- Okay. So the only remaining stock part
on the Miata's exhaust is the catalytic converter.
Now the catalytic converters are great for
reducing unwanted emissions
and burning off the toxic pollutants
that come out of your exhaust.
And I can really honestly get down with that.
But in the case of the Miata,
I'm looking for unbridled horsepower.
And the catalytic converter
is kind of a restriction, or is it?
How much is it restricting my exhaust flow?
That's what we're gonna find out today.
We're gonna make a straight pipe to replace the cat.
Then we're gonna go back to the dyno to see
how many ponies that straight pipe frees up.
We got a welder.
(upbeat music)
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Now let's get back to Money Pit.
(gentle music)
So this is what the inside
of a catalytic converter looks like.
It's basically a honeycomb pattern
coded in some rare earth metals like
Palladium, Platinum and Rhodium.
So as you force hot exhaust gas
through your catalytic converter
it makes a lot of chemical reactions happen
and basically cleans your exhaust.
A bunch of harmful pollutants
that would come out of your tailpipe are scrubbed off
in the catalytic converter,
and the only things that come out in your tailpipe
for the most part are harmless.
So the goal today is to replace this catalytic converter
with a straight pipe
or maybe you've heard it called
test pipe before. Same thing.
To do that, that means we're gonna have to make that.
So let's go see what we're working with
and come up with a game plan.
This is aluminium steel.
This is gonna be really easy to work with, easy to weld
maybe rust over time, especially these mild steel flanges.
But it's gonna be relatively easy to make,
and this is also the cheapest materials that we can get.
So the first thing I'm gonna do is
try to figure out the angles of these flanges
on the pipe in terms of degrees.
We got 86.3. So we basically got about four degrees
of angle from straight vertical.
So here we've got 82.1
so that's about eight degrees off of vertical.
And now we know that we are aiming for
eight degrees this way and about four degrees this way.
These are the flanges that I got.
She is flat.
She is mild steel and she is cheap.
And she's for a two and a half inch pipe which this is.
Now you can see there's a little bit of a gap.
What that means is that you can go like this.
So I think we're gonna be able to get enough angle out of it
without really doing too much.
The trick is gonna be setting that angle before I weld it.
All right. So there were plenty of ways
to cut exhaust tubing.
The other week when we did Nolan's exhaust cutouts
we cut exhaust pipes by hand.
You could also use a reciprocating saw like a sawzall
or a cutoff wheel.
But to make nice repeatable cuts
a band saw really is what the doctor ordered.
Now, this is a pretty cheap one, about as cheap as they get.
Think they run from about 275 bucks these days.
Basically what I'm gonna do is
cut a little sliver off the end,
but at an angle at about eight degrees
let's get to cutting.
Okay. So bandsaws like this
generally have some sort tension control
so that you can set the tension
and then you can walk away from the cut
while it's happening.
So, I've got her set.
(bandsaw sreeching)
Okay. So we've got our little wedge
about four and a half degrees this way
and about seven degrees the other way.
All right. So we're actually really close to our first try.
Now I just need to get the overall length of this thing
measured, cut, and then do this again for the other flange.
(bandsaw screeching)
Okay. Our pipe is ready to weld.
So now we need to get our flange ready to weld.
And the only thing we need to do there
is clean it up.
whenever you're welding anything
it's really important to clean your metal.
So I'm gonna clean the flange up
and I'll clean the bottom of this pipe up a little bit.
But I am gonna be careful with this because
I don't wanna grind off too much of the aluminized coating
because that's what keeps it from rusting.
All right. So we're ready to tack up
this flange to this pipe.
So welding in and of itself is a huge money pit
and a very deep rabbit hole.
So we're just gonna get started today.
And we're just gonna focus on MIG welding today
which again is in my opinion,
the easiest version of welding out there, anybody can do it.
It is pretty simple.
You just got to know a few basics.
So that's what we're gonna cover today.
The first thing we're gonna do is tack weld this pipe
to this flange which means,
we're just gonna put a few little pieces
of weld just to hold this thing together
so that we can test it
on the car and make sure everything's good
before we fully weld all the way around.
Okay. So the first thing we're gonna do
is flip on the switch in the back of the machine
and then I'm gonna open my gas.
So you might notice I have two gas tanks back here.
That's because this machine does MIG and TIG welding
which use different gases.
So this is my MIG tank.
It's a mixture of 75% argon and 25% carbon dioxide.
That's what you use generally speaking for MIG welding.
So I'm just gonna open it up.
And then we've got this pressure regulator here
which meters the gas flow into your machine.
I've got to set it about 30 CFMs
or cubic feet per minute of gas.
That's kind of standard-ish for MIG welding
as far as I know.
And this machine is super easy to set.
It has an auto set feature.
So you can just select the thickness
of material you're working on
and then it will work out how much heat
and how much wire speed do you use.
Now on any MIG welder those are really the two big settings,
heat and wire speed.
So I've got this selected at 18 gauge thickness material.
These numbers don't necessarily matter.
Most welders will just have two knobs
with random numbers on them.
And it doesn't really matter.
It's just the relationship between the heat
and the wire speed that you need to find.
And it's really dictated by what you're working on
in terms of what kind of metal it is and how thick it is.
So those are the basics you with me.
Okay. So now this thing's ready.
We're gonna attack our pipe into place.
So the only thing we need to do apart
from use our torch is ground our work piece.
So you can obviously ground to whatever you're working on,
but especially if you're working
on a nice welding table like this,
we can just ground to the table.
Then we'll get our pipe set
up and then put a few tacks on it.
Let me find a welding helmet.
(upbeat music)
(welder crackling)
Okay. Well, she's tacked on.
Now. We can take this to the car
and make sure things are looking right.
Similarly, how we had to trim the bottom
of the pipe up there
because it would have stuck past the flange.
We're gonna have to do the same thing here.
You can go like this.
(blade buzzing)
(upbeat music)
Okay. So we've got our test pipe kind of in place.
We've got our flange bolted to the rest of the exhaust
and this looks like it's gonna work great.
So now I gonna bring the welder down here.
I'm gonna tack this flange into place.
And then we're basically ready to go welder up all the way.
It's always a good idea to disconnect the battery
of a car that you're gonna be welding on.
If you're gonna be actually welding on car.
Basically when you're welding
you're using a lot of electricity.
And if any of that electricity finds its way
into your electrical system, it can do bad things.
One of my buddies growing up actually
shattered his rear window
welding on a car because he left battery connected.
(welder crackling)
Okay. Now we got this thing tacked up.
It's time to take it off the car
and go weld it up and actually talk about how to weld.
So as I go around this
I'm gonna be welding in kind of a C pattern.
capital C, capital C all the way around.
Now, since our flange is a lot thicker material
than the pipe itself,
it's gonna be able to take a lot more heat
before burning through.
So what I'm gonna do is basically
spend most of my time on the flange, plowing heat into that.
And then I'll kind of walk up onto the pipe
just for a minute, just for a sec.
That's the method.
Now, the other thing that's important is how far away
you are from the piece with your torch.
So you wanna be about three eights of an inch
half of an inch away from,
from the surface of what you're welding with the torch
and on something like this,
where we've got this 90 degree joint
I'm gonna be at about 45 degrees in this direction.
And then I'll kind of be at an angle in this direction.
If this makes sense.
Now there are two ways to go about it.
You can lead the puddle where you're
kind of welding this way
and dragging your torch in front of it.
Or you can push it
where you're pushing the torch from behind.
It's kind of personal preference.
I do both of those things.
Depending on what I have to do,
depending on what I'm working on.
So once you understand kind of how to hold your torch
and everything like that,
do kind of a dry run where you don't actually weld
but you just confirm that you can actually do,
see like I'm hitting, I got a little issue there.
So, I should have this over my shoulder.
Now I should have probably just done that from the start.
But, I didn't, and I wouldn't have
if I didn't make that dry pass.
So we'll do like this.
And then we've got a nice clear path all the way around.
I'll probably do this in like
two or three different sections.
So with that said, let's do it.
(upbeat music)
(welder crackling)
All right. So the first side
of the test pipe's all welded up
and it doesn't look terrible if I do say so myself.
I'm gonna let that cool down for a minute
just as is, and then we'll flip it over,
Weld the other side.
(welder crackling)
Okay. So Test pipe is completed.
Now, the only thing we have left to do
is go to the dyno and test it
and see how much horsepower we gained.
Let's go.
We are back at my friends at EF1 Motorsports
to get some dyno time from EF1 tuning.
So the stock cat is on the car right now.
So we're gonna put the car on the dyno
and do some polls and see how much power we're making as is.
And then we'll pull that off
and install our test pipe for our straight pipe.
And then we'll make some more polls
and see how much horsepower that straight pipe left us.
(upbeat music)
So that's three runs with the cat in place.
And our average power is 234 and a half horsepower
and 215.6 foot pounds of torque.
So now we're gonna swap back to our test pipe
do this again and see what the numbers provide us with.
(upbeat music)
Okay. So we are having some interesting results
and I'm gonna try to explain what I think is happening here.
We put the test pipe on
and kind of lost the ability to control boosts
getting a little bit of boost creep.
Now, what we're looking at here is boost.
Now the dotted blue line
that's our run with the cat, and you can see boost comes up
and red stays pretty steady at where we want it.
But the magenta line is with the test pipe.
And you can see it comes up
and it starts to flatten out like we're controlling it,
but as RPMs come up and our exhaust is flowing so well
with our new test pipe that the internal waste gate
on this turbo is overwhelmed basically.
And isn't able to bleed off enough pressure
to keep our boost at the level we want.
We're telling it to completely dump boost at that point.
It doesn't matter. It's just boosting.
As we're so high in the RPMs
and that tiny little internal waste gate
is just overwhelmed.
So we're kind of stuck with this.
I mean, we're making like 260 horsepower with the test pipe
because we can't keep boosts down to where we want it.
So that's kind of cool.
I mean, we made like 30 horsepower, but we're also
apparently at the limits of our waste gate setup
and as such our turbo setup.
So we might have changed turbos
in the not too distant future,
if we wanna change the way things like are going.
Okay. So with our boost creep issues explained
I still wanna try to make this test a little bit
more apples to apples.
So I just put the cat back on
and now what we're gonna do is,
try to match that boost creep with our tune
so that we try to put the same amount of boost
through the cat on purpose.
So then we can at least see how much power we make
at those boost levels with the cat in place
versus those boost levels with the test pipe.
Even though the test by boost levels
are on accident, make sense?
I hope so.
(upbeat music)
All right. So we just got done retesting with the cat.
And we're looking at our boost map here again
and you can see our original boost line
that we were kind of chasing,
that magenta line is in there somewhere,
just buried by all these other boost lines
because we did a really good job of mimicking that boost,
that boost creep that we were having.
So, once we did that and we retested the cat
the numbers that we got are as follows,
we have 252.8 horsepower on average with the cat
and 210.1 foot pounds of torque on average.
Then with the test pipe,
we managed 257.7 horsepower on average
and 217.2 foot pounds of torque on average.
That means we picked up 4.9 horsepower
and 7.1 foot pounds of torque with the test pipe.
Not too shabby. Its certainly not those 30 horsepower
that we were seeing in difference.
But with our boost creep issues taken into account,
I think this, is a pretty valid test
as far as tests go.
well, we sort of did it.
We made a test pipe.
That was pretty cool.
We put it on the Miata
and we definitely made way more power with it.
Now I'm not too happy with the way that we made the power.
I think we've got some issues like we talked about.
So I'm gonna have to address those issues in the future.
But for now we are making 260 horsepowers.
So I've got some more work to do on the Miata.
Now, if you also like working on stuff
and like the types of videos where we work on stuff,
then you gotta go check out yesterday's bumper to bumper
where Jeremiah goes over and insane 2000 horsepower Altima.
They talk about 3D printing body panels.
They talk about how the heck it even makes sense
to basically delete the whole chassis
and replace it all with tubes.
And they'll divulge a little secret.
Which seat is the most fun to ride in, in a drift car.
Hint, it's not the front seat.
So go watch that bumper to bumper.
You will not regret it.
You just got to click right here.
Oh, and also don't forget, we've got an underground,
the Donut underground.
And one of the perks which ends tomorrow
is that we'll send you a free sticker every three months,
if you're a member.
But you got to get signed up by tomorrow
to take advantage of the free stickers.
For more information about Donut underground
just click the join button below
and I'll see you in the underground.
And also with all that said,
I'll see you guys next Wednesday.
Don't forget to follow me on Instagram @Zachjobe
and I will catch you cool cats,
in a week.
Goodbye.