Join Shelby Forums Today

Performance issue

Discussion in '2nd Generation Shelby Mustangs' started by Stevo, Aug 31, 2009.

  1. Stevo

    Stevo Member

    Posts:
    14
    Likes Received:
    0
    Joined:
    Aug 18, 2009
    Hi all, I've owned my Shelby GT for about two weeks. It has approximately 1000 miles. I've given it a responsible break-in and after 500 miles had the first oil change. Unfortunately the car sems to have lost a little power. Before the oil change the car would easily chirp into second gear when pushed to do so, now it won't. I figure one of three things has happened, either the power is down, the clutch has been rubbed, or the green tires have been seasoned. Any ideas? does your SGT still give an audible second gear chirp if pushed?
     
  2. Kazman

    Kazman Member

    Posts:
    10
    Likes Received:
    0
    Joined:
    Sep 12, 2009
    You really need to put it on a Dyno . If you can get a baseline of the power its putting out , that would be a good start . Mine made 440 from right off the dealer lot to the dyno . We downloaded a SCT tune and it woke the car up to 478 rwhp . Thats quite a difference you Can Feel .
     
  3. Stevo

    Stevo Member

    Posts:
    14
    Likes Received:
    0
    Joined:
    Aug 18, 2009
    I'd be very happy with 440...lol. My car is a Shelby GT with 325hp if that! this winter I 'm going to have get some serious upgrade. Still not sure about an SC or some internal upgrades. It seems like for the same cost of the Shelby GT/SC package I could get a decent crate motor. I do like the handling of the small block package though.
     
  4. firetruck

    firetruck Well-Known Member

    Age:
    73
    Posts:
    50
    Likes Received:
    0
    Joined:
    Jul 12, 2009
    Location:
    Desoto, Tx
    one thing most people don't consider is the fuel, the fuel. remember these engines are hand built. power variations are nill. just because you're not chirping the tires everytime, does not mean power is down.
     
  5. Kazman

    Kazman Member

    Posts:
    10
    Likes Received:
    0
    Joined:
    Sep 12, 2009
    What year and what mtor is in the car ? I just traded my 97 Cobra in on this new one , that car made 444 rear wheel horsepower from when i first put a Supercharger on it way back in 1999 .
     
  6. Stevo

    Stevo Member

    Posts:
    14
    Likes Received:
    0
    Joined:
    Aug 18, 2009
    2007 Shelby GT 4.6 Black w/Silver stripes. I'm probably just getting use to the power. I purchased the car used with only 53 miles on it, I bet the tires were just so new they chirped easily. The car has lots of grunt off the line, it just seems that the power has flattened out up top. I'm curious if it may have somehow lost its Shelby tune, can the the ECU/PDM get corrupted? How do you know if the Shelby custom tune is still in place? What specifically does a Ford tech look for?

    I noticed that Ford Performance group has larger throttle body specifically for the non supercharged 4.6; between that and the Steeda performance intake elbow I wonder what the gain would be. I dont have the $$$ for a supercharger. Has anyone done this mod? if so, what tune have you used?
     
  7. Kazman

    Kazman Member

    Posts:
    10
    Likes Received:
    0
    Joined:
    Sep 12, 2009
    I bought my 97 Cobra from new . Back then , there were only a Handfull of people doing anything with these cars in the way of performance. I did the larger TB, changed exhaust from headers back, underdrive pullies , bigger Mass Air Intake , basically lots knowing that i was going to get a Supercharger . You can spend quite a bit of money just on the small stuff for very littke gain in power . Ultimately , though expensive at first , the Supercharger is the way to go . I paid an awful amount of money back then as they were so scarce , but the rewards were a car that was ( at the time ) one of the fastest on the road . Back in 1998/99 , the amount of cars that had 500 HP were very , very few . With the 3 valve engine you have , i would expect the same power as my old 4 valve , in other words over 400 to the rear wheels with a safe tune . If you gat the chance to drive a 4.6 with a supercharger , just try it and try and keep the smile off your face .
     
  8. Stevo

    Stevo Member

    Posts:
    14
    Likes Received:
    0
    Joined:
    Aug 18, 2009
    "just try it and try and keep the smile off your face"

    I'm gonna have to get one, done deal. I have all winter to put it together. I'd like to pay for the Shelby GT/SC upgrade but I think it just may be to much. Are any of the Ford performance groups SC's worth the investment? I still have some warranty on the car.
     
  9. Kazman

    Kazman Member

    Posts:
    10
    Likes Received:
    0
    Joined:
    Sep 12, 2009
    I had the Votech SC on my old Cobra . It was aftercooled and lots of other mods done to accompany the newfound power . Boost would kick in at around 4000 rpm , now , with the new Shelby , these sport an Eaton Blower . Boost comes on QUICK with these . Its all a matter of preferance as to where you want the power to start . Heres something to think about

    Theres on such thing as "Bad Beer " some just tastes better than others . Same for SC,s , just deppends on your Taste .
     
  10. BAMMER9992000

    BAMMER9992000 New Member

    Posts:
    1
    Likes Received:
    0
    Joined:
    Sep 15, 2009
    I AM HAVING 1ST TO 2ND GEAR GRINDING AT HIGHER RPM IS ANYONE ELSE:huh:
     
  11. firetruck

    firetruck Well-Known Member

    Age:
    73
    Posts:
    50
    Likes Received:
    0
    Joined:
    Jul 12, 2009
    Location:
    Desoto, Tx
    if you're not fully depressing the clutch it might grind. that is the only thing that will make it grind. first to second maybe a little notchy but no grind.my response only applies to the 2010.MHO:dance:
     
  12. SnakeStrike

    SnakeStrike Member

    Posts:
    9
    Likes Received:
    0
    Joined:
    Oct 19, 2009
    I have a problem with my 2010 GT500. When I am sitting at a red light @ about 3000rpm and let the clutch out when the light turns green I get alot of smoke coming out of the rear wheel wells. Does anyone else have this problem?:doh:
     
  13. RWM

    RWM Member

    Posts:
    17
    Likes Received:
    0
    Joined:
    Jul 14, 2008
    Location:
    Carolinas
    LOL good one SnakeStrike. :laf:
     

Share This Page