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-   -   Auto Good Match for lack of low end torque? (http://www.wranglerforum.com/f274/auto-good-match-for-lack-of-low-end-torque-127296.html)

theotis 12-12-2011 06:32 PM

Auto Good Match for lack of low end torque?
 
The biggest concern regarding the 3.6 seems to be a lack of low end torque. Since the automatic's torque converter has a torque multiplying effect at low RPM's, it seems that an auto is well matched for the 3.6. Does this theory hold water?

Comac90 12-12-2011 07:52 PM

:confused: If you're comparing it to the 3.8L, it's not a "lack of". The 3.6L has a peak torque of 260 lb-ft and nearly all of that (250 lb-ft) is available at only 2k RPM and the torque curve stays nearly flat to nearly redline. The old 3.8L doesn't even hit 250 until north of 5k RPM and at 2k RPM it's less than 100 lb-ft.

However, the old I-6 4.0 hit 240 lb-ft around 3k RPM and was relatively flat compared to the 3.8L. Given the weight of the JK, the 3.6L may feel a bit less torquey than the 4.0. I had a 4.0 TJ, but it's been so long since I owned it I can't give a fair comparison ... the difference certainly isn't noticeable enough to me for feel an issue, though.

I read some preliminary review online somewhere that said the motor felt weak below 4k RPM and that it lacked low-end torque ... my question after reading that and after driving mine was "compared to what ... a HEMI?".

I've wheeled and rock-crawled with mine already and the slushbox, 4.10s, and 35s are perfect for a relatively stock, general all-around wheeler, IMO.:thumb:

T

kjeeper10 12-12-2011 07:52 PM

Not sure what your asking but----

Its all In the gearing. Both the 3.6 and 3.8 are not know to be power houses down below..
I hear no complaints with the new 5speed auto in the 2012. Good match? Better than
the 4 speed in previous years. The 6 speed has a lower first gear, compared-I really don't know.

That work for ya?

i82much 12-12-2011 07:59 PM

I see where you are going with this and yeah, the converter provides some torque multiplication. That said, you can store an awful lot of energy in that manual trans flywheel if you want, although that's hard on parts.

signkutter 12-12-2011 08:11 PM

I dont see where the Auto lacks in torque at anything over 1500 rpm.. I have a deadspot at that rpm where the drive train seems to get hesitant going to tell the stealership guys about it next time I go to town

JIMBOX 12-12-2011 08:15 PM

:D YUP, the torque converter is just a fluid connection between the engine and tranny that acts as a reduction gear and-


Quote:

Originally Posted by i82much (Post 1822813)
I see where you are going with this and yeah, the converter provides some torque multiplication. That said, you can store an awful lot of energy in that manual trans flywheel if you want, although that's hard on parts.

It's particularly beneficial on the JK/JKU Rubi, with the NV241 ROCK-TRAC xfer case, that electronically "LOCKS" the torque converter in 4lo--really does a job when engine braking on downhills !!

I imagine the 2012 is similiar !IDK

:dance::rofl: JIMBO

joe002 12-12-2011 08:19 PM

The 3.8 has a little more torque then the 3.6 below 1K, but I doubt you'll notice it.

rics1997 12-12-2011 09:48 PM

Quote:

Originally Posted by Comac90 (Post 1822793)
:confused: If you're comparing it to the 3.8L, it's not a "lack of". The 3.6L has a peak torque of 260 lb-ft and nearly all of that (250 lb-ft) is available at only 2k RPM and the torque curve stays nearly flat to nearly redline. The old 3.8L doesn't even hit 250 until north of 5k RPM and at 2k RPM it's less than 100 lb-ft.

However, the old I-6 4.0 hit 240 lb-ft around 3k RPM and was relatively flat compared to the 3.8L. Given the weight of the JK, the 3.6L may feel a bit less torquey than the 4.0. I had a 4.0 TJ, but it's been so long since I owned it I can't give a fair comparison ... the difference certainly isn't noticeable enough to me for feel an issue, though.

I read some preliminary review online somewhere that said the motor felt weak below 4k RPM and that it lacked low-end torque ... my question after reading that and after driving mine was "compared to what ... a HEMI?".

I've wheeled and rock-crawled with mine already and the slushbox, 4.10s, and 35s are perfect for a relatively stock, general all-around wheeler, IMO.:thumb:

T


Your numbers are not correct at 1800 rpms the 3.8 has a torque of 145 and that is at the wheel numbers and it peaks at around 4K. Also your 3.6 numbers are engine numbers and not at the wheel. Like comparing apples to oranges. Seems like your really trying to raise the 3.6 higher and put the 3.8 down harder. Not sure why. The 3.8 may not be completely flat but it is closer then many are stating it is. AT wheel numbers the 3.8L isn't that far off the torque numbers of the 3.6L.

3.8L dyno at the wheel not engine numbers. Blue numbers stock and red tuned motor.

http://i114.photobucket.com/albums/n.../Stk_87_JK.jpg

theotis 12-12-2011 09:56 PM

Quote:

Originally Posted by JIMBOX (Post 1822872)
:D YUP, the torque converter is just a fluid connection between the engine and tranny that acts as a reduction gear and-




It's particularly beneficial on the JK/JKU Rubi, with the NV241 ROCK-TRAC xfer case, that electronically "LOCKS" the torque converter in 4lo--really does a job when engine braking on downhills !!

I imagine the 2012 is similiar !IDK

:dance::rofl: JIMBO

That is the direction I was going. For crawiling, V6's (in general) could use more torque. I was reading up on torque converters and the article talked about the torque multiplication for low speed. So while I haven't down much crawling, seems like the automatic would have a distinct advantage over a manual in crawling. Whether it takes the fun out of it is a whole different question.

rics1997 12-12-2011 10:17 PM

Here is the engine numbers of the 3.8 and 3.6. Not that engine numbers mean as much as at wheel mumbers

http://image.fourwheeler.com/f/roadt...ower_graph.jpg

The thing about it is the 3.6L at wheel number don't look close to the at engine numbers. In the real world the torque looked almost the same as the 3.8 at wheel numbers and in the end the dyno showed the 3.8 actually had higher top end torque at the wheels.

3.6 vvt dyno result 180 whp 150lb/ft w (3.8 dyno stock 151 whp 178lb/ft w)

RIPP 2012 Jeep Wrangler 3.6L V6 Dyno Test - YouTube

TXJKU-Rubi 12-12-2011 10:22 PM

There's no way I'm equipped to argue with the stats and numbers you guys posted but I do know that my auto 3.6 rubi w/ 4.10 is lots of fun! The only hold up I've experienced is my driving skills. :dance:

rics1997 12-12-2011 10:39 PM

Quote:

Originally Posted by TXJKU-Rubi (Post 1823417)
There's no way I'm equipped to argue with the stats and numbers you guys posted but I do know that my auto 3.6 rubi w/ 4.10 is lots of fun! The only hold up I've experienced is my driving skills. :dance:

Well the biggest difference is the Auto. It a lot better with better O/D gearing and the hp, even though not as tremendous as many thought still makes a huge difference in moving a brick. But the Tranny is sweet. And another improvement that was of great help was throttle response.

i82much 12-12-2011 11:06 PM

Did anybody really expect the peak torque of the 3.6 to exceed the 3.8 by any substantial margin? Peak torque is mostly about displacement & compression (or forced induction/nitrous).

One way to look at the benefit of a high-revving engine is that at a given mph you can be in a lower gear (the higher revving engine shifts later). The torque that the wheels see is multiplied by your gear ratio. This is one way of looking at why the Pentastar out-accelerates the 3.8.

Of course, off-idle situations, towing or hills at cruising speed, etc. there is not much of a difference between the two. When you step on the pedal though, the Pentastar can drop into a deeper gear and take advantage of the gear reduction to out-hustle the 3.8.

JIMBOX 12-13-2011 08:59 AM

:whistling: there's no doubt, that the industry graphs/comparisons are a needed scientific requirement, but

When you get right down to the Brass tacks individual USES/-personal mods ,will surpass/circumvent any graph figures and we all have individual goals !

The 3.6L/5spd auto is the latest and greatest operating power system for the average 4x4 consumer, I have the faith, but

There is and can be a real awakning to the previous 3.8L/42rle owners and even though buying a new jeep is EXCITING and SUPERCALAFlAGHALSTIC-there are mods that can be done to the 07/11, that'll come close to the new jeeps prowess-

Never give up the ship !

If you're a newbie-then getting the 2012 is a no-brainer, it's a real "top drawer" JEEP-

if you're a 07-11 jeep owner and are unhappy with the performance, just read the internet/personal reviews for the ONE MODIFICATION of REGEARING--

It's a godsend !

:dance::rofl: JIMBO


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