Low Dyno Numbers, Need Help

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by 91331, Jul 6, 2014.


  1. 91331

    91331 New Member

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    Hello everyone! Las Vegas mustang here. Low dyno numbers brings me here, confused why my numbers are so low. Looking for advice on where I went wrong? What I should do to fix or change . Have been told I should be around 390 WHP, spun the rollers at 272 hp and 316 ft-lb. 4th gear pulls..
    331ci forged 18cc dish forged pistons
    AFR 185 heads, upgraded springs, studs, and 1.6 roller rockers.
    Ford motorsport X cam
    Explorer gt40 upper lower intake, 1 inch spacer 30 lb injectors upgraded throttle body.
    ceramic equal length 1 1/2 shorty headers, x pipe, ultra flow mufflers 3" tail pipes
    under drive pulleys, electric fan
    msd coil, frpp wires / plugs
    stock pcm / distributor
    #1
  2. Gearbanger 101

    Gearbanger 101 Straight Outta Locash Super Mod

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    Moved to the correct forum. Not likely to get many responses in the Welcome Wagon.
    #2
  3. 84Ttop

    84Ttop They make new pistons every day, so why worry? SN Certified Technician Mod Dude

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    Welcome to Stangnet!

    A little more about your combo would be helpful. What is the compression ratio of the engine? Do you know the total timing that was in the motor when you made the dyno runs? What type of dyno were you using? What fuel were you using? Has the car been tuned or were you just doing standard dyno pulls? Is this car a stick shift or automatic? Do you have any copies of the dyno graphs?

    I'll be more than happy to help if you can just give me a touch more information!

    -Nick
    #3
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  4. TOOLOW91

    TOOLOW91 Mustang Master

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    Tuning in for this one. Some things i see as potential points of holding back in the combo already are the intake and maybe the cam but more the intake. But i am gonna let nick drive this one and ill take a back seat !
    #4
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  5. VibrantRedGT

    VibrantRedGT "STANGNET'S PENGUIN SMACKER" Super Mod

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    X cam and GT40p intake and small diameter shorty headers? If you change just this you'll pick up big time.

    My 347 runs a Holley Systemax with ported elbow, Comp custom grind cam and 1-3/4" Long Tubes with 3" Collector. If I ran an X cam, GT40P intake and shorty 1.5" headers without a tune I'd make under 300HP too.
    #5
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  6. FoxMustangLvr

    FoxMustangLvr Mustang Master

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    Explorer intakes are great upgrades on stock 302 blocks but once you graduate into the big time w/ a 331 or a 347 stroker you should ditch the factory upgrade mods and go pure aftermarket for the best HP increase.

    Did you buy the engine this way or did you build it this way? Like other have mentioned your intake and headers are choke points. Long tubes all the way!

    On top of what @84Ttop asked, what MAF and TB are you running?
    #6
  7. bentley429isBAC

    bentley429isBAC Well-Known Member

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    Junk intake junk cam junk headers. What rpm was it at? What compression? What kind of dyno? What was the correction factor? What were the conditions?
    #7
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  8. stykthyn

    stykthyn Commander of the snuggie cultists

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    Ditto on all the above. Like Nick said give us the whole run down. As for intakes I agree with the systemax, eddy rpm II would also be a great choice.
    #8
  9. FastDriver

    FastDriver Mod Dude

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    The numbers are still too low. 1 1/2 headers doesn't sound right at all. They're probably 1 5/8". I'm not sure I've even seen 1 1/2" aftermarket headers. I had a 302 with a cobra intake, mild OTS cam, and GT40X heads, and a shorty 1 5/8" headers that made 270 rwhp on a Dynojet 248c through the stock 5-spd. You've essentially got the same combo except with much better heads and more cubes. Maybe this would make sense through an automatic on a mustang dyno, but I still would think there should be more.

    The others are right, though. There is a ton of power waiting to be unlocked with a better intake (systemax II would be my pick with the RPM II close at hand), better cam (I prefer FTI customs), and long tube headers @ 1 3/4. That combo with good compression through a manual should reach the kind of numbers you've been told about. Your intake is not going much over 330rwhp in ideal circumstances, IMO.
    #9
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  10. revhead347

    revhead347 I have face herpes.

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    Pretty much everything said above. 18cc dish sounds like a lot. Should be 9.2:1 to 9.4:1 compression, something like that. HP numbers actually sounds above right with that combo. Change the cam, intake and exhaust and you could pick up another 80 to 100hp.

    Kurt
    #10
  11. tannerc91gt

    tannerc91gt More durable than coconuts and twice as fast

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    Ya know...some dynos just read low...
    Not really a mystery there. Whoever told you that combo would make 390wheel was on drugs.
    300hp all day. 325 I'd believe with some real headers and still sub 350 with an intake that doesn't suck
    #11
  12. Dave2000GT

    Dave2000GT Active Member

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    Probably needs to be tuned, get the timing and fuel setup right for your MAF and injectors. Check the basics too like correct plugs wires and stuff. Something isnt right and its not just the intake which should still easily support over 300.
    #12
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  13. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    I believe JBA made 1 1/2" headers back in the day
    #13
  14. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    Flowtech actually makes 1.5" headers, go figure
    #14
  15. FastDriver

    FastDriver Mod Dude

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    In that case, I wouldn't put those on a bone-stock 5.0.
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  16. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    I know, right. WTF?
    #16
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  17. 89stang1

    89stang1 Stroked and Juiced

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    whats an upgraded throttle body? and what mass air meter are you using...you can still make tons of hp with that intake on a 331 with afr 185 heads i did with a cobra intake which is very similiar to explorer but that cam and low compression will only get you so far.
    #17
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  18. 93TRANSAM

    93TRANSAM Founding Member

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    You guys noticed the -18cc piston.... so with that head and gaskets and not knowing the deck of the block- dudes rocking around 8.8-9:1 compression... intake not great for what the 185 head will want and the cam is nothing great either, couple that with not knowing the tuneup and you got a 275rwhp car- especially on a dyno with an eddy brake- That motor just needs boost and an intake swap!
    #18
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  19. 94coupe

    94coupe Member

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    how are those flowtech long tubes? I was gonna order a set?
    #19
  20. barnett468

    barnett468 Active Member

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    hello;

    what cc are the heads?


    x cam 286 - 224 - .542
    Last edited: Aug 4, 2014
    #20

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