Common questions

Back To Table Of Contents

4.1 What is the "exhaust system overheat" light for?

The "exhaust system overheat" light is connected to a temperature sensor inside the car, under the carpeting, by the passenger seat. The location of this sensor is just above the main catalytic converter, and its purpose is to warn of excessive heat being generated by the converter. When the temperature of the passenger floor reaches about 220 degrees F, the ECU activates the relief air bypass and bleeds off air that would   otherwise go to the catalytic converter. This has the effect of cooling the catalytic converter.

4.2 When I start my car, the RPMs go to 3000. Why?

All 1993+ RX-7s have what is called an "Accelerated Warmup System" that revs the car up to ~3000 RPM when it is cold-started. Its purpose is to heat up the 02 sensor and first catalytic converter to operating temperature as soon as possible. If you don't like the thought of your motor revving that high when cold, you can start the car in 1st gear (with the clutch in), and the AWS will only take the RPMs to ~1500 or so.It is also possible to bypass the AWS solenoid (see the performance section of this FAQ).

4.3 What does the "mileage switch" do?

The "mileage switch" is in effect for the first 20k miles on a new RX-7. It has the same effect as the "power steering switch". It adds some RPM to the base idle to help keep the engine from dying.

4.4 What type of gas should I use?

The RX-7 requires "super" or "premium" unleaded gasoline. Use only gas with a 92 or higher octane rating. Using leaded gas will coatboth your catalytic converters and your oxygen sensor, rendering them useless.

4.5 Should I use this additive?

• Synthetic oil - Mazda specifically says not to use synthetic oils in your RX-7 on page 7-11 of the owner's manual. So, for warranty purposes, you do not want to use synthetic oil. Some people on the RX-7 net have run synthetic oil in their cars with no ill effects, Pettit racing recommends using synthetic oil in the RX-7. If you choose to use synthetics or not, the most important thing to remember is to change the oil and filter regularly, at 3000 mile intervals, or less.
• Slick 50 - Slick 50 claims to reduce engine wear because it contains PTFE. PTFE has been proven to break down when used in engines, and thus Slick 50 would not provide any additional protection.
• Octane boost - You do not want to buy regular, 87 octane gas and then rely on octane boost to meet the minimum octane rating required by your car. Buy the good gas to begin with.
• Water Wetter - use Redline's Water Wetter in my car, and it seems to run slightly cooler than it does on a 50/50 antifreeze mix.
• Oil premix - Pettit sells an oil premix to be added to the gas tank called "Protek-R". It probably won't hurt the engine, but if you have a functioning oil metering system, it probably won't help either.
• RedLine MTL - The net consensus is that Redline's MTL appears to help the shifting on cold mornings and reduce notchiness in the 5-speed equipped RX-7s.

4.6 Why does my airbox have a hose that is not connected to to anything?

The hose that comes out of the right side of the airbox and goes down under the box is not supposed to connect to anything. It serves as an escape route for the air coming from the compressor bypass hose. It is not open to the rest of the airbox, and "dirty" air will not be drawn through it into your engine.

Back To Table Of Contents