Low Dyno Numbers, Need Help

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

  1. 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
  2. Moved to the correct forum. Not likely to get many responses in the Welcome Wagon.
  3. 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!

    A5literMan and FoxMustangLvr like this.
  4. 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 !
    tamadrummer88 likes this.
  5. 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.
    A5literMan likes this.
  6. 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?
  7. 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?
    tannerc91gt and A5literMan like this.
  8. 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.
  9. 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.
    89stang1 likes this.
  10. 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.

  11. 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
  12. 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.
    FastDriver likes this.
  13. I believe JBA made 1 1/2" headers back in the day
  14. Flowtech actually makes 1.5" headers, go figure
  15. In that case, I wouldn't put those on a bone-stock 5.0.
    89stang1 likes this.
  16. I know, right. WTF?
    89stang1 likes this.
  17. 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.
    TOOLOW91 likes this.
  18. 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!
    A5literMan and TOOLOW91 like this.
  19. how are those flowtech long tubes? I was gonna order a set?
  20. hello;

    what cc are the heads?

    x cam 286 - 224 - .542
    #20 barnett468, Aug 3, 2014
    Last edited: Aug 3, 2014