Nitrousbird Posted July 13, 2002 Report Share Posted July 13, 2002 Okay, I tossed in a set of used SVO injectors that I got off the net into my car, and reprogrammed the PCM for the injectors, using the proper calculated size (since Ford rates their injectors weird). Ever since I did that, the car started running like total ass, almost like I pulled a couple plug wires. (and for those that don't know, L98/LT1/LS1's and 5.0's all use the same type of Bosch style injector). Well, I yanked those, and tossed in the stock injectors out of my roomate's 96 SS, since I sold my stock 24# GM injectors. These only have 30k on them. Well, the car runs fine w/ these stock injectors. The problem is, these are just not big enough for my heads and cam. Here is question #1: - While running my scanning software on the car, I noticed that its running pretty rich. Nothing off the scale, but is rich for sure. - Making a couple WOT runs, I noticed that my injectors go to 100% duty cycle at 5700 RPM. Ouch; not good since my cam is good for 7000, perhaps even a tad more w/ all my top end goodies, though I'll never shift above 6800-7000. - BUT, as the RPM goes up past 5700, the injectors actually flow less, because they were already flowing their max, and now they have less time to flow due to the higher RPM (hence the reason why high-reving cars have such large injectors). Now, what if I watch my O2's carefully, and figure out what RPM is the limit, how the car is currently tuned, where the car is pretty much stoich or the slightest bit lean (basically, around 890-900mv). I made one run where I hit the rev limiter (I forgot to change in from 6300 I used to have it set at). It wasn't lean when I hit it. I don't plan on racing or running nitrous like this, but as long as I set rev-limiter right, do you think it will be safe running the injectors at 100% duty cycle that long?? Basically, so I can get on it here and there when I feel frisky on the street until I can get another set of injectors (I'm feeling REAL poor right now, and probably for another week or two). Then I'll go w/ a set of 30# injectors. QUESTION #2. Is there any place locally that can clean/test/repair injectors at a GOOD price. I'm pissed these are fudged up as it is, but I bought them so long ago, I don't even remember who I got them from (they were used). They are 24# SVO's (which are equivalent to a 26.5# normally rated injector). I want to go 30#, because I think these are going to be a little too much on the edge, seeing how I'm going 100% duty cycle so soon now, and I don't want to tax my fuel system (and fudge up my nitrous jettings) by bumping the fuel pressure up. But I need to sell my SVO's to pay for a set of 30# (or bigger) injectors. Quote Link to comment Share on other sites More sharing options...
Guest 614Streets Posted July 13, 2002 Report Share Posted July 13, 2002 What else do you have done to your fuel system? Quote Link to comment Share on other sites More sharing options...
slow4now Posted July 13, 2002 Report Share Posted July 13, 2002 Hite Parts Exchange on McKinnely Ave. cleans and balances fuel injectors, it costs $25 each injector. I have never had them do this for me, but I know a few repair shops use them. Just curious, but how much fuel pressure are you running? What fuel pump are you running? Is your fuel pressure regulator in good shape? Is your fuel filter clean/free of blockage? These are all thing I would check out, unless you know for a fact that those injectors aren't supposed to be big enough. Go to www.raceeng.com, they have injector calculations setup so you can figure out what size injector you need (you must supply some info first though). It sounds to me like your injectors could be starved for fuel, so even at 100% duty cycle (the injectors are stuck open at this point) they aren't getting enough fuel to the engine. Well, hopefully I'm not too far off with any of my suggestions. Later! Quote Link to comment Share on other sites More sharing options...
Nitrousbird Posted July 13, 2002 Author Report Share Posted July 13, 2002 Right now, the fuel system is bone stock. I HAVE to add a fuel pump (I'll be doing a 255lph intank) to run the nitrous. W/ that fuel pump, the fuel system is good for around 700RWHP. LT1's come w/ pretty decent fuel systems stock. smile.gif My fuel pressure is 36 psi at idle, 44 psi at WOT (stock settings, I have a fuel pressure gauge in the car). Fuel pressure doesn't drop at all, that's where it is supposed to be. Stock fuel system is supposed to be good for a heads/cam + bolt-ons car, other than the injectors. I did some more research (after getting those 24# SVO's ), and most guys running ported heads and a CC306 cam (its large hyd. roller) end up bumping their fuel pressure up to about 50psi at WOT (but, I don't have an adjustable FPR, and really don't want to buy one just now). As for having injectors cleaned at $25/injector. For that, its about enough to buy a new set, and more than enough to get a used set of injectors. Quote Link to comment Share on other sites More sharing options...
330racing Posted July 14, 2002 Report Share Posted July 14, 2002 I am curious why with all of your mods you dont just buy an adjustable regulator. They are not that expensive..... Quote Link to comment Share on other sites More sharing options...
Nitrousbird Posted July 14, 2002 Author Report Share Posted July 14, 2002 Originally posted by OhioGN: I am curious why with all of your mods you dont just buy an adjustable regulator. They are not that expensive.....I don't have a job anymore. Getting laid off really kills the mod fund. That, and since I want to keep my fuel pressure stock, I really have no need for one yet. As for my injector question, its a moot point now. I got enough money to get a set of 30#'ers now, and a guy from my car club is selling his SVO 30# injectors, so I'll have those tomorrow. Quote Link to comment Share on other sites More sharing options...
Boost-n-Juice Posted July 15, 2002 Report Share Posted July 15, 2002 how did it go? the 30#er's? Quote Link to comment Share on other sites More sharing options...
GRN96WS6 Posted July 15, 2002 Report Share Posted July 15, 2002 I don't think he is getting them till later this evening. I plan on stoping by his house this afternoon. smile.gif Quote Link to comment Share on other sites More sharing options...
Nitrousbird Posted July 15, 2002 Author Report Share Posted July 15, 2002 The 30#'ers are sitting here right now. I need to work on some other issue (I'm thinking O2 sensor related) before I toss them in. Always something to do to the car. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.