Tremec Magnum XL swap

Discussion in 'Drivetrain, Exhaust and Electrical' started by 12coBoss, Feb 8, 2015.

  1. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    Where did you source yours?

    What supporting conversion items did it require? I know that the shifter is semi-remote without being the same as the shifter for a 3650, and I think it uses the same sort of attachment for the driveshaft on the output shaft (not at all sure about driveshaft length). I'm sure I'm missing a number of details.


    Norm
     
  2. racer47

    racer47 All I got left is fast

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    I'm a patient guy. I knew what trans I wanted and just looked for one occasionally. Eventually I found one local out of wrecked gt500.

    As far as parts, you need the trans mount, shifter and 26 spline clutch. The driveshaft needs to be 3/4 inch shorter. Many aftermarket gt shafts have to enough travel to work with the tr6060.
     
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  3. tetstang

    tetstang TMO Intermediate

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    Okay Drivers, I finally got in two real good track days at Laguna Seca with my new Tremec Magnum XL swap. Here's the general parts list:

    Tremec Magnum XL
    MGW short throw shifter
    Driveshaft Shop one piece lightweight driveshaft
    Ford Performance Torsen T-2R differential
    Ford Performance 4:10 rear gears
    JPC driveshaft loop
    Braided clutch line
    Trans cooler from parts

    I sourced the parts as follows:
    Got the Tremec, driveshaft and Tremec oil from Joe Dederichs at Dederichs Motorsports, Texas -- (682)-231-3510, and (682)-365-5555 mobile. I dealt with Joe directly. He's a Mustang guy, Ford guy and racer, and Elite Tremec Dealer. He knows this stuff and is very easy to work with. He had in stock a 2.66/1.78/1.3/1.0/.80/.63 box. The overdrives are a swap from the 2.97 box. My mechanic (see below) and I debated over which box to get.... the 2.66 (above) or the 2.97/2.1/1.46/1.0/.80/.63; since I only run road course HPDE, and gears 3 and 4 are the most important. Joe pitched in his opinion as well. And, doing some research I found that:

    2008 FR550S car uses Tremec 2.97/1.78/1.3/1.0/.80/.63 (the same as mine, except 1st gear)
    2013 Boss S car uses Tremec 2.66/1.82/1.3/1.0/.77/.50

    Both of the above have 3:73 rear gears. We liked the progression of gearing in the Tremec XL 2.66 box, even though the gearing is taller than the 2.97 box. To compensate for this, and doing some math on various turns at the tracks I run (Laguna, Sonoma, Thunderhill), we opted for the 4:10 rear gear. This would keep the car in the power band/speed realms I was used to and keep end of straights/corner entry/shifting in a reasonable realm.

    As mentioned above, I sourced the parts. MGW shifter directly from MGW website, and the other stuff from either Summit Racing or American Muscle. The car already had a McLeod RXT clutch, so the discs had to be sent back to Mcleod to be resplined to match the Tremec. My mechanic and his shop did the swap -

    Michael Thompson at McGee Motorsports, located at Sonoma Raceway. (707) 996-1112. All his shop does is race cars and track cars, and some vintage race cars too. Michael himself races, and Matt his lead mechanic, is superb. They are easy to work with, and Michael and Matt give 120%.

    Okay, the on track experience. As expected, first gear is uncomfortable in the paddock (would never work on the street). It takes a lot of clutch work to get the car rolling, but who cares: it's the paddock. (By the way, this is a track car, sees no street time and runs maybe 25 track days/year. Dyno'd 424hp to the wheels, and is not stripped out but no A/C, 4pt roll bar, seats, 6pt harness, Cortex/JRI Track suspension, Apex 18x10 wheels).

    The shifting is flawless. A far cry from the OE junk. A good, solid mechanical feel, short and quick. No guessing anymore. Reverse takes some getting used to and is a hard-slow push to the right and up. There's no chance to blow it. The progression 2-3-4 is excellent, although, as expected, the car feels a bit sluggish due to the Tremec gearing. Thank gawd I went for the 4:10 rear. The FR500S and BOSS S are lighter cars; the Boss S with more HP, which is why they get away with the 3:73, I assume. Sluggish noted, the car is very driveable; gear progression right where you'd expect it and **important**, I am shifting less, at least at Laguna. Laguna is all 3-4, except for T11 where I go to 2nd gear now. And the 2-3-4 on the main straight around T1 is a joy. Downshift (DS) to 3 for T2 is smooth (whereas the OE was troublesome, and I had to do a 5-4-3 DS). Exiting T2 in 3rd is a little slow, but 2nd would be a poor choice I think. Then 3rd gear all the way through T4, which also is a joy as I had to 3-4 shift between T3 and T4 with the OE then roll through T4. Exiting T4, shift 3 to 4, then DS to 3 for T5, up the hill in 3rd (pedal to the floor - no sound violation), shift to 4, then back to 3 to enter T6. I can pull through T6 in fourth fine, but get better oompf going uphill to T7 in 3rd. Upshift to 4 after T6, then DS to 3 for the corkscrew. Then downhill through T9, T10 all in 3rd. Being in 3rd here is great because it makes passing a snap (I had to be in 4th with the OE). T10 to T11 in 3rd, then DS to 2nd for T11, and then exit T11 for the straight as mentioned above.

    I'm still getting used to it, and it will take some time. I need to improve corner exit because I can't just depend on power to catch me up. Honestly, I think this is a good thing. My driving will improve, and therefore be faster and smoother. My buddy with his FR500S was there for the second day and we ran together some. When we were exiting T11 together and shifting on the front straight, he pulled away from me. Even though his car has about 325hp and 3:73 rear, it's lighter and he's a better driver, and the 3-valve motor has different power. I'll work on getting weight out of the car next, and always am working on my driving.

    Bottom line: The Tremec is a great change. After blowing up two OE's, I'd had enough. It's an expensive swap, and there is more inherent vibration. But hey, it's a track car. I'm running two days at Thunderhill soon, and excited about the change for that track.

    If you can spend money, get one.
     
  4. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    I can spend the $, but I only want to do this one once, so I'm still in research mode.

    Pretty sure you've got a 2012 with the 5.0, which is probably a hundred or so lbs heavier than my '08 . . . what size tires are you running and what rpm are you shifting at?

    I'm not writing off the idea of a lighter steel flywheel quite yet either.


    Norm
     
    Last edited: Sep 13, 2018
  5. tetstang

    tetstang TMO Intermediate

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    Norm, you are correct. 2012 GT with CAI and a tune. Tires are Nitto NT01 275/40-18. I need to look at my in car video to see my rpms, but casual glances at the tach at Laguna and one rev limiter hit, looks like I'm shifting at about 6400. I did feel like I wanted to wind it out more than with the OE trans - quilty as charged - but I was happy to see that my CH temp was staying reasonable. I'm going to try 275/35-18's to reduce the gearing a tad. It was a few years ago that the McLeod RXT was installed, but I'm sure I also got a new lighter flywheel at the time, packaged from McLeod.

    I knew the money question after I killed the first OE tranny, and wimped out and tried it again. Bad idea, it lasted a year. I think the Tremec is a good option for converting our street cars to track cars, but if I could do it all over again....uh, huh..... I'd just buy a Boss S, if I could find one.

    BTW - you have a full cage, don't you? Who did it ??

    TS
     
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  6. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    No cage, as it still sees significant street duty (sometimes with a passenger) and runs on true street tires (currently MPSS). Maybe you're thinking of somebody else?

    For me, it's beginning to feel like a close-ratio Magnum XL will be worth the upgrade just to get rid of the huge gear-spacing gaps in the 3650 (2-3 and 4-5 are both about 1.5:1). Even in street driving.


    Norm
     
  7. racer47

    racer47 All I got left is fast

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  8. tetstang

    tetstang TMO Intermediate

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    Norm,
    I looked at my video. At Laguna, exiting T11 in 2nd gear, 2-3-4 upshifting on the straight, I shift at about 6300 and the rpms drop back to about 4900-5000 at each shift. The progression/splits are very good.

    I also looked a bit at my data, and I am a bit slower in most areas of the track, especially T6 - T8 up the hill. Lots of variables: tires, track conditions, psi etc.. I drove near the front of the pack both days, so it may have been just the conditions. There were vettes, a Mclaren and a Ferrari; Bimmers as usual. I do need to re-learn how to drive this tranny, but it's not a bad thing. Just will take some time.

    If you drive your car on the street, and go with the 2:66 box, remember, first gear is a challenge. But, enjoy.

    TS
     
  9. 302BOB

    302BOB TMO Addict

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    My question to this day....Why didn't the Boss get the better tranny in the first place????....The ONLY reason has to be the cost involved............I would have paid the difference!!!!!!!!!!!!!
     
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  10. racer47

    racer47 All I got left is fast

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    It always comes down to cost. I've worked at 3 big oems and see this all the time. We see how good stuff could be for just a few dollars more. But sometimes decisions are made based on nickles
     
  11. 302BOB

    302BOB TMO Addict

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    I agree, Most Corps will nickel and dime us to death to show a profit...But they should note..All the five & dime stores around here have long since gone! Folks don't mind spending a little more to get a little more.
     
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  12. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    Thanks for the above information; it's all valuable because it helps clarify what I should expect.

    I'm already anticipating at least a brief learning period, since I went through a learning period when the shorter tires I went to (285/35-18's from 255/45-18's) caused shifts to happen at different points on the track - and actually added an extra upshift/downshift pair on each of NJMP's courses.

    One thing I intend to do (but haven't gotten around to yet) is run a comparison of your setup against various options for my own. I'm still thinking in terms of 3.73's, because I do want 4th to be good for a bit more than 110 mph @ 6000 rpm, and there are more times on the street where I'd rather have a few more mph available in 1st than have stronger acceleration in that gear. Maybe I really don't have a single drag-racing bone in my body.


    Norm
     
  13. Norm Peterson

    Norm Peterson Corner Barstool Sitter

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    That's a dual-disc unit, correct? If so, don't they tend to be a bit abrupt in their engagement? With only a NA 4.6L, a 6000-ish redline, and anywhere from about 70% up to 95% street driving, I'm not looking for a dual-disc any time soon. Maybe never. Basically, I'm guessing that this has a lot to do with your warnings about 1st gear with the 2.66 1st on the street.

    I did run your numbers against one set of mine, and it turns out that we'd be shifting at very similar speeds, just that you'd be running 400 - 500 rpms more than I and shifting sooner after track out even if we passed the apex at the same speed.


    Norm
     
  14. tetstang

    tetstang TMO Intermediate

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    Just got back from 2 days at Thunderhill 3 mile. Must say, the gearing is almost darn perfect for that track. To your point about stretching out 4th gear around 110mph.... I captured data from yesterday that shows I'm at 120 just past the S/F tower at about 6200 rpm. I'm still in the throttle there. THIS is the ONLY place that I'm even a tad nervous about the gearing. For now, I'm stretching 4th out there and not going to 5th. That was the plan all along with my gearing choice. I really don't want to short shift into 5, then back to 4th like the OE tranny. It's on the edge... If I change tires from 275/40-18 to 275/35's, the shift may be required. The slightly lower gearing resulting from the 35's would help at Laguna a tad. Will be running Sonoma at the end of October, so we'll see how she does out there.
    FWIW - I have two buddies that track FR500S cars; the 4.6L motor, and their gearbox 2-3-4 is the same as mine, but with 3.73 rear. They both stay in 4th thru the front straight and T1. We all run similar shifting habits.

    Regarding the McLeod RXT, yes it is dual disc. It also takes some rpm run-up and clutch slipping for engagement, and is a bit ubrupt, now that you mentioned it. The OE clutch got swapped out years ago, and that was the first thing I noticed. That aspect, combined with Tremec's tall first gear, would make stoplight driving a PITA, IMHO.

    BTW - I mentioned in a post earlier about a little more vibration. I didn't even notice it that last two days, so it obviously isn't bad at all...
     
    Last edited: Sep 17, 2018
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