- 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.
