dosquattro Posted October 28, 2006 Author Share Posted October 28, 2006 I'm picking up a adj fmu so that should be fine. 280Zforce..I'll pay you tuesday for the fmu. Thanks bro Quote Link to comment Share on other sites More sharing options...
Guest ZFury Posted October 28, 2006 Share Posted October 28, 2006 Had an adjustable FMU also. Ranged like 0 to 100 psi. With the stock ecu you could turn up the FMU to like 55psi, no problem. Much over 60psi and you might make the stock fuel pump go kaput! Quote Link to comment Share on other sites More sharing options...
dosquattro Posted October 30, 2006 Author Share Posted October 30, 2006 I have to pick up a new 255 lph pump so no worries about that. Come tuesday it'll be a turbo shopping spree. 700 to spend on turbo goodies for the Z. But for the like of me I find a damn manifold. Anyone have a good manifold laying around? I'm picking up a TIG/plasma for christmas but till then I still need just a stock unit for now. Quote Link to comment Share on other sites More sharing options...
Pyro Posted October 30, 2006 Share Posted October 30, 2006 Use the pressure ratio to determine how much more fuel you will need. This is how Corky Bell does it in his turbo manual. For example: if you are going to run 8 psi of boost then the pressure ratio is (8 + 14.7) /14.7 = 1.544. So you will be making 54.4% more power and will need 54% more fuel. (In theroy). So.... (pressure ratio x pressure ratio) x 36 psi = FMU pressure needed. FYI, 36 psi is Z full throttle fuel pressure. (1.544 x 1.544) x 36 = 86 psi. 86 psi will be a good starting point, but you need to check a/f during boost and make adjustments. 85 psi doesn't take into account boost acting on the injector or a turbos need for more fuel/hp. Corkey Bell says the FMU is only good for 10 psi because the fuel pressure gets to high after that. You will need a fuel pressure gauge in the car to check the pressure when driving. That pressure may be hard to hold during high fuel rates. I have run as low as 65 psi with 8 psi and 85 psi with 12 psi of boost, but the a/f ratios were about 14:1 which is not the best to make power and reduce detontion. I currently run 11 psi of boost with 95 psi of fuel pressure. I had run 13 to 14 psi of boost with that fuel pressure, but recently turned down the boost a little to get more favorable a/f ratios and haven't noticed a lost of power. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted October 30, 2006 Share Posted October 30, 2006 Look for some old threads from cygnusx1 (me) and baastad525. We both ran FMU's and stock Turbo FI. I currently still run a Begi FMU, stock 83 Turbo Injection, Walbro Pump, 15psi boost, 65psi fuel at max boost. I will go lean after about 5300 rpm but if I turn up the FMU then it goes too righ in the midrange. Quote Link to comment Share on other sites More sharing options...
Pyro Posted October 30, 2006 Share Posted October 30, 2006 cygnus, if you use the pressure ratio to determine the required extra fuel pressure then your 65psi is just about perfect. Stock boost is 7.5 psi, 1.54 pressure ratio, and 15 psi has a 2.02 pressure ratio and 2.02/1.54 is 1.344, which means 34% more fuel is needed to run 15 psi from the stock boost level of 7.5. And the FMU will add 34% more fuel with 65 psi, (65psi/36psi)square root = 1.344. The difference is you are using turbo injectors and ecu, so your starting point to add more fuel pressure is 7.5 psi of boost. dosquatto is using nonturbo injectors and nonturbo ecu so his starting point to add more fuel pressure is 0 psi. Quote Link to comment Share on other sites More sharing options...
dosquattro Posted November 1, 2006 Author Share Posted November 1, 2006 My turbo spend spree has started!! Bought my adj fmu, walbro 255lph fuel pump, stock 280zx turbo mani that'll i'll modify for a ext wastegate. T4 60-1, 60mm wastegate and tial bov and a nice bar plate fmic is also on the list to buy. Just need to deposit my money from an engine I sold to today before I can buy it all. Stay tuned for pics. Now your saying...ummm t4 and a fmu...woah buddy you need to set your priorities straight but while I have the money I'm getting something I won't have to ever upgrade. The fmu was cheap and it's something I can use on other cars and it was cheap so I couldn't pass it up. Quote Link to comment Share on other sites More sharing options...
nienberg.11 Posted November 1, 2006 Share Posted November 1, 2006 If you really are into buying things that won't need upgrading in the future, an FMU isn't the way to go. You'll end up wanting to go standalone. Speaking from experience. Quote Link to comment Share on other sites More sharing options...
dosquattro Posted November 1, 2006 Author Share Posted November 1, 2006 The MS will come soon. It's almost winter soon so if I can get this all bolted and welded up before the first snow fall then the FMU will be used basically just for that short time. I can get MS for my birthday in March and give me time to wire it up since there's snow on the ground still and get all t's crossed and i's dotted. Quote Link to comment Share on other sites More sharing options...
col10see Posted May 24, 2013 Share Posted May 24, 2013 Wow this is old...but....updates or where is the other half? Quote Link to comment Share on other sites More sharing options...
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