Power loss from 35's? & pwr mods - Page 2 - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > JK Wrangler Technical Forum > Power loss from 35's? & pwr mods

Introducing MONSTALINER™ UV Permanent DIY Roll On Bed LineFS: Wrangler RGB Multicolor Fog Light LEDs: Awesome EffectSavvy Aluminum Gas Tank Skid

Reply
Unread 07-20-2010, 04:25 PM   #16
ribs
Registered User
2007 JK Wrangler 
 
Join Date: Feb 2008
Location: canada
Posts: 804
Quote:
Originally Posted by JLC08JK View Post
Just to give a real world example; I just came back from a road trip on 35" tires and stock 3.21 gears. In fifth gear at 2k rpm it was at 65 mph, there was absolutely no power available to accelerate without down shifting into fourth gear. I ended up running 90% of the 600 mile round trip in fourth gear at 75 mph with an occasional shift to third to climb the hills.
I have the 4.88 gears and they will go in as soon as I get my ARB locker for the rear.
The Flash Pack could have helped but it won't change the rpm/mph ratio!
Wow 3:21s and 35s, fun times. I had 3:07s and 31s on my TJ...that even sucked.

Why just 4:88s for the regear not 5:13s? Just curious.

__________________
Quote:
Originally Posted by notoriousdoa View Post
we had a peep hole looking into the girls jeep forum, but someone used it as a glory hole so they patched it up.
Quote:
Originally Posted by LarryGrant View Post
...And no the truck dont give BJs but guess you are not married as wifes dont give them either. :rolleyes:
ribs is offline   Reply With Quote
Unread 07-20-2010, 05:03 PM   #17
takeda54
Registered User
2008 JK Wrangler 
 
Join Date: Jul 2010
Location: dallas
Posts: 39
im so lost, lol .The shop is telling me to do the predator intake and exhaust first before the regear. Said it will balance it out and is less expensive. Still have to check and see if mines a 4:10 or 3:73.
takeda54 is offline   Reply With Quote
Unread 07-20-2010, 05:04 PM   #18
JLC08JK
What was I thinking?
 
JLC08JK's Avatar
2008 JK Wrangler 
 
Join Date: Sep 2009
Location: Los Angeles, California
Posts: 5,768
Quote:
Originally Posted by ribs View Post
Wow 3:21s and 35s, fun times. I had 3:07s and 31s on my TJ...that even sucked.

Why just 4:88s for the regear not 5:13s? Just curious.
4.88 will put it in a very good range for low gears as well as highway.
My build plan calls for an Atlas 4 speed T/C that has a very low 5.44/1 reduction.
The lower chart is for the 6 speed trans and shows that the 4.88 will put it in the blue.

Edit: These charts have been updated to include the 2012+ 3.6 liter engine
jk_ratio-chart-1.jpg

gearratio12.jpg

__________________
Jim
Jim's Jeep; THE OBSESSION LIVES ON!
Jim's JK D44 Rear Axle Build

99% of Your JK Questions will be Answered Here
JK F.A.Q./WILL IT RUB and Popular Threads

Protect Our Rights to Freedom and the Environment
Visit the EnviroBeat

Last edited by JLC08JK; 10-29-2013 at 07:08 PM.. Reason: Added new charts
JLC08JK is offline   Reply With Quote
Unread 07-20-2010, 06:09 PM   #19
1222
Make mine a Jeep!
 
1222's Avatar
2012 JK Wrangler 
 
Join Date: Jul 2007
Location: Henderson, Nevada
Posts: 11,700
Quote:
Originally Posted by takeda54 View Post
im so lost, lol .The shop is telling me to do the predator intake and exhaust first before the regear. Said it will balance it out and is less expensive. Still have to check and see if mines a 4:10 or 3:73.
Don’t be lost. All you need to do is search this forum or any other and you’ll see that what they’re (shop) telling you has no merit. All of the people here over the past 3-4 years should be more than enough proof that what they’re (shop) saying is bull. Listen to experience. That’s one of the reasons for this forum among others.
__________________
1222 is offline   Reply With Quote
Unread 07-20-2010, 06:25 PM   #20
MoparToYou
Registered User
2014 JK Wrangler 
 
Join Date: Sep 2008
Posts: 632
Be very careful with aftermarket cold air intakes and exhaust systems for this engine. Most make no improvement what so ever, and some even decrease performance.
__________________
2014 Wrangler Sport: 3" lift, 35s, Dana 60s, Poison Spyder armor, Warn winch
MoparToYou is offline   Reply With Quote
Unread 07-20-2010, 10:56 PM   #21
2thbob
Registered User
2010 JK Wrangler 
 
Join Date: Jul 2010
Location: south dakota
Posts: 42
On the top chart for auto trans, it shows that the factory setup on a rubicon of 4:10 gears and 32" tires its in the sluggish/yellow area. Is that accurate? Why would the factory do that?
2thbob is offline   Reply With Quote
Unread 07-21-2010, 06:49 AM   #22
plac
Registered User
2012 JK Wrangler 
 
Join Date: May 2006
Location: CA
Posts: 1,425
Quote:
Originally Posted by 2thbob View Post
On the top chart for auto trans, it shows that the factory setup on a rubicon of 4:10 gears and 32" tires its in the sluggish/yellow area. Is that accurate? Why would the factory do that?
The question of the month.
__________________
2013 VW GTI
plac is offline   Reply With Quote
Unread 07-21-2010, 08:00 AM   #23
2thbob
Registered User
2010 JK Wrangler 
 
Join Date: Jul 2010
Location: south dakota
Posts: 42
You guys all know more about this stuff than I do, so..setting your own driving habits aside, if you were to setup a jeep with an auto, 2" OME lift, and the options of either 33" tires or 35's, and the ability to have it regeared, (Im hoping the advice is 35's), what gears would you do? I was thinking 4:88 + 35's, but Im not so sure 5:13s wouldnt be bad. Which would be close to factory but slightly lower?
2thbob is offline   Reply With Quote
Unread 07-21-2010, 08:38 AM   #24
MoparToYou
Registered User
2014 JK Wrangler 
 
Join Date: Sep 2008
Posts: 632
Read the question of the month, above your post. The stock gearing on an auto trans Rubicon (4.10) is sluggish. Why would you want to spend the money it takes to re-gear your Jeep to re-gear it to "sluggish". If it is sluggish to begin with, and you add bigger and heavier tires, re-gearing to stock gearing is going to be even more sluggish. You need lower gears to even start to come close to stock performance with the larger tires.

I went with a 2.5" lift and 35" tires on my auto trans Rubicon, and re-geared the differentials to 5.38. I still lost performance relative to stock. It is fine around town, and get up and go from the stop light is fantastic. But out on the highway, when it is in that deep deep overdrive top gear, it has a hard time getting out of its own way, and it still downshifts just to make it over a freeway overpass. I personally think that if they made a gear ratio of 5.88 it would be perfect for an auto trans JK with 35s.

I say go as low as you can. If you have a Dana 30 front end that is 5.13, and if you have a Dana 44 it is 5.38. Definitely don't go 4.88, it will be total waste of your money.
__________________
2014 Wrangler Sport: 3" lift, 35s, Dana 60s, Poison Spyder armor, Warn winch

Last edited by MoparToYou; 07-21-2010 at 09:43 AM..
MoparToYou is offline   Reply With Quote
Unread 07-21-2010, 08:45 AM   #25
mckenzm
Registered User
2008 JK Wrangler 
 
Join Date: Sep 2007
Location: Plano
Posts: 39
I would do new gears first with a flashpaq. Best bang for the buck!!! Don't spend $$$ on intake and exhaust until you absolutely have too. I have 35" and with auto tranny and went to 5.13 b/c I have the D30 in the front. Mine feels like it did when it was stock.
mckenzm is offline   Reply With Quote
Unread 07-21-2010, 01:19 PM   #26
RockyClymer
RedRock4Wheeler
 
RockyClymer's Avatar
2008 JK Wrangler 
 
Join Date: Apr 2008
Location: Colorado
Posts: 4,419
Ditto - intake and exhaust are poser options IMNSHO no gain but loss in your wallet - go with a regear to a good range - for 35" most use a 5.13 with auto and 4.88 with manual and then try a flashpaq or such, esp for auto to reset the shift points. Your dealer is just trying to sell you some junk for profit...sorry to be so blunt, but have seen it happen too many times before.
__________________
08 JK 23S - Colorado Jeep Club No. 204
Too much to list - see my profile for details on build
NRA Life member
"It takes a special kind of stupid to believe criminals will follow gun laws."
I do not consider myself a smartass. I point out the obvious, search for the truth, and speak fluent sarcasm. I am, by experience, an accomplished curmudgeon.
RockyClymer is offline   Reply With Quote
Unread 07-22-2010, 04:57 PM   #27
RustyStolzz
Registered User
2010 JK Wrangler 
 
Join Date: Jun 2010
Location: San Diego
Posts: 27
I have a 2010 2dr 6sp. I just put 4:88"s on last weekend and bought the Superchip. I gotta say it feels better than before the 35"s. IMO it was well worth the money.
RustyStolzz is offline   Reply With Quote
Unread 07-22-2010, 05:16 PM   #28
MilitaryJK4455
Web Wheeler
2010 JK Wrangler 
 
Join Date: Mar 2009
Location: Ft. Detrick MD
Posts: 2,631
Quote:
Originally Posted by JLC08JK View Post
4.88 will put it in a very good range for low gears as well as highway.
My build plan calls for an Atlas 4 speed T/C that has a very low 5.44/1 reduction.
The lower chart is for the 6 speed trans and shows that the 4.88 will put it in the blue.
According to this chart, for an automatic to match me at 3.73's and 35's they would have to run 4.56's. And the highest that they can go in the D44 would be the bottom end of stock performance.... Sucks to have an auto.
MilitaryJK4455 is offline   Reply With Quote
Unread 08-23-2010, 05:16 PM   #29
derekryan84
Registered User
2000 WJ 
 
Join Date: Aug 2010
Location: Henderson, Tx
Posts: 43
so you can run 35s on a stock rubicon w/man and not have to do any gear swaps am i right?
derekryan84 is offline   Reply With Quote
Unread 08-23-2010, 10:16 PM   #30
RockyClymer
RedRock4Wheeler
 
RockyClymer's Avatar
2008 JK Wrangler 
 
Join Date: Apr 2008
Location: Colorado
Posts: 4,419
You can run whatever tire size you want - the question of "right" is your judgment as to what is acceptable performance with the gear/tire size. 35s and a 4.10 may be right for you and not someone else. I run 35s with 4.88 and it performs just about as good a it did stock with 32s and 3.73 - and I am getting about 19 mpg with no offroading - drops considerable when off road.
__________________
08 JK 23S - Colorado Jeep Club No. 204
Too much to list - see my profile for details on build
NRA Life member
"It takes a special kind of stupid to believe criminals will follow gun laws."
I do not consider myself a smartass. I point out the obvious, search for the truth, and speak fluent sarcasm. I am, by experience, an accomplished curmudgeon.
RockyClymer is offline   Reply With Quote
Reply

Tags
3.73 gears , 35" tires , JK Wrangler , power loss , stock gears , wrangler
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.