Air Intake

Mod Benefit Drawback Is it a problem? Notes
Replacement performance panel air filter
e.g. K & N, TRD
  • Improve turbo spool up time
  • Improve air flow into engine
  • More power
  • Probably will never need to buy another air filter!
  • Less restrictive
  • Need to wash it out and maybe oil it now and again


Don't get a foam filter as these are generally poor at filtration and if they disintegrate it'll disappear into your turbo and engine

Induction kit
e.g. HKS, A'pexi
  • Improve turbo spool up time
  • Improve air flow into engine
  • More power
  • Probably will never need to buy another air filter!
  • Less restrictive
  • HKS is foam - not a great idea imho
  • Draw hot engine bay air into intake system


Replacing stock system with an induction kit yielded a 1psi increase in boost for the same boost controller settings, just by replacing part of the stock intake system

Straight air intake and large cone filter
  • Stock air box and ribbed air feed pipe to turbo restrictive and in the way
  • Improve turbo performance and spool up time
  • Less crap in the engine bay
  • More power
  • More efficient
  • Bit tricky to do
  • Draw hot air from engine bay into engine - bad
  • Need to buy or fabricate adaptors for idle up and PCV breather hoses
  • Need to extend the air intake temp sensor wiring loom

ish - takes time/effort

Several companies manufacture cone air filters. K&N is a good choice and an alternative is the A'pexi filter which has proven to filter and flow well

Blitz make a shiny stainless steel mesh filter - you can see through the filter, so it doesn't filter very well!

Fabricating a cold air box may help but I found this to have very limited effect to my surprise!

Remove intake resonator
  • Less pipe work, crap, complexity and weight
  • More room in the engine bay area/wheel arch
  • Meant to be a noise reducer but I found very little difference!


May provide enough space for:
  • WI reservoir tank
  • Cold air feed to air filter
  • Space to fit alarm siren
Cold air box
  • Feed the air filter with colder air
  • Reduce intake temps
  • Helps to prevent detonation
  • More power
  • Needs fabrication and fitting

ish - takes time/effort

Found very little difference to intake temps... unfortunately!

Improved PCV catch can
  • Prevent more oil mist from entering the air intake
  • Ensure IC operates efficiency
  • Stop coating everything in oil
  • Stop burning oil
  • Help to prevent detonation
  • Requires fabricating or to buy
  • Make sure it is internally baffled


ish if fabricating, No if buying!

The Mocal, TRD and  GReddy catch cans are not internally baffled

The 205 come with a catch can as standard but its effect is limited

Port intake manifold
  • Increase power
  • Reduce intake restrictions
  • More power
  • Turbo spools earlier
  • Need to remove manifold very awkward if engine still in car, but can be done

Yes, very awkward

Need a Dremel or something similar to do the porting. You can pick something similar up for <20 Sanding drums are available and shift aluminium in no time

Port matching the manifold to the head and also to the throttle body helps, but not a massive step forward!

Cold Air Intake
  • Improve cold air flow to air filter
  • Provide more cold air to intake
  • Reduce intake temps and thus help prevent detonation
  • None


Try running a length of hose front the front bumper back and up where the intake resonator used to be and out just by the air filter. Note this is the stock air intake path...
Larger Throttle Body
  • Can force more air through the throttle body
  • Porting of manifold to accommodate larger TB

ish - porting required

Of limited benefit and "popular" belief is this is of little benefit until >500hp
Side feed manifold
  • Better distribution of the intake charge to the cylinders
  • Probable increase in output power
  • Tidier engine bay
  • Not currently available off the shelf
  • Torque output maybe affected, but this may depend upon manifold design
  • Limited space in which to fit

Yes - careful design required may be able to help...

The Corolla WRC with the 3SGTE engine has a side feed manifold...