Retro Rally: Rhys Millen’s Group B Rx-7

There’s little wonder that so many people look back on the mid ’80s as the golden era of rallying. Group B not only reinvented the sport from a technical standpoint, but it re-popularized it too. For a while, the World Rally Championship was bigger than Formula 1. During those crazy years from 1983 to 1986, Group B’s regulations – or lack thereof – challenged manufacturers to build the most extreme rally machines their competition departments could dream up. But it was a double edged sword. The cars became too fast and too dangerous, and that ultimately led to their abrupt demise. Those glory days may be long gone now, but the spirit of Group B lives on in the machinery that survived rallying’s wildest years. Cars like Rhys Millen’s perfectly preserved ex-Works ’84 Mazda RX-7.

Rhys certainly needs no introduction in the Speedhunters world. 2012 has been a busy year for the Kiwi-born and US-based professional driver. He won the Pikes Peak International Hillclimb outright, he podiumed in the Formula D Championship, and he even launched a new rallycross-style motorsport called  Formula Cross. But the year isn’t out just yet, and as we speak he’s ticking off another long-time “to do”.

For more than a decade Rhys has dreamed of building a car to go classic rallying – an experience he could share with his father, Rod, another Millen who’s reputation proceeds him. Although best known for his Pikes Peak performances during the ’90s and early ’00s, and subsequent successes in off-road trucks, Rod cut his teeth on rally special stages. Before taking his career to the US he dominated the New Zealand Rally Championship, winning it three years running from 1975. Rhys’ idea was to build a replica of the Mazda RX-3 that took Rod to those victories. He bought an original NZ-new right-hand-drive car, shipped it to the States, and began preparing it for competition duty at his RMR compound in Huntington Beach, California. But those plans changed earlier this year when very special slice of rally history came up for sale in Belgium. A deal was struck, the funds were wired, and the car: one of a handful of Mazda RX-7s built in Belgium in 1983/1984 by Mazda Rally Team Europe (MRT) for Group B, had Rhys’s name on the papers.

If that fact didn’t make the Mazda a rare enough commodity on its own. Apart from being re-shelled into another genuine MRT-prepared RX-7 body after a crash in 1990, it’s the very same car that Rod used in the British round of the 1985 Championship. This week it’s in New Zealand, competing in the seven-day Silver Fern Rally – a marathon-style event classic and historical rally craft.

Unlike other car makers which had to manufacturer 200 road going versions of their chosen car to get a ticket into Group B, the RX-7 was accepted into the mix through prior homologation in Group 1, Group 2 and its subsequent Group 4 upgrades. Group B homologation signed off by the FIA on February 1 1984 allowed 20 ‘Evolution’ competition models to be built. Although the MRT Group B RX-7 was a highly capable rally car, the overall package built around a naturally aspirated engine and rear-wheel-drive chassis that proved no match for machines like the Audi Quattro S1, Peugeot 205 Turbo 16 and Lancia Delta S4 which all featured forced induction and four-wheel-drive. Then there was the fact that MRT never had full factory backing from Mazda Motor Company, which ultimately shunned the RX-7 and decided to put its weight behind the development of the Group A Mazda 323/Familia 4WD. But that’s another story.

But regardless of the RX-7s Group B success, there’s no denying that MRT created a very special, and very cool car. And apart from a couple of retrofitted (and easily removable) accessories – Rhys’ example is as original as they come.

If you were a Mazda Rally Team Europe mechanic back in ’84/’85 this is the scene that would have greeted you when you lifted the hood: a simple but very effective set up based on a factory Mazda peripheral ported 13B twin rotor engine. For better weight distribution the motor was shifted 4 inches (10cm) rearward from the production car position and fitted with a dry sump system.

Exotic carbon fiber/Kevlar was used prevalently during the Group B era as teams looked for ways to shed weight from their cars without reducing the stiffness or the impact resistance of the parts. MRT used the exotic material to form the engine’s intake plenum chamber which draws air from a filter mounted where the right-hand-side factory pop-headlight would normally sit.

Beneath the plenum is an MRT-modified Weber 51 IDA carburetor delivering the fuel and air mixture straight into the MFR (Mazda Factory Race) rotor housings via their peripheral intake ports.

Of course, a peripheral ported 13B driven with the butterflies of its 51mm carb wide open will consume a lot of fuel in not a lot of time. In the rear a trio of pumps fitted with large stainless steel braided lines satisfy the thirst.

The rear compartment is also home to the dry sump oil reservoir. Engine oil is cooled through a large core which is positioned in the rear wing to pick up air flowing over the car.

It all adds up to an engine that developed a reliable 300 horsepower at 8500rpm. However, due to the nature of the beast it was designed to be revved much further. In testing Rhys was keeping it safe with a self-imposed 9K limit, but realistically there’s at least a couple, maybe a few thousand more revolutions per minute in it. And yes, it makes all the right noises – you’ll just have to wait until some of Rhys’s in-car and on-car footage makes it onto RMR’s YouTube channel so you can hear it sing for yourself.

As opposed to the stark interior of a modern day WRC machine, the RX-7′s cockpit is a busy place with a dashboard that looks more like that of an aircraft than a car.

The Sparco suede-wrapped rally steering wheel and Pro 2000 seats are couple of upgrades made by RMR to improve the tactile driving experience. The vintage MRT Europe embroidery is a nice touch.

Mazda gauges keep an eye on all the critical pressure and temperatures throughout the engine and driveline. Fuses are at close-hand, too.

Terratrip recently brought back its iconic ’80s ‘Terratrip 2′ computer to satisfy the needs of classic rally car owners wanting to fit an authentic retro rally meter. Of course, this one isn’t a re-issue.

And that’s the original ’80s-cool wooden gear knob. As the pattern suggests, the MRT/PBS five-speed manual transmission features a dog-leg first gear to keep second and third gears in a straight line for quick and reliable shifts.

As I mentioned previously, there’s a very good reason why the tachometer reads to 12,000rpm!

Besides power output and chassis setup, MRT did a lot of work to the RX-7s body, adding widened fiberglass fenders front and rear, a fiberglass front cowl panel and a vented fiberglass hood. There’s also a large duck-tail fiberglass rear wing/oil cooler housing.

Lightweight fiberglass doors feature as well, as do Lexan windows, both here, in the side three quarters and in place of  heavy rear hatch glass. The total curb weight is around  the 2120 pound (960 kilogram) mark, which back-in-the-day was comparable to the Peugeot 205 Turbo 16′s original Group B rally guise.

The RX-7′s iconic pop-up lights are replaced with fixed fiberglass pods, which I’m guessing were made for weight saving reasons as well. Or maybe having fixed lights was a category requirement?

What the RX-7′s headlight don’t do for the drag coefficient, the aerodynamic side mirrors try to make up for. Of course they’re formed from fiberglass too.

In its own right the MRT Mazda is an impressive looking, sounding and performing machine, even 27 years after it last competed in a World Rally Championship event. I just can’t help but think what might have been though. How good could the RX-7 have been if Mazda had properly invested in the Group B and brought a four-wheel-drive and turbocharged rotary powered car to the table? We’ll never know I guess..

I’m going to wrap up this post with a couple of photos of Rhys’ Mazda Rally Team Europe RX-7 doing what it was originally designed to do, but with Rhys at the wheel, in what– believe it or not – is his very first stage rally in a rear-wheel-drive car. In the company of some very quick, and extremely well-sorted BDA-powered Escorts the RX-7 might not be the fastest car out there, but it’s definitely one of the spectator favorites.

On a side note, anyone who’s planning to attend Rod Millen’s 2013 Leadfoot Festival happening in March should be happy to know that the car will be staying in New Zealand until then so Rhys can run it up the 1-mile long tarmac driveway.

I’m hoping he’ll do it on half-worn rally rubber..

– Brad Lord

SPECIFICATIONS

1984 MAZDA RX-7 GROUP B

Engine: Mazda 13B twin rotor; factory MFR peripheral ported rotor housings; Weber 51IDA carburetor; 3x high-flow fuel pumps; braided stainless steel fuel lines; MRT carbon/Kevlar intake; K&N air filter; factory dry sump; trunk-mounted engine oil reservoir; rear-mounted oil cooler

Driveline: MRTE/PBS 5-speed dogleg gearbox; twin-plate clutch; MRTE rear axle; limited slip differential

Suspension/Brakes: Custom-built Bilstein shock absorbers; improved parallel links, four-wheel disc brakes

Wheels/Tires: Enkei 15×6″ alloy wheels, DMack DMG2 195/65R15 gravel tires (front); Enkei 15X7″ alloy wheels; DMack DMG2 205/65R15 gravel tires (rear)

Exterior: MRT Group B fiberglass wide body kit: front fenders; rear fenders; boot spoiler; vented hood; front cowl; Lexan door windows; Lexan rear screen

Interior:  Sparco Pro2000 seats; Sparco suede steering wheel; Mazda 12,000rpm tachometer; Terratrip 2 rally computer

DESKTOPS


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13 comments
Jason R
Jason R

Too dangerous? We all know that it was the spectators stupidity that led to the end of group b.

Mats
Mats

I was working for MRTE Mazda rally team europe 1983 to 1989 so i am real happy to se this nice  group B car i remeber the nice sound from that 13B rotary engien

EricSeanDelaney
EricSeanDelaney

If there's anyway you guys can feature a true Delta S4, I would be the happiest person in the world.

Curlytop
Curlytop

Which car would win or be faster out of a old school group b car and a up to date wrc car? Very good post anyway! ;)

Corey K
Corey K

What an awesome machine! I love me some 1st gen RX-7's; they don't get enough attention! It's cool to see the "License by NSU" badge on that 13B. I forgot that Felix Wankel was part of NSU (now absorbed into Audi) when the engine was designed. Neat stuff! Now if only Rhys was able to acquire one of Rod's old 4WD RX-7's!

Spike4090
Spike4090

I would love to take that car down a dirt road, wide open, and sideways.

 

kmakzi
kmakzi

hey brad, are you doing any coverage of d1nz rd1 manfield?? also do you have a contact email.thanks

freeskier7791
freeskier7791

I had never seen a Mazda group B before, great feature on a car from the most interesting racing series ever.

Angela
Angela

This is a car that really looks like it came through a time machine. I think the headlights give it a nice touch. 

greenroadster
greenroadster

Always cool to see a rotary Mazda in race colors

Ziemas
Ziemas

 @Curlytop The modern WRC cars would be much faster. The bigger power put down by the group B cars is no match for the technology of the WRC cars.

Trackbacks

  1. […] case, as unabashed rotary fanboys we had to post this up. There’s lots more to explore in the Speedhunters feature on Rhys Millen’s Group B RX-7 which he recently purchased and is now campaigning in historic […]

  2. […] Retro rally: rhys millen’s group b rx-7 | speedhunters […]


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