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Old 03-22-2006
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some torque converter questions...

i have 5r44e auto tranny, and I have some questions about the torque converter...

I know that the torque converter can multiply the torque generated by the engine... is it doubling the flywheel torque? and does that doubled torque get lost, or is it transferred to the wheels? for example... when engine specs say that the 3.0 can generate, say, 183 tq, is that 183 torque AFTER the torque converter has 'done its thing' or before? if its before, then does that mean that if the torque converter multiplies that 183 torque by, say, 1.5, youd have 275tq at the wheels?

since manuals dont have torque converters, does that mean that they generate less torque, assuming same engines?

does the torque converter double the torque in every gear, or does it affect the torque less and less with increases in speed, or vice versa?

i'm trying to get a better understanding of the torque converter so i can more acurately decide how and when to spray juice, and if i could kick up the jetting in higher rpms or certain gears, etc...
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Old 03-22-2006
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ok so go to howstuffworks.com and it will tell you all about it, but if you want a quick answer then yes it does give you more torque but only underload when the input is spinning faster then the output on the torque converter. it would happen no matter what gear your in but it does not stay with you as soon as the load is lessened or the output = the input your just at normal torque. This is the reason most autos are rated to tow more weight then a manny
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Old 03-22-2006
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The doubleing is not a constant.

keep in mind the 44 is the torque rating of your converter.

44 x 6 = 264

So when you reach the limits of the converter it will comeaprart. Granted you have an over head of 81 foot pounds assuming that equation is true. I read that long ago over on RPS.
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Old 03-22-2006
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I would love to see any auto trans with the same engine as any manual trans actually pull/tow more weight and last. It's simply not going to happen. torque convertors generate heat...heat kill auto trannys. auto trannys slip, making even more heat and causing more damage under load.
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Old 03-22-2006
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well i just looked on fords website for towing specs and didn't find it on the rangers but this is for the superdutys http://www.fordvehicles.com/Trucks/s...res/specs/#tow

I'll just quote the 5.4L with the 3.73's in it cause its on top

Auto F-250/ F-350 SRW 4x2 10100lbs

Manual F-250/ F-350 SRW 4x2 9100lbs

thats 1000 more lbs for the auto then the Manual
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Old 03-22-2006
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interesting....now lets look into real world info as to what works/what does not and what last/what does not. I have been pulling trailers that are at or slightly below the many different vehicles I have owned rated capacities for many years. To make a lond story short, if you are pulling a considerable amount of weight often, a manual is the only way to go. The model or make of the vehicle is not a factor, a manual is simply a more reliable trans. All the data sheets in the world are meaningless. They all come out of some engineers computer and just about all of the engineers that I have delt with are only as smart as the book in front of them. Sure they are book smart, but when it comes to real world situations....they are clueless!
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Old 03-22-2006
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Quote:
Originally Posted by RNGMSTR
All the data sheets in the world are meaningless. They all come out of some engineers computer and just about all of the engineers that I have delt with are only as smart as the book in front of them. Sure they are book smart, but when it comes to real world situations....they are clueless!
Ford sells vehicles designed to operate under a wide variety of conditions. Engineers must develop a vehicle that satisfies as many of a wide a variety of requirements as possible. If they only had to satisfy conditions in one part of the country or for one type of consumer, their job would be a lot easier.

Manuals are rated lower than automatics because the clutch is the limiting factor. A Ford performance test requires that the vehicle loaded to GCWR must be able to launch from rest on a steep test hill. This test exists because drivers in some parts of the market can find themselves in a similar sitaution while towing.

An automatic uses the torque multiplication of the torque converter to nearly double the available torque at launch. The manual, on the other hand, not only doesn't have that torque multiplication advantage, it also must waste part of its available power to heat loss through the clutch during initial launch.

If you loaded otherwise identical automatic and manual Rangers to the automatic's maximum GCWR rating and tried to launch them on the test slope, the automatic would slowly crawl away while the manual smoked its clutch into oblivion.

I prefer manual transmissions myself but I can't deny that the automatic holds a distinct advantage under certain conditions. You may prefer manuals as well for the towing that you do. However, that doesn't make engineers "clueless" because they are designing and developing for a wider market.
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Old 03-22-2006
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Quote:
Originally Posted by Blhde
The doubleing is not a constant.

keep in mind the 44 is the torque rating of your converter.

44 x 6 = 264

So when you reach the limits of the converter it will comeaprart. Granted you have an over head of 81 foot pounds assuming that equation is true. I read that long ago over on RPS.

so whats this 44 x 6 = 264 stuff all mean.

as far as engineers being clueless i take offense to that i dont think that i have wasted the last 6 years of my life studing to be clueless
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Old 03-22-2006
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Quote:
Originally Posted by RNGMSTR
I would love to see any auto trans with the same engine as any manual trans actually pull/tow more weight and last. It's simply not going to happen. torque convertors generate heat...heat kill auto trannys. auto trannys slip, making even more heat and causing more damage under load.
You don't seem to understand auto trannies at all. Auto trannies slip? Not in the same sense of a manual tranny. Anyways, auto trannies have transmission coolers also.

Aaron
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Old 03-22-2006
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Quote:
Originally Posted by Blhde
The doubleing is not a constant.

keep in mind the 44 is the torque rating of your converter.

44 x 6 = 264

So when you reach the limits of the converter it will comeaprart. Granted you have an over head of 81 foot pounds assuming that equation is true. I read that long ago over on RPS.
i know where you got the 44, but where'd the 6 come from? would that mean 264 flywheel or wheel torque?

i thought the 44 mean 440 max torque (without considering the near doubling effect of the converter.)

Quote:
Originally Posted by Rwenzing
An automatic uses the torque multiplication of the torque converter to nearly double the available torque at launch.
So bob, does that mean that as speed during a gear increases, the multiplication effect decreases?
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Old 03-22-2006
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44 is the model of the transmission it has nothing to do with the torque.

The torque converter has roughly 1.8 to one multiplication of torque at very slow speeds ie 1mph on boat ramp so if your engine put 170lb torque it might be
306lb after the torque converter this is simplistic but I'm not writing a book on
this. Of course manuals are also geared higher. 1st gear in a manual is
Much higher than 1st on an auto because of the torque converter.

Since we now have LOCKUP torque converters they dont produce as much heat
as in days long past.. and they do have transmission coolers.

Otherwise on the 5r55E that would mean im only achieveing 330lb of torque
when the engine produces 250? or a mere 1.3:1 or so torque multiplication.
So I have to call BS on the 6x44=torque posted above.

Rand
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Old 03-23-2006
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relating this to nitrous- two general rules apply. Spray at 2500 rpm or higher, don't spray unless at wide open throttle. I higher stall will get you to that equation quicker.
I have an s-10 that i can pre rev to 2200 rpm so I should be able to hit it at the line. I'm currently working out the traction issues related to doing that. I am getting 2.0x 60' times without the nitrous currently.
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Old 03-23-2006
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Quote:
Originally Posted by barrman
So bob, does that mean that as speed during a gear increases, the multiplication effect decreases?
A speed differential between the input and output of the TC is required to see the torque muliplication. The speed differential can be at its highest when the engine is turning and the rest of the powertrain is stopped with the transmission in gear.

At idle, the torque output of the engine is very low and the speed differential in the converter is small. As the engine RPM increases from idle to the stall speed of the converter with the powertain stopped, the torque available at the output side of the TC increases dramatically. The design of the torque converter allows it to multiply the engine torque hydraulically instead of mechanically as gears do in the transmission.

As the transmission input speed increases, the torque multiplication advantage fades and it is not necessary or desirable to have the converter operational to maintain a steady road speed. The torque converter clutch can then be engaged to eliminate the losses through the converter. This improves fuel economy and may also reduce transmission temperature.
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Old 03-23-2006
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Quote:
Originally Posted by Rand
44 is the model of the transmission it has nothing to do with the torque.
44 does have something to do with the torque rating of the transmission assembly but it is not the torque rating of the converter alone.

In Ford shorthand, "44" means a 440 lb-ft torque rating. "55" is for 550 lb-ft.

5R55E:

5 = 5 forward gears
R = Rear wheel drive (primary)
55 = 550 lb-ft maximum input torque
E = electronic control
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