By Pat Griffith

Don’t tell John Vitamvas he has the wrong car for the class. 

Over the winter, John bought a 1990 Mazda RX-7 GTUs to prepare for Street Touring Sport (STS).  The second generation RX-7, known to the world of car geeks as the FC RX-7, doesn’t exactly have the following in autocross like the Honda CRX or Miata, which rule STS and are also competitive in Stock and Street Prepared.  Being stuck in E Stock where the MR2 reigns and in CSP where the Miata is king, it’s a rare occurrence when an RX-7 is sighted at an autocross.

But John thinks the non-turbo FC RX-7 has potential in STS.

“I had always thought the car could be a bit of a ringer in the class but nobody had really tried one,” John said.  “But really, I like being different and find it more fun driving a car people aren’t used to seeing.”

If the first WDCR points event is indication, John may have found that ringer.  His co-driver, Greg Olsen, won STS by almost 0.3 over Ian Baker, last year’s third-place trophy winner at the Solo National Championships in a Honda CRX.  

John finished fifth but had raw times on par with Greg.

“The first win was awesome, but I’m not reading too much into it,” John said.  “The surface wasn’t what it usually is, Ian’s car wasn’t working right and we were way off where we should have been based on PAX.”

He was still surprised at how quick they were out of the box considering it was the car’s first event, and it hasn’t been tuned yet.  The car also doesn’t have ABS, which John admits will take some getting used to.

“The biggest surprise for me was experiencing so much rear brake lockup,” he said.  “It was causing the engine to stall out and then restart when I got back on the gas, which really upset the chassis.  Obviously my braking technique will need some work, but it was only on the sealed areas.”

The only changes John and Greg made were lowering tire pressures to deal with the slick conditions of the newly sealed FedEx Field lot. 

With the first win out of the way, John and Greg are looking forward to competition at the Northeast Divisional at the end of May and the Pro Solo in June, both being held on home turf at FedEx Field.  One of the bigger tests will be the Pro Solo in July in Ohio at Toledo Express Airport, which has a concrete surface.

“I don’t know what I’ll end up changing with the suspension right now since the [FedEx] lot is so slippery,” John said.  “I’m really concerned that we won’t have any knowledge of what the car will do on concrete until we get to Toledo.” 

In search of …
John’s search for an STS class killer began about year ago when he went looking for a GTUs RX-7, a rather rare model that has the brakes from the turbo RX-7, a shorter 4.30 gear and a viscous limited slip differential. 

“Some earlier cars were available with a clutch diff which is not legal for STS, and some cars had an open diff which is obviously not desirable,” John said.

The GTUs is also lighter due to no power windows or sunroof.  Air conditioning was only an option, so it can be removed under the Street Touring rules.

What he found during the search were either cars that were too modified to be brought back within the Street Touring rules or pristine garage queens that were being sold for too much.  He finally found a car for sale in Colorado.  In the small world that is autocross, Chris Hammond, who he bought his old Z06 Corvette from, was able to look at the car.

“He described the car as being all there and totally stock – no sunroof cut into the body like so many of these cars got early in life,” John recalled.  “It ran okay, but had high miles, burned oil and was stuck in reverse.  The owner wanted $950 for the car, and I was able to talk him down from that because of the stuck transmission — which I knew was an easy fix — and the fact that the title wasn’t in his name.”

He had the car shipped to Maryland via a transport company and immidiately went to work.  And it definitely needed work.

“It rained the entire trip and one of the door seals had popped loose so the car was full of water when I got it,” he said.  “I had a lot of cleanup work to do, but I love that kind of thing so it wasn’t an issue; plus it gave me an excuse to really go through the car looking for issues.”

The dashboard needed repair, an aftermarket alarm system had been clumsily installed, and thumping amplifiers were located behind the seats.

“It’s a rough car, but I still think I got a good deal,” he said.

Prior experience
He has autocrossed a Z06 Corvette, Mazda RX-8, Porsche Boxster and E36 BMW M3, but FC RX-7s aren’t new to him.  He owned a 1987 RX-7 turbo when he was 16 and had actually rebuilt the 13B rotary engine on that car himself, so rebuilding the 170,000-mile engine in the new car wasn’t that much of a hassle 16 years later.

“The original rotor housings were trashed due to failed oil-injection lines, so I picked up two low-mile used housings off the rx7club.com forums,” he said.  “I got two stock ’89-’91  high-compression rotors with new rotor bearings and a set of low-mileage irons as well.”

John prepared the irons using a palm sander and kerosene “to get a good oil-holding finish.”  Everything was cleaned and thoroughly inspected for wear per the Mazda factory service manual – “lots of measuring!”

He also put in new factory Mazda seals and springs, and the original eccentric shaft was used as it was in perfect shape.

Unfortunately, the freshened 13B rotary developed a small problem that crept up when he was putting on some miles to break the engine in. 

“The motor ate a side seal due to a bit of overzealousness on my part.  That combined with a side seal that was probably a little on the tight side,” he said.  “Fortunately the engines are easy to tear down so it took less than a week to get it out and back in.  Nothing else was damaged, so it went together fast.”

He estimates it will approach 190 horsepower to the wheels once he gets some dyno time and weigh just under 2,500 pounds in STS trim.  While it will be the heaviest car in the class, “it will have the best power-to-weight ratio.”

While the car is familiar to him, autocrossing in a street-tire class is not.  Greg has experience with his old E36 BMW and Volkswagen Jetta in Street Touring classes, but John has only driven on R-compound tires in Stock.  But the 225/45/17 Bridgestone RE-11 offers surprising grip.

“They’re not in the same league as a Kumho V710 or Hoosier, but for a low-powered car with lots of camber they were still very enjoyable,” he said.  “Very predictable and the grip was excellent.  Big side benefit is that the tires on this car are so small, they are very inexpensive.  And they should last for many runs before heat cycling or wearing out.”

Modifications

Suspension

• Ground Control custom-valved Konis
• 450lb/in front springs, 350lb/in rears
• Low profile camber plates up front
• Suspension Techniques two-way adjustable front sway bar
• Stock rear sway bar with extra holes drilled, plus an RB rear sway bar for testing
• Adjustable rear camber links
• Competition suspension and solid subframe bushings
• -3.5 degrees front camber, 1/8” total toe out, 6 degrees positive caster
• -1.5 degrees rear camber, 0 total toe
• Polyurethane front control arm bushings
• Stock Mazda bushings everywhere else

Drivetrain

• Stock motor
• Stock intake with K&N filter
• Custom shorty header with stepped primaries and 3-inch megaphone
• Magnaflow 3-inch highflow pre-cat
• Magnaflow 3-inch highflow main cat
• Resonator and straight-through muffler (“Too loud right now, but I have a better muffler to help with sound.”)
• Digital Tuning Rtek7 rebuilt ECU with full fuel and spark table tunability in the factory ECU case
• Innovate LC-1 Wideband O2 sensor controller
• New stock clutch and flywheel
• No factory A/C (optional on GTUs)
• 17×7.5” wheels, 14lbs, with Bridgesone RE-11s – 225/45/17
• Mazdatrix short shifter

Brakes

• Stock with Hawk HPS pads
• Red painted front calipers

Other:

• Braille 11-pound battery relocated to passenger’s storage bin
• Corbeau seats
• Momo Champion steering wheel

Not enough info for you? John also posted his progress on the buildup in the forum at carmudgeons.com.