My newest aqusition

My RX-7's have given me as much Joy as they have grief, the RX-7 is a true "hobby" as it requires time, energy, and most of all money.

These cars were last manufactured in the U.S. in 1995, with model years in 1993, 1994 & 199. At  about $40,000.00in 1993 Dollars, the RX-7 was by no means a commuter, or everyday vehicle. The RX-7 has defined the rotary powered sport car in the Automobile Market. The unusual design, and technology makes for a very unique motor in a multitude of ways.

• Combustion Chamber
• Split timing ignition
• Mechanical / Technical knowledge (Mechanics)
• Weakness in design (Apex Seals)
• High Redline (8000-9000 rpm)
• Low horsepower numbers without forced induction (2'nd Gen RX N.A. @ 146-160 HP)
• High horsepower numbers with twin hitatchi turbos @ 255 HP

The third generation (FD) was also the only RX to have twin Hitatchi Turbo's across all models, from base all the way to deluxe touring.

The 1993 R1 was particularly sought after, due to its lighter weight @ apporx. 2700 lbs, and its sporty spoiler, faux saude seats, and dual oil coolers. Which were all meant for track use.

So one could deduct that the RX-7 (FD) was born to be taken out on the track, and that's where it performed quite well, so well in fact that it got bumped from the SCCA class it was in before to a higher class to compete with the Corvette v8's. This put th elittle mazda at a distinct dissadvantage as it's 1.3l had troubble keeping up with the large 5.7l V8's of the day, yet with a skilled driver it was still a formitable opponent on the track. 

This then brings me to the sad part of my RX-7 hobby, after multiple (3) engines, and lots of money spent on upgrades to make the RX-7 feel as fast as it looked. I came to a crossraods. 

The Rx-7 had rescently had issues after tuning wearing in a seal that had warped. And it was rebuild time again, when I put some gas into the tank, and drove down the road babying it so not to put excessive strain on the motor. When out of nowhere someone was going to cut me off, and I had a rough morning allready and I wasn't going to let him/her. So I stepped on the gas, and the car accelerated better than it has in months, spin tires in 1'st and 2'nd, and then I got to third and after a very unusual sound the car lost all willingness to idle. Well at that point it was obvious to me what had happened, I lacked the understanding though what the extent of the damage really was. 

After sending the entire car to Dallas Tx, where a very repuatble rotary mechanic at the time had his shop, who incidentally also tuned the car, and felt compassionte enough for me to offer to help with the rebuild at a lower than usual rate. The phonecall came back one Sept Afternoon, "Well, we pulled the motor appart, and here's what we found."

• Two Apex seals Broken
• 1 Fist size Dent in one of the rotor faces
• Scratched both housings
• Destroyed the turbine impeller (Turbo)

"And BTW, the port job you had done is bogus, and the manifold you used for the turbo isn't what I'd recommend"

Well the recommendations aside I was staring an estimated $8,00.00 Rebuild in the face.

I asked what the cause of the failure was. And to my surprise, he claimed it was bad fuel. Bad Gas ? I did some research online, and found out Shell had been having issues at some of their southern california facilities, and was adding too much teflon, reducing the octane rating of the gas. Which is deadly for a rotary, which unlike conventional motors cannot just sustain some knocking and pinging. once knock is loud enough to hear, the motor is toast, and due to the design of the combusion chgamber.

The sealing mechanism of a conventional motor is the "O Ring" which generally sits in it's grove once broken, and causes some bad wear, and an obvious loss of power. The Rotary Seal sitting at the tip of the trident, breaks, gets tossed loose, and flies into the combustion chamber where it gets tossed around doing damage to the walls, before exiting out the exhaust, where a very fast spinning turbine awaits to finally chew it to bits, or chew the turbine to bits in the process.

Well the $8,000.00 wasn't easy to swallow. And furthermore, apparently it wasn't the fault of the tuner, or the fact that the seal was warped. Which to this day I can't rule out were part of the failure. But the nagging feeling that after an $8,000.00 repair I was going to have a potential danger of equal measure to this one,of having another catastrophic failure due to fuel was unacceptable to me.

LINK: Rx7 Rotors Destroyed, as well as turbo Gallery

So I sought out an alternative, if forced induction was the leading failure of these beautiful cars, then a Naturally Aspirated (Non Turbo) solution was the answer. But with 2Rotor motors being so bad on power naturally aspirated, I figured more displacement (Additional Rotors)  would be the answer. I sought out information on 3 and 4rotor conversions. Of which the cheaper one (3 Rotor) was somewhere around $30,000.00 and I could never quite solidify what a 4 Rotor conversion would run in totoal, since very few of them had been completed. The other factor that was of concern was the HP numbers. A 3Rotor N.A. motor spits out around 350 HP a 4 Rotor supposedly somewhere around 450 HP. I always wanted to fall in somewhere around 400. $30k+ wasn't exactly appealing to me either, since a lot of the headaches I hadwith the rotary were Mechanics, and The Cost of failure. With 2 rotors failure is bad, with 3+ rotors it's much worse. So the N.A. rotary line of thinking was quickly dismissed as very costly and still not as "Reliable" as I'd liek my vehicle to be.

On to other solutions, the RB-20 and the 2J2 Sylvia and Supra motors were considered, but were quickly dismissed due to the exotic nature of the engines they fetched a premium price, and fitment, as well as weight ratio were considered, as well as compentant mechanics that could perform such a "heart transplant".I quickly realized I needed something more "Conventianl" I had heard about LT1 Swaps into Lamborghini's, in the 80's/90's and knew small block chevy and ford motors came as crate motors for hotrods and all sorts of "Frankenstein" projects. After doing some research I found the swap to be about $10,000.00 which was still more than the $8k I was facing with the rotary but with some distinct advantages. 

• Better Fuel Economy
• Readily Available Capable Mechanics 
• Local Support
• Reliability
• Ample Information Online
• Proven installation in other RX vehicles

Combined all these things spoke to me to keep the RX on the road, and finally being able to enjoy driving a vehicle instead of fearing doing damage to the motor.

Conclusion:  

the V8 is all those things, I've recorded 27 & 28 MPG on long runs in 6'th gear, I've had little to no major repairs. I've had ample support locally, and it is very fast @ 300 RWHP, and 308 RWTQ, which is still untuned off the Camaro SS LS1 ECU. So with some LS6 Heads, and a decent Cam I'm looking at my 400+ (maybe 430 rwhp) mark. But right now it's plenty fast for me, gets great gasmilage, and is reliable.

More Information

• 1993-1995 RX-7 Specs: Specs on the 3'rd Generation RX-7
• RX7 Forum: The most comprehensive gathering of RX7 brainiacs, and knuckleheads
• V8 RX7 Forum: A gathering of the Crazy people who can provide more info about swaps.
• Hinson Supercars: Where I got my subframe / conversion kit from.
• Gant's Garage (AKA Granny's: Where other people get their subframe / kit from