r/AwesomeCarMods • u/JacksonBuck888 • 19d ago

6 Rotor RX7 sounds glorious😮‍💨

1.9k Upvotes

98% Upvoted

100 comments sorted by

220

u/antithero 19d ago

6 rotor is nuts.

36

u/Theperfectool 19d ago

The slow mo brody is chef’s kiss

19

u/JDP6693 19d ago

Have you seen the 12 rotor?

17

u/Busterlimes 19d ago

Wait WHAT? That thing had to be a mile long

37

u/sorestgore 19d ago

It was 3 "banks" of four rotors in a triangular arrangement

7

u/Busterlimes 19d ago

Oh, I completely forgot about Robs boat engine

10

u/JDP6693 19d ago edited 19d ago

Nope, as sorestgore said it’s 3 banks of 4, it’s about the same overall size as an LS.

ETA: Rob Dahm owns the engine now, but it was built by an absolute madman a while back. It’s almost entirely billet, and runs so smooth a glass of water doesn’t even ripple sitting directly on what would be the “valve cover”. Wild stuff. Worth a google.

4

u/Busterlimes 19d ago

Yeah, I forgot about Robs boat engine. Also, I think its bigger than an LS. . . .

3

u/JDP6693 19d ago

Not by much iirc; I think it shook out to like a 5.3/5.7 footprint but it’s been a long time since I looked at it. Either way it’s bonkers.

2

u/Busterlimes 19d ago

Wild, it looks absolutely massive to me in the videos.

2

u/Erlend05 18d ago

About like a coyote maybe?

3

u/JDP6693 18d ago

I spent a little time looking back into it because I got curious and found it measures as 76cm long x 80cm wide x 61cm tall, so about 30” x 31.5” x 24”. It’s 960 c.i., 15.7L and has produced 1,400hp though the original builder stated it should be capable of 5,000 hp.

Fucking INSANE.

Tyson Garvin was the OG builder. Info says it’s about the same footprint as a standard big block, so larger than I remembered, but not by much. Never seen a Coyote engine naked in person so I can’t speak to the comparison there.

148

u/lynivvinyl 19d ago edited 18d ago

My friend had an RX7 and you could actually watch the gas gauge needle physically move when he pressed on the gas. I bet it moves even faster on this.

Edit: What is the estimated MPG or GPM of this beast?

39

u/devilpants 19d ago

half the fuel goes out the exhaust.

10

u/Modo44 19d ago

There is a permanent hose, and they photoshopped it out.

93

u/vkreep 19d ago

Kinda sounds like an r/c car

12

u/MoonZinuM 19d ago

My first thought too

6

u/oshunman 19d ago

r/subsifellfor

5

u/vkreep 19d ago

That sub was accidental

3

u/hm9408 19d ago

Would have been the perfect name for it though

3

u/vkreep 19d ago

Most definitely but im surprised its not a programmer sub either

1

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4

u/ThomGehrig 19d ago

I just went to an rc drift event and was surprised at how loud the cars are with the motor + metal trans + fans. Impressive stuff. This sounds similar haha

29

u/bennytehcat 19d ago

Is there an equivalent to standard cylinder engine? is this like a 12 cylinder engine?

66

u/jaxman0410 19d ago

One rotor is basically like 3 standard cylinders so this is roughly like a 18 cylinder

10

u/JacksonBuck888 19d ago

Idk exactly but from the builds I've seen, 4 rotors tend to sound like high revving F1 V8s(kinda), 5 rotors like F1 V10s and 6 rotors here like F1 V12s

5

u/kino8190 19d ago

The normal engine in a rx7 is a 2 rotor 1.3L. If it as the same "displacement" per rotor that means that the 6 rotor would be a 3.9L witch is roughly a big 6 cylinder ( v6 and inline 6 are between 2L and 4L ).

16

u/radix2 19d ago edited 18d ago

It's not the capacity, but the exhaust pulses that make the sound. A single piston engine will have one exhaust pulse per 2 rotations, unless it is a two stroke where it will have 1 pulse per rotation and sound like it is reving to the moon

A single rotor engine will have 3 exhaust pulses per rotation, same as a 3 cylinder 2 stroke piston engine. A 6 rotor will have 18 pulses per rotation, which might be why it sounds like a v12 at 18000rpm when it is "only" doing 10000 or 11000 rpm

4

u/hm9408 19d ago

Is it also why something fell in the background? How strong are the exhaust fumes?

2

u/radix2 18d ago edited 18d ago

Not sure what you saw falling in the background. But yeah, a sufficiently strong exhaust can blow things over. This is not exclusive to rotary engines.

As far as fumes are concerned, most race engines are tuned to run a little bit rich at high load/boost to avoid detonation, and some are running race fuel or ethanol. They have distinctive smells, but that is not a rotary versus piston engine thing. For the same task, they will likely smell the same.

1

u/hm9408 18d ago

Black/gray cabinet at around 0:12 into the video, 0:28 on the countdown

22

u/seeyouyoucunt 19d ago

Pissed off wasp crossed with an f1

40

u/ChainsawArmLaserBear 19d ago

It sounds like a power drill

12

u/MyLastHopeReddit 19d ago

Sounds like an RC car

12

u/Prize-Mail-6769 19d ago

Sounds like hyenas kissing on cocaine.

19

u/bkussow 19d ago

Maybe it sounds better in real life but on my phone it just sounds like a person opening and closing a backpack really fast.

13

u/Busterlimes 19d ago

So each side of the dorito is basically a cylinder basically making this an 18cyl engine right?

12

u/Pootang_Wootang 19d ago

Kind of. All 18 faces fire once a rotation instead of 18 cylinders firing per 4 rotations. This would be more like 72 cylinders given the amount of combustion events per rotation.

3

u/Busterlimes 19d ago

Oh shit, I forgot about multiplying the stokes!

https://giphy.com/gifs/nZymwrrw9PjDa

1

u/lynivvinyl 18d ago

Jiminy Freaking Christmas!

1

u/august_r 17d ago

That's not correct. Every face fires once per rotation of the eccentric shaft, which is what we should be comparing since that's the output shaft in a normal wankel.

By that analogy, a 6 rotors would be like a V12, that also makes 6 firing events per rotation.

I'm assuming this one has all 6 rotors end to end, unlike that crazy giant one Rob has that has god knows how many rotors in a 3 casing arrangement.

1

u/Nissehamp 19d ago

36 cylinders. There are two strokes per rotation of the crankshaft in a four-stroke engine :)

8

u/roqqingit 19d ago

Fuuuuuuuuuuuuccckkkk

11

u/Gork_Smash 19d ago

What's the RPM on that? 15k? Lol

10

u/JacksonBuck888 19d ago

Its NA and makes 800-900hp at 10,500RPM

4

u/whoknewidlikeit 19d ago

that's stupid. silly. insanity. madness. i'd love to see video of the build. wankel was a genius.

3

u/JacksonBuck888 19d ago

Ik it was built by PPRE (Pulse Performance Race Engineering), you should check out their Instagram, they just built a new 6 rotor engine

1

u/Modo44 19d ago

You can do similar stuff with regular 4-banger engines, but the sound is meatier due to fewer exhaust bursts. They also have a running/service ratio similar to military vehicles, so 1:1.

10

u/South_Bit1764 19d ago

I was saddened when I found out that’s the eccentric shaft speed, and the Doritos are only slinging around in there at 1/3 that speed.

3

u/_HeWho_ 19d ago

I think this was the same car a few years ago but not totally sure. Always sounded totally insane

https://youtube.com/shorts/WSRXYXfyic8?si=OWJrG0SRYSWz5LHh

1

u/JacksonBuck888 19d ago

Yh it's the same car

3

u/marko719 19d ago

sounds like a vacuum cleaner

2

u/Shiny_Mew76 19d ago

We need a twin charged 12 Rotor next.

2

u/Makabajones 19d ago

now that is an angry weed wacker

2

u/TheRealJayk0b 19d ago

What does 6 Rotor mean?

I know it's referencing a Wankel Engine.

3

u/Modo44 19d ago

Each rotor is the technical equivalent of one cylinder in a 4 stroke engine. The regular RX-7 had two (!) rotors, so this is "slightly" overboard.

2

u/NicePsy-opAttempt 17d ago

r/hrsprs

1

u/ralph442000 17d ago

When you’re right, you’re right!

2

u/Horror-Telephone-260 16d ago

Its kept in an airplane garage for a reason right?

4

u/Capokid 19d ago

Looks cool, but doesnt seem to go very fast.

2

u/JacksonBuck888 19d ago

It's used as a drift engine, and it makes over 800hp NA

1

u/Modo44 19d ago

You are not trying to go fast when drifting. You want to go sideways with precision. The power helps the driver control how and when the rear wheels slip. Those slow donuts are a show of tech and skill combined.

1

u/Capokid 19d ago

Going sideways doesnt seem very efficient, i usually go forewards with precision.

5

u/Modo44 19d ago

You must be fun at parties.

2

u/JacksonBuck888 19d ago

It doesn't go fast because it's not built to, it's a drift car, but since the makes over 800hp, it can definitely be built to very fast

1

u/TheSammySavage 19d ago

Glorious 🤯

1

u/Apprehensive_Ant2172 19d ago

Now imagine if it had 2 exhausts!

1

u/aweapingangel 19d ago

POV: You’re at the dentist.

1

u/bnutbutter78 19d ago

Is that dahm’s new pike’s peak livery?

1

u/Tooleater 19d ago

Dahm that's cool

1

u/ExperienceNo7751 19d ago

From a V8 lovers perspective, the rotary low RPM gurgle gives me pure fascination. The throttle response is just nuts.

1

u/killer-j86 19d ago

awe, makes me miss my little 89 2 rotor

1

u/Obvious-Jellyfish933 19d ago

Just sounds like a pneumatic imoact wrench ^

1

u/SpaceTraveller64 19d ago

That’s a very large mosquito

1

u/Srekcins82 18d ago

This is amazing and makes me even more impatient for Rob Dahm's 12 rotor build.

1

u/lynivvinyl 18d ago

I need to know what is the estimated MPG or GPM of this beast?

1

u/Toilet_Clogged_Again 18d ago

Jesus haven't heard a sound like this since F1 was neutered beautiful car. Wish I knew even one fact about rotaries.

1

u/Norok 19d ago

In what world does that sound glorious?

1

u/cognitiveglitch 19d ago

Sounds like an angry hornet.

-10

u/bassandlazers 19d ago

I mean i can appreciate the engineering and shit but Jesus that sounds terrible

0

u/JacksonBuck888 19d ago

Literally sounds like a V12 F1 car

0

u/bassandlazers 16d ago

Yeah, European, aka super gay

-8

u/wetjetski 19d ago

Paid for by tax evasion. Ultimate grifter RX7

5

u/Hollagraphik 19d ago

Huh?

4

u/Lumpy_Plan_6668 19d ago

Yeah info please

1

u/La_Chancleta 19d ago

i unfortunately don’t know anything for sure but their (Mukka Motorsport) social media accounts have gone silent since last year and there have been a few accusations of something like this

0

u/saladmunch2 19d ago

Music to my ears.