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Symptoms of belt slip?

Discussion in 'SVT Shelby GT500' started by HKusp, Aug 19, 2019.

  1. HKusp

    HKusp Member Established Member

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    I am definitely feeling like the car is down on power and seems to take longer to build boost. I have no dyno numbers or 1/4 mile runs to back this up, but the butt dyno is telling me I have an issue. I had lost almost 3 miles to the gallon about a month ago and it turned out to be bad 02 sensors and and older spark plugs. Changed them out a couple of weeks ago and I am back to getting what I was accustomed to in mixed driving, approximately 14 mpg. The car is definitely not pulling as hard or as quickly as it used to and the next thing I would like to check is if it's a belt slip issue. I have a smaller pulley and accessory tensioner, but I don't know how old the belt is and thought maybe that could be the issue.
     

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  2. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    A slipping belt could show a lot of belt dust around the upper pulley. But rubber dry rots over time and if the belt is original, slipping might have more to do with it being too hard and not necessarily generating any dust. Those auxiliary idlers generally do a pretty good job with belt wrap. It's make sure your intercooler pump is running. Heat sink from a dead pump will definitely zap some power.
     
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  3. lexustech48

    lexustech48 RIP FoMoCo 1903-2014 Premium Member Established Member

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    Factory s/c belt tensioners are known to be weak over time as well.
     
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  4. HKusp

    HKusp Member Established Member

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    What is the best procedure to test the pump, do I just look in the reservoir and see if it's circulating?
     
  5. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    I'd probably use a jumper and see if you can see it running or hear the pump motor. It's easier to see turbulence in the reservoir with the engine off. That would be one way of doing it, but wouldn't tell you if it's an intermittant problem, or just a bad relay. If you have an infrared heat thermometer, you could see what the coolant in the heat exchanger and the reservoir are doing by periodically checking. Just realize on a cold engine, your pump may not energize until the intake reaches the set point for IAT2. I shouldn't take long.

    If your heat exchanger is always ambient, you might have a pump issue. If you have a later programmer, you could monitor IAT2 with your flash tool. If you see temps exceeding 130 degrees when you go WOT, you probably have issues with the pump. Best method would be to see what IAT2 is doing. If the pump isn't working, your IAT2s will just continue to get warmer as you drive because coolant is staying in the intercooler. You could also do a data log with a lap top and monitor IAT2, coolant temps, timing and rpm.
     
  6. GT Premi

    GT Premi Well known member Established Member

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    It's the middle of summer. All GT500 owners are down on power right now. Even with the Killer Chiller, my GT500 still isn't pulling as hard now as it did back in the spring or will in the fall. But it's still pulling harder than most.
     
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  7. HKusp

    HKusp Member Established Member

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    I got crushed yesterday by my buddy's AMG63 on 95. I beat him at a 40mph roll but it was back in January and it was about 28 degrees out that night. Yesterday he pulled me like he had 200 more HP at least. I do have the SCT BDX programmer brand new in the box, which I have never used before. I bought it from Venemous tuning in preparation for my future mods. I also have an AutoEnginuity with the full domestic bundle that can log data. I have to hook it up and see if I can find the IAT2's parameter on it. This issue with it, is the dongle for the OBDII port when it is connected, hangs down where my shin is for the clutch, so I will have a hard time driving with it hooked up, unless I move the OBDII port.
     
  8. merkyworks

    merkyworks Well-Known Member Established Member

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    Try using a 90* adapter.


     
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  9. HKusp

    HKusp Member Established Member

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    Thank you sir. I appreciate that.
     
  10. PM-Performance

    PM-Performance Active Member Established Member

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    Is your buddies C63 stock? Or modded? I have a friend with one as well and don't sleep on them. If you are on the stock blower with basic bolton stuff and he is tuned and boltons, with his being auto, he is gonna get out on you hard. My friends is a mid 11 car at like lower 120's
     
  11. HKusp

    HKusp Member Established Member

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    As far as I know, he is mostly stock. He is the type of guy to have something done to it and not tell me, and believe me, I know those cars will get, but mine has been feeling down on power and I am certain something is going on. I am going to take the suggestion above and try and data log IAT2's this weekend and see what's up. I still have the stock HE and maybe the pump is on it's way out.
     
  12. PM-Performance

    PM-Performance Active Member Established Member

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    Honestly, best thing you can do it have something hooked up to see vitals all the time. I keep my ngauge installed all the time. Its makes you obsess, but it also keeps you on top of things like when my pump was shutting off periodically.
    Jumper the pump quick. its a super easy way to quickly test that theory.
    But again, its summer, these cars are ****ing dogs in the summer! Even with cooling mods, its just the nature of the beast. I lose races in the summer that in the fall I would put busses on. Ive accepted it for the remainder of the summer. lol
     
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  13. HKusp

    HKusp Member Established Member

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    Well, this is good to know, and a little disheartening too. This is the first summer that I have owned the car. I bought it last year right after Labor day and it proceeded to rain every day for almost 20 days afterwards, so I really hadn't driven it in the extreme heat of the summer. If it's just a situation where these cars are just dogs in the heat, that makes me a little less anxious, but certainly is a bit of a disappointment. I guess I have to power up if nothing is fundamentally wrong with the car. :)
     
  14. shelbygt500hoss

    shelbygt500hoss Member Established Member

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    I would definitely invest in a HE, I remember vaguely the summer I first got my GT500. After the 1st pull it fell on its face hard. I got my HE a few weeks after that, the car was pretty consistent after that. Still u could tell the drop in power, cause of summer, but not nearly as bad with the stocker
     
  15. PM-Performance

    PM-Performance Active Member Established Member

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    Since my post yesterday never posted. . .
    But powering up the car will not help, it will actually hinder things. More power= more heat.
    I know the feeling. Its the first summer with my car as well and its modded to the gills and I cannot enjoy it because Im always hawking the IAT's and knowing im down on power. I just been dealing with it praying for cooler days
     
  16. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    That's the nature of these cars and the stock heat exchanger is pretty dinky. If you haven't driven the car in summer before, it could be all you're experiencing is heat soak. An upgraded heat exchanger can help. The M-122 is also a big heat pump the harder you spin it.
     
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  17. HKusp

    HKusp Member Established Member

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    Mine is spinning pretty hard. By the stock gauge in the cluster, I am pegging it past the 15lb mark. I know it's not the most accurate thing on the planet, but it's not 7 or 8lbs off either. It's been in the 90's here for weeks and of course, this weekend the highs are not expected to go above 82 degrees. So my data will not be an apple's to apple's comparison. Just driving the car this morning in the low 70's the car feels much stronger.
     
  18. PM-Performance

    PM-Performance Active Member Established Member

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    ALL PDB cars are heat pumps. My TVS seems like its gonna melt every time I take it out. lol
     
  19. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    True, but the TVS' rotor design is much more efficient and you have to spin the 2 liter blower to the moon to make worthwhile boost.
     
  20. PM-Performance

    PM-Performance Active Member Established Member

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    I mean technically you do on the 2.3 as well. Only reason I don't have a lower on mine right now is because the thing runs hot enough in its current config and worried about spinning it any harder and making more heat while on pump gas.
     

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