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Topic Review (Newest First)
11-04-2013 01:36 PM
TOK
Quote:
Originally Posted by Strokerswild View Post
Guys, the OP ordered already, an auto with 3.73s.
OK, so its back to discussing whether people who drive automatics are uncoordinated, one-legged, gay men or if people who drive sticks are obsolete losers stuck in the 50's.

11-04-2013 11:58 AM
Strokerswild Guys, the OP ordered already, an auto with 3.73s.
11-04-2013 10:47 AM
Numbercruncher
Quote:
Originally Posted by ohioviper View Post
Find where I said peak ? I said can double or triple torque on takeoff.This is why you can take your foot off the brake pedal and ease away in an auto and the manual you have to increase the rpms as you let out on the clutch.The A580 has an advantage to get the Jeep moving from a dead stop and in high gear on the highway over the manual due to the torque converter and the lower geared OD .I can not explain it any better than that sorry.

Here I found a video since you prob dont want to read.

Torque Converter Movie - YouTube
Nevermind. I'l delete the post but don't see the delete button.

NC
11-04-2013 10:24 AM
Proxy404 I'm going to agree with NFRs2000NYC's statement. Go with the highest numerical value you can. I have a '12 Sahara with the Pentastar V6 and 3.21 gears. While it did absolutely fine on the stock 32" ATs, the second I switched to my 35" duratracs, performance suffered a lot. I have to rev higher through all gears to get the same acceleration that I had with the stock tires. And forget about using 6th gear. It doesn't have enough torque to keep speed on a flat highway. Even if you don't think you're going to get bigger tires at some point, still get the higher gear ratio. The power is worth the 1-2 mpg cost.

As another note, if you're thinking that you'll save the money now and swap out the 3.21s for higher gears later, keep in mind that the dealership will only tack on about $400 to the total price of the vehicle while getting a shop to do it later (like I'm trying to do) will cost you anywhere from $1200 - $3000.

Edit: I just posted a thread asking about input and experiences with getting a ratio swap done here: http://www.wranglerforum.com/f33/loo...ml#post5877794
11-04-2013 09:40 AM
mikedboyd As the OP person here, I sometimes don't like the wandering topics, but in this case I've really enjoyed it. I didn't really know much about torque converters, so this is good. I also found this guy that is pretty good explaining it.

Torque Converters Explained -EricTheCarGuy - YouTube
11-04-2013 09:37 AM
ssteacher95
Quote:
Originally Posted by mikedboyd View Post
Watch the video in the post above .................

http://www.wranglerforum.com/f33/3-2...ml#post5848138
Yeah, I was jesting. I knew what a torque converter was, but it had absolutely nothing to do with the OP's question. I was adding my contribution to the others that posted how far off topic this post has gotten.
11-04-2013 09:32 AM
mikedboyd
Quote:
Originally Posted by ssteacher95 View Post
What's a torque converter?
Watch the video in the post above .................

http://www.wranglerforum.com/f33/3-2...ml#post5848138
11-04-2013 09:10 AM
ssteacher95 What's a torque converter?
11-04-2013 08:48 AM
frankieg913
Quote:
Originally Posted by Plasticpirogue View Post
It amazes me just how far topics can wander from the OP.
i was thinking that exact same thing lol
11-03-2013 03:28 PM
Strokerswild ^ Yes.

Of course, part of the reason the 6-speeds seem so pokey is the five seconds it takes to make the throw between gears.
11-03-2013 10:27 AM
redneckwelder
Quote:
Originally Posted by daggo66 View Post
One last time. A torque converter is a clutch for an auto trans. It has to increase torque in order for the vehicle to move. A clutch disengages the gear and you can increase the torque with the gas pedal then release the clutch. Immediate torque. An automatic needs a way to achieve the same thing and that is the purpose of a torque converter. Any torque amount that a torque converter can produce can be replicated with a clutch.
The torque converter does the same thing as the clutch when it comes to disengaging the engine from the transmission. Power is transferred very different from one to the other. The clutch is a slip, and offers no mechanical advantage. It slips to allow a percentage of torque to be transferred through the clutch from the engine to the transmission until rotation speed of the engine output and transmission input match. Allows for a less abrupt start and prevents engine stalling. This is why extra throttle has to be applied on taking off to compensate for the loss in slippage.

With a torque converter, it's like a tiny hydraulic continuously variable transmission. It has a minor amount of slip like a clutch, but engages at a much lower rpm without stalling the engine. It does this by gearing down the motor speed like a tiny transmission. This allows the engine to immediately engage the transmission as soon the brake is released. The torque converter gives a mechanical advantage by converting higher rpm engine speed to a lower output speed, which inversely increases the applied torque to the transmission. When enough resistance is applied to the wheels to cause the torque converter to amplify torque, which can essentially double to triple the gearing mechanical advantage. This is why the engine of a standard has to be revved and slipped at about twice the rpm to get the same power output to the transmission.

The reason why standards are still available is because they boost the MPG ratings of vehicles do to less resistance when traveling at highway speeds. However, in city driving situations where gears are being shifted constantly, the automatic becomes more efficient. Standards are also cheaper to construct, so it allows car companies to advertise a lower entry buying price. The sport manual starts in the low 20's and the rubicon ends the range in the 40's with the automatic.
11-03-2013 08:59 AM
Plasticpirogue
Quote:
Originally Posted by mikedboyd View Post
getting ready to order (Unlimited, 6-speed, round-towner, no rock climbing). Can I assume that if I go off-road (mud, water, some inclines, etc.), but not severe inclines or rock climbing, that the 3.21 will do fine? Also, how much real variance might one expect for the 3.21 with 6-speed manual vs. the 4.21 with automatic?

thanks for any info
It amazes me just how far topics can wander from the OP.
11-03-2013 08:50 AM
kjeeper10
Quote:
Originally Posted by TOK View Post
I think the key to the confusion here is about 3 minutes into that video. It doesn't increase the torque, it "amplifies" the torque within the converter. The torque increase being argued about here is completely contained within the converter... The converter takes the engines power and multiplies that within itself to overcome loss through the impellers. If it didn't do that, the vehicle wouldn't move. Companies are still experimenting with other technologies because of the inherent weaknesses of the torque converter -heat and power loss. DSG gearboxes wouldn't exist if the current automatic was perfect. They use a second computer controlled clutch to mimic the torque converter.
Opening statement.
"The torque converter amplifies engine torque and sends it to the auto transmission" (Not to the wheels)
As said the engine torque alone would not power the vehicle.
I'll admit ... I had no idea how a TC worked. This video was great and proved most wrong.
11-03-2013 07:52 AM
TOK
Quote:
Originally Posted by ohioviper View Post
Find where I said peak ? I said can double or triple torque on takeoff.This is why you can take your foot off the brake pedal and ease away in an auto and the manual you have to increase the rpms as you let out on the clutch.The A580 has an advantage to get the Jeep moving from a dead stop and in high gear on the highway over the manual due to the torque converter and the lower geared OD .I can not explain it any better than that sorry.

Here I found a video since you prob dont want to read.

Torque Converter Movie - YouTube
I think the key to the confusion here is about 3 minutes into that video. It doesn't increase the torque, it "amplifies" the torque within the converter. The torque increase being argued about here is completely contained within the converter... The converter takes the engines power and multiplies that within itself to overcome loss through the impellers. If it didn't do that, the vehicle wouldn't move.

Companies are still experimenting with other technologies because of the inherent weaknesses of the torque converter -heat and power loss. DSG gearboxes wouldn't exist if the current automatic was perfect. They use a second computer controlled clutch to mimic the torque converter.
11-03-2013 01:22 AM
MikeK46 There is more parasitic loss through a fluid coupling like a torque converter than a clutch. Throw them on a dyno: the 6-speed will have more power & torque at the wheels.

The torque converter unlocks so as not to bog the engine, by allowing the engine to rev higher while taking load off of it. An unlocked torque converter wastes a ton of the engine's power.

This is hugely apparent at one particular point of my daily commute where I come down a very steep hill under braking and then have to immediately accelerate up a very slight uphill grade to merge with traffic. This tricks the torque converter into unlocking completely, and pressing on the gas just raises the RPM and makes noise. There is literally zero acceleration with the motor sitting at 3000rpm, despite going only 20mph on an almost imperceptible uphill grade.
11-02-2013 10:29 PM
daggo66 One last time. A torque converter is a clutch for an auto trans. It has to increase torque in order for the vehicle to move. A clutch disengages the gear and you can increase the torque with the gas pedal then release the clutch. Immediate torque. An automatic needs a way to achieve the same thing and that is the purpose of a torque converter. Any torque amount that a torque converter can produce can be replicated with a clutch.
11-02-2013 10:23 PM
daggo66 I'm talking about a starting from a dead stop.
11-02-2013 10:22 PM
ohioviper
Quote:
Originally Posted by daggo66 View Post
Explain to me why manual transmissions even exist if automatic transmissions can double or triple the peak torque output of an engine. I'll wait.
Find where I said peak ? I said can double or triple torque on takeoff.This is why you can take your foot off the brake pedal and ease away in an auto and the manual you have to increase the rpms as you let out on the clutch.The A580 has an advantage to get the Jeep moving from a dead stop and in high gear on the highway over the manual due to the torque converter and the lower geared OD .I can not explain it any better than that sorry.

Here I found a video since you prob dont want to read.

Torque Converter Movie - YouTube
11-02-2013 10:16 PM
spinlock
Quote:
Originally Posted by daggo66 View Post
It doesn't not double or triple the torque capacity of the engine. It allows the engine to idle at a higher speed. That is why you will move forward without your foot on the gas.

With a manual, you do not have to "wait until the rpm's match up". You can deliver the torque that you want by immediately going to that RPM.

If you granny shift a Wrangler with 3.21 and then drive one with the auto, the auto will feel far superior to you.
Not exacctly true. The clutch on the manual. Must still equalize rpm and load with help of the syncros.
11-02-2013 10:16 PM
daggo66 Explain to me why manual transmissions even exist if automatic transmissions can double or triple the peak torque output of an engine. I'll wait.
11-02-2013 10:12 PM
ohioviper Im not going to argue with you . I grew up on the farm and worked as a heavy equipment mechanic for years. I have rebuilt my share of auto and manual transmissions.I have seen torque converters tore apart and rebuilt, I have seen them ran on test machines and I fully understand how they work.
You are just plain wrong.
11-02-2013 10:09 PM
daggo66 You are still not getting it. Yes it multiplies the torque. That same thing happens with a manual when you engage the clutch and increase the RPM with the accelerator. Then you release the clutch at a given RPM and torque. An automatic cannot do that. Therefore the torque converter must increase the torque until the engine RPM can match it.

It doe not increase the overall torque capacity of the engine.
11-02-2013 10:03 PM
ohioviper
Quote:
Originally Posted by daggo66 View Post
It doesn't not double or triple the torque capacity of the engine. It allows the engine to idle at a higher speed. That is why you will move forward without your foot on the gas.

With a manual, you do not have to "wait until the rpm's match up". You can deliver the torque that you want by immediately going to that RPM.

If you granny shift a Wrangler with 3.21 and then drive one with the auto, the auto will feel far superior to you.

Get back to me after you have read this.

HowStuffWorks "Torque Converters Benefits"
11-02-2013 10:01 PM
daggo66
Quote:
Originally Posted by michiganadam View Post
I dont understand why people on here claim you only need lower gears for offroading. My gears are great offroading but when I get on the highway in over drive they suck....
OD is lower than a 1 to 1 ratio. It is meant for cruising and maintaining a speed already achieved in order to save fuel. It is not for passing or climbing hills. In an automatic you must either turn it off or wait for the engine to shift. With a manual, you simply select the gear you want.
11-02-2013 09:57 PM
daggo66
Quote:
Originally Posted by ohioviper View Post
Multiplying your rear axle ratio by your transmission gear ratio in OD or top gear yields the final drive ratio .


And yes the torque converter does give an advantage as it can double or tripple the torque output on take off and then lock up for a direct drive when rpms match up. This is why the A580 does better with the 3:21s than the stick does.It has a mechanical advantage over the direct drive of the stick . The older autos didn't do as good of a job at this as the A580. It seems to have a very efficient design on the torque converter and near perfect ratio spread in the gears. Its almost like it has a 2 speed converter effectively making the 5 speed a 10 speed.
It doesn't not double or triple the torque capacity of the engine. It allows the engine to idle at a higher speed. That is why you will move forward without your foot on the gas.

With a manual, you do not have to "wait until the rpm's match up". You can deliver the torque that you want by immediately going to that RPM.

If you granny shift a Wrangler with 3.21 and then drive one with the auto, the auto will feel far superior to you.
11-02-2013 09:55 PM
frankieg913 Just picked up my 3.73 Sahara unlimited manual on Monday I love it!! Would not have it any other way except maybe 410 if I could have ordered a sahara with them. I did special order the 3.73 after test driving the 3.21 manual. My 2002 explorer also had the 3.73 gear. So far driving my new jeep is like going to an amusement park every day!! Ps I also recommend the LSD but that's a whole other thread !!
11-02-2013 09:42 PM
daggo66
Quote:
Originally Posted by Strokerswild View Post
Might want to read up: Torque converter - Wikipedia, the free encyclopedia

As stated earlier, the difference in on-road performance between my 6-speed '12 and my auto '13 (both 3.21s) is night and day, the '13 stomps the wee out of the '12.
I did read and understand it. The difference very well good have felt night and day to you. It also depends on how you drove the 6 speed. Once again, the torque converter is the auto trans equivalent of a clutch. If it doubled an engine's torque, there would be no more manual transmissions in existence.
11-02-2013 07:50 PM
Bill Crockett
Lots of chatter over axle ratios

I have the 3.21 standard ratio with 6-speed and here are my opinions after driving it about 2500 miles in all on-road conditions - mountains, in town, mixed. I like most will never do much off-roading; snow and ice in the mountains will be enough for me here in Northern California.
  • I don't plan to put huge tires on it, I'm enough of a "poser" as it is driving a Jeep on pavement!
  • I am fine with the lower ratio most of the time - I'd take slightly better gas mileage as a tradeoff, and don't mind downshifting if need be.
  • The negative I have found is - even in 2nd gear going downhill in the mountains, I sometimes find there's not enough engine braking! As opposed to all the other comments, if I had a reason to pay more for the higher available ratio, it'd be to get more engine braking.
  • I've driven every kind of manual for many years - Corvette, Miata, Honda, Acura, Trucks, Fiats, on and on. It's a matter of personal opinion but mine is that the standard shift on the Jeep is outstanding and excellent - for the kind of vehicle that it is! Mine and the several that I test drove ('14 and '13) all shifted smooth, fast, positively. By the way I drove automatics and they drove very well too - I just prefer a manual especially in a vehicle like a Jeep.
  • I looked at a lot of dealer inventory and I'd say while the optional ratios are on a lot of vehicles (maybe 20% or less) the COMBINATION of finding one in stock with manual AND higher ratio is rare is Hell. If you are ordering one and getting EXACTLY what you want, take your time and drive all the possible combinations.
  • Even though I am super-happy with my Jeep, so far I love it - if I were to order one from the factory, I'd probably order the 3.7 higher gears so I'd have more flexibility including beefier tires some day. Cheap insurance.
  • Not contradicting myself here, I just bought the one from dealer inventory that came amazingly close to what I wanted (they tend to load 'em up with crap I didn't want). Most important decision - Buy a JEEP!!
11-02-2013 06:47 PM
Strokerswild Nice, you'll love it!
11-02-2013 02:35 PM
mikedboyd Just ordered a Copperhead Wrangler Unlimited with the 3.73 and the auto. Really thought I was gonna get the stick, but between driving several different variations of transmission and rear ratio this morning, and all of the input I've gotten, I went with the 3.73 and the auto. Thanks again all.
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