Power upgrade guide for
Mazda 3 SP25 non turbo petrol 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
There are some great features of this car, 2500 cc torquey engine and most of all, a sensible budget with some well planned upgrades and it turns a great car into a much better car!

ECU
(All Australian and Japanese models)
Can NOT be converted and tuned, using any ECU software that will deleiver ANY reliable power 

ENGINE WEAKNESS's
Not any to note

 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
Too costly. 
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.)
Some small gains to be made here with a good complete engine back exhaust
The rear muffler and centre pipe adds no value in just replacing it and should be left stock std to save $$.

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.
 

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

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 investall of my budget in 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. New brake pads and discs if needed
  5. Front and rear sway bars.
  6. Complete (quality) exhaust.
  7. Front and rear sway bar links

OTHER RESOURCES