[SamuraiSam]

Originally Posted by Paul Clark

overall reliability,decent diagnostics, millions of man hours of tuning, knock control. To be honest i'm never going to have monster break horsepower. I'm just looking to produce an above average daily driver and if that means a few after market mods and fine tuning that will do for me. If I can produce and effective and stable setup without going stand alone then that will do.

Everything is wrong with a piggyback. Piggybacks LIE to your stock ECU on the input side. So you end up with a different fuel output and a different timing output.

Millions of man hours of tuning? HAH. A few hundred maybe and SO WHAT?? It is NOT tuned for the fuel you are running or the mods on your engine so it doesn't make a shit lick of difference. That's like saying a Ferrari ECU would be good for your car because it was programmed with intense care paid to all parameters and designed for max power. You changed a variable - fuel or cams or turbos or MAFs or injectors or pressure regulator or downpipes or elbows or exhaust or cat converters or intake pipes or intercooler. Now you need a retune and The only thing that an extensively developed map is good for anymore is to use as a basemap in a standalone Engine Management System: Invalid point.

Diagnostics. A Power FC or HKS unit can give you ALL the info a consult port will. It will show you exactly what sensors are doing what so you know what is going on with the engine or what sensor failed: Invalid point.

Knock control: Have the car mapped by a professional, use good fuel, and you will have no knock issues. Knock Control is bogus anyways as pulling timing some time after detecting knock is NOT a safe way to run an engine.

If you insist on running a stock ECU have it chipped and reprogrammed with an EEPROM based tune. It will be as good as an equivalent standalone.

You will NEVER find a professional tuner reccomend a piggyback over a standalone on ANY car where there is an affordable plug and play option available because Piggyback fuel foolers are absolute complete garbage and should not be used.

HKS V pro is not a piggyback computer. It can be used in parallel with a stock ECU (but doesn't have to be) It reads sensors, uses its internal map, and sends outputs to the mechanical components, therefore, it is a standalone. A Greddy emanage is a piggyback computer. An Apexi AFC is a piggyback computer. Do not use them.

Before you start telling me how wrong I am and how great piggyback detonation devices are, do a tiny bit of research and maybe blow up an engine or two with a piggyback. I have been reading everything I can and taking EFI and tuning courses, and tuning as many cars as I can for the past few years.

Sorry to be such an ass, but once you understand how EFI systems work and depend on accurate inputs to function, you will understand how terrible these sensor signal distortions are on an engine you want to make power and be reliable.