Power upgrade guide for
Mazda MX5 1800 cc engines

We get many calls for upgrades on this model, as a guide to assist you we have created this list to save your time, guarantee your money is invested correctly and most of all give you maximum value!.

SUMMARY
Typically this car in Australia  has a cult following and has many options for improvement.
However rhe biggest limits was its ECU and now its also available to be custom tuned for even more engine power AND reliability 
There are some great features of this car, and most of all, a sensible budget with some well planned upgrades and it turns a great car into a great super car beater!

ECU
(All Australian and Japanese models)
Can be converted and fully tuned, using EcuteK Software for almost any improvement, and allows solid results with correct settings and allows good improvement.
If the car has been run on the wrong fuel (jap models are tuned for 100 Ron) then the ECU will have detuned it more and a retune on 98 will make more power, more reliably.
Dont under estimate the incredible improvement with a good ECU retune. 
All of these can be adjsutred and retuned with an EcuteK factory ECU retune.
more info here on an EcuteK Factory ECU upgrade for the Mazda 3 MPS 

ENGINE WEAKNESS's
Factory ECU settings dramatically control ignition and knock. Above 5000 rpm the engine will randomly ping badly causing engine damage
Bottom end and mid range performance can be dramatically improved with ECU tune. The engine is detuned by Mazda and also power limited due to emisions requirements when delivered by the factory.
Car should be run on 98 Ron Fuel unless a custom (ecuteK) map is done.

ENGINE SENSORS
On this model the aif flow meter sensor is very reliable
Depending on model, Jap spec or Oz the twin rear exhaust O2 sensors if located incorectly related to modified exhaust can cause problems, if old can also dull the cruise performance of the car and increase fuel use.
Crank, cam  and Knock sensors are reliable, but with age can fail. 

INTERCEPTOR ECU OPTION
Not worth considering as the intercptors simply do not have enough options to tune and modify the latest technoplogy control inputs.
ZERO VALUE

NEW (replacement) ECU
Factory ECU retune is best value unless a really serious engine rebuild is chosen. 
See notes above

INJECTORS
Bigger injectors empty your wallet and add no power unless part of a E85 fuel retune or major engine rebuild. Save your $$ for suspension and get some GOOD improvements.
OEM Injectors are big enough unless you do a major engine rebuild.

FUEL PUMP
More than adequate

EXHAUST
(Some traps for people here, unless carefully chosen.)
Get this wrong and the car will suffer CEL lights, and cause poor fuel economy.

AIR INTAKE
Other than a intake noise no power here, unless you have or plan a huge engine upgrade.
A replacement panel filter in the std airbox will save on future servicing but give no power improvement.
Replace the air intake with a pod style filter and you simply ad cost to retune time with the ECU upgrade 

ENGINE ANCILLIARIES
Items such as aftermarket plug leads, high capacity discharge ignition systems etc all will ad very marginal if any improvement.

ENGINE INTERNAL
Like above if you have a solid budget, then a rebuild will give some great and huge benefits, the engine is a very very good package and flows great HP and is very tough, BUT they have common rod failure if boosted over a certain amount and then head flow issues after a certian HP target. 
A rebuild will cost over $7k and then you need to choose carefully there are many options, but only if you REALLY want to.. 

OTHER OPTIONS
Is the car serviced correctly? Because often a service by a workshop who really knows Mazda's will be your best choice for first place for power and reliability.

IE:

  • Upper engine cleaner and in tank fuel additive. (when was this last done, as often the Jap import cars have huge carbon build up).
  • Good quality low friction engine oil such as Mobil 5 w 30 will give around 5 kw and better fuel economy over a non synthetic oil.
  • Fuel system service, MRT offer this and often get good results, cleans the EGR "gunk" out of the intake and combustion area.
    Also injectors as well as inlet manf and exhaust as well as fuel pump, lines and sensors.
  • Synthetic gearbox, transfer case and diff oil, again like engine oil this adds up in benefits.
  • Timing belt, fuel filter are again areas that should be checked and renewed.

SUSPENSION
Check out the performance / suspension section for REAL gains and benefits.
If I owned this car, I would invest some of my budget in the MRT XB kit and then brakes and suspension as this is guaranteed BEST VALUE!
more here http://mrtperformance.com.au/performance/suspension

FREE CHECK
Refer the MRT vehicle service section here and take advantage of our free 78 point check to ensure your car is in top shape!

PRIORITY LIST

  1. Check service history.
  2. Check the O2 sensor
  3. Check brakes
  4. ECU upgrade and re tune to suit local fuel (as all EVO V11's are tuned for 100 ron fuel).
  5. New brake pads and discs if needed
  6. Front and rear sway bars.
  7. Complete (quality) exhaust.
  8. Front and rear sway bar links

OTHER RESOURCES