the car,
you'd end up with your spring perch really low,
which would mean the spring would be all slack and rattly
when the suspension is unloaded.
So separating ride height and spring preload
means that you can keep your spring nice and snug,
and do whatever you want with ride height.
And it helps keep the pistons travel in its intended spot
inside the shock body.
So it's really nice to have a set
with separated ride height and spring perches.
All right, so some coilovers offer adjustable damping,
and we already talked about damping earlier,
so we already know what that is, right?
Well sort of, there are two types of damping,
there's compression and there's rebound.
Rebound damping is damping as the suspension
extends back to its normal position,
compression damping is the exact opposite.
It's damping as the suspension compresses,
or as you're hitting a bump.
So these two types of damping are adjustable
by changing the hydraulic resistance
by changing the size of the orifices
that the hydraulic fluid is forced through
on that piston inside there.
So you can't see the holes in the piston,
because they're inside,
but what you can see is how you adjust 'em.
It's usually just a little clicky boy like this.
Like that.
So this has 12 clicks of adjustment,
from soft to firm.
Usually on most coilovers, like this one,
the rebound and compression damping are tied together,
but on some of the higher end stuff,
you get separate adjustability
so you can tune your rebound and compression damping
as you see fit, got it?
Okay, so.
- [Man Behind Camera] That was a lot to take in.
- Yeah.
Roll back a little bit.
Now let's talk about the springs.
So let's start with the spring rate,
basically how stiff your spring is.
Empirically speaking, or in American units,
if you have a spring with a rate of 100 pounds per inch,
that means that if you put 100 pounds
on top of that spring,
it will compress one inch.
For reference there, the Miata springs
are eight kilograms per millimeter in the front,
and six kilograms per millimeter in the rear.
This is a front, eight kilograms per millimeter.
So that is pretty basic and pretty easy,
but that's only if we're talking about linear springs
like this one, this is a linear spring.
However, there are springs
that change how much they compress
depending on how much weight they already have on them.
These are what's known as progressive springs,
this means that the more a progressive spring compresses,
the more it resists compressing further.
The closer coils compress first,
and then you get to the stiffer coils.
The softer coils will absorb shocks and bumps,
while the stiffer coils
give you good handling characteristics.
Sometimes they'll also be shaped like a cone too
where the diameter also changes.
Speaking of different types of coils,
sometimes you'll see
a second spring altogether on a coilover, like this,
and that spring is not for doing anything
while you're driving.
That's just what's called a helper spring.
They're just in there to hold the springs in the right place
when the suspension is unloaded.
So I think that's about it for springs for now,
so now let's talk about our mounts,
our upper mounts or our top hats.
It's basically the bridge
between your suspension and your car.
So here we've got our nice aluminum mounts
with rubber in here.
So the rubber mounts will absorb a lot of road noise,
and some vibration to keep the cabin
pretty quiet and pretty comfortable.
Some will have what's called a pillow ball mount,
they are a spherical bearing
which means they're metal on metal.
Very crisp, very responsive,
nothing like a pillow.
Not all coilovers will actually come
with top hats or mounts,
so in that case you can reuse your stock ones
if you want to, if they're in good shape.
On some coilovers you'll get camber plates,
or you can add them later.
They're basically just top hats
that give you some graduated slots
so that you can slide your whole coilover in and out
to adjust your camber.
But on the Miata they're kinda useless
because we've got a double wishbone suspension
which means that the angle of the coilover
really doesn't make much of a difference.
So some shock absorbers will have an external reservoir.
Why you may ask,
the reservoir generally relocates
that high pressure gas chamber
that we talked about earlier,
which means now the entire shock body is full of fluid,
which battles cavitation even better
than just having that high pressure pocket in there.
It also adds for a little longer travel range
in the same shock body,
and the added fluid that the reservoir adds
also adds a little greater heat capacity
to the whole system
so your shock can handle more heat before it fades.
So that's good too.
So now that we know what coilovers are,
and how they work,
how do you know which ones to pick for your car?
Yo check check, do not scratch or cause,
or cause surface defects to the damper shaft.
Contains pressurized gas and oil,
do not puncture.
So the more features a coilover has
from the list of features we were just talking about,
the more expensive they're gonna be generally speaking.
You know if you're looking for really good handling,
durability, longevity,
customer support that you can actually call
and get something done with,
you should go with a coilover kind of
in this mid range category in my opinion.
Around 1000 to 15 or 1600 bucks for most platforms,
and of course you can spend more,
knock yourself out.
Honestly, nice suspension is,
as far as car parts go, money pretty well spent.
But if all you wanna do is go lower,
you can also go the avenue of lowering springs,
these days, it can be a good option
especially for some of the fancy cars out there
that have like electronic damping control
and stuff like that.
There is a time and a place for lowering springs I think,
but it's not this.
So I know there's probably a few of you out there
waiting for me to say it,
so there is also air suspension.
There is some air suspension out there
that handles pretty damn well.
In my opinion it's never gonna be quite as good
as a good coilover,
and they're just always prone to leaks and issues.
Okay, so all that said,
these are what we picked,
which the picking is probably the hardest part
'cause there are just so many options,
you get option paralysis.
And because installing them is typically pretty easy.
It's probably gonna take you
like two to four hours depending,
it's always nice to have a helping hand,
have a buddy around.
You shouldn't need too many tools,
some wrenches, some sockets,
a jack and jack stands, that's about it, let's do this.
Wash your hands.
(upbeat music)
All right so the first thing you gotta do
when you're gonna put new stuff in
is take the old stuff out.
So that's what we're gonna do,
it's really easy in theory
there's just two nuts at the top,
one big bolt at the bottom,
we also need to disconnect our sway bar end link.
Our stock stuff is so long
that I think it's gonna be a little bit of a battle
to get it out of the suspension.
Sir Ron, help.
Get in here.
- So close.
Ow.
- We got glue.
Alternatively, you can take out the upper control arm
which makes this a lot easier.
- It's a boy.
(glass breaking)
(cat meowing)
- All right well the front came out super easy,
so I'm expecting more of the same on the rear.
We got two nuts on the top inside the trunk here,
so we had to remove a little interior stuff,
and then disconnect the sway bar,
pop out the big bolt at the bottom of the stock suspension,
should come right out.
Pretty easy, now it's time to put in the new ones.
First I wanna talk about that height difference.
I don't know what ride height
ultimately we're gonna want to sit at,
so I'm gonna match them all up,
make them all this size, then install 'em,
and then we'll adjust ride height to our taste.
They go in a lot easier than they came out.
So the torque spec for the lower bolt here
is 54 to 69 foot pounds,
so 69 it is boys.
All right so when you're tightening any rubber bushings
in your suspension,
it's important to do that at ride height
or else they'll kind of always be bound up
because you tightened 'em when the suspension was drooped,
and then you twist 'em up as you go to ride height,
so when you're tightening rubber stuff,
tighten it at ride height.
You can do that with just putting a jack
under your suspension and cranking it up a little bit
which is what I'm doing here for the end links.
(upbeat music)
All right so we're all done with the front,
time to move on to the rear.
We're running out of light and quick,
so I'm gonna tighten up the rear ones, 69 foot pounds,
get that rear sway bar on, beautiful.
All right all four suspensions are on,
so now it's time to roll them fenders.
This is our fender roller,
it goes on the hub like so,
you can also get pretty far with a hammer,
in fact I'm gonna start with this
and then we'll probably use this to finish up.
Kind of just get that fold started.
In case you haven't talked to your neighbors in a while,
do this and trust me, you'll talk to 'em.
Hammer portion done.
Roller portion next.
Boy, I don't know if this is gonna go short enough.
Um, (bleep) maybe it'll work on the fronts.
Well our fender roller doesn't fit in the front either,
it's just too long for the Miata's tiny wheel wells,
so I guess that means
we're just doing the whole thing with a hammer
which is honestly fine in my opinion,
you can get very good results with the dead blow,
that's how I've done it in the past.
I was hoping to be able to show you how that thing worked,
but it's very simple,
you'll figure it out if you ever get there.
Maybe we'll be able to use it on something else someday.
Anyway we're just gonna hammer these fenders
and get it done with, you know.
All right we're gonna put the old wheels and tires back on
and if you remember from last episode
I forgot to buy hub centering rings,
but I got some.
So in they go.
We'll see how our ride height is,
just kinda took a guess in the dark so,
let's find out.
Oh (bleep)
Well I'm pretty sure that's gonna rub.
That's gonna be close, that's worth a drive
to see if that rubs.
All right so upon further review,
I don't think we're gonna be able to run
our precious little fender liners.
Maybe I'll be able to trim 'em up someday
and put 'em back in,
but for now we're going no fender liners.
All right so right now I'm adjust the ride height on the car
to try to raise the front a little bit.
So to do that all I had to do
was break loose the lower collar
that locks in place the ride height.
You break that loose and then spin the spring perch collar
with your wrench like this,
and it spins the body in that lower bracket.
'Cause now the lower bracket's mounted,
it can't move, so we spin this,
and that changes our ride height.
Then we'll spin this collar back down,
lock it in place, call it a day.
All right so I'm just measuring
to see how much I've raised both sides
to make sure I do 'em kind of evenly.
Looks like I've got it even,
so we're gonna lock these down
and see how this looks.
You can also just measure the gap
from your tire to your fender as well
for measuring ride height.
But since we have this open, we measure it there.
No rubbing, that ride height looks pretty good to me.
Looks nice and low.
Before we go driving we gotta do a couple tests,
first thing you're gonna wanna do
is turn the wheel all the way left
and all the way right,
ideally while rolling a little
to make sure nothing rubs, okay?
Nothing rubs.
Now meet me at the end of the driveway
for the second test.
This one's called the driveway test,
and it's whether or not
you can still get out of your driveway.
This Miatas great.
Let's go for a drive boys and girls.
(upbeat music)
This thing feels great.
So on hard bumps we still have
a little bit of rubbing in the rear,
so I'm gonna have to roll the rear fenders a little bit more
but otherwise it feels great.
It's stiff, it's not too harsh,
it's comfortable but it's not bouncy.
So I'm really happy with this,
so we lowered it today
which means that we've changed the alignment.
So next week we're gonna figure out
how to do a full alignment in the garage,
so check me back for that
next Wednesday on Money Pit,
in the meantime follow me at Zach Jobe,
follow Donut at Donut Media
and I'll see you guys next week.
Stay safe, wash your hands, and keep your distance,
see ya.