hey guys im too cheap to afford an safc or emanage and i saw my friend use this for his ka-t setup, well, something like this, what does this ratio exactly mean, i read it but dont get it, is 10:1 or 12:1 better ? one is more lean and one is more rich, let me know guys. http://cgi.ebay.com/ebaymotors/OBX-12-1-FMU-FUEL-MANAGEMENT-UNIT-NEON-240SX-350Z-TURBO_W0QQcmdZViewItemQQcategoryZ33553QQitemZ7993896915QQrdZ1QQsspagenameZWDVW
if your gonna do it, do it right or dont do it at all.
it will work crudely.
it’s useable but it’s got two drawbacks first off you can’t set base rate with this so you will be floating all over the map with pressure OFF boost, nest it uses 1/8" barb fittings for fuel supply, not nearly big enough for boost flow rates. Your going to need some form of pulsation dampner and a surge tank.
IF you wish to go mechanical then use a Vortech Super RRFPR or a Cartech RRFPR they use 1/4" barb and have the ability to set base fuel rates and have built in adjustability for fuel ratio… 1:1 to 14:1 … Do not use this with an AFR of any kind, you’ll end up screwing yourself up. for ignition find a Hi-6 with the TRC-2 and the MAP sensor. this will allow you set retard timing on the car using boost as a refernce.
using these items does not release you from the need to upgrade your fuel and ignition subsystem
The ratio means (Fuel pressure added in PSI) : (Per Pound Of Boost).
People use FMU’s a lot on temporary, low-boost setups. They usually run rich and push the limits of the injectors, but they do seem to do fulfill their purpose.
Vlad, do it right with proper engine management or don’t do it at all. You can cheap out on little things, but don’t cheap out on engine management.
Andrew.
if you look at the cost of a RRFPR you’ve got the price of a Megasquirt I system which is a standalone for the KA/SR with the right SW installed.
shhh :lol:
sorry guys im clueless, im not loaded at the moment and doesnt look like im going to be but i want to run my ihi hbr5 turbocharger at 8psi and have a normal setup for that, im not looking to push MAD power, just so it would run efficently and have good boost, y’know how it is, thanks alot for telling me about other things but how much tuning would be required for what, i know safc2 you need almost a whole day on the dyno, isnt there a cheaper way ?
Yes street tune.
Andrew.
what else is cheap that I can get, im not lookin to spand half a grand on management, I know a guy running this fmu thing on a ka-t its stoich when running normal and in boost its mild-rich, hes running 7psi. stock injectors. my wastegate lets off at 8psi, similar. i already got the walbro fuel pump too
As I’ve mentioned in other posts the Safc in whatever form is NOT for boost/fuel ratio control… it WILL not do what you need it to do
the SAFC is a 2D system dependant on RPM NOT boost to increase fuel flow… If you do this then you are in serious risk of grenading your engine… OR you can just saturate your engine and run 10:1 loose all sorts of power , kill your fuel mileage but cover your boost points … your chioce. I would seriously look at holding off on boost till ou have the money to do it right, the first time… it’s SO much cheaper then having learned to do it right the Second time …
edit: ok, let me explain the SAFC/SAFR’s use… when you increase injector size you change the fuel ratios… your adding more fuel per pulse. THe Safc/AFR is to re table that number by fooling the computer into seeing a different air ratio. The computer then does a look up table and reduces or increase flow based on what numbers you put into that rpm band. That’s it, that’s all it does. The SAFC would need a 3rd look up table and a MAP sensor , with a wiring bypass on the ECU for MAP based increases… for that you need to go to a piggyback with a 3D fuel mapping capability…
IAP (Import Auto Performance) and their turbo kits come with either an FMU or Walbro High-Pressure pump. That’s it. And they advertise one or the other as being enough.
Now sure that’s the stage 1 kit and all, but they sware to the fact that with just the Walbro pump, providing you stay 7 PSI and under, you will run slightly RICH throughout the rev-range - right to redline. Not dangerously rich. With no lean spots, either.
I would prithee that if they’re correct it would be a SAFE setup (minus the injector load and boost spike risks), but not necessarily a prime or TUNED setup by any means.
^^^ is there such thing as dangerously rich? I thought you could get stupidly rich and lose all your power and paint your bumper black … but where’s the danger? From fouling spark plugs? Shooting flames from exhaust? Or something I’m missing … ?
Yes when you wash the oil off your rings with fuel.
Andrew.
^^^ got it … thanks 