What's the right RPM? - JeepForum.com

 
LinkBack Thread Tools
post #1 of 14 Old 07-20-2010, 05:22 AM Thread Starter
KJNewbs
Registered User
1983 CJ7 
 
Join Date: Jul 2010
Location: St. Louis
Posts: 577
What's the right RPM?

The last manual trans I owned was an 87 Celica GT, which I could run to red on every gear and no worries. Last car I ownded before getting the Jeep was on '07 G35, auto - which had plenty of get up and go....

Now onto the JK, manual....I feel like if I go above 4k RPMs that I'm going to blow my engine up (even though it doesn't red line for awhile).

Question: Where are you all shifting at in your JK? Any advice or lesssons learned on shifting in general?

Cheers.

KJNewbs is offline  
Sponsored Links
Advertisement
 
post #2 of 14 Old 07-20-2010, 05:27 AM
RAZORBILL
Registered User
 
RAZORBILL's Avatar
2014 JK Wrangler 
 
Join Date: Mar 2007
Location: Sault Ste Marie
Posts: 2,685
I guess I'm just an old slow guy, I shift between 2500-3000 rpms.

Previously owned: 80 CJ-5, 97 TJ,99 XJ, 95 YJ,10 JK Rubicon Unlimited, 10 JK Sport
RAZORBILL is offline  
post #3 of 14 Old 07-20-2010, 05:31 AM
Vin
Registered User
2012 JK Wrangler 
 
Join Date: May 2010
Location: Long Island
Posts: 3,472
What have I learned?

1) If I keep my shifts around 2.5k I get around 20 mpg

2) She sounds really nice after 3k

3) If I'm shifting past 4k, I can watch my gas gauge move like my Tach in the opposite direction.

Vin is offline  
post #4 of 14 Old 07-20-2010, 06:41 AM
Ravik
Registered User
2010 JK Wrangler 
 
Join Date: Mar 2010
Location: Colorado
Posts: 133
The 3.8 seems to make the most torque at around 4k rpm - so when you shift really depends on what you're trying to do.

I agree completely with Vin - shifting at 2.5-3k seems to get the best mileage and shifting at the top of the torque band while heaps of fun, is much like pouring gas on the ground.

I have a 2dr Rubi manual, and I do a lot of up and down here in the mountains, so the 'lesson learned' from me would be - don't be afraid of RPM, going up a 6-7% grade, you'll be in 4th and hovering around 3.5-4k for the duration and getting about 16-18mpg.

The same is true going down hill, if you put it in 5th and set the cruise at 60, it'll just hang out at that speed due to compression without really using any gas. I can get 22-23mpg average (calculating the 16-18mpg to get to the top in the first place) on the down-hill sides of Vail or Loveland pass.

2010 2dr Rubicon
-=-=-=-=-=-=-=-
Ravik is offline  
post #5 of 14 Old 07-20-2010, 07:22 AM Thread Starter
KJNewbs
Registered User
1983 CJ7 
 
Join Date: Jul 2010
Location: St. Louis
Posts: 577
Cool - yeah, i've been shifting right around 3k for my day-to-day driving. As I get up close to 4k, I guess I've just got to get used to the sound of the engine. Coming off of a rice burner with 306hp is a huge difference with the sound of the growl. Thanks guys.....
KJNewbs is offline  
post #6 of 14 Old 07-20-2010, 07:57 AM
Armycop
Registered User
2014 KL Cherokee 
 
Join Date: Jul 2007
Location: Fort Lewis, WA
Posts: 126
http://www.hypertech.com/PerformanceGraphs/Dodge/52001_2007_2010_Jeep_Wrangler_3_8L_V6.pdf

According to the Hypertech Dyno results, looks like peak horsepower is in the 4500-5000 rpm range and peak torque is in the 3500-4000 rpm range.

2014 KL SPORT BILLET SILVER l 9-SPEED l 25% TINT l MB ICON WHEELS l OEM SPLASH GUARDS
Armycop is offline  
post #7 of 14 Old 07-20-2010, 08:27 AM
Chuck_Bullitt
Registered User
2009 JK Wrangler 
 
Join Date: Apr 2009
Location: Providence Village, TX
Posts: 36
FWIW - normal around town driving, I shift between 3000 - 3500. Getting on the highway, I do 4000 - 4500, unless I really need to scoot...then I'll take it past 5000.

2009 Black JK Unlimited X, M6, 35's, 2.5" lift, 4.88's, locked on both ends
Chuck_Bullitt is offline  
post #8 of 14 Old 07-20-2010, 08:48 AM
fernjack
Registered User
2007 JK Wrangler 
 
Join Date: Apr 2009
Location: Winnipeg
Posts: 1,031
If I'm just driving around with no particular place to go I generally shift at about 2500-3000 . If I have to get somewhere or enter traffic I'll shift anywhere up to about 5000 . It actually does growl a bit after 3000 and up but you can feel a bit of power after the 3000 mark .
fernjack is offline  
post #9 of 14 Old 07-20-2010, 03:13 PM
95Cherokee-
Registered User
2010 JK Wrangler 
 
Join Date: Feb 2005
Posts: 50
So what do you guys figure the optimal RPM is for shifting to ensure the best MPG? Sitting in traffic when theres no rush, I might as well try and save some gas
95Cherokee- is offline  
post #10 of 14 Old 07-20-2010, 03:26 PM
yukonmuscle
Registered User
2009 JK Wrangler 
 
Join Date: Oct 2008
Location: Peterborough Ontario
Posts: 215
2500 rpm i would say as long as its flat road

so much sunshine, the jeep gods are smiling at me
yukonmuscle is offline  
post #11 of 14 Old 07-20-2010, 09:26 PM
fernjack
Registered User
2007 JK Wrangler 
 
Join Date: Apr 2009
Location: Winnipeg
Posts: 1,031
Quote:
Originally Posted by yukonmuscle View Post
2500 rpm i would say as long as its flat road
Yup X2 on that ......get my best milage there .
fernjack is offline  
post #12 of 14 Old 07-20-2010, 11:05 PM
MilitaryJK4455
Web Wheeler
2010 JK Wrangler 
 
Join Date: Mar 2009
Location: Ft. Detrick MD
Posts: 2,624
So it really doesnt hurt to rev to motor close to the red line?
MilitaryJK4455 is offline  
post #13 of 14 Old 07-20-2010, 11:14 PM
fernjack
Registered User
2007 JK Wrangler 
 
Join Date: Apr 2009
Location: Winnipeg
Posts: 1,031
Quote:
Originally Posted by MilitaryJK4455 View Post
So it really doesnt hurt to rev to motor close to the red line?
I can honestly say I have many times and with 65,000km+ on the clock my Rubi still runs smooth and quiet . I do over kill on my oil changes trying never to exceed 3000km even though I use synthetic oil and the Fram synthetic filtre . I was one time driving north for a job and had the tunes going had the JK in 5th at 4000rpm for about an hour before I realized what I was doing ....that was about two years ago ....still no ticking and smooth .....Just sayin' and that was about half way through a 9hr. drive north of Winnipeg past Thompson ........
fernjack is offline  
post #14 of 14 Old 07-20-2010, 11:38 PM
tennistom1
Registered User
2009 JK Wrangler 
 
Join Date: Aug 2006
Location: Left Coast
Posts: 922
It has a governor to prevent it from being over-reved doesn't it?

2009 JK Rubicon 4-Door
2006 TJ Rubicon Unlimited
tennistom1 is offline  
Reply

Tags
6 speed , JK Wrangler , manual transmission , shift points , shifting , wrangler

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome