Turbo FMU Help

[Quad4Civic]

First I need to say that Im a newbie about turbo stuff, so yeah.
Im puttin this on a 94 Civic with A D16Z6 5 speed, and running 7 pounds of boost
I just bought a used turbo setup from my friend. I have a 1st gen auto eclipse turbo, manifold, downpipe, intercooler, and all pipes. From my understanding I need a boost controller (going Turboxs), FMU, blow off valve (going Turboxs), and gauges (going autometer). I have all the little things to adapt the oil lines and coolant lines. Here is my question. I need an FMU, but what one do i get? From my understading an FMU regulates how much fuel is put in the combustion chamber when a turbo is spooling or when it is spooled all the way. Is an FMU electronic or mechanical? Electronic being going into the ECU, and mechanical just going off the fuel pressure lines (Vortech FMU). Do i absolutly need an FMU? Or can I just get a fuel rail, and a fuel pressure regulator?


PS: The pipes, manifold and downpipe are all custom.

Thanks alot,
Dustin

 

[Handlebars]

an fmu is mechanical, it works by pinching the return line to raise fuel pressure. it is vaccume sourced to measure boost. it will have numbers, say 12:1, which means it adds 12 psi of fuel pressure for every 1 psi of boost pressure. thats what you should run. you need an fmu.

 

[baby99si]

12-1 isnt a little rich?

 

[baby99si]

What is an FMU?
The letters FMU stand for "Fuel Management Unit". Basically, an FMU is a fuel pressure regulator. The FMU is used on fuel injected, supercharged engines using the factory electronic engine management system.

When an engine is supercharged the air delivered to it is greatly increased. For the engine to run properly and make max power a 11.5:1 air/fuel ratio must be maintained. Since the factory electronic controller can compensate for this increased air flow (it was not designed for supercharger use) another way has to be found to supply the necessary additional fuel. The FMU is the device that does this.

The FMU is installed just down stream of the stock fuel pressure regulator. It does not control fuel pressure until the engine manifold pressure comes under boost from the supercharger. As the manifold pressure increases, a pressure line from the manifold to the FMU causes the FMU to increase the fuel injector rail pressure. The increased fuel pressure causes the injectors to deliver more fuel to the engine. With this system the stock factory electronic controller can be used without modification on a supercharged engine with good results. The reason the Vortech supercharging systems are smog legal is because the stock controller is retained unmodified and at part throttle the engine's performance and emissions are not effected.

Hope that helps you out. (copy and pasted vortech.com)

 

[Quad4Civic]

so wait. Your saying i should get a 12:1 FMU on a D-Series motor? That just doesnt sound right. So 12 psi for 1 lbs of boost. SO 12 times 7 is 84. So 84 psi in my combustion chamber? Are yo sure. hat sounds soooo rich. Vortech has a 10:1 12:1 6:1 8:1 4:1

Which is the best?

 

[baby99si]

Probably 8-1 or 10-1

 

[Quad4Civic]

basically i want it around to what my stock compression ratio is or no?

 

[Sound Streamin']

Get hondata with boost, You wont need an FMU.

 

[baby99si]

But you will need bigger injectors.

 

[Handlebars]

so wait. Your saying i should get a 12:1 FMU on a D-Series motor? That just doesnt sound right. So 12 psi for 1 lbs of boost. SO 12 times 7 is 84. So 84 psi in my combustion chamber? Are yo sure. hat sounds soooo rich. Vortech has a 10:1 12:1 6:1 8:1 4:1

Which is the best?

no.. wow man, you really shouldnt be boosting if you dont know basic engine dynamics. that raises the FUEL pressure, not the combustion chamber pressure. cc pressure is determined by flow, boost, backpressure and most of all compression ratio, it has nothing to do with fuel pressure. and the greddy, drag, fmax, vortech and most other off the shelf turbo kits use a 12:1 fmu disk. richer is always better when your dealing with an fmu, as they are a poor way to manage fuel.

 

[baby99si]

no.. wow man, you really shouldnt be boosting if you dont know basic engine dynamics. that raises the FUEL pressure, not the combustion chamber pressure. cc pressure is determined by flow, boost, backpressure and most of all compression ratio, it has nothing to do with fuel pressure. and the greddy, drag, fmax, vortech and most other off the shelf turbo kits use a 12:1 fmu disk. richer is always better when your dealing with an fmu, as they are a poor way to manage fuel.

Sweet that helped i didnt know if to get 8-1 10-1 or 12-1 but i guess ill just get 12-1 and figured f**k it if its to rich.

 

[Quad4Civic]

Ill just get the 10:1 fmu, thanks for all the help. This is my first "tricked out" import ive ever had, im expecting to make mistakes, if it happens it happen. Money is no object to me...

 

[Sound Streamin']

That's why Im getting an Apexi Power FC, and handing to my tuner and saying here, you make it run for me

 

[baby99si]

Ill just get the 10:1 fmu, thanks for all the help. This is my first "tricked out" import ive ever had, im expecting to make mistakes, if it happens it happen. Money is no object to me...

If money is no object dont get the fmu, get a hondata s200 with boost, some 450 injectors and high pressure fuel pump, then get it tuned. That is the best thing to do if money is no object.

 

[Quad4Civic]

Well money is an object but it isnt. Anyway, i called and talked to a guy from vortech today. He said that with 190cc-210cc i have to run the 12:1 fmu. So that is what im gonna get.

 

[SeanMc300]

11:1 disc has been running on a friends stock 93 si motor for a little over a year, it runs fine. good job on asking the right people! but im gonna have to say get a hondata s200 w/boost. youll be much much much much much happier. itll be more reliable, itll run better, itll just be a better car.