RX8 Tuning Tips

"Renesis Renaissance"

Mazda had great success with the RX7 and proved that a rotary engined car can be fun to drive. The successor came in the form the lovely RX8. It was leaps and bounds better than the RX7 in many respects.

The angular lines, edgy design and interior trim all won the hearts of RX8 around the world. Mazda updated the 13b Wankel engine creating the innovative Renesis rotary engine.

Tuning the RX8 rotary engine is considered difficult by some but there are a few options that can transform the RX8 performance. Bear in mind that these come from the factory in a pretty highly tuned state, so end user improvements are smaller than they would be on a run of the mill production car where little attention has been made to tuning them up.

The RX8 comes from the factory in a pretty highly tuned state, so end user improvements are smaller than they would be on a run of the mill production car!

The benefits of a rotary engine include the ability to provide high rpm tolerances and a silky smooth power delivery.

Problems though include a lack of low down torque at low RPM but when driven correctly these cars have a lot to give. Standard power figures of around 200bhp from a 1300cc engine really pushes the envelope of what is possible.

Your RX8 tuning should start off with some improvements to the handling and brakes. A big brake conversion kit will really pay dividends and give a progressive brake feel. The car can be lowered around 35 mm. We would recommend adjustable suspension so you can set the damping and spring rates to suit your driver preference.

The engines need to be properly looked after and serviced regularly. Do not let the unusual rotary engine put you off. These are much better than early rotary engines and are every bit as flexible and reliable as a reciprocating piston setup.

The RX8 is just crying out for a turbo conversion and this is probably one of the few "bolt on" options although it can prove expensive.

A turbo will raise the standard power to around 400bhp! Sadly in the real world there is a lot more to it than just bolting on a turbo. A whole host of other components will need uprating and strengthening and the mapping will need to be spot on.

The 4 port engines are more suited to turbo charging than the 6 port ones but both conversions require a lot of work and planning and we would not recommend undertaking this unless you have obtained a full kit and have facilities to set up and create a custom map.

Obvious power mods for  a turbo RX8 would include a larger front mounted intercooler. The intercooler can suffer from heat soak on long runs so channelling lots of fresh air through this will pay dividends. Power can also be increased with the addition of a larger turbo or a turbo with higher performing internals (a hybrid).

Engine heat build up is a massive problem when adding forced induction and a larger oil pan and even an oil cooler will help address this issue. It would also pay to get the exhaust down pipes coated or wrapped to contain the heat.

Further engine cooling mods will include an uprated water pump and thermostat, and use of a synthetic water cooler additive with some high performance silicone hoses to avoid leaks from higher pressures.

When pushing larger power gains you will also need to uprate the fuel delivery system to prevent the engine from running lean - if anything these engines prefer to run rich.

We have looked remaps for the RX8 and sport chips without much success. Hopefully RX8 remaps will become available.

The best option we could find is fitting a full aftermarket engine management system.

This allows you to fine tune the timing and fuel delivery for the maximum power gain and this will also allow you to factor in any other mods you have done. On a standard car with an aftermarket engine management system you can see power gains of around 2-5%.

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Porting the Renesis engines, if done properly, can have a big impact on the power delivery and torque curve. This is not a simple job though and is only really worth doing if you are already stripping down and rebuilding the engine.

Lapping the flat housings and adding high quality ceramic seals are considered important mods here, and dynamic engine balancing will also help you reach higher power gains retaining reliability.

A sports exhaust and induction kit can help provide power gains a little, but in the opinion of TorqueCars members, the standard setup is pretty good and gains are only noticeable high up in the RPM rev range.

There are not many 200bhp NASP 1.3 engines out there so you have something special in the RX8 and the nature of the way the engine works means it is ideally suited to hydrogen as fuel! (Perhaps this dream may become a reality one day but for now I guess we have to stick with petrol!)

Adding a sports cat will also free up a bit more power, on the Renesis these little gains all add up quite effectively.

Reducing the weight of the flywheel to around 9 lb's seems to be a popular choice and does change the nature of the engine quite a bit, but we should add not always to the taste of drivers, try one fitted to an RX8 first before you commit yourself here.

Why not join our friendly forum and swap tuning ideas and share pics of your RX8 with our other members.

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Your Constructive comments on this article

12 Responses to “Tuning the RX8 rotary”

  1. fadzilah says:

    my plan want to add jdm turbo kit to my mazda rx8,what else?item ADd.

  2. Matt says:

    The renesis engine is still a Wankel engine. Named after the Felix Wankel the German engineer responsible for the design. The renesis is simply a revised 13b

  3. ray says:

    i added a intake and a sports exhaust,and its back firering on the highway about 4000rpms , is there a place close to cincinnati that i can get it fine tuned

    • brandoW says:

      Dude, its gonna back fire. Thats just a one of the quarks of the renesis. It runs rich, leaning it out would do more damage than good.

      • kas says:

        I would say the rx8 is already a higly tuned car out the factory, just like a civic type r there are only small hp gains to be had from tuning and bolt ons, if your looking to stay NA I would say focus on handling, light weight and driving feel to be faster around a track. Turbo or 4-rotor conversions are the only way to get big power, however you need deep pockets and mechanical skills. There’s always Nos but thats not really a long term or reliable option.

  4. Norman Grant says:

    My Local RX tuning specialist Re-Works tell me that it is not possible to tune a RX-8 ???

    • Darren says:

      Absolute rubbish you can easily tune a rx8 if you have the money.simply putting on a full blower rather then a turbo will see massive gains once set up correctly.Re.Work talk out of their backsides I’m afraid.Take a look at some American tuning sites for the rx8.Say no more.

  5. jake says:

    I have a 2005 rx8 inside compartment by the clutch pedals is getting hot any body knows what wrong

  6. Paul says:

    What consists of fitting a turbo to the rx8

  7. Ben richardson says:

    Hi ive got a 08 rx8 and she just got 100 thousand on engine, i love the handling even as stock. Rensis i need more power was thinking about track meets and drifting in future. Should i just go back to racing bridge port turbocharged or rebuild 4ensis

  8. Dessycorry corry says:

    I have just bought an rx8 r3 with an stage 2 tune kn filter intake and big exhaust but Mel came on second day cat inefficiency would a sports cat be a better replacement

  9. Pablo Iglesias says:

    I’m new to the rotary world and will take all info and advice that I can get. I don’t want world record speed or power, just enough to have some fun.

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