Changing Rear Ratio for Track

Discussion in 'Drivetrain, Exhaust and Electrical' started by docs302, Dec 5, 2018.

  1. Coz

    Coz TMO Race

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    I'm not sure the semantics make any difference in the end but Torsen seems to differentiate between the T2 and T2R. In addition to the link I provided in post #4 Torsen also differentiates them in the attached
     

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  2. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    See my first post in this thread:
    https://trackmustangsonline.com/threads/os-giken-vs-torsen.13780/#post-201891

    Also note that there is some confusion about the T-2/Boss/T-2R Torsens. The Boss is also a T-2R design, just with the 2.7 bias . The FR-500 or 4.0 bias unit is also a T-2R, but often the only one referred to as a T-2R.

    T-1:
    [​IMG]

    T-2:
    [​IMG]

    T-2R:
    [​IMG]

    Spotting an assembled "R" should be easy and see the Thrust Plate differences:
    https://torsen.com/product/ford-8-8-t2r/
    [​IMG]
    or
    https://torsen.com/product/ford-8-8-31-tooth-spline-t2r/#
    [​IMG]

    T-2:
    https://torsen.com/product/ford-88-31-tooth-t2/#
    [​IMG]

    JMO, but I'd get the 4.0 bias T-2R for AutoX or tight courses. Boss T-2R for track.
     
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  3. docs302

    docs302 TMO Race

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    I have an AED Kooks tune now. Definitely wakes the car up. But at a track day this year I chatted with a local drag racer who was running his GT350 with our group. He also happens to have a performance shop and told me I was missing out on big HP by not having a CAI. I was under the impression that a CAI was only good for a handful of HP. He tells me to specifically get the JLT as he has dynoed all of the popular brands and that makes the best HP. With a custom tune (cam phasing?) he is telling me I can see 35-40HP gains. For less than $300 for an intake plus a few bucks for a tune that's money well spent. Guess I will see if he is right. I will post dyno results once I have it done.
     
  4. Mad Hatter

    Mad Hatter Gotta go Faster

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    Hmmmm....... Having the LTH in first makes the CAI useful.... Not much point till you improve the exhaust side of the engine.... Always hear about CAI adding massive hp but never seen it... I Think my airaid CAI plus accufab 84.5mm TB with a tune probably gave me 15rwhp.... I really really doubt that its more.... I think the PMAS CAI (tune needed version) is one of the best right now (but ugly)... And I think the Airaid is better then the JLT from what I have seen.... Lots of CAI's don't do a dam thing. And when they say....NO TUNE NEEDED, then you know its just window dressing.

    As far as tuners go..... I would just go with what Shaun from AED says... He lives and breaths Coyotes (cam phasing??.....my alarm bells went off)
     
  5. docs302

    docs302 TMO Race

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    Boy I hope that's not the case. I went with his recommendation. He said he has tested them. I got the new version JLT that was released but I have no idea if it really is any different. I still think 15 RWHP is worth a CAI and tune cost but I was stoked about 30-40. Maybe my interpretation of the conversation is a bit off but he seemed very confident about what he has seen and what he can do. He was aware of the difficulties in cracking the Coyote computer but said he has worked with the experts and has it down. Guess the dyno will tell...…or a blown motor :eek:
     
  6. Coz

    Coz TMO Race

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    Not sure which JLT but in general be careful of the open ones that take in hot air from under the hood.
     
  7. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    Quoted the wrong post before...this was actually the one that clarified that the Boss Torsen is a T-2R unit. From their website:

    "(T-2R) differentials are in the 2nd generation of design, now employing Equvex II parallel-axis gears, which make use of Split-Gear technology. Split-Gear, first introduced for the 2012 Ford Mustang Boss 302, uses a helical spline coupling to the side gears. This gives the model tunable friction characteristics, allowing it to meet OEM customers’ specific needs in a way no one else in the industry can."

    https://torsen.com/how-it-works/

    [​IMG]

    This helical spline 'update' is a good reason IMO to go with the Boss unit. Probably also the main reason it costs more.
     
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  8. Coz

    Coz TMO Race

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    Got it, thanks! I wish Torsen would be consistent in their terminology.

    In any case the Boss Torsen is very strong and possibly better suited to our cars - especially those with power adders - than the other T-2Rs.
     

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