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Tremec Magnum XL swap

Norm Peterson

Corner Barstool Sitter
939
711
Exp. Type
HPDE
Exp. Level
5-10 Years
a few miles east of Philly
I would be willing to bet that the ".80/.63" on the 2.66 box are misprints, AFAIK that is not offered off the shelf anywhere.
Dederichs Motorsports or Liberty's Gear would be able to handle the spec/sales/upgrade.

I got my entire package (minus clutch, had already obtained) at Dederichs and they really know what they are doing. http://www.dederichsmotorsports.com
Thanks for the link.

I'm pretty sure that the 2.66/0.80/0.63 gearset is available in the non-XL Magnums (Grassroots Motorsports recently had a T56 article with a whole page of variations), so I can't see it being a major undertaking to offer it in the XLs.


Norm
 
5,658
6,744
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
At Laguna I am in 4th the whole track except I briefly touch 3rd for turn 2, top of the screw and 11 and then quickly back to 4th.
I'm basically either on the rev limiter in 3rd or bogging it in 4th.
Not very satisfying if you know what I mean.
 

ArizonaBOSS

Because racecar.
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Arizona, USA
Thanks for the link.

I'm pretty sure that the 2.66/0.80/0.63 gearset is available in the non-XL Magnums (Grassroots Motorsports recently had a T56 article with a whole page of variations), so I can't see it being a major undertaking to offer it in the XLs.


Norm
Basically they change the overdrive "gear cluster" out--it's not a huge deal but there is a cost associated.
 
At Laguna I am in 4th the whole track except I briefly touch 3rd for turn 2, top of the screw and 11 and then quickly back to 4th.
I'm basically either on the rev limiter in 3rd or bogging it in 4th.
Not very satisfying if you know what I mean.

Interesting. In my mind, since I have yet to run Laguna, I'll be downshifting to 3rd for T2, and stay in 3rd until exiting T4. Upshift to 4th, then downshift to 3rd for T5, exiting T5 up the hill to T6.....not sure if I'll upshift to 4th as the math says I should be able to hit 95 in 3rd; 3rd thru T6; upshift to 4th after T6; back to 3rd for the corkscrew; .....T8A .... also not sure here as I used to upshift to 4th and run all the way thru T10 in 4th, which I may still be able to do (flying, mind you..) then back to 3rd for T11. I expect 3rd to be too tall for T11.... may try to carry that with more momentum, or if in traffic I'll have to go down to 2nd for sure. We'll see !! The pluses of potentially holding 3rd from T2-T6, may balance out with any fumbling at T11. I expect T11 to take some work, for sure......Important corner.

I shall report....
 

Norm Peterson

Corner Barstool Sitter
939
711
Exp. Type
HPDE
Exp. Level
5-10 Years
a few miles east of Philly
Ditto.... to Dederichs Motorsports. Joe Dederichs is the man. He'll put together the whole package for you, including harnesses, driveshaft and trans fluid, and his prices are good. He'll work with you directly and you can get him on the phone. He has lots of experience with Mustangs, and good access to Tremec.
Thanks.
Now where's that 'thumbs-up' smiley . . .


Fair warning: the 2.66 is pretty tall for initial starts - need to slip the clutch and rev a bit - but it's a good gear for rolling in the paddock, once you're rolling.
I'm well aware of what a 2.66 1st gear ratio implies - with 3.73's it's 7.5 mph/1000 rpm with the 26"-ish tall tire sizes I'm running these days (285/35-18's and 265/40-18's). That compares against about 6.5 mph/1000 for the car in its all-OE condition and 6.2 or so with my short tires.

I once daily-drove a '79 Malibu that had only a 305, 2.56s in the axle and a 2.85 1st gear in the transmission so I don't expect much difficulty with 2.66s and 3.73s (and more torque than the 305). That was also on ~26" tall tires, for a little over 10 mph/1000 in 1st . . . more like what 2nd gear should be giving you.

The feel of the shifter is night and day to the MT-82. Very crisp, very positive.
That I can believe. I eventually swapped a TR3550 (kind of a light-duty TKO) into the '79 Chevy Malibu, and the 3550 also had everything but the shift handle internal to the transmission assembly.

Expensive, yes. But the aggravation of numb shifting, missed shifts, 4-3 instead of 4-5 mis-shifts, etc., will be gone....finally.
Like when I stepped up to the TR3550 in that other car, I only want to be doing this one time. So I've been calling up past experiences, paying closer attention to current experiences, running numbers, and revising/upgrading an old spreadsheet.

MXLc 373 vs 3650 355.jpg


There are still a few minor issues to resolve, but it's a clean retrofit package. And this - one bonus I noticed - my car is running 10-20 degrees cooler. I suspect this is primarily due to less running near the rev limiter (due to the ratios) and maybe secondarily due to the trans runs cooler. I also had a trans cooler installed (protecting my investment).
Talk to Joe and good luck.
That side effect had not even occurred to me. Thanks.

Sounds like Joe is going to get a call once I've got everything nailed down.


Norm
 
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Fabman: One of my loose ends is the reverse lights. I bought the harness with the whole package, but there doesn't seem to be a connector for it available on the car. Speed sensor and reverse lockout were re-used, so that only leaves the skip shift connector (2012 GT had skip shift - worthless).

Any hints ? My reverse lights are always on......so I pulled the bulbs for now.

TS
 
5,658
6,744
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
Fabman: One of my loose ends is the reverse lights. I bought the harness with the whole package, but there doesn't seem to be a connector for it available on the car. Speed sensor and reverse lockout were re-used, so that only leaves the skip shift connector (2012 GT had skip shift - worthless).

Any hints ? My reverse lights are always on......so I pulled the bulbs for now.

TS
I didn't install mine, AED swapped it over from an automatic and did a bunch of other work at the same time so I couldn't say how they did it. (This was a drag car originally)
All my lights work, but there's no real reverse lockout so it is possible to hit the reverse gate going for 5th. Also, downshifting from 5th you could hit 6th instead.
The gates are all so close and the spring tension is very low so that in the heat of battle I don't always know what I'm going to get.

Actually I do know what I'm going to get....a sequential shifter. ;)
 

Norm Peterson

Corner Barstool Sitter
939
711
Exp. Type
HPDE
Exp. Level
5-10 Years
a few miles east of Philly
Fabman: One of my loose ends is the reverse lights. I bought the harness with the whole package, but there doesn't seem to be a connector for it available on the car. Speed sensor and reverse lockout were re-used, so that only leaves the skip shift connector (2012 GT had skip shift - worthless).

Any hints ? My reverse lights are always on......so I pulled the bulbs for now.

TS
How was the OE reverse light switch wiring set up for the MT-82? I'd think there had to be a car-side connector for that. Any chance the reverse switch itself was part of the semi-remote shifter assembly?


Norm
 
It's a head scratcher. We looked over the MT-82 and what was connected to it and find nothing for reverse lights. Have the question in to Joe Dederichs - hopefully we'll get an answer soon.
 
147
60
You will not be disappointed with the trans linked to in the above post.
Strong as a bulldozer and shifts like butter. Silky smooth.
If you call RSG, ask to speak to Mike Maida. He builds all the race transmissions for the race teams.
He really knows his stuff and is great to speak with. You may tell him Bruno sent you.
 
Before getting my new Tremec T56 Magnum XL, my research found:

T56 (found in the FR500S car) 2.97/1.78/1.3/1.0/.80/.63 I have two friends both with 2008 FR500S cars, and they claim they shift precisely without issue, and one on them says that first gear is useless except for loading in the trailer.

T6060 (found in the 2013 Boss 302S car) 2.66/1.82/1.3/1.0/.77/.50

T56 Magnum XL options:
2.97/2.1/1.46/1.0/.80/.63
2.66/1.78/1.3/1.0/.74/.50
2.66/1.78/1.3/1.0/.80/.63 (overdrives swap - what I purchased)

Stock MT-82 (from my 2012 GT, other years similar):
3.66/2.43/1.69/1.32/1.0/.65

You can see why gearing change for the rear is so important. Once I get more track time on the car, I'll report back here..
 
5,658
6,744
Exp. Type
W2W Racing
Exp. Level
20+ Years
Pleasanton: 1/2 way between Sonoma and Laguna Seca
Before getting my new Tremec T56 Magnum XL, my research found:

T56 (found in the FR500S car) 2.97/1.78/1.3/1.0/.80/.63 I have two friends both with 2008 FR500S cars, and they claim they shift precisely without issue, and one on them says that first gear is useless except for loading in the trailer.

T6060 (found in the 2013 Boss 302S car) 2.66/1.82/1.3/1.0/.77/.50

T56 Magnum XL options:
2.97/2.1/1.46/1.0/.80/.63
2.66/1.78/1.3/1.0/.74/.50
2.66/1.78/1.3/1.0/.80/.63 (overdrives swap - what I purchased)

Stock MT-82 (from my 2012 GT, other years similar):
3.66/2.43/1.69/1.32/1.0/.65

You can see why gearing change for the rear is so important. Once I get more track time on the car, I'll report back here..
I called Tremec today, he said there is something definitely wrong with my trans and to have it checked out...so here we go.
 

Norm Peterson

Corner Barstool Sitter
939
711
Exp. Type
HPDE
Exp. Level
5-10 Years
a few miles east of Philly
T56 (found in the FR500S car) 2.97/1.78/1.3/1.0/.80/.63 I have two friends both with 2008 FR500S cars, and they claim they shift precisely without issue, and one on them says that first gear is useless except for loading in the trailer.
Makes sense for a dedicated road-race car, 1st only being good for 40 mph or a bit more.


Stock MT-82 (from my 2012 GT, other years similar):
3.66/2.43/1.69/1.32/1.0/.65

You can see why gearing change for the rear is so important.
Absolutely. It continues to amaze me the number of people who can't bring themselves to budge from that "don't fear the gear" mentality, particularly with that earlier MT-82 gearset.

Looking forward to a review.


Norm
 
Last edited:

racer47

Still winning after 30+ years
384
473
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W2W Racing
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20+ Years
SE WI
I'm particularly intrigued by the 2.97/1.78/1.30/1.00/0.80/0.63 gearset.

T56 (found in the FR500S car) 2.97/1.78/1.3/1.0/.80/.63 I have two friends both with 2008 FR500S cars, and they claim they shift precisely without issue, and one on them says that first gear is useless except for loading in the trailer.

I wasn't really thrilled with either of the magnum gear sets and definitely not thrilled with the magnum price tag. So I went with a used 09 GT500 trans. In my opinion, this is the best gearset for a mostly street / part time track car. You still get a decently low 1st gear for the street with farily close and evenly spaced 2-3-4-5.

gt500 trans ratios
gt500 trans.jpg

09 gt500 gear spacing
09 gt500.jpg

magnum wide, same 1st but 2nd and 3rd are too low = big gap to 4th
mag wide.jpg

magnum close, same 2,3,4,5,6 as 09gt500 with taller 1st
mag close.jpg

All of these plots are with 315/30-18, 3.55 rear gear and 6000 rpm shifts
 

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