hwy rpm - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > YJ Jeep Wrangler Forum > YJ General Discussion Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 07-13-2010, 07:55 PM
Thread Starter
  #1
Jeeper
 
tracy's Avatar
 
Join Date: Jun 2010
Location: winnie tx
Posts: 214
hwy rpm

my 87 yj with stock 4.2 5 speed 37 inch swamps. runs about 1900 rpm in 4th gear at 65. seems alittle low- its never seen 5th. think i might have to put some new gears. any suggestions?

tracy is offline   Quote
Old 07-14-2010, 10:07 AM   #2
Jeeper
 
flatline's Avatar
 
Join Date: May 2010
Location: pinole ca.
Posts: 680
when I run 38's, rpm in 4th is about 2500. I have 4.56 gears and I think I should go to 5.13's. but that won't fit in a dana 30. I'd go to 4.88's.

flatline is offline   Quote
Old 07-14-2010, 10:43 AM   #3
Jeeper
 
debodave's Avatar
 
Join Date: Jul 2010
Location: Greenville, SC
Posts: 29
I run 35's with 4.10 gears in my ford 8.8, and at freeway speeds in 5th gear im running right at 2k rpm. Not sure the exact speed, as my speedo doesnt work, but i would guess its at 60 or 65mph.

If your YJ is completely stock with a dana35 rear you most likely have 3.73 gears. With those giant 37's attached to them it would be in your best interest to upgrade that axel to at least a dana44. Put in 4.56 or even 4.88 gears to help turn those big tires and you will start to see 5th gear.
__________________
87 YJ (aka: Layla)
4" SL | 35x12.50 BahaClaw's | AX15/NP231 | Ford 8.8 with disks and 4.10's | Xenon flat's
debodave is offline   Quote
Sponsored Links
Advertisement
 
Old 07-14-2010, 10:57 AM   #4
Aka Vaultzz

WF Supporting Member
 
Vaultzz's Avatar
 
Join Date: Jul 2009
Location: My Secret Lab
Posts: 5,624
I run 33's with stock gears and I'm at ~1600 rpm at 55 and I thought that was normal
__________________
The YJ is in Rebuild Mode
Vaultzz is offline   Quote
Old 07-15-2010, 12:45 AM   #5
Jeeper
 
tlrrob1000's Avatar
 
Join Date: Jul 2009
Location: Pain is a gift...Fear is not an option!
Posts: 787
Running 33's and I cruise about 70, 75 at 26-2700 rpms in 4th Shift into 5th it drops down to 2 grand and close to 80. I think I'm running 4.10's been awhile since I looked.
__________________
No Bad Days!
tlrrob1000 is offline   Quote
Old 07-15-2010, 12:55 AM   #6
Jeeper
 
minderbinder3's Avatar
 
Join Date: Apr 2007
Location: East Texas
Posts: 273
You either need new gears or smaller tires.
__________________
Respect is earned and Honor is given
2005 LJ 6-speed with 3" Zone & 33" BFG A/T's
minderbinder3 is offline   Quote
Old 07-15-2010, 07:42 AM   #7
Jeeper
 
Matcheen's Avatar
 
Join Date: Apr 2010
Location: Aurora, ON, Canada
Posts: 421
I'm running 33's and at 65mph I'm running around 2200 rpm in 4th. If I shift to 5th it drops to 1500rpm but I have no power and am slowing down at 50 mph. Any sugestions?
__________________
You're never to old to have toys!
'90 YJ, 4" RC Suspension lift, 1" Shackle lift, SYE and CV, Holley Carb, 33/12.50/15 Dynapro M/T's. RIP my old friend.
Matcheen is offline   Quote
Old 07-15-2010, 09:09 AM   #8
Jeeper
 
tlrrob1000's Avatar
 
Join Date: Jul 2009
Location: Pain is a gift...Fear is not an option!
Posts: 787
Quote:
Originally Posted by Matcheen View Post
I'm running 33's and at 65mph I'm running around 2200 rpm in 4th. If I shift to 5th it drops to 1500rpm but I have no power and am slowing down at 50 mph. Any sugestions?
Change your gearing.
__________________
No Bad Days!
tlrrob1000 is offline   Quote
Old 07-16-2010, 01:35 PM   #9
Jeeper
 
debodave's Avatar
 
Join Date: Jul 2010
Location: Greenville, SC
Posts: 29
Quote:
Originally Posted by Matcheen View Post
I'm running 33's and at 65mph I'm running around 2200 rpm in 4th. If I shift to 5th it drops to 1500rpm but I have no power and am slowing down at 50 mph. Any sugestions?
Get at least a 4.10 gear installed. Its what I run with 35's and its golden.
__________________
87 YJ (aka: Layla)
4" SL | 35x12.50 BahaClaw's | AX15/NP231 | Ford 8.8 with disks and 4.10's | Xenon flat's
debodave is offline   Quote
Old 07-18-2010, 01:11 PM   #10
Jeeper
 
Matcheen's Avatar
 
Join Date: Apr 2010
Location: Aurora, ON, Canada
Posts: 421
I'll add it to the list...
__________________
You're never to old to have toys!
'90 YJ, 4" RC Suspension lift, 1" Shackle lift, SYE and CV, Holley Carb, 33/12.50/15 Dynapro M/T's. RIP my old friend.
Matcheen is offline   Quote
Old 07-18-2010, 02:09 PM   #11
Jeeper
 
madrnch's Avatar
 
Join Date: May 2010
Location: wetumpka alabama
Posts: 136
31s 4:10s 65mph 5th gear 2600 rpm

madrnch is offline   Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not 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 Off
Refbacks are Off






All times are GMT -5. The time now is 01:59 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.

Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, Gladiator, Mopar and Grand Cherokee are copyrighted and trademarked to FCA US LLC.
Wranglerforum.com is not in any way associated with FCA US LLC.