A lot of people have asked me why I am putting a V8 in an RX-7. There seems relatively little concern over using the SA22C chassis as a basis for a performance build-up, but the idea of adding a V8 seems to raise both questions and eyebrows. A lot of this is due in no small part to the RX-7 being the only way most people have ever been able to buy a rotary engine. Thus, in the minds of many, the two have become inseparable and having one without another seems to upset some people.

Let me start-off by saying that I am in no way anti-rotary. In fact, it is my opinion that the Mazda rotary is actually a fine engine. The long history of successful involvement in motorsports at the amateur and professional levels speaks volumes about the fundamental strengths of the rotary and its fitness for hard use. Mazda Competition’s excellent support program makes the engine even more inviting to someone like me looking to run in amateur events.

So why not run one if it has all these positives? Actually, there are a number of things that make the rotary less attractive in my eyes.
1. Other than the currently rare and expensive Renesis in the RX-8, the last rotary sold in the USA was in 1995. That means there is about a ten year gap where there were no domestically available rotary engines. The used rotary engine market has the same gap.
2. Compounding this, the 1993-1995 (FD3S) model of the RX-7 sold poorly, suffered from premature engine failures and has the highest output of all rotaries ever sold here. All these factors push the demand and thus price of these engines up.
3. Rebuilding a rotary can be much more difficult than a conventional engine, especially compare to a small block V8. Rotaries generally require machine work done by specialists. Special knowledge commands a premium price, thus cost goes up.
4. Torque is not the strength of the rotary. While it can make up for it using its unbelievable rev capabilities to make horsepower, in order to increase output at lower RPM, boost is required. For me, boost is just more complexity, more chances for failure and more cost. Yes it can be done, as many have, but a high output rotary is not a cheap or simple proposition.

So then why a V8? Let me first address, the myth that a V8 will destroy the weight balance of an RX-7, as that is completely untrue. There are a number of people that have done conversions and published before and after weights and everyone has shown that the change in both total weight and balance is minimal. I don’t have a before weight since the car was purchased as a roller, but I will publish the corner weights when I am done. A search on any of the popular RX-7 sites will show real before and after weights and the minimal change that occurs. For me, it is a dead issue.

The decision to put in a V8 was actually pretty simple. A kit is available to do it from Granny’s Speedshop so I don’t have to rely on my own abilities to figure things out. An American pushrod V8 is cheap, readily available and since they have been around for decades, there are no surprises when it comes to making them both fast and last. While often looked down on by those without it, displacement remains just about the most cost effective way of adding power. Furthermore, the production longevity of these engines also means multiple configurations of just about everything engine related, significantly easing their adaptation to a different chassis. Really, there is nothing that hasn’t been done with a small block V8. Cheap, powerful, well known, common as dirt and served by an aftermarket that is second-to-none are a combination of V8 attributes that trump not only what the rotary has to offer, but every other engine as well.

On a less objective level, I think V8s sound great. Everyone has their favorite engine sounds, but the rumble of a V8 is usually regarded as automotive symphony. I have also never had a V8, and being an auto enthusiast in the USA, that just isn’t right. Finally, engine swap cars are just plain cool. Sure, a rotary RX-7 is a fun car, but it isn’t exactly going to make anyone do a double take. A V8 powered RX-7 is not something you get to see everyday.

So there you have it. Rotaries are good, V8s are just better in my opinion. I am sure some will disagree, and that is fine by me. If we all did things the same way, it would be a boring world. Hopefully you will still find something on this site useful, entertaining, or maybe even both. However, if you feel compelled to rant about how I have taken the heart out of the car, that it is no longer an RX-7 without a rotary, or that pushrod V8s are a pathetic relic from a bygone era, don’t expect me to care. I am happy with the choice I have made and am in way too deep at this point to change course!