Chacko

A boost controller allows you to control fuel curves right? With a controller do you need an FMU? Or does the controller control the FMU?

Thanks

Chacko

Actually if anyone could give me a thorough walk through of the fuel management for forced induction set ups I would appreciate it (this is about the only part I get confused on).

ComposiMo

The boost controller (generally) does nothing to the fuel pressure/curves/flow. The boost controller only controls the level of boost by regulating the wastegate.

The part that controls the fuel pressure based on the boost pressure is a "rising rate fuel pressure regulator". These raise the fuel pressure in pre-defined amounts depending on the amount of boost. Generally you don't want to run these regulators with high-boost applications, because after a while, the fuel pressure can get into astronomical levels. This is why it is better to not use a rising rate regulator, and instead jusst a standard regulator, with larger injectors, and a fuel controller (either piggyback, or standalone) to control them. That way you can easily program the exact amount of fuel you need, and keep the fuel pressure within reason.

Did that clear anything up?

Chacko

It did and it didn't. Heh.
Let me see if I post what I know and maybe you can clear it up from that.
I understand that to properly gain power from a turbo you have to increase the amount of fuel being dumped in (because more air is being packed in) and if you don't you're going to go way past stoich...Now I also understand that the stock Honda fuel system can not meet the demands of boost (though I am unsure to what level). Which would mean you need larger injectors, and to adjust injector pulsing, and to even adjust the amount of fuel being fed to the rail?

Am I right on this?

I guess what I'm really after is, what IS necessary to run 9-11 lbs of boost on a stock honda engine (aside from the turbo/manifold/bov/wastegate) - on the fuel side.

Thanks

ComposiMo

I understand that to properly gain power from a turbo you have to increase the amount of fuel being dumped in (because more air is being packed in)
Correct. There are two ways of doing this. One way is to increase the fuel pressure, thus force-feeding more fuel through the injector than it was designed to flow.. this is basically the rising rate regulator method. The other way, is to keep fuel pressures the same, and just increase the amount of fuel that the injectors can flow. But if you do that, you have to do something to keep the injectors from flowing too much while off-boost, which is where the AFC/SMC hack comes into play


Now I also understand that the stock Honda fuel system can not meet the demands of boost (though I am unsure to what level).
Actually, for what you are talking about, the stock fuel system (minus injectors of course) can handle it. If you are going to use larger injectors, plus something to control them, then the fuel system should work, but i would suggest that you upgrade the fuel pump at least.

Which would mean you need larger injectors, and to adjust injector pulsing, and to even adjust the amount of fuel being fed to the rail?
Yes, yes, no... You need the larger injectors, and something to help control them, yes... but you dont necessarily NEED something to control the amount of fuel being fed to the rail... the stock fuel pressure regulator is a very good piece and will work fine up until you get to the point where it just can't flow enough.


I guess what I'm really after is, what IS necessary to run 9-11 lbs of boost on a stock honda engine (aside from the turbo/manifold/bov/wastegate) - on the fuel side.
Ok, lets have a quick looky at my setup, since i think this is what you want to know. Aside from the 450cc injectors, and the ZDyne SECU that is controlling them, my fuel system is completely stock. That means pump, filter, tank, rail, regulator, everything... I am running between 10-12psi on my setup, depending on how i'm feeling and what i'm running against, and it is handling matters nicely. SO, for your setup, if you really are going to keep it under 10psi, i'd say that the injectors and some type of controllers ought to do jusst fine. Again, i do recommend a fuel pump upgrade... i sshould have done it to mine, but i couldn't justify the cost of buying it when i already had a different pump ready to go in (note: big red canister next to firewall in one of the engine shot pictures of my car.. hehe).

Hope that helps some... if not, let me know, and i'll explain more

Chacko

Ah yes it did, thank you!