Forced Induction Installed Supercharger, Now The Car Is Slower?

Discussion in 'Fox 5.0 Mustang Tech' started by montyd, Aug 4, 2012.

  1. so i installed a powerdyne( i know its not the best but it was cheap) on my 93 lx and the car lost ALOT of power. it has edelbroc performer heads. ported and polished edlebroc performer intake, 70 mm edelbroc throttle body, f cam(retarded 4 degrees on the timing chain) basically stock bottom end (new rings and bearing) , 24lb injectors with pro flow mass air, electric fan, griffin 4 core radiator. i have put 3500 miles on it this year naturally aspirated and ran across this powerdne set up really cheap. the car ran awesome until i put this blower on. from a roll in first it would blow the tires off with out the blower, now with it it wont. hell i ran an srt4 neon last night and only pulled a car length on it and when i didnt have the blower i pulled 5 cars on the same car. the powedyne has the 6 lb pulley and is making 6 lbs. i have the timing set at 10* (which is really 6* seince the cam is retarded. has an anderson power pipe, the piggy back fmu on the fender with a new 24lb calibration in it. and my fuel pressure it set at 40lbs at adle with the vacuum line off the regulator. i have run a powerdyne before this one and hte car was stupid fast and undriveabl;e almost in 1 and second gear. any ideas would be great, kinda thinking aout taking it to brenspeed (since i live 45 min away) and letting them dyno tune it. but if i can get it that would be awesome. thanks in advance for the help
  2. I may be way off here and fixing to insert my foot in my mouth....but here I go: I don't believe retarding your camshaft will affect ignition timing. You are simply changing when the valves open, 4 degrees sooner or later. When you adjust timing with the distributor, you are changing at what time the spark is sent to that cylinder. Either way, I don't think timing is your problem, I just thought I would mention this. My foot and mouth await to meet if someone can correct me. :)

    I don't know if this could be related to your problem, but I would think that 24lb injectors are a bit small for an aluminum headed motor with a blower. Could it be possible that you are running out of fuel (dangerous!)?

  3., the cam timing has nothing to do with the ignition timing, and you should probably be running at least 12-14 degrees of ignition timing, and you have to make sure you pull the SPOUT connector out when you set it, and just as importantly, put it back in when you're done. I bet you either didn't pull it, or didn't replace it, and you have WAY less timing than you think you do.
  4. i did pull the spout when i set the timing and then replaced it when i was done. i wasnt sure if the cam would effect the timing or not. i just wanted to have the full specs of the motor listed so everyone knew everything. ill try throwing some more timing at it and see what that does. i have safely run this same set up before but its been a couple years and i cant remember the settings lol. im just back in the single life and am out racing a little more and have some neon guys running there mouth, so of course i wanna go faster
  5. Dumb question did you pull the plugs see what they look like?...what plugs do you have what gap are you running?...Maybe spark blow out?...What igniton system you using?.....
  6. 24 lb injectors sound to small, what type of fuel pump, mass air and throttle body? I'm not a huge fan of the letter cams but I don't think it's hurting you.
  7. 10* base timing for power adder is about right
    Cam hasn't got a thing to do with what your base timing is set at
    You say you're running an FMU but you didn't say what fuel pump you're running
    What is fuel pressure at boost? Should be over 60 psi with an FMU at 6 lbs.
    What is your AFR meter reading?

    Taking it to Brenspeed for a REAL tune is a much better idea then tossing power adders on without the equipment necessary to at least CHECK the tune. If you're going to do that though, you may as well ditch the FMU and crappy fuel injectors for some 42s and call it quits.
  8. I agree.. Fmu is a bandaid.. Dont get the car tuned with that installed..
  9. 24 lb injectors with 6 lbs of boost is plenty imo, have never run into any lean situations running that setup or even with closer to 10 lbs of boost or have I just been lucky? Of course I do agree that FMU is a bandaid and a pump upgrade should be a must when adding any kind of forced induction.
  10. Decent chart and good rule of thumb for fuel injectors.

    Note: These ratings are for stock fuel pressures and do not indicate max HP potential at elevated fuel pressures (like what you'd get with an FMU).

  11. I absolutely disagree with the 24 lbs injectors being enough. IMO they are barely enough for your n/a setup. Stop what you are doing... do not bump up the timing. I think you might not have enough fuel. Advancing the timing will only worsen the situation.

    If you're sure there's nothing wrong with the powerdyne itself, you shouldn't have lost any power unless the tune is bad, your fuel system is incapable, your ignition system is incapable, you have a significant vacuum leak, or there is some other significant problem. Stop playing guessing games, because under boost it becomes very easy to kill a motor. Pull the FMU off, ensure you have a boost sensitive fuel pressure regulator, swap the 24 lbs injectors for 42s, and drag it down to a good tuner in your area for a custom tune. A good tuner will also help you diagnose any problems the car is having.

    Good luck!

  12. These are not for stock fuel pressure ratings. 45 psi is considerably more fuel pressure. Also, can anyone please explain why a turbocharger would need more fuel injector than a blower? I've seen that before, but I don't believe it.
  13. Equal pressure from both sources (turbo or SC), I don't either. It's not a bible... just a chart.

    Oh... and fuel pressure @ WOT is roughly 38-39 psi. Adjustable FPR and boost... typically I adjust a hair higher.
  14. Wow, guess I have been lucky then never had any bigger than 24s and haven't had any problems yet but don't exactly beat on her to much. How the heck can vortech get away with selling their 5-6 psi kits saying you can use 19 lb injectors? Surprised they haven't been the cause of a bunch of trashed motors. Anyway I know there is math to back you guys up, not arguing, just saying from my personal experience with a daily driver that I occaisonally stand on plenty hard I havn't had any lean problems with 6 psi and 24 lb injectors. Its been dyno tuned so maybe thats my saving grace.
  15. They do it by using an FMU. The FMU ramps up fuel pressure to get more gas out of a smaller injector. It works pretty well unless.... something goes wrong with either the FMU (say, hole in the diaphragm) or and injector sticks because of excessive pressure. You get a lean condition and boom.

    Spray patterns aren't great at elevated pressures either but I haven't noticed much of a difference between apps where the AFR is in the sweet spot.
  16. Not to mention, you're talking about putting a vortech kit on a stock 5.0 as opposed to putting it on an already modified 5.0 that is using every bit of what the 24s are capable of.
  17. A powerdyne blower that makes 6 lbs on stock engine is only going to make a couple of lbs on an engine that breathes well. So you may have been expecting too much. Me personally cheap or not, i wouldn't have bothered putting it on.

    Boost needs more injector to begin with, couple that with adding power and 24's are definitely not enough.
    30's should probably be good enough with that SC.
    The 24's you have are barely enough to feed you NA setup.
  18. i knew the fmu was a band aid, and that i needed 34's or 42's just dont have the cash. i pulled the plugs and there perfectly tan. i have put two different boost guages on it to double check my boost and both read 6lbs of boost. the only difference from the last time i ran this same blower set up is i changed from a cobra upper and lower to an edelbroc. maybe it does breath to well for it i dunno. the car will probably sit for a while untill i can but some injectors, the blower has to stay because i had to drill a 4 inch hole in my brand new hole less engine compartment to run the power pipe.. oh and its got a 255lbh pump in it
  19. if you don't have the extra money for injectors, you probably shouldn't be messing with boost
    2000xp8 likes this.