[Hayden224117]

Hello, I am new to cars in general and was wondering why there is a max injector size you can use with an FMU. For example, what would be the problem with running 1000cc injectors with a stock ECU and just an FMU? I am not planning on running 1000cc injectors but I want to know the reason why there is a limit to how high you can go with a stock tune and an FMU. The injector size I would like to run is 650cc. The FMU is just a temporary thing until I learn how to install megasquirt. Thanks.

 

[BISHILVR]

Its because you can only tune out the traits of larger injectors to a certain point without actually re-writing the ecu code, the fmu is a band aid at best and not a very good one at that.

 

[Hayden224117]

Its because you can only tune out the traits of larger injectors to a certain point without actually re-writing the ecu code, the fmu is a band aid at best and not a very good one at that.

So what is the maximum size injector I can run?

 

[Iceman21]

Why do you want to run a larger injector on a stock non-turbo motor?

You're going about the upgrade path wrong.

 

[Hayden224117]

My plan is to turbo it first at around 8 psi then upgrade the engine internals to handle more boost. The injectors will be one of the later parts but this process will happen fairly quickly because I have a decent amount of money saved up.

 

[Iceman21]

Get the tuning device installed and a wideband, then worry about the other stuff.

 

[Hayden224117]

Get the tuning device installed and a wideband, then worry about the other stuff.

The problem is finding an available megasquirt unit. The places I have looked so far seem to be out of stock. I was thinking about running 8 injectors and an AIC. The process seems to be fairly straight forward and there are plenty of controllers available.

 

[BISHILVR]

Did you try going directly to diy autotune?