GTT Injector FAQs (Gen 1 Supercharged) questions answered here..

posted in: GTT Blog & News

Our most asked injector (Gen 1 Supercharged) questions answered here….

What size injectors should I buy?

In almost every case for a supercharged mini’s…. 440cc. Whether it’s a modified Cooper S, JCW, or GP1 the answers the same.. Please check any injector size calculation website and the answer will be very close to 440cc for 230- 260/270bhp Max.

What brand and design should I choose?

Genuine Bosch… Made to GTT Spec, these are the Modern injector type and not the very old oversized slow responding types. Ours are Brand new and made in Germany (not reworked second hand units!)

Is spray pattern the same as OEM?

Yes as is the projection into the manifold.

Do I need a remap at vast expense and inconvenience?

Short answer is NO. The cars feedback from the lambda sensor in closed loop uses clever adaptation to maintain correct scaled fuelling in open loop to. Simply fit and play. Correct fuelling occurs very quickly. You can remap if you want to but not necessary

Any other tips for me?

Yes use 99 Ron fuel (99 Octane) whenever possible. Detonation is reduced using GTT 440cc injectors and this fuel. Use double Iridium sparkplugs only, and not too cool a ‘heat range’ as can foul due to plug tip running insufficient heat. With NGK going from a ‘6’ to a ‘7’ is the correct approach. Cheap copper core plugs with large electrodes are a big No No.

GTT PowerMist methanol injection kits take pinking prevention/anti knock to another level BTW.


GTT Stage 2 Tuning Kit Features the 440cc Injectors:


Injectors Page:


R53 Cooper S GTT 440cc Fuel Injector Replacement Tutorial




Gen 1 Power Mist (Methanol Injection Kit)