hi I have a Evo 4 with a 6 engine running on stock Evo 4 ecu and have just put a 500hp walbro fuel pump in and will hit 6,000 rpm and start struggling for fuel. Have 560cc injectors installed and a evo 6 ecu ready to be installed. Any ideas on what the problem could be?

 

Walbros are rated in liters per hour not hp, which one are you using?

 

Are you running 560s on an Evo 4 ecu? Thats your issue. The Evo 4 ecu is scaled for the Evo 4 510cc that come stock. The car will drive like **** under load. You need to run the 6 ecu and injectors simultaneously, or run the 6 ecu and then scale it for 510s.

 

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I've been running the 560 injectors for a while now on Evo 4 ecu and standard fuel pump and was running fine (no power increase) until I put the walbro pump in. Cheers for the help