Who enjoys being left out of things? Not me.
But the test subject of our next myth
happens to be a two-seater.
So, we drew straws.
And guess who gets to scope out the next location?
I'm gonna hit the road and I'll catch y'all on the flipside.
Enjoy this one.
This is like an artform.
It's just like, making sure the steel's lining up.
Making sure the form is perfect.
Following the original top.
It's more like sculpting than it is fabricating.
Oh, she's ready to drive.
- We got a chop top. - Yes we do, sir.
Jim, look at how much headspace we have in there.
Meet the team.
This might be the miracle coolant
that everybody's been searching for.
- Oh, no! - Oh, jeez.
With the mechanical expertise...
My main concern is structural integrity.
To test all things automotive.
- Oh! - The engine died.
The more air we push through,
the more fuel we siphon out.
And boom!
This is Motor MythBusters.
Hit it!
Where science...
...meets the streets.
This car is insane! Do you hear that engine?
It just wants to go fast.
But it's not just about the engine,
it's also a lot to do with the aerodynamics.
Back in the old days, the guys driving hot rods,
they figured if they chopped their cars
and lowered the roof,
that would give 'em better aerodynamics.
Therefore, allowing their vehicles to go faster.
Chopping the roof off a stock vehicle
is a topic often talked about in hot rod forums.
It's a technique that was first pioneered in the mid-1930s.
Believe it or not, from a standing start,
some of these draggers would beat a jet plane down that quarter-mile stretch.
But did lowering a hot rod's roof
really make it go faster?
So that is the myth.
If we chop our car,
can we get more speed?
In order to test this, we need a vehicle.
Oh!
So, Tory, I have the perfect vehicle.
The most unaerodynamic car we have.
The worst vehicle we have in the whole fleet
-of vehicles on MythBusters?
The Tradesman is perfect.
Brake pedal.
This van was used when we tested a movie scene
about sabotaging brake lines.
- Oh, that feels good. - Yeah. All right.
And returns beautifully.
For that myth, we moved the driver position
and controls from the front to the backseat.
- Oh, my gosh!
But this time it's going to get an even more radical makeover.
All right. So we're gonna chop this.
- Yes. Well-- - But first, we need to get some data.
To see the top speed of this big, crazy van.
Yee-haw.
All right. Why don't we do a control test?
We'll get this to the end of the runway, I'll floor it.
Oh! You're going 21 miles an hour. Look at that.
Oh, my gosh!
So we're going to see how fast we get up to
in the quarter mile.
Then we'll be able to compare results before and after we modify it.
Are we sure we're good?
- Are there any more airplanes coming? - I don't,
- I don't see anything. - Are they not?
Here we are on an active airport
and let's just say that this runway is quite active today.
- This is exciting. - You feel that adrenaline?
- Oh, totally. - Oh, yes.
- Oh, it's there, right? - Yeah.
And on the mark, you go pedal to the metal.
I'm gonna go through the metal. Pedal to the rust.
- Might go through the floor.
All right. Here we go.
Three! Two! One! Go!
- Twenty-seven, 30.
- Look how long it's taking to get up to speed. - 40.
Fifty.
Fifty-nine. 60.
Sixty-five. 67. 68.
71 miles an hour.
Whoo-hoo.
The throttle's stuck. Bisi!
Oh.
- That was exciting. - Throttle was stuck.
- I kinda feel like a near death experience. - Oh, no! Stop!
- Is your heart beating fast? - No.
- You're fine. You're fine. - That was awesome.
- It was cool. - It was literally, it literally was like,
Oh, my God!
When that throttle stuck and the brakes stopped working.
It was like, "Oh, wow.
The runway is almost finished.
How are we gonna stop this thing?"
- Oh.
Anyway, bottom line is,
- we were hauling that-- - Yeah.
- 71 miles an hour. - Yes.
Sixty-seven.
Now with two more runs...
That's it.
Whoo-hoo.
Go.
...we've got all the data we need.
Sixty-seven. 68.
That's it. Quarter mile!
All right.
So, now that we know our average top speed of our unchopped van,
before we actually chop it, we should get more info on its aerodynamics.
Oh! I have the perfect answer for that.
- What? - So in racing, I did a lot of tuft testing.
- Oh! - I don't know if you know what tufts are.
- Tufts are when you put little pieces of fabric... - Yeah.
- on the outside of the vehicle. - Yeah!
I love using yarn, especially one that contrasts the body of the car.
- Yeah. - Color-wise, that'll be perfect!
And it's funny, 'cause it seems a little archaic,
but they still use it in modern-day racing.
Anyone who is serious about aerodynamics,
- still today respects that particular procedure. - I love it.
Now we'll use these pink tufts,
as a weight, see what type of turbulence we see on the van.
I know it looks like we're decorating a Christmas tree,
but this is actually very important science business.
Pink is good because it really stands off very nicely
and as we film it allows the opportunity
to see how we can improve
on the aerodynamics of the van.
I think a huge problem you're gonna see is just,
- right now, this is just such a big, flat surface. - Yes.
Up to the top, you know, up to the windshield,
you know, that means, this a wall pushing through wind.
I think, we're gonna see a lot of problems.
What I'd be very curious about as well is, what happens in this region,
- so if you put tufts here... - Oh, yeah.
- you see things standing right up? - 100%,
- we definitely do the roof as well. - Yeah.
And if we see any movement that goes upwards or downwards,
we know we have turbulence and we need to modify the van accordingly.
All right. We're all tufted up.
- Yeah. - We're going to see how aerodynamic this thing is.
This van is looking pretty tuffed.
Here we go.
Tracking with us is a car with a high speed camera.
Filming at 5000 frames per second.
To get an adequate amount of airflow over the van,
we need to get it up to around 25 miles an hour.
- We're getting a lot of turbulence on the top. - Okay.
- Tremendous amount of turbulence. - Yeah.
As in the eddies are forming on the top there,
the string will just pull them right up.
- Flipping around. - Yeah.
And then we've got a really good wind flow just on the windshield
but I mean, that makes sense,
- that's where most of the wind is getting pushed. - Of course.
Everywhere around the flat windshield,
- we're getting all kind of turbulence. - Absolutely.
It's going to be interesting
to see what the high-speed camera is picking up.
We're limited to what we can see here.
It's so critical for us to take a look at the film...
- Yeah. - And see what our tufts are doing around the vehicle.
All right. Before we start,
- we're gonna look at our modern-day vehicles. - All right.
Just to see what an aerodynamic car should look like.
What's interesting is, as you see
it's flat across all around.
-We don't have any eddies or vortices forming, -Right.
- which is pretty nice. - And we're definitely seeing
a little bit of turbulence in the back here,
- which you expect. - To be expected.
But, I mean, this is what a aerodynamically-designed vehicle would look like.
This is good though. Because now we're seeing how the tufts should behave.
Yes. We have a frame of reference.
- Yeah and then I can't wait to see how our van looks like.
- Okay. - Okay, here's our van.
And... Look at the top of the roof, there's nothing hugging.
Things are actually... The tufts actually move upwards.
Yeah. They're just flapping all over.
- They're like... - Yeah, they're partying...
-And we weren't invited.
It's almost like, a flat wall.
You know what this points to?
Once we chop this roof, we're gonna gain significantly.
Imagine getting rid of all of this.
- Yeah. - The advantages we could experience.
-Yeah. 'Cause it will just be a big wedge. -Oh!
You know what would be cool, is if we could actually build - a 3 - D model of the van.
Then we could play with the shape of it and see if we can make it more aerodynamic.
Wow. That's pretty cost-effective
and to do that properly,
we need to digitally scan the car.
And then, in software, model anything we desire.
- Yeah. - And test accordingly.
- I like where that's going. - Yup.
I know the perfect person to call for this particular exercise.
- Awesome. - Yeah.
In the olden days, hot rodders had to physically cut the roof of their cars,
without even knowing if the results will be positive or not.
Nowadays we have access to modern technology, we can digitize our vehicles,
model them in CAD software, 3D print them and do a small-scale test.
Now, that's exactly what we're gonna do with our van.
To do that today, we have Martin Horton, from blupointscan
and he's going to scan the entire vehicle and allow us to model properly.
These are scanning targets.
They're a five-millimeter diameter target
and the scanner picks up the center of each one of these targets
and assigns an XYZ coordinate to it.
And from that, it develops what that surface looks like.
- Very nice. - Yeah.
- I'd love to see a test scan. - Okay, let's try one.
So, what we can do here is set up the scanner so that
I have all of these targets that are gonna be captured
in the scan,
and I'm gonna capture a surface.
- And there's my surface. - Very nice.
So, what would happen if I put my head into the photo when you take a scan?
- Well, your head would get captured in the scan. - Oh, okay.
- 'Kay? - Okay.
Hey, we got it! Check it out.
Oh, my goodness, that's crazy!
It captured me properly.
- Yeah. Yeah. - Oh, my goodness, with good detail too.
- Oh, yeah! - Oh, wow!
How long will it take to scan this entire vehicle?
Probably about four hours.
I'm gonna scan the side,
the front,
the roof and then the rear.
-And stitch all of these together. -Wow.
Well, Bisi, I have taken the model of the van that we scanned
and so now we can modify this van in any way we want with the computer.
That is really good.
So, in this myth, we want to see
if chopping the roof would help us get any aerodynamic advantage.
So, I'm thinking about, yes, doing something standard
and...
old school, just to see, and it may look pretty cool,
we chop the front and then have that section taper upwards
- towards the factory rear. - Oh, okay.
So, you're thinking of taking a chunk out of the A pillar, maybe a little bit of B pillar
- and leaving the back of the van the same? - Yes, absolutely.
So, let's see.
How much roughly would you say are we taking out of this, on the real van?
So, you know, I kind of still want to be able to see out the van.
That's a good idea.
So maybe,10 inches.
10 inches or so? Let's see, we have a bit of a slant chop here.
- Oh, that's perfect. - Yeah, there we go.
- So, that's from the other side. - Mm-hmm.
We can look at it. Perfect. That's roughly 10 inches.
Nice. But I still want to explore the traditional full chop.
- Yeah-- - So, 10 inches all across.
Yeah, same idea. Taking roughly 10 inches out of the front A pillar.
But now we're extending that all the way to the back.
So we've got 10 inches, 10 inches and 10 inches here.
- Beautiful. - Is that about what you were thinking?
- That's perfect. - Right on.
- Looks pretty cool. And strange. - Yeah.
Now that we have our models iterations done, - we're gonna 3 - D print them
and compare them against each other in a small-scale test.
All right, so now it's time to pick what type of chop we're gonna do on this van.
- So, we have our 3 - D-printed van models.
We have the regular shape, then we have our slanted shape
and then we just have the straight chop shape.
We have created our own little wind tunnel.
We're gonna put each of those shapes in
so that way we can decide which version is the most aerodynamic.
This is my smoke leak detector.
I use it for turbo charge applications
to see if the systems have any leaks.
Oh, I see some smoke right here.
So we need to fix that.
But it's the perfect device to create smoke for our miniature wind tunnel.
What is it?
- It is vape juice. - Is that really vape juice?
It is. Without the nicotine.
Don't stick you head in the end of the box.
Yeah, that looks great.
Our home-made wind tunnel is done.
We have our plexiglass shape,
we have our fans that are blowing air into the tunnel.
Then it's going through a bunch of straws.
Now the straws are going to keep that air moving in one direction,
which we need, so we could see our line of smoke.
And then we have a fan at the other end of our chamber,
that's actually pulling the air out.
So, that way we get a nice, even flow of air
so when we send our smoke through the tunnel,
we can see which van shape is most aerodynamic.
- This is our base model, we're looking at... - Yeah.
In terms of the factory then and how it looks in its originality.
And what we're gonna look for is that flow around the entire van,
- better that we can see, while sitting inside the van. - Yeah.
I feel like a mad scientist. All right.
- You ready? - Yes, so here we go.
- Okay. So, Tory, you see that upward stream? - Yeah.
It hits around the wind shield and it has a large disruption just like we saw in the video.
- Very similar. - You know what else is happening?
Look back here, at the back of the van.
See, there's like a vortex being created?
Yes, we have a lot of eddies forming back there.
- That's not good. - Which is to be expected.
So, now, we are going to do another test.
So, this is the van now, that has the flat top, no rake whatsoever.
- Standard chop. - Here we go.
Okay, Tory, this is painfully obvious. Look what's happening.
- Look at that. - That is beautiful! That's exactly what we want.
And we decreased the wind drag at the back of the van, tremendously.
It's obvious, this is a much more aerodynamic design.
Yeah.
You see how that upper current flows so nicely
and doesn't have that disruption the initial one had?
- Yeah. - That's very promising.
- And if you look at the smoke, it's just rolling off... - Absolutely.
The back of the vehicle, where before,
we saw a huge amount of turbulence right at the back of the van.
So you're telling me, those old hot rodders were onto something?
- I think so. - Oh, my goodness.
- Okay. - All right, the last design
we're gonna go for, is the slanted roof.
- I'm not too excited about this one. - No.
Only because,
I mean, just looking at this shape, and how air will go...
- it's still gonna hit the top of this, but... - Yeah.
Who knows, maybe it'll help us.
Okay.
The rear dimensions are the same as the original van,
but the front has a much lower frontal area.
So, I'm curious to how this is gonna work out.
And...
So, we have a nice
stream going all over the top, onto the middle--
- Yeah, there's a lot of turbulence. - We have turbulence
- from the middle. - I'm not really thrilled about this
design, even though it looks cool,
it doesn't seem to be helping aerodynamics.
It does not.
Well, right now, I'm favoring just the straight chop.
I'm right there with you.
So, the winning design is the straight chop.
Now, I was actually hoping that this wedge chop
would be the winner, just because it looks cooler,
but it turns out, the old school, just dropping the roof,
is going to be the most aerodynamic, so...
now all we have to do...
is do this,
to our real van.
You know, Tory, I've never cut a van up before.
- You know what, I've sheered the top off of a car. - Oh.
- On purpose? - Yeah.
- Driving underneath a semi-trailer. - Oh, my God.
But, I've never actually done
a proper chopping of a hot rod.
- But I know how, like I kinda know the basics. - Okay.
- All right. - And so we wanna cut it down, almost ten inches.
- Okay. - Sorry.
- Seriously, I mean-- - So, basically, we're gonna have...
Like viewing of... we'll have like a six-inch
viewing windshield.
- I think if, you know, if we get real low...
- I mean that's how hot rods did it, right? - Yeah.
- That's a healthy chunk of... - Yes, it is.
...of cut there.
- What if we took out 16 inches? - What?
- If 10 inches is good, 16 inches-- - Oh, my...
- 16 inches might be amazing. - Tory!
- Like, just think about it. - Tory...
- Just listen, hear me out, hear me out. - Okay.
Okay, so, we have...
- like 15 and a half inches, so we could technically... - Right.
cut this to 12...
- And you still have-- - And you have three inches of windshield?
- How big are your eyeballs? You don't need to see--
All we need to see, is the road.
Like, look, look, all we need to do, is this.
- Look at this. - See, here's Tory again,
- Look... - going crazy. He's always trying to find...
take something extreme, and even go...
- Tory extreme with it. It's, it's... - Look at this.
I have plenty of head room.
Why does everything have to be crazy with you?
Why can't you just be...
- normal? Oh, my God. - If it's worth doing, it's worth overdoing, right?
- When we start winning races with this van, you'll know. - Then...
"Now I understand what you were talking about."
Okay, you know, that's...
- That gives us 12 inches. - It's still aggressive, but that's not as bad.
- Twelve I'm okay with... that'll be pretty cool. - I love it.
- Okay. Cool. - It would look so sick when we're done.
So, after a bit of back and forth,
Tory and I have decided to chop 12 inches.
Will this be enough to improve its aerodynamics,
and beat 71 miles an hour, in a quarter mile?
- I'm excited. My first chop. - Me, too.
- All right. -But before we get chopping,
we've got to get weighing.
'Cause once we chop this vehicle,
- our weight's gonna change, quite a bit. - Oh, totally.
And I think it's very important that we keep our van
- the same weight as the control test. - Good point.
That way we keep it just looking at...
Is the aerodynamics making this van go faster?
- Ah... right there, right there, right there. - Okay.
All right, how much does the van weigh with us in it?
4,198 pounds.
So, we'll chop the top,
make all the modifications, and, when we're done,
- with you and I, in the car... - Yeah.
- We need to have this as our control weight. - Yup.
All right, first thing we need to do is, we need to strip
- the entire interior of the van. - Yes.
'Cause if we're gonna be cutting this, there's gonna be sparks flying.
- We don't wanna set the interior of the van on fire. - Yeah.
Now that we know our weight...
We can take everything out, and just put the weight back in, as we need.
Sounds good.
So far, so good.
So, right now, I notice that the front windshield is really dry-rotted.
So, I'm gonna cut this seal on the inside, which is little more pliable,
allowing me to release the pressure around the windshield, push it outwards,
and hopefully save the windshield.
Because we're gonna replace the glass with a polycarbonate-style material,
and I want to use that windshield as a base,
to form that polycarbonate, so we can have a nice shape
to the front of the van,
Uh, Rose, we have some questions for you.
We're about to start this chop,
and neither of us have ever done like a professional chop.
Yeah, the size makes sense, but...
to be able to make this section,
that's where I'm a bit confused.
Automobiles are a football shape, so as you lower the roof,
it's a little too narrow.
So, we've either got to widen the top,
or we've got to move the pillars in.
- The plan is, we wanna take out 12 inches-- - Oh, that's good.
Cause when you cut these roofs, you should cut them a lot.
- Yeah, that. See? - Oh!
- She agrees with me. - You're onto something.
Thanks.
What I'm doing right now, is just putting in some cross bracing,
because once we cut the top of this van off,
those walls are gonna wanna fluctuate,
and we don't wanna loose our shape, so...
once we have those welded in place,
then we can start cutting our support beams.
If we don't cut these structures out,
it'll really pose a problem for us, to remove the top entirely.
And then, we can actually do the roof chop.
My first door.
- This is just a straight edge. - So you can use that to...
- So, it'll be a nice straight cut. - Okay.
I'm partial to vans and I put tons of power in them.
I love building 1000 horsepower minivans
but cutting the roof off of one,
I have never, ever done that,
even thought I'd ever do it.
So, we're making some great progress on the van chop.
Once we have the entire thing cut,
we'll drop the roof, and see how it looks.
So, Rose is bringing the forklift in,
- because we're at a very critical point right now, - Coming in.
where the roof is actually going to
be detached from the van.
So, we don't want that thing just to fall on us,
so we're gonna put the forks in,
cut the rest of the door frames,
and then, our front supports,
once we're done with that.
It's a good thing we got the forklift in place.
This is so cool-looking.
This is gonna be...
- crazy, huh? - ridiculous, I mean...
it's gonna sit right on the dashboard.
That was a lot of rust.
All right, you guys ready?
And then we're gonna start lowering that roof.
Gonna get it to the right height.
Oh, my goodness!
But we are at the point where this van is chopped.
That looks, oh, my God, that looks cool!
- Like, that's ridiculous.
- Is that not hilarious? - It is.
- Tory, can you see me? - Oh, I've got plenty of room.
We just got to get rid of these visors.
Well, we chopped 12 inches out, and now...
you know, Bisi said I was crazy. I'm starting to feel like, maybe I am
a little crazy, too.
I only have, maybe about...
4 inches of windscreen
to see out of, but, I don't know,
this might actually work.
- Wow.
I don't think I have said as many wows in my life, as I have today.
- Yeah, you've been saying wow. - Wow, wow, wow!
- Bisi, you've been wowed by this whole thing. - Yes, I have been.
So, now that we've cut out 12 inches from our pillar,
the pillars don't match up any more.
So, what we need to do, is actually cut the roof,
into couple of sections...
...bring them out, so the pillars line up.
Let's just make it a convertible.
Weld those...
We gotta make sure all of our angles are lining up,
so this thing goes back together beautifully.
- Look at that. - So, imagine...
- Imagine it's a nice, summer day... - Oh, yeah.
- Can you just sit lower?
- Oh, yeah. - That's what I'm talking about.
Whoa!
Then we have to put pieces of steel in between our gaps.
These pieces allow for adhesion of the center section
to the outer sections, and...
I had the opportunity to curve them using a hammer and anvil,
to allow for a nice curvature, so it can follow the same lines
as the top of the van.
Meanwhile, Rose is using the planishing hammer to shape
the largest two pieces that will fill in the bigger sections of the roof.
Yeah this gives it strength, so, that's you know, it's dent resistant.
So, it has dimensional stability.
So, it gives it a little bit more structure.
- Yeah. - Good.
It's just like an art form.
It's just like, making sure the steel's lining up,
making sure the form, the top of the van, is perfect,
following the original top.
It's more like sculpting than it is fabricating.
Oh, she's ready to drive.
- We got a chop top! - Yes, we do, sir.
Dude, look at how much head space we have in there.
That's plenty of room to see.
Our steering and pedals go back to the original position,
and the seats are bolted to the floor.
So, this is all about aerodynamics and it's not about weight.
3,952.
We need to make sure it weighs the same as it did
before we chopped it.
All right, what are we at, Bisi?
We are 4,228.
How about now?
4,199.
- I'll take it. 4199. - Close enough.
I christen her... Ruster.
Ah, I love it.
- How's that? - Perfect. There you go.
-Wow!
-This thing is so cool-looking. -It's beautiful.
I have built vans in my time, but nothing this exquisite.
And, I thought when we said we're gonna chop this van,
it was gonna be as easy as
- take out a section, drop the roof... - Oh, no.
Weld it back, and we're done.
I had no idea how much work this was gonna take,
but hopefully, it's gonna pay off.
Well, there's only one way to find out.
Take it to the tarmac, and see what happens.
I love it when a van comes together.
- I pity the fool who doesn't like this van.
Does size matter, or not?
They're about to find out.
With the top of the van now 12 inches lower,
it's time to discover whether chopping the roof off
really does make a vehicle go faster.
But first they're gonna re-do the tuft test,
to compare the van's pre and post chop aerodynamics.
- All right, Bisi, the chop is done. - Yes.
- We have the tufts on it. It's time to do a run... - Absolutely.
To see if our chop helped us, or hurt us.
Yes, we saw some good results in a small-scale test.
Now, we can monitor what happens
in real life!
- All right, you ready to do this? - I'm ready, sir.
- All right, here we go. - All right.
- Might help to put it in gear. - That would help a little bit.
Like before, we're being tracked by a high-speed camera.
Oh, wow!
Oh, look at that. So, initially, with the old body,
- we saw a lot of turbulence on top. - Yeah.
Everything's laying flat.
- Remember we had a lot of disturbance before? - Yes!
-All on the roof before they were flapped around... -It's just laying flat.
And now they're laying flat.
Look at our windshield. Beautiful.
I mean, that's hopeful for us.
I think we're in the right path, Tory.
Let's see if this changed the aerodynamics.
Wow, Tory, look at that.
That shape actually has made a difference.
Initially, when the van was in factory form,
we saw a significant amount of turbulence, on the roof of the van...
-Yeah. -telling us that it didn't do very well
-in allowing us to cut through the wind easily. -Yeah.
- And now, all that-- - And now, everything's just laying flat.
- They're all laying flat. - Oh, my goodness.
It's like we've almost created a wedge to cut through the air.
A beautiful, aerodynamic wedge.
I'm excited because, this is now mimicking the aerodynamic profile
- of a modern car. - Yeah.
That means, what we saw on the small scale, translated very well,
-to real life. -Which also means, that might translate
- to us getting a faster speed. - Can we do it?
- Ready for the real test? - I'm so ready.
If we get a faster speed,
than 71 miles an hour,
this is a completely confirmed myth.
I agree.
Chop top, final test.
Quarter mile.
Three.
Two.
One.
- Hit it.
C'mon, baby!
You can do it.
49.
50.
- 60. - C'mon!
- Are we gonna do it?
We're gonna do this!
- That's good!
- We did it! - That's great!
- We went 6 miles per hour faster. - I will take it.
I will take that.
And, after two more runs...
That's good!
-It's crazy! -Oh, my God!
Three, two, one.
...it's a done deal.
You can do it!
Chopping, and lowering this van's roof...
- Oh, my goodness! - We confirmed it.
...has made it quicker.
Those old timers knew what they were talking about.
- Chopping your car will make you go faster! - Absolutely!
- That's great! - It worked!
- Wow!
That was crazy!
I can't believe it.
Ruster did it.
All we did is, we just chopped it and brought it down by 12 inches.
And that gave us a faster speed.
You're absolutely correct. The van weighs the same,
same driver, same low horsepower power plant,
six miles an hour is a big deal.
- I'll take that. - Yes.
And the thing is, in a race, any little bit of advantage you can take,
- you'll take it. - Right.
- So, we had to confirm this myth. - Yes!
Those old hot rodders, they were onto something.
- They knew what they were doing. - Awesome.
- Good job. - That was a lot of work.
Let's go see if we can find people to drag.
Oh, they won't know what's coming.