MugenRioS2k1

With out give away the bigger picture of what I am trying to do with forced induction.

I have some questions.
The idea is to add the additional fuel required my mechanical means rather then electrical controls.

Key points
1)Stock injectors remain in place
2)Stock fuel rail pressure regulator remains in place with vacuum line still going to the factory location.
3)New fuel rail setup has an addition fuel line T

hukares

Mechanical fuel injection has been around for a very long time, since before electronic fuel injection. I think you are talking about a hybrid system? Anyway, diesels and the really big drag racers all run that setup. The drag racers aren't worried about having fine control over the fuel. In fact they want the engine to run extremely rich for the cooling effect. They run a few laps and then they drop in a new engine and rebuild the old one. So they really don't care about the long term effects.

Scorpion

The real question here is why? There are so many better ways to get fuel to your engine. But to humor you...

Static fuel pressure in the rail is 47psi +/- 3psi. Only real way to know if to hook up a pressure gauge. The Stock FPR is not a "pressision" unit. And assuming you aren't trying to run over 500hp, the stock fuel pump will be fine.

MugenRioS2k1

Just trying to see if this system can the run FI requirements with out using any electrical controls (just to see if it can be done.)

Hukares the effect you are talking about is latent heat of evaporation and yes I am trying to get that effect.
I was to unaware that drag races use this setup I thought that were either fuel inject or carb setups not a hybrid

So it looks like I would need to get a rising fuel pressure regulator (RFPR) to replace the stock unit
So controlling the amount of additional fuel added is a combination of the control slopes of both the RFPR and the fuel jet regulator (FJR) in unison.

I would need to calculate the increased supply the stock injectors would be putting out based on the new rising fuel rail pressure and stock ECU fuel maps (WOT) and adjust the new regulator to match the fuel profile required.

I am trying to design a system that is closer to just bolt on and go.
And can be tuned with an EGT and A/F gauge and can be easely adjusted with a turn of a screw when going from the street to teh track.

Just thinking out of the box here.

keep the sugestions/ options comming.

hukares

What I meant is that you seem to be trying to go for a hybrid system. I meant that diesels and top fuel dragsters run mechanical injection. I see how I could have wrote that better.

MugenRioS2k1

Are there any downfalls with a hybrid system if the components can be design properly.

Slows2k

IIRC, Bosch K-Jetronic mechanical injection runs on 100-120psi. The Walbro 255lph pump can make that kind of pressure, but not all the time. You'd need a dedicated fuel pump, and lines. Having dual fuel systems and dual delivery controls makes it more complicated than neccesary.

A centrifugal SC can get away with a FMU and a drop in fuel pump. What type of application do you wanty to run a dual fuel system?

MugenRioS2k1

The design is going to use RP's axial supercharger but on a custom setup.
Working on the conceptual drawing next week.

The main draw back right now is there will need to be a new manifold manufactured. I am going to see if I can just get the new manifold that BR performance has made for there roots S2k supercharger and modify it for my design.

Slows2k you are somewhat local to me so next time there is an Alabama meet that I can go to I will show you the design plans.

MugenRioS2k1

Well just had another thought

since the Axial has the capability to have fuel injected before the compressor

In the idea above replace the fuel jets with single large injector that activates to 100%duty cycle by way of a pressure switch. injector is calibrated to flow based on fuel pressure which is controlled by a new rising FPR like what comes with the vortech setup.

new injector is sized to add l additional fue based on the calculated the additional fuel the stock injectors would be adding because of the new fuel pressure.

Same idea just another way do the same thing

Even thought the sompressor has an efficency in the +85 range the ability to add the fuel before the compressors helps increase that efficency due to the cooling of fuel injection.

Boostedtaco

There are AIC (Additional Injector Controller) kits out there, HKS, Greddy, Split Second and many others.

You'd just need to buy injector bosses and weld them into the intake pipe. But this is space consuming, seeing how you wanted to use it with the Axial s/c.

Maybe go with direct port nitrous nozzles for fuel, but that's taxing for the solinoids.

I doubt any of this is helpful, but i'd thought i'll try.