High performance RX7 Tuning

"Wankel engines, what goes around comes around."

The RX7 was the car that made the Rotary engine cool.

With a displacement of only 1400cc it matches the power output of engines nearly twice that size. 

The beauty of the Rotary engine is that it can enjoy much higher speeds without being subject to the same internal forces as a reciprocating engine.

This means that  you have a lot of scope for increasing the power without having to resort to extensive modifications. The turbo engine gives a lot of scope for tuning with the addition of a larger turbo, a hybrid turbo (uprated internals in a standard case) or a twin turbo setup. A remap will help release more power in all cases.

Because the engine is so light it makes the car feel a lot faster than it should be, this also means you get a massive and noticeable hike in power from most modifications.

Weak spots include gearbox issues caused by loose mountings which can be addressed with a reinforcing frame. The issue usually manifests itself as an issue in 2nd-3rd gear changes and will get worse if ignored.

Oil leaks have also been reported but a number of specialist RX7 tuners offer stronger sumps with a better o ring seal.

The car is relatively light but this shouldn't stop you taking it further with a carbon fibre bonnet and even carbon fibre wings and panels.

The key to power gains on the rotary engines is air flow through the engine, a low resistance high flowing air filter and porting within the engine are well documented power adders. A better flowing exhaust will further help to improve peak power. The turbo chargers on the RX7 can be uprated to larger flowing units and because of the high RPM characteristics to the engine they are well suited to a twin turbo setup to avoid lag.

Get an uprated intercooler to save the power lost by heat gains. If you are serious about power gains then lose the air conditioning and fit a larger intercooler mounted at an angle in the engine bay. The intercooler will benefit from a bonnet vent if possible.

A set of coilovers will stiffen the handling and if this is matched to a rear strut brace you can have a very sharply cornering RX7. Reinforcing the front and rear suspension turrets are beneficial and give noticeably improved handling on older cars.

Talking with some of our members who own RX7s we find that the rear wing is actually quite important and that without it the back is pretty light at high speed. Relocating the intercooler and putting a vent in the front bonnet will also help minimise heat soak and push up the power figures.

When buying an RX7 you should ensure that it has been well looked after and properly serviced. These are specialist engines so need the attention of a specialist. Reports of unreliability and requirements to rebuild are largely unfounded provided the car is properly serviced and looked after. This is also an engine that requires you to read the manual, particularly with respect to starting and stalling the engine. As the engine is very high revving to many drivers it can feel quite powerless low down and they will generally stall it. If you get it badly wrong you risk flooding the engine and it requires dealer attention.

We shouldn't really give attention to making the RX7 go faster without looking at the brakes. There is a nice range of large brakes available such as the KAD 356mm discs mated to 6 pot calipers. Even the standard brakes can be greatly improved with a high friction performance pad, and there are plenty of vented and upgrades available for the standard size discs.

Why not join us in our Mazda forum and meet our other resident RX7 owners and swap tuning tips and advice with them.

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