T56 Magnum F conversion Advice
02-20-2024, 11:43 PM
#1
Teching In
Thread Starter
T56 Magnum F conversion Advice Hello,
Anyone have experience with the 2.97 gear set on the T56 magnum F? The reason I'm considering one is because I'd like more torque at low speeds without giving up the low rpm cruising in 5th/6th gear (which is why I haven't swapped the rear gears to a 3.73). Mainly, for a daily driver that is used for canyon carving and scenic mountain drives, It seems like this checks all my boxes, but I ran the numbers on an RPM calculator and it seems that each gear shift from 2-4 puts me at a lower rpm (around 3900-4100) after the gear change (compared to 4100-4400 with the current 2.66 set up). I'm not sure this is actually a problem since the torque multiplication is higher but can anyone confirm what the experience is like with the shorter gears 1-3?
Car is a daily driver that is also used for pleasure cruising/canyon carving, etc.
Dynos at 355 rwhp, 347 rwtq.
Stock 10 bolt 3.42. (Any reason to think that the 2.97 would be "too much" for the 10-bolt?)
Any other issues I should be aware of?
Anyone have experience with the 2.97 gear set on the T56 magnum F? The reason I'm considering one is because I'd like more torque at low speeds without giving up the low rpm cruising in 5th/6th gear (which is why I haven't swapped the rear gears to a 3.73). Mainly, for a daily driver that is used for canyon carving and scenic mountain drives, It seems like this checks all my boxes, but I ran the numbers on an RPM calculator and it seems that each gear shift from 2-4 puts me at a lower rpm (around 3900-4100) after the gear change (compared to 4100-4400 with the current 2.66 set up). I'm not sure this is actually a problem since the torque multiplication is higher but can anyone confirm what the experience is like with the shorter gears 1-3?
Car is a daily driver that is also used for pleasure cruising/canyon carving, etc.
Dynos at 355 rwhp, 347 rwtq.
Stock 10 bolt 3.42. (Any reason to think that the 2.97 would be "too much" for the 10-bolt?)
Any other issues I should be aware of?
02-29-2024, 06:44 AM
#2
The 2.97 gearset is basically the same first gear LT1 F-bodies had. It's going to act like you installed a gear between 3.73 and 3.90 in your rear axle. ( 3.81 to be exact ) My 2013 SS has a 3.07 first gear and 3.91's out back and it revs through first pretty quickly. The 2.97s are a wide ratio set, so your RPM will drop more on gear changes. I'm not sure why you wouldn't want to change gears in your axle... that .50 overdrive in 6th tames even really steep gears. I have 4.30's in my Formula and it's only turning 2000 RPM at 80 MPH ( 28" tires ). I don't see any issues arising from the swap, but you do have to change the slip yoke on your driveshaft, I believe.
As for your 10 bolt surviving, it'll be fine until you shock load it on a drag strip. Otherwise it'll hold up fine.
As for your 10 bolt surviving, it'll be fine until you shock load it on a drag strip. Otherwise it'll hold up fine.
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Naaman (03-07-2024)
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Naaman (03-07-2024)
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Naaman (03-07-2024)
03-25-2024, 12:47 AM
#6
Teching In
Two Associated Questions Two related questions on Magnum F:
1. If you're making about 650 RWHP into the rear end in a turbo setup (moved up to 9inch Ford recently with ~3.50 gears), are there benefits to going with the 2.66 gear vs 2.97? Trying to get a better feel for that.
2. I paid a pretty penny for my aftermarket custom cut driveshaft. Will I be able to use that driveshaft with the Magnum F? What I'm reading from Tremec is that it "requires use of 31-spline slip yoke and modifications to the driveshaft length". Just this past week I lost 6th gear in my bone stock T-56, and it's popping out of 5th gear (all else works normally for the moment). I may have mine shipped off for a re-built/buildup instead of going with the Magnum F if I have to purchase another driveshaft.
Anyone have experience with the 2.97 gear set on the T56 magnum F? The reason I'm considering one is because I'd like more torque at low speeds without giving up the low rpm cruising in 5th/6th gear (which is why I haven't swapped the rear gears to a 3.73). Mainly, for a daily driver that is used for canyon carving and scenic mountain drives, It seems like this checks all my boxes, but I ran the numbers on an RPM calculator and it seems that each gear shift from 2-4 puts me at a lower rpm (around 3900-4100) after the gear change (compared to 4100-4400 with the current 2.66 set up). I'm not sure this is actually a problem since the torque multiplication is higher but can anyone confirm what the experience is like with the shorter gears 1-3?
Car is a daily driver that is also used for pleasure cruising/canyon carving, etc.
Dynos at 355 rwhp, 347 rwtq.
Stock 10 bolt 3.42. (Any reason to think that the 2.97 would be "too much" for the 10-bolt?)
Any other issues I should be aware of?[/QUOTE]
1. If you're making about 650 RWHP into the rear end in a turbo setup (moved up to 9inch Ford recently with ~3.50 gears), are there benefits to going with the 2.66 gear vs 2.97? Trying to get a better feel for that.
2. I paid a pretty penny for my aftermarket custom cut driveshaft. Will I be able to use that driveshaft with the Magnum F? What I'm reading from Tremec is that it "requires use of 31-spline slip yoke and modifications to the driveshaft length". Just this past week I lost 6th gear in my bone stock T-56, and it's popping out of 5th gear (all else works normally for the moment). I may have mine shipped off for a re-built/buildup instead of going with the Magnum F if I have to purchase another driveshaft.
Anyone have experience with the 2.97 gear set on the T56 magnum F? The reason I'm considering one is because I'd like more torque at low speeds without giving up the low rpm cruising in 5th/6th gear (which is why I haven't swapped the rear gears to a 3.73). Mainly, for a daily driver that is used for canyon carving and scenic mountain drives, It seems like this checks all my boxes, but I ran the numbers on an RPM calculator and it seems that each gear shift from 2-4 puts me at a lower rpm (around 3900-4100) after the gear change (compared to 4100-4400 with the current 2.66 set up). I'm not sure this is actually a problem since the torque multiplication is higher but can anyone confirm what the experience is like with the shorter gears 1-3?
Car is a daily driver that is also used for pleasure cruising/canyon carving, etc.
Dynos at 355 rwhp, 347 rwtq.
Stock 10 bolt 3.42. (Any reason to think that the 2.97 would be "too much" for the 10-bolt?)
Any other issues I should be aware of?[/QUOTE]
03-25-2024, 07:03 PM
#7
I don't think anyone is going to suggest 2.97 over 2.66 for a turbo build in an F-body weight vehicle.
You're building around a driveshaft length? With no measurements, tough to tell if a yoke swap only will work. The Sonnax yoke (1350) should.
I know the F appeals to guys into an F-body T56 already. But, a standard length (longer) magnum, rear offset shifter, crossmember mounted torque arm and shorter driveline would improve critical driveline speed, and fix stock vibrations.
You're building around a driveshaft length? With no measurements, tough to tell if a yoke swap only will work. The Sonnax yoke (1350) should.
I know the F appeals to guys into an F-body T56 already. But, a standard length (longer) magnum, rear offset shifter, crossmember mounted torque arm and shorter driveline would improve critical driveline speed, and fix stock vibrations.
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Azgeodude (03-25-2024)
