There is no doubt that just injectors and pump could make over 600rwhp with gasoline. Its just not recommended as it wouldnt be considered "safe". But if you know what you are doing and watch what you need to watch, and dont mind constantly watching it... than it can certainly be done. Youll just never get anyone who is remotely responsible for that engines longevity to recommend it!

?

I have no information about the flow of the stock pump, so I dont know if its good enough for E85 NA or not.

Boost pressure fights fuel pressure -- so long as AFR's are maintained, the pressure may drop, but it would technically be sufficient.

If it skews lean under the right conditions, and there's no more bigger pump or injectors to use (or if there's driveability issues -- poor spray pattern/atmomization/cylinder wetting from the injectors or too much pressure from the pump for a smooth idle), I suppose you could try a rising rate/variable fuel pressure valve.

I thought switching to a return system brought with it a whole host of potential running and tuning issues (including possible vapor lock) under all circumstances except high load and high boost -- maybe I'm mistaken?

It all depends on how much more fuel you need to maintain the same torque levels. If you need, say, 20% more fuel, you need 20%+ more pump. Sounds like the OEM pump will be struggling with that.

Synolimit -- see what the infamous 250+ whp E85 Z is using. Sounds like that's what you would need. I think there's at least one other member on here who switched to an E85 safe set-up too.

Pressure drop is a sign of approaching the limit. The limit will shift around based on environmental conditions, system voltage, filter condition, etc. So if you find yourself at the limit of your fuel system, for the sake of consistency, its a good idea to upgrade and protect your engine.

There are generally no problems, if its built and installed correctly.


That is not exactly how it works. If you need 20% more fuel, but your pump is large enough to supply it already, than you dont need 20% more pump. There are just limited samples of anyone even bothering experimenting with the stock pump to get a solid idea of how much fuel its moving.