Len Posted December 3, 2002 Share Posted December 3, 2002 I'm familiar with 280zxt fuel press with vac. disconnected at idle runs around 38psi. Does anyone know what fuel pressure the 370cc. svo injectors would normaly run? I'm guessing about the same. They just need to put out more fuel to run those 2.3 liter 4 bangers. Am I right? Quote Link to comment Share on other sites More sharing options...
Guest Zcarsmakemyheadhurt Posted December 3, 2002 Share Posted December 3, 2002 Len, the larger injectors are going to run at the same injector speed as the stock injector yet flowing more fuel because of the injector size. Lowering the fuel pressure is going to slow down the flow rate but your not going to get a good automization. The real need is to adjust the injector time but you really cannot do so with a stock fuel computer. Some people try closing the AFM and lowering the fuel pressure but I think your pushing your luck with this approch and most likely not going to have a very drivable car. Your real need is I'm sorry to say it is a programable fuel computer to have complete controll over injector time. Or try it the tricks of the Z and see how far you get. Good luck. Quote Link to comment Share on other sites More sharing options...
Guest Zcarsmakemyheadhurt Posted December 3, 2002 Share Posted December 3, 2002 The other option is the opposit of what your thinking. Raise the fuel pressure at boost on a stock fuel injector, the way you do this is with a fuel pressure riser that is boost sensitive and works in conjuntion with a stock regulator. The stock regulator maintains correct fuel pressure for daily driving a fuel economy and the FMU (fuel managment unit) will raise the pressure as boost comes in say 2 pounds of fuel pressure per pound of boost so if your car is boosting 15 psi it will give you 30 additional pounds of fuel pressure. Hooked up! Every time the injector opens you get a higher volume of fuel due to the raised pressure. This is one option other than larger injectors and a fuel computer if you need more info give me a call. Alex Costa Precision Machined Engines 1-800-665-0405 Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted December 3, 2002 Share Posted December 3, 2002 The 370cc SVO injectors are spec'd at 43psi, but at 36psi they still flow respectably. I tested flow patterns and quantity at 36psi, and get 350cc/minute out of them. "Headache" is right about running them at lower fuel pressure than stock - you would hit a point where the spray pattern would get bad, and also unless you ran some goofy setup with a rising rate FPR, you would never get the flow out of them with a stock FI system. And RRFPR is NOT the answer in this case, your fuel mixture would vary widely with rpm, and would be a PITA to tune to run well. Just MO, if someone has done it, chime in, but unless you had lots of patience and dyno time, I doubt you could get it to run acceptably. Quote Link to comment Share on other sites More sharing options...
Len Posted December 3, 2002 Author Share Posted December 3, 2002 Alex Thanks for the input. I was just thinking (which gets me in trouble sometimes) . I realize injectors are rated at 2 bar (43lbs) just didn't know if the Mustangs had a different lower operational fuel pressure. With this AFPR I am thinking maybe lowering fuel press. just a tad. Trying to find a medium between lowest output without being so low to dribble injectors (not allow proper atomization). This comes from my old Carborator way of thinking. Carborators are not as exact, they dribbled at times, but they ran alright. Anyway I don't want to lower fuel press. so low as to not get full benefit of the 370cc. output (or max output at WOT). Oh yea; I thought about a RRFPR (4 to 1)with my old 260cc stock injectors's but then I didn't think they would equal what the 370's would put out at WOT! You know the need! MORE POWER! Nathan I love the way she runs now. She is rich, but not that bad. Starts, idles, runs fine. I just know she is rich and that in itself bothers me . As we have discussed over the years I'm hoping to maybe lower press. (as you say 36 or maybe 32 or 34psi.) to possibly find a better medium (along with adjusting AFM) than what I currently have. I agree PITA but at times we all have that playing with our Z's . Anyway I've read alot of talk on the subject (I could be wrong. If so; somebody chime in)but I haven't read one thread of someone actually dialing in the most Max performance (while not losing all around performance (right mix at normal operations)while still using stock computer. Its a dice toss I'm gambling $114 (FPR) that something benefical will come out of this. Its really not a gamble. I will need this FPR if I decided that I really, really needed (and could afford $850) a SDS at a later date. I know you and Tony went one step further with a 300zxt computer setup. Which sounds like a great cheap way to allow more adjustability. I afraid I'm not that electronicly gifted along with the fact its hard to find at the salvage yards around here. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted December 3, 2002 Share Posted December 3, 2002 Originally posted by Len:I haven't read one thread of someone actually dialing in the most Max performance (while not losing all around performance (right mix at normal operations)while still using stock computer. I know you and Tony went one step further with a 300zxt computer setup. Which sounds like a great cheap way to allow more adjustability. I afraid I'm not that electronicly gifted along with the fact its hard to find at the salvage yards around here. Actually the 300ZX ECU, while delivering more power than the stock ECU with the same size injectors, is less flexible for tuning for larger injectors. I am currently knee-deep in modifications to allow the use of 370cc injectors. I have an adjustable FPR on the way (20psi to 80+), a new fuel rail and filter built, and currently being plumbed. I will soon be ordering new intake piping, and installing the Z31 MAF sensor inside it (I am taking a risk on it working at all, but it won't be the first time I've wasted $$ on my car). Then all the tuning will be done with the FPR as the MAF is not adjustable. The end result should be max duty cycle available on the 370cc injectors (modestly about 325rwhp) while retaining stock mileage and driveability. There may be some tricky ignition timing to deal with, but it should be a secondary issue. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted December 14, 2002 Share Posted December 14, 2002 ford ran 40 psi no vacuem-32 psi at idle.my turbo z has lucas disc type injectors that are oem size.it passes smog in ca.but if pressure is turned up these injetors are supposed to spray more fuel.when its on 12 psi boost i see 56 to 60 psi on my mechanical fuel pressure gauge.o2 sensor is running rich-.86 .so i know i am getting plenty of fuel.the 40-32 thing is common on efi systems that are bosch based. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted December 14, 2002 Share Posted December 14, 2002 Randy, I have been reading about those injectors you have in Fuel Injection and the guy really likes them. They are supposed to be one of the best around. Where did you get them and how much $$$???? Davy Quote Link to comment Share on other sites More sharing options...
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