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2650 pulley/boost

Discussion in 'SVT Shelby GT500' started by einehund, Oct 30, 2018.

  1. einehund

    einehund Well-Known Member Established Member

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    I have seen the 2650 advertised boost reference by pulley size, but those all are assuming stock crank size. Is the 3-4psi increase with a 10% lower still the same on this blower, or does the larger size increase the psi to say 4-5? Also, is the safe psi still 19psi on pump gas, regardless of the size of the blower? I ask as the larger blower should be turning slower for the same CFM airflow, thereby reducing heating, resulting in the ability to run a bit more boost. I am just trying to figure out what combo I need.
     
  2. Klaus

    Klaus Well-Known Member Established Member

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    I ran mine at 18lbs on 91.
     
  3. einehund

    einehund Well-Known Member Established Member

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    So would the 3.0 pulley on the 2650 (supposedly 15-16 psi) plus the 10% lower I have on my car equal 19-20psi? This is where I get worried, as I don't want to run the risk of popping my motor. However, the 3.3 pulley (12-13 psi) plus my 10% lower would be 16-17 psi, which is a little tame....
     
  4. Klaus

    Klaus Well-Known Member Established Member

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    I ran 2.8 with factory lower. 3.0 is slightly on the conservative side but what I would run for 91. Do you have headers?
     
  5. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    Sort of depends which lower you have too. IW's lower is more like a 12% overdrive, vs. ATI's which is a true 10%. But, since there is no upper between 3" and 3.3", you're sort of stuck. Even ATI's standard balancer is 7.5", a 5% increase over stock (7.1"). On an ATI, I know you can just replace the blower damper and not pay the price of a whole new lower. I don't have any experience with IW.
     
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  6. einehund

    einehund Well-Known Member Established Member

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    I've got the IW lower. I don't have headers, but i do have an O/R H pipe and noticed a slight decrease in boost pressure once the cats were gone.
     
  7. Catmonkey

    Catmonkey I Void Warranties! Premium Member Established Member

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    Just working the math on the blower ratios, I think would be in the ranges you're expecting, so boost will be on the high side with the 3". Might want to ask VMP if they have plans to offer anything between 3 and 3.3.
     
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  8. Klaus

    Klaus Well-Known Member Established Member

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    I should have noted that my 3.0 was with LT headers and full exhaust which I think is worth about 1-1.5 lbs of boost.
     
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  9. boduke0220

    boduke0220 Well-Known Member Established Member

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    Check out VMP's Instagram, they just had a 2010 Makes 850 on 93/torco with a Gen 3, 2.4 upper, 67mm tb and ARH Longtubes. Dyno graph showed 23psi. Seems like a little much for a stock motor but whatever floats their boat
     
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  10. biminiLX

    biminiLX never stock Premium Member Established Member

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    I’m going to Mod Nats with the same pulley from my 965rwhp Gen2R package. ATI 15% with 2.5 upper.
    Made 19psi peak and dropped to 15psi at 7000rpm on the 2R and I’d love to see a flat 20psi til redline.
    Also bringing 2.4/2.6 pulleys with me but not planning a swap. I think Lund got 1100rwhp out of a 10%/2.4 on my Gen3 TVS2650.
    We shall see.
    The real question is who makes the best max grip upper pulley?
    What best belt now?
    Running a Gates Racing black and VMP 2.5 pulley currently
    -J
     
  11. red3v

    red3v Well-Known Member Established Member

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    Not putting it back on the dyno? Curious to see how it does.
     
  12. evasive

    evasive Premium Member Premium Member

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    Interested as well. Thinking of making the swap from the 2013 TVS with 2.4 pulley to the 2650 with 3.0 pulley and ATI 10% lower.
     
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  13. einehund

    einehund Well-Known Member Established Member

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    Seeing that there is a lack of anything between the 3.0 and 3.3 pulley sizes, I think I'll get the 3.3 to start and see where it goes from there.
     

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