S550 Mustang Suspension and Powertrain Discussion

Norm Peterson said:

This sounds more like the gear spacing is a little too close.

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Yes, way too close.

gmitch said:

No real plan here. 5th (which is the first OD in my trans) works fine. The way I am geared (3.55's) I'm good for 221mph at 7,000rpm. I've only gone 208 so far though.

If I wanted to go faster I would put a taller tire on or swap out to 3.08's.

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Why not go with a higher gear ratio and use 6th gear?

I would expect because 6th is an overdrive gear. Meant for MPG on the highway, not performance driving. I'm sure you've noted the RPM spacing & how much larger 5th-6th is compared to the rest of the box.

claudermilk said:

I would expect because 6th is an overdrive gear. Meant for MPG on the highway, not performance driving. I'm sure you've noted the RPM spacing & how much larger 5th-6th is compared to the rest of the box.

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He hasn't gotten to that experiment yet. Be prepared for his full findings when he does, they're sure to be idiotic.

Dubstep Shep said:

Why not go with a higher gear ratio and use 6th gear?

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Lower losses when the power is carried straight down the input shaft/mainshaft instead of across two sets of meshing gears when the countershaft has to be used (which is any time the gearbox ratio isn't 1.000).


Kind of makes you wonder why top gear isn't 1.00, though doing so probably forces other compromises like getting a low enough 1st ratio without making the case physically bulkier. Actually, 1.000 top gear 5-speed boxes have been produced. I think the 928 Porsche box was set up this way.


Norm

Norm Peterson said:

Lower losses when the power is carried straight down the input shaft/mainshaft instead of across two sets of meshing gears when the countershaft has to be used (which is any time the gearbox ratio isn't 1.000).


Kind of makes you wonder why top gear isn't 1.00, though doing so probably forces other compromises like getting a low enough 1st ratio without making the case physically bulkier. Actually, 1.000 top gear 5-speed boxes have been produced. I think the 928 Porsche box was set up this way.


Norm

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Ah. That makes more sense. That goes back to the 1.00 ratio making the most power on the dyno as well.

So how do these top speed monsters like the twin turbo Ford GTs and the 1900hp Lambos do their gearing?

and without using more then 2 shafts to make a gear (some transmissions use more then 2) the deepest gear you can put in the trans will always be limited by the largest gear(and the smallest) you can get in there. i.e. 5.30 1st might set you up for a great 6th or 7th gear, but now you need to fit (I am pulling numbers out of my ass) a 20 tooth and a 106 tooth gear. oh yeah, and that 20 tooth gear has to hold 600hp+ in a 400hp car because 50% of the people who own the car with that trans will never leave well enough alone.

as far as the exotics, its a totally diffrent ball game. lambos come with 600hp so lets start there. a huge part of advertising and pulling in customers for exotics is having beast 0-60 and 0-100 numbers. So though they don't always get it, they often try to make 0-60 first gear, and the 2nd takes you over 100. by eliminating upshifts you can take the timed numbers down, even though, in an actual distance/time race, a lambo with deeper gears would win.

then on the top instead of having 5th be top speed and 6th being economy gear, often 4-5-6-7 are spaced like road course guys try to make 3-4-5 so that as you are accelerating, and wind speed is increasing, you stay in the power band.

and I mean, if you have a 7 speed trans and 2nd takes you over 100, you definatly have wiggle room for your top ratio.

and if you tried to put deep gears in a 1900hp lambo that would be intresting. Have you ever tried to nail the 1-2 shift on a high power car with deep gears? lets say you geared your 1900hp lambo to 1-2 at 40mph, I don't know how many people here could imagine really trying to nail that shift. remember, if you miss poof goes the $300k motor build.

NUTCASE said:

and without using more then 2 shafts to make a gear (some transmissions use more then 2) the deepest gear you can put in the trans will always be limited by the largest gear(and the smallest) you can get in there. i.e. 5.30 1st might set you up for a great 6th or 7th gear, but now you need to fit (I am pulling numbers out of my ass) a 20 tooth and a 106 tooth gear. oh yeah, and that 20 tooth gear has to hold 600hp+ in a 400hp car because 50% of the people who own the car with that trans will never leave well enough alone.

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That 5.30 would be the product of two gear reductions, one from the input shaft to the countershaft and one more from the countershaft to the mainshaft. 2.00 and 2.65 would be one possible combination, though I doubt any transmission designer would ever choose exactly 2.00 anywhere.

One or possibly more of the gears with ratios immediately greater than 1.00 may actually have to use "step-up" gears between the countershaft and the mainshaft.


There is an interesting little video that you can get to from this page.


Norm

With that much power I imagine a tall first and second gear would be nice, then have the later gears closer together.

Which brings you right back to having to shift more often, at least at the track, particularly when you've got big torque or at least big power and gearing. There are times where you really don't want to have to shift, but tight gear spacing makes it more likely that you'd feel pressured to do so anyway. Keep in mind that dogleg maneuver from 4 to 5 (or from 2 to 3, for that matter). And the zig-zaggy downshifts between the same gear pairs.

I forget how many times they used to figure a Formula 1 driver shifted over the course of a race, but it was some crazy big number. I'm talking about before sequential gearboxes here.


Norm

Department Of Boost said:

I'm not attempting to argue this with you. Just inject a perspective that most people don't have an option of experiencing.

I have spent a lot of time on a lot of different tracks playing with gearing in a quest for faster lap times. Most of the time by playing with final drive ratio's, but from time to time I have had the ability to play with the transmission ratio's at the track. I always had the ability to swap ratio's at home base, but testing at the track same day, same conditions is preferable. Based on that experience I can confidently say that it can be a lot better than a MT-82.

It's not one dimensional either. A person learns how to drive/ride around what they are given to use. They develop techniques/patterns to cope. When the gearing options open up/change different techniques/patterns can be used sometimes to great effect. Changing the gearing up and driving/riding exactly the same will not net the gains one will see form changing the gearing up and then taking advantage of what it has to offer.

I've driven in anger S197's with 3650's, T-56's (pretty much a 6060) and MT-82's. I also have a ton of gearing development under my belt. I don't like the MT-82. As far as I know you have only ever driven that car with a MT-82 in it. And I think it is safe to say you haven't done gearing development in the past. If I'm incorrect I apologies. That said, maybe I have some insight and can draw some conclusions that you can't?

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I've logged quite a bit of track time in 06-07 GTs with and without boost with 3650s. I prefer the MT82. Haven't driven a 6060 but I don't have any complaints so why bother?

ArizonaGT said:

I don't have any complaints so why bother?

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Because faster.

I've had combo's that would run very respectable race winning times. But I went looking for for more. And from time to time that paid off in easier wins and in a few cases lap records (The lap record, not some class lap record).

Are you the fastest guy in your class?

Department Of Boost said:

Because faster.

I've had combo's that would run very respectable race winning times. But I went looking for for more. And from time to time that paid off in easier wins and in a few cases lap records (The lap record, not some class lap record).

Are you the fastest guy in your class?

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Wait, did you change your username or become a sponsor?! I'm on my phone so I can't tell.

Dubstep Shep said:

Wait, did you change your username or become a sponsor?! I'm on my phone so I can't tell.

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Both.

Department Of Boost said:

Both.

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Very niiiice!!

So I'm talking to a friend who knows a thing or two from time to time today and I told him I was underwhelmed with the GT350. He asked me why. I said "Man, that car has be $55K or it's overpriced". He said, "I think it will be $55K without all the options (nav, etc)". I felt better. I said, "Over 500hp sounds a lot like 515hp to me". He said, "I think it will be 550ish". Ok, I feel even better. Then he tells me he was right there in the chassis dyno cell with one screaming at 8250 and it sounded glorious if the person listening likes that rip snorting exotic sound (I do). Ok, things are looking up. Then I bitched about the trans. He said what's wrong with a 6060? I said it's got some hot rodded 3160 in it. He was really confused. I told him it was announced that the unveiling of the car (I think that's right). He was even more confused. He was certain it was a 6060. So maybe the trans is a 6060. I guess we will know soon.

I'm interested again.

GT350 vs Hellcat (aka Fatcat) vs Z28

This is good.

I'm pretty damn sure it's a TR-3160.

Take a look at the picture of the bottom of the transmission case from the teaser videos (#3, 15-17 seconds):
http://www.mustang6g.com/forums/showthread.php/svt-gt350-mustang-5525.html

Now, look at this picture from the underbody of an ATS with TR-3160:
http://www.iveho.com/wp-content/uploads/2012/07/P10100074.jpg

Finally, compare to a TR-6060:
http://www.supraspeed.com/images/tr60601.jpg

It is a modified 3160. When the Ford rep, Jamal Hameedi, was asked the question directly, that is what he had said:

http://www.mustang6g.com/forums/showthread.php/new-shelby-gt350-6265.html?p=162964#post162964

Mountain said:

I'm pretty damn sure it's a TR-3160.

Take a look at the picture of the bottom of the transmission case from the teaser videos (#3, 15-17 seconds):
http://www.mustang6g.com/forums/showthread.php/svt-gt350-mustang-5525.html

Now, look at this picture from the underbody of an ATS with TR-3160:
http://www.iveho.com/wp-content/uploads/2012/07/P10100074.jpg

Finally, compare to a TR-6060:
http://www.supraspeed.com/images/tr60601.jpg

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Boaisy said:

It is a modified 3160. When the Ford rep, Jamal Hameedi, was asked the question directly, that is what he had said:

http://www.mustang6g.com/forums/showthread.php/new-shelby-gt350-6265.html?p=162964#post162964

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Well, that's too bad then.