No Napalm Required: The Fire Breathing Four-Rotor RX-7
Sweet Balls of Fire

If Goku was any car, it would be David Mazzei’s four-rotor RX-7.

While I’ll be the first to admit that I don’t know much about Dragonball Z, I do recall there being quite a few fireballs, and as Rob Dahm’s video below shows, Mazzei’s FD isn’t shy with them either.

David’s car may not be the world’s first four-rotor FD, but it has to be one of the best sounding, fireballs included. Of course. his car doesn’t sound this way by accident. Reminiscing on the glory days of F1 when the V8s and V10s screamed and howled like high strung banshees all day long, he began to plot a way to bring those sounds and feels from the ’90s into a modern RX-7.

Step one, was obvious. The Mazda 787 and 767 factory racecars, and specifically the Le Mans winning car, the 787b, powered by none other than the famous 4-rotor race engine would be the primary inspiration. Their pitch and sound at 9,00RPM rivalled that of an F1 car revving at 18,000RPM, courtesy of the rotary firing once every revolution, compared to a piston engine which only fires once every other revolution.

Additionally, Walker Morgan of Morgan Performance Fabrication, created an equal length manifold to ensure the correct pitch and tone of 600Hz at 9,000RPM.

4Rotor Rx7 - Keiron Berndt - Speedhunters - SEMA 2018 Deliverables - 10 - 29 - 2018

Building a car that would perform in a visceral way was his first priority, as it was built to drive and entertain. Second, came the accessories and styling that accentuate the look and feel of the car so well.

4Rotor Rx7 - Keiron Berndt - Speedhunters - SEMA 2018 Deliverables - 10 - 29 - 2018

When I asked David for some power figures his response was priceless: “We decided to call it quits at 20psi, as the car was spinning tires on the dyno, reading 1,000whp and 650ft/lbs.” While he assured me that a thousand wheel horsepower is plenty to have fun with, he’s confident that the four-rotor can put down more than 1,400whp at 40psi.

4Rotor Rx7 - Keiron Berndt - Speedhunters - SEMA 2018 Deliverables - 10 - 29 - 2018

In any of the driving videos of the car, the boost has been turned down to 12psi – resulting in 680whp – due to the FD3S’ behaviour from his past driving experiences with the car.

4Rotor Rx7 - Keiron Berndt - Speedhunters - SEMA 2018 Deliverables - 10 - 29 - 2018

In my opinion, this car was one of the gems at SEMA, and like many SEMA cars it had quite the journey in getting to the completion stage.

4Rotor Rx7 - Keiron Berndt - Speedhunters - SEMA 2018 Deliverables - 10 - 29 - 2018

The project started in early 2016 and while it was a running car through 2017, it had to be torn down and rebuilt due to some engine complications. Buying a ‘drop-in’ setup (without an ECU, fuel system and wiring) sometimes doesn’t go to plan, especially with high horsepower builds as David found out.

4Rotor Rx7 - Keiron Berndt - Speedhunters - SEMA 2018 Deliverables - 10 - 29 - 2018

The previous setup arrived late, and had an oil pump with the wrong gear ratio which in-turn destroyed the shaft. The exhaust manifold wasn’t correct either, with incorrect tube sizing and insufficient wastegate priority, leading to excessive back-pressure and uncontrollable boost. The list goes on…

With a handful of friends and rotary experts, work on the second iteration of his car began in May 2018, and was buttoned up just weeks before SEMA which included a full engine rebuild to correct the extensive list of issues along with many chassis upgrades.

4Rotor Rx7 - Keiron Berndt - Speedhunters - SEMA 2018 Deliverables - 10 - 29 - 2018
4Rotor Rx7 - Keiron Berndt - Speedhunters - SEMA 2018 Deliverables - 10 - 29 - 2018

With a new tubular front end fabricated, they opted for a larger radiator and turbo (a GTX553 98mm Generation 2) along with a rear-mounted intercooler water core for the integrated inter-cooled intake manifold.

While this wasn’t an easy project to tackle, David is proud to say that he couldn’t have done it without everyone who helped make it happen. Ever since he was a kid, owning and building an FD was nothing but a dream.

4Rotor Rx7 - Keiron Berndt - Speedhunters - SEMA 2018 Deliverables - 10 - 29 - 2018

Fast forward a few years of penny-pinching, riding the bus, and a lawn maintenance gig; he was finally able to buy one. Ever since then, he has been putting in the time and effort to research and develop how to make it more reliable, and crank out even more power.

But that’s not the end of the story, as David has something in the works which he can’t quite share yet. He did mention that it will be a rotary powered, transaxle based, rear-engined hypercar. That’s all he would say, no matter how much I pried. I guess we’ll have to check back with him and his team in the months to come…

Keiron Berndt
Instagram: keiron_berndt

ADVERTISEMENT

Comments



Comments are closed.

29 comments

by Oldest
by Best by Newest by Oldest
1

Why burning fuel if it's not at 10000 rpm?
Because you can burn it at 4x 10000 rpm!

2

Not being a hater, but in the real world that thing is a complete turd.
NO power before 5000rpm? It's painful to watch that thing just trying to get it's wheels rolling.
Maybe with a lower geared rear end a 7speed transmission it could somehow be raced at some half mile events, provided that every other car was a Golf TDI.

3

dumbest internet comment goes to....

Author4

Um..?

5

This makes no sense.
Ignoring the fact that the whole 90's and early 2000's scene was built on cars with big single turbos doing exactly this and it was a ball of high speed fun (not a complete turd). But this car revs to 9,000, surely you realize that driven aggressively and being a rotary there would be no real time spent under 5,000rpm?

6

Sorry, what?

7
thathellastockusdm3rdgenyaris@instagram

the trying to be unique name is killing me with laugther.

8

It's the Irish - and legitimate - spelling of my name ;)

9

Beautiful piece of work!

Author10

Agreed!

11

You ain't puttin down 1,400whp through those POS maxxis tires. I can tell you that right now lol.

12

Funny, i just watched that youtube clip the other day

13

“Modern” RX7. The car is 26 years old! We probably won’t see a rotary as iconic as these 26 year old beasts ever again.

14

Needs bigger brakes now!

15
thathellastockusdm3rdgenyaris@instagram

i totally had this video in my recommendations and forgot to watch it. nice you got some killer ass photos <3

Author16

Thanks, man!

17
thathellastockusdm3rdgenyaris@instagram

you're welcome man.

18

DROOOOOOOOOOOOL!

19

Love to see a turbo the size of my head. Definitely not just a show car.

20

It's just a well done rx7 wich happens to have 1000hp

21

Looks great, and 1000+ hp is a super impressive technical achievement. At the same time, the owner seems to be recognising that they may have taken things a bit far, given they have turned the boost down to 12psi for any road use.

Fundamentally, the RX-7 was created as a sports car in the same mold, and by the same people, as the MX-5. A relatively short wheelbase, 50/50 balance, and a suspension set up to be responsive, interactive and agile. A car created to be great fun to drive with its original 255hp two-rotor powerplant. Given a car that so willingly rotates on the throttle from the factory, it's little surprise that it might become a bit much to handle with four times the original power. Ultimately the small, light, FR coupe package is a great choice for a certain range of power outputs, but it's no surprise that it works less well when taken so far beyond its original design parameters.

The mid-engined rotary hypercar mentioned at the end of the article seems potentially a much better package for this amazing engine, with more weight over the driven wheels and potentially a longer wheelbase and the sort of downforce a supercar can develop. Plus, of course, it could carry off the legendary green/orange livery with style :)

22

Its almost as if the engine, a four rotor, just materialized in the engine bay. No mention of PPRE in New Zealand being involved with the 4 rotor development and custom integrated intercooler and intake manifold. Again, lazy telling of the story.

23

+1 for this. Come ON, the car is only featurable because the 26b makes it and not a single sentence about PPRE? Especially disappointing since this thing has been floating the net for a year and every video says underneath it is a PPRE block

24

That's because PPRE built a boat anchor of a motor that needed a complete overhaul. Total frauds.

25

Well, you should ask the owner what he thinks about PPRE, then you'll understand why their name isn't mentionned here.

26

This car is unreal. Funny how rotary heads always love to bring up the 787b...it was so much slower than the piston driven Saubers.

27

Ask me about how PPRE ruined his first motor.

28

How is that plated, how long before the pigs take them away haha!

29

So...
I'm assuming the ECU has two "mappings" and he got a button/switch to go from 12 to 20psi and back?

OFFICIAL SPEEDHUNTERS SUPPLIERS