Under construction - not yet accurate...

Fuel


Mod Benefit Drawback Is it a problem? Notes
 
Larger injectors
  • To increase fuelling due to increased demand for fuel, probably due to increased boost pressure and flow from your turbo
  • Not required for power increases up to ~340hp
  • Car can run higher boost
  • Reduce injector duty cycle
  • Less chance of detonation
  • £
  • Increased fuel consumption
  • Need a rolling road or similar to set the Air Fuel Ratio
  • Need a replacement or add on ECU
  • The 185 can use the standard fuel rail and use the larger ST205 540cc injectors. The 165 cannot use either the 185 or the 205 fuel rail

Yes

 Need to set the car up properly and fit an aftermarket ECU to correctly deliver the fuel

The 205 injectors are a direct replacement and will drop straight into a 185 fuel rail
Fuel pressure regulator
  • To increase the fuel pressure at the fuel rail
  • To increase the fuel delivered by the injectors
  • May be able to install an adjustable regulator to avoid buying and fitting larger injectors
  • A higher quality FPR may react faster than the stock FPR
  • £
  • Connecting to the existing fuel rail
  • Need a fuel pressure gauge to correctly set the pressure

ish

Will need to get the car setup properly if you alter the pressure away from the standard specification
Larger fuel pump
  • To increase fuelling due to increased demand for fuel, probably due to increased boost pressure/flow from your turbo
  • Not required for power increases up to 300hp
  • Car can run higher boost
  • Reduce injector duty cycle
  • Less chance of detonation
  • Able to supply a greater volume of fuel
  • ~£100
  • You will probably over fuel like mad if you don't get the car tuned
   The Walbro 255l/h is a popular choice

ish, need to get the car setup again
Upgrade fuel rail connections
  • Improve fuel flow
  • You might need the car tuned in order to cope with the increased delivery

ish

 Improve the flow to the fuel rail by reducing the restriction from the existing connectors, fit AN style connections instead of banjo connectors

May need to get the car setup

You won't need this mod until >300hp
Upgrade fuel rail
  • Improve fuel flow
  • Expense

No

 The 205 rail is the best flowing rail of all the GT4s

The 205 rail will not fit either the 165 or 185 had

A Wolfkatz rail might be the best solution
Increase fuel RON rating
  • To improve power output
  • Reduce chances of detonation
  • More expensive

No

Shell Optimax is currently the highest RON fuel in the UK - 98

BP Ultimate - 97

Other methods to increase the RON rating are the addition of Methanol in the WI system or to use a "one shot" octane booster in with the fuel