May i be having too much exhaust??>>>>

Discussion in 'Performance Modifications' started by NO HEMI, Aug 26, 2013.

  1. NO HEMI

    NO HEMI Viper Owner

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    recently i did some mods on my car which are : JTSVP Underdrive pulley, and Billet TB,K&N cai, Stock manifolds with 3 inch exhaust , NO cats and A small(14 in) Kooks race muffler on each side, Roe CMR tune, new spark plugs, and i have a cooler t-stat in the box, ready to go in, i feel the car accelerates quicker, and blows the tires quick too, but yesterday i got passed by a 2013 bmw M5!!!, which makes me wonder if i maybe losing too much back pressure. any ideas?

    P.S. I was in a mouintain ride and PPl were telling me they could see 3 foot long fireballs coming out of the exhaust of my car when i let of or got on the gas!!! Fun but i think not good for the engine!
     
  2. MoparMap

    MoparMap VCA National President

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    I think there's a common misconception regarding "backpressure". Less backpressure is always better. If there is pressure in the exhaust pushing exhaust back into the cylinder, you're losing space that would otherwise be filled with fresh air and fuel. I think most people confuse the real potential benefit of smaller pipes: exhaust velocity. Smaller pipes keep the air moving faster and help "pull" other pulses with them. There might be a small increase in backpressure because of the smaller pipes, but it's not the backpressure that's doing you any good, it the velocity that comes with it. That being said, I'd doubt that the small difference you might see with different exhaust would be all that noticeable. Headers might make a bigger difference you could feel, but I don't really think the change in pipe behind them will be too significant.
     
    Last edited: Aug 27, 2013
  3. NO HEMI

    NO HEMI Viper Owner

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    I didn't know that , thanks!!, so are those M5's really that fast??? how much Hp do you think i might have gained with this "mods"??
     
  4. Tail lights

    Tail lights Viper Owner

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    When that m5 got you did he come from behind already going faster than you? When you tried to race him were you in the lowest gear possible, even though our vipers have a bunch of torque, if you're in the wrong gear you're gonna get beat.
     
  5. gutterworks129

    gutterworks129 Viper Owner

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    You might need a Hemi!:)
     
  6. NO HEMI

    NO HEMI Viper Owner

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    Haha Jeremy!!, maybe , lol

    Tail lights, i think i was in the wrong
    Gear because i was in 3rd and i jumped and he came from behind, but when i shifted to 4th i started to reel him in, and we went from a slow roll when i was in 1st and we went all the way to almost the top of 3rd and i killed him twice!
     
  7. CEJ

    CEJ Viper Owner

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    Without a dyno pull, its hard to know what power your Viper is producing. I think you have the dyno pull from this past March Dyno Day. Maybe time for another dyno pull when you're in Raleigh?
     
  8. AZTVR

    AZTVR Enthusiast

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    2013 BMW M5 stock specs: Power (SAE): 560 hp @ 6,000 rpm; 500 ft lb of torque @ 1,500 rpm

    So, what is your car pulling with the mods you have done?
     
  9. NO HEMI

    NO HEMI Viper Owner

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    AZTVR: i don't know, when it was stock it dynoed 446 rwhp and 472 rwtq , which is about 525 flywheel hp, i'm taking it to a dyno and also doing some datalogging to see how's the tune, but i was reading on the internet about those M5's and on independent dynos they have shown about 620 flywheel hp, and i also read that the 560 hp is (by bmw standards) the LEAST hp those engines would make, so i guess i didn't do that bad.
     
  10. kennyhemi

    kennyhemi Viper Owner

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    that's why I believe in a 200 hp NOS shot only used for certain situation, like when you realize you may not have enough. That's when you press the the little button and all order is restored.
     
  11. klamathpro

    klamathpro Viper Owner

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    I too believe.
    Release the power of the bottle, it will reward you.
     
  12. ulllose

    ulllose Viper Owner

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    The 2013 m5 is an extremely fast car....sure it's heavier than the viper but don't be surprised at some hesitation from you will result in you looking at a quad exhaust of a BMW.
     
  13. NO HEMI

    NO HEMI Viper Owner

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    Iwas thinking about nitrous, but i'm not sure how much is safe and how well it works on our cars( since i' ve seen maybe one or two cars with nitrous)
     

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