Installed a Tremec Magnum XL in my S550

[db252]

Thanks for your thoughts. I keep changing my mind, but I think I've talked myself into the 2.66 gearing with the long 0.50 6th. I figure that 1st and 2nd are up in smoke on the street with the MT82, and 3rd is a beast that usually hooks. With the 2.66 gearing, 2nd is pretty close to 3rd, so I'm hoping to hook 2nd on the street. With the 2.97 I think 1st and 2nd would still be pretty useless on street tires.

For 5th and 6th, the tall gearing is the only option for lower highway rpm since the 0.62 6th is about the same as the MT82. With the 3.73 gears, it wouldn't hurt to be taller for the highway. Having the 0.5 6th is a little taller than having 3.15 gears in the diff.

You’re not alone in that decision of choosing the first gear ratio and you know my story since I made the post. I have zero regrets about choosing the 2.66 as the ratio pattern is perfect. Also know that GT500’s had the 2.66 stock with 3:73 rear end gears and they don’t make as much power as us Whipple’s guys. Of course the 2.97 is better for starting off but I don’t 1/4 and I don’t care about getting off the line on the street quicker than anyone else and anyone that drives my car doesn’t complain about it. I would however encourage you to go with the shorter over drive gears. I’ve driven both and the tall 6th is taaaaaaaaaaaall in the version you are referring to. If you do super long drives on a freeway without traffic go for it but 6th in the shorter version is more than fine even cruising at 90mph. In the mt82, you’re basically going from 4th to 6th in relation to the shorter overdrive and having the 5th in between on the Tremec is extremely nice to have and functional. First and foremost everyone has different wants and I always encourage that choice for them regardless of my experiences. My 2 cents.

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[Ruiner46]

You’re not alone in that decision of choosing the first gear ratio and you know my story since I made the post. I have zero regrets about choosing the 2.66 as the ratio pattern is perfect. Also know that GT500’s had the 2.66 stock with 3:73 rear end gears and they don’t make as much power as us Whipple’s guys. Of course the 2.97 is better for starting off but I don’t 1/4 and I don’t care about getting off the line on the street quicker than anyone else and anyone that drives my car doesn’t complain about it. I would however encourage you to go with the shorter over drive gears. I’ve driven both and the tall 6th is taaaaaaaaaaaall in the version you are referring to. If you do super long drives on a freeway without traffic go for it but 6th in the shorter version is more than fine even cruising at 90mph. In the mt82, you’re basically going from 4th to 6th in relation to the shorter overdrive and having the 5th in between on the Tremec is extremely nice to have and functional. First and foremost everyone has different wants and I always encourage that choice for them regardless of my experiences. My 2 cents.

I think you might be right. I drove my car today to test out driving around at low rpm in 6th to see how it felt. I came to the conclusion that my comfortable cruise RPM range is roughly 1800-2400RPM. Plotting those RPMs with the tall gear choice gives me 54-71mph in 5th and 80-105mph in 6th. That leaves a hole from 71-80mph where I would be too low in 6th or too high in 5th. With the shorter gearing, it is 50-66mph and 64-85mph. No hole, so I think the shorter gears are the better choice. I do a lot of freeway driving in the 75-80mph range with varying traffic.

 

[Nutones]

Hey db252: did you have your tune re-adjusted after the clutch break-in period? My shoppe has recommended a re-tune after I break in my mantic clutch (sprung hub cerametallic). I have a whipple stage 2 making 720 rwhp and 555 ft. lbs. torque. Last summer the shoppe initially tuned it using HP Tuners. I picked up my car yesterday after they carried out the transmission swap; went with the 2.66 paired with a 3.55 rear gear as advised by the shoppe owner. The shoppe owner was not available yesterday for me to ask why he recommends a re-tune but my instincts tell me that because now the transmission in the car can handle 700 ft lbs of torque right out of the box and maybe more the shoppe wants to adjust the tune to capitalize on this. The shifts are crisp n tight but the gears are very tall (lol). Definitely will be an adjustment for me in terms of my driving style but I can see that having the whipple blower or any other blower for that matter is a necessity for this particular transmission swap. Performing the swap on an N/A vehicle would be superfluous unless like others have mentioned here on the forum you change the rear gears to compensate.... I purchased and installed the Bowler all in one wiring harness. It was a piece of cake for the shoppe to install and configure. I ordered my transmission kit from Blow By Racing. Their kit didn't include the Bowler wiring harness, only the pigtails. After coming across this post last week and read some of the horror stories of others trying to try wire their transmission using other methods and components, I quickly ordered the Bowler unit and had it delivered quickly to the shoppe in time for the install (lol). The driveshaft that came with my kit is an aluminum one piece made by Shaftmasters. No noise or vibration, but I do need to purchase a driveshaft safety loop since the driveshaft is aluminum. The clutch at times seems a bit tricky to slip in first gear to get moving but my guess is that over time that will get better. Let me know if you've had a retune since the swap or was that advised ti you by the shoppe that installed the transmission for you. Thanks.

QUOTE="Ruiner46, post: 2816859, member: 25894"]I think you might be right. I drove my car today to test out driving around at low rpm in 6th to see how it felt. I came to the conclusion that my comfortable cruise RPM range is roughly 1800-2400RPM. Plotting those RPMs with the tall gear choice gives me 54-71mph in 5th and 80-105mph in 6th. That leaves a hole from 71-80mph where I would be too low in 6th or too high in 5th. With the shorter gearing, it is 50-66mph and 64-85mph. No hole, so I think the shorter gears are the better choice. I do a lot of freeway driving in the 75-80mph range with varying traffic.[/QUOTE]

 

[db252]

@Nutones

Never have I had a tune for clutch reasons nor have I ever heard of that.

I would imagine the gears feel long as you say and your start off from a stop is probably a little difficult. Bear with me here and I’m not insulting your build; I just want you to be informed.

I feel like your shop gave you a little bit of bad advice on your first gear choice compared to your rear end ratio. 3:73 would be about the lowest in relation to shorter choices like 4:10’s and above. The 3:55’s, while not so far from 3:73 (what I have), is a pretty significant difference when starting from stopped position and basically a 4000 lb car. In relation to building a drivetrain from scratch, weight of the car, hp/tq, transmission gearing and rear end ratio is a fairly complex issue and throw in what the intention of the vehicle is supposed to work wise makes it change fairly dramatically.
Stepping back a little, in choosing rear end ratio to a starting transmission gear ratio and only referring to a manual transmission for a car daily driven on the streets you are looking for a factor of 10 by multiplying first gear ratio by rear end ratio. By example, my car is 3.73 x 2.66 = 9.9218 and yours is 3.55 x 2.66 = 9.443. Those two number don’t seem far apart but in the scale of operation of starting from a stop it is and that’s all I’m referring to in this example. Guys who go after 1/4 mile track car are closer to a factor of 12 or even higher with a manual transmission. My car is fine off the line but I’m not set up to run quick off the line and yours is obviously working also but I know you know what I mean.
Next thing being the clutch. I had the Mantic (organic) before in my mt82 and it was an awesome clutch but it is one of the lightest clutch kits out there and they push that in their description of low MOI, Moment of Inertia, with the 9” discs. It’s also a great thing for track cars that want quicker acceleration and assistance in engine braking when off throttle which is something I do but the car is waaaaaay more street driven and I want the street experience smooth. What it’s not good for is a street factor of 10 by the formula I mentioned above with a light clutch as it compounds the problem. What made it great with the mt82 was a first gear of 3.66 which factored a total of 13.6518 using 3:73 gears. I switched to a heavier setup, basically closer to what was stock, with the Ram setup to help counter the problem I knew that would even make my setup more difficult in operation. The higher weight in inertia assists in maintaining the clutch slip while keeping the rpms up as friction increases until full clutch engagement. The other factor you have is the ceramitallic discs don’t favor slip as much as organic. They want to bite and go. It is really nice that both your discs are sprung hub. One of mine is and the other solid. I’d like to try the new Tilton organic that has both sprung hub discs.

I really hope your start off situation gets better and keep us updated if you think it’s great cuz it will give others the choice of following your route as well. I’m glad the aluminum shaft is vibration free since we hear plenty of stories about that. The re-tune thing is weird to me but maybe someone else has heard or experienced it. 4:10’s or even shorter would be better for me and you as well but I doubt I’ll change and if a minivan wants to race me off the line, I’ll give them the win.

 

[Nutones]

@Nutones

Never have I had a tune for clutch reasons nor have I ever heard of that.

I would imagine the gears feel long as you say and your start off from a stop is probably a little difficult. Bear with me here and I’m not insulting your build; I just want you to be informed.

I feel like your shop gave you a little bit of bad advice on your first gear choice compared to your rear end ratio. 3:73 would be about the lowest in relation to shorter choices like 4:10’s and above. The 3:55’s, while not so far from 3:73 (what I have), is a pretty significant difference when starting from stopped position and basically a 4000 lb car. In relation to building a drivetrain from scratch, weight of the car, hp/tq, transmission gearing and rear end ratio is a fairly complex issue and throw in what the intention of the vehicle is supposed to work wise makes it change fairly dramatically.
Stepping back a little, in choosing rear end ratio to a starting transmission gear ratio and only referring to a manual transmission for a car daily driven on the streets you are looking for a factor of 10 by multiplying first gear ratio by rear end ratio. By example, my car is 3.73 x 2.66 = 9.9218 and yours is 3.55 x 2.66 = 9.443. Those two number don’t seem far apart but in the scale of operation of starting from a stop it is and that’s all I’m referring to in this example. Guys who go after 1/4 mile track car are closer to a factor of 12 or even higher with a manual transmission. My car is fine off the line but I’m not set up to run quick off the line and yours is obviously working also but I know you know what I mean.
Next thing being the clutch. I had the Mantic (organic) before in my mt82 and it was an awesome clutch but it is one of the lightest clutch kits out there and they push that in their description of low MOI, Moment of Inertia, with the 9” discs. It’s also a great thing for track cars that want quicker acceleration and assistance in engine braking when off throttle which is something I do but the car is waaaaaay more street driven and I want the street experience smooth. What it’s not good for is a street factor of 10 by the formula I mentioned above with a light clutch as it compounds the problem. What made it great with the mt82 was a first gear of 3.66 which factored a total of 13.6518 using 3:73 gears. I switched to a heavier setup, basically closer to what was stock, with the Ram setup to help counter the problem I knew that would even make my setup more difficult in operation. The higher weight in inertia assists in maintaining the clutch slip while keeping the rpms up as friction increases until full clutch engagement. The other factor you have is the ceramitallic discs don’t favor slip as much as organic. They want to bite and go. It is really nice that both your discs are sprung hub. One of mine is and the other solid. I’d like to try the new Tilton organic that has both sprung hub discs.

I really hope your start off situation gets better and keep us updated if you think it’s great cuz it will give others the choice of following your route as well. I’m glad the aluminum shaft is vibration free since we hear plenty of stories about that. The re-tune thing is weird to me but maybe someone else has heard or experienced it. 4:10’s or even shorter would be better for me and you as well but I doubt I’ll change and if a minivan wants to race me off the line, I’ll give them the win.

Hey db252: thanks for the feedback and insight; I definitely don't take it as an insult but rather as a basis for asking the shoppe owner his rationale for recommending the transmission gear ratio he did. On the invoice he noted that a re-tune is recommended after the break-in period of the clutch. I will ask him why a re-tune but I think it is to make some adjustments to the horsepower and torque as the tremec can handle up to 700 ft lbs of torque out of the box. The shoppe wouldn't adjust to tune now because the clutch has to be first probably broken in. I see your point about the 3.55 rear making the car slower off the line but I don't drag race the car. It's pretty much a weekend toy around town for fun. Sounds like you're saying that the 2.97 would have been the better gear option. Maybe down the line I'll look into swapping the rear gears to the 4.10 as you recommended. Other than that, I really have no complaints about the car or transmission. The car's suspension has been built with the steeda stop the wheel hop kit, seed front and rear sway bars, adjustable koni shocks and struts lowered 1 inch all around, dss rear axles, Apex racing EC-7 19x10 wheels paired with Mickey Thompson Street comps 285 35 R19 square stance; the exhaust setup is catted ARH longtube headers paired with the Corsa sport 3 inch catback. Like you, I'm not interested in being the fastest at stop light (lol). I know what I have and just want to stay alive in one piece to enjoy it on the weekends. Would you recommend a complete pumpkin swap or the gears alone would be fine? How much power are you making? What's your suspension and exhast setup?

 

[db252]

I’ll send you a pm in a little while about your other questions but in short, the 2.97 would have been a better first gear choice with the 3:55 but that just boils down to starting off the line. I gather you love the way the car is once you start moving.

 

[ponie1992]

Does anyone know exactly what in the tune needs to be adjusted for the cruise control to work? Mine is still not working and PBD says the T56 has been accounted for in the tune. I would just like to be able to tell them what needs to be done to avoid any drama. It took a few emails to get the shift assist removed, as I don't think it was understood what I was asking for.

 

[Ruiner46]

I'm not 100% on this because I haven't received my trans yet, but maybe it will help. I'm surprised PBD can't get it sorted. Are you sure the Bowler harness is setup correctly? If not, VSS error could be causing your problems.

I think the gear ratios get adjusted in two places shown in HPTuners. There's the gear ratio table under Shift-General. And the min/max ratio ranges under the Manual tab. This screen shot shows those tables for my 2016 stock tune with the MT82.

 

[ponie1992]

I'm not 100% on this because I haven't received my trans yet, but maybe it will help. I'm surprised PBD can't get it sorted. Are you sure the Bowler harness is setup correctly? If not, VSS error could be causing your problems.

I think the gear ratios get adjusted in two places shown in HPTuners. There's the gear ratio table under Shift-General. And the min/max ratio ranges under the Manual tab. This screen shot shows those tables for my 2016 stock tune with the MT82.

Yep, Bowler harness is set up correctly. Sent an email to PBD, so we'll see what they say.

 

[ponie1992]

Update on mine: PBD sent a new tune that my car did not like at all. Got misfire codes and the car almost didn't start after I shut it down. Exhaust note changed as well. When I say wouldn't start, I mean pushing the start button did absolutely nothing. Engine wouldn't even turn over. Thought it was bricked for a minute. Loaded the previous tune and all was well again, except for the cruise. The cruise worked only once in 5th gear at 53 mph with the newest tune. Didn't work in any other gear or speed. Not sure what they did with the newest tune, but something was way wrong. Sent them an email last night to see what they say. Can't believe this hasn't been sorted yet.

 

[RubberFeet]

Just getting the Tremec swap set-up running (new clutch, trans, diff) and trying to get the tune worked out from Lund. They just got back with me telling me I can't have cruise control with the T56. Anyone find this is a fact?

 

[ponie1992]

Just getting the Tremec swap set-up running (new clutch, trans, diff) and trying to get the tune worked out from Lund. They just got back with me telling me I can't have cruise control with the T56. Anyone find this is a fact?

Negative. There's something in the tune they have to adjust for it to work. Still trying to sort through mine.

 

[aleccesarenriquez]

Just getting the Tremec swap set-up running (new clutch, trans, diff) and trying to get the tune worked out from Lund. They just got back with me telling me I can't have cruise control with the T56. Anyone find this is a fact?

I don't think that's a fact but I never made the effort with the speedo box like Brandon suggested. It's so strange that tuners will say totally different things to their customers. Who is your tuner at Lund? Have they addressed the rev hang for you already? That will require an update as well

 

[RubberFeet]

John Nardi replied with the negative for the cruise control. I spec'd to disable the launch control and rev hang on my tune request, and, so far, haven't been queried one way or another on their viability. Not in super hurry here, as the entire driveline is hardly broken in. Trying to work all this out.

 

[db252]

My Lund tune fully supports my cruise control in almost any gear I choose and certainly in 5/6 where it gets used mainly.

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