FMU's

[DeleriouS]

If you have an FMU, you dont need a FPR right? Or do you? Also what do the different ratios mean. I have seen that a lot of people with turbochargers have gone with the 12:1, but what does the ratio pertain to? And, which one would be best for a turbocharged application? Thanks

[Kven]

i dont really remember i think for a a 12:1, every pound of boost is gonna raise fuel pressure by 12psi. cant say for sure. isnt the FMU a FPR so to say?

[DeleriouS]

Originally Posted by Kven

isnt the FMU a FPR so to say?

well ya, except the FMU automatically compensates for the air from the MAP sensor. So if you put more boost in, the FMU reads that through the MAP sensor, and injects more fuel (I THINK). Am i right?

[nZero]

Originally Posted by DeleriouS

Also what do the different ratios mean. I have seen that a lot of people with turbochargers have gone with the 12:1, but what does the ratio pertain to?

Stoichiometric ratio between fuel and air, probably.

[Whtehnda93DXSdn]

If I'm correct 12:1 would be 12 parts fuel 1 part air...
and from my understanding the FPR and EMU are kinda the same w/ the exception w/ some of the FMU you can change the fuel part, 12:1 to 13 or 11:1...

[civickiller]

if your gonna go turbo a good a/f would be around 12:1 or 12.5:1

if you wanna get a management of some kind i would recommend aem, hondata or eberdata.

[Kven]

i disagree that the FMU controls a/f, because the FMU is connected only to the fuel line, it cant control the fuel injectors which are responsible for the volume of fuel that gets introduced into the intake manifold/ports.

Originally Posted by cartech

One truly unique feature of our design is the ability to begin raising the fuel pressure before getting under boost. This ability will tune out the inherent turbo/supercharger lean flat spot at the onset of boost.

[Kven]

heres the fuel article Cartech

Originally Posted by Cartech

Purpose of the Rising Rate Regulator
The Cartech regulators are designed specifically to add fuel to modified EFI engines (turbos, superchargers and normally aspirated). This is accomplished by using the manifold vac/pressure to drive the fuel pressure up as the boost rises, or with the N/A engines, as the vacuum goes toward atmospheric. If we already build the best FPR’s (often called FMU’s), what’s the sanity of making another? The answer is to keep the copiers way behind. Our original FMU, introduced in 1975, has been copied six times and is still used by four companies. The 2020 series regulator is the fourth generation design to come from Cartech, and every new design has been better than the previous. Imagine how vastly better these new designs are than that 25 year old relic the other guys are still producing!

The broad range of tuning capability by changing fuel pressure has yet to be fully explored. We have pioneered this concept with the introduction of the rising rate fuel pressure regulator. It has been created for the purpose of increasing the fuel flow through electronic fuel injection systems when conditions of engine load demand more fuel. Unique to the rising rate regulator is that the pressure only increases when needed then returns to stock. This concept does not keep the fuel pressure up all the time. The concept of the rising rate regulator is particularly useful in three circumstances:

1. The factory turbo/supercharger car when the stock boost pressure is increased.
2. An aftermarket turbo/supercharger system applied to an EFI equipped car.
3. A normally aspirated EFI car with modifications that increase the air flow.

These regulators are unique with the adjustability of rate of gain as well as onset of gain. The potential for increasing fuel flows is very large, with as much as 40% more fuel available. This solution is particularly attractive as it is less expensive and tunable. The regulator installs in the EFI return line after the stock regulator and overrides the stock regulator at full throttle or when under boost. One truly unique feature of our design is the ability to begin raising the fuel pressure before getting under boost. This ability will tune out the inherent turbo/supercharger lean flat spot at the onset of boost.

[jeffseby]

12:1 IS to high for some applications, Expecially if you got Aftermarket Injectors. Picture This: You are running 10 PSI of Boost on the turbo, and you have a 12:1 FMU. The vacume line is atached to the Intake Manifold, thats how the FMU knows. You boost to 10 PSI. (12*10=120) so you have 120 PSI of fuel, not including the 40PSI that you have at 0 boost. so that is roughly 160 PSI of fuel!! Not many fuel pumps can handle that, yet alone any fuel systems. So many Turboers use HonData or an AFC to tune the ecu to do it automaticly. Most Turbo Dudes, will say Fuck the FMU. Just because they are included in some Turbo Kits, doesn't mean they are very good.
And NO, Fuel Regulators are not the same as Fuel Managment Units, but kinda, in the fact that they controlle fuel.

[DeleriouS]

Originally Posted by jeffseby

Most Turbo Dudes, will say Fuck the FMU. Just because they are included in some Turbo Kits, doesn't mean they are very good.

So if I were to change my integra to run a turbo application, then i dont really need the FMU? - the hondata will take care of it?

[jeffseby]

Originally Posted by DeleriouS

So if I were to change my integra to run a turbo application, then i dont really need the FMU? - the hondata will take care of it?

WELL, I need people who have experienced this to reply. I don't use HonData or Apexi, so I don't want to stear you in the wrong Direction. Someone will reply to your question shortly.

[boosted331]

Originally Posted by DeleriouS

So if I were to change my integra to run a turbo application, then i dont really need the FMU? - the hondata will take care of it?

If you run Hondata and big enough injectors NO, you do not need an FMU. An FMU in a setup with a proper EMS such as hondata is sometimes used to allow you to run significantly more power on small injectors by bumping the fuel pressure way up, but as long as you have big enough injectors you don't need to mess around with a FMU.

And a 12:1 FMU is boost referenced and bumps your fuel pressure up 12 psi for every 1 psi of inlet pressure.

[Kven]

technically the FMU is a FPR. why? fuel regulator regulates the fuel pressure allowed. the FMU is sort of a variable regulator ; it still regulates fuel but changes the pressure accordingly to a variable(boost). if you read the article, cartech calls it a rising rate fuel regulator instead of FMU. ive only seen i think two manufacturers that call it FMU, the only one i can remember right now is Vortech.

[DeleriouS]

Originally Posted by boosted331

If you run Hondata and big enough injectors NO, you do not need an FMU.

What size injectors do i need if i am going to be running 12psi MAX? Is there a limit to how big of injectors i get? i.e. - i am only running 4psi with t3-t4 but have 1000cc or 800cc injectors - would that be a problem? because i will always want to do more psi in the future, and i dont want to keep on buying new injectors every time i increase the boost.

[jeffseby]

Wow, This guy is smokin some great shit. 800cc. J/K.
That setup (4 psi) might be posibile on 400 cc. If you want to drive your car on the street, pretty much never go over 550 cc injectors.