Power loss from 35's? & pwr mods - JeepForum.com

Reply
 
LinkBack Thread Tools
post #1 of 103 Old 07-19-2010, 07:33 PM Thread Starter
takeda54
Registered User
2008 JK Wrangler 
 
Join Date: Jul 2010
Location: dallas
Posts: 39
Power loss from 35's? & pwr mods

How much power loss can you expect from going to 35's from the stock tires(255/70/17) "32" on a stock JK X with 3.73 gears. I plan on doing exhaust and cold air intact with predator , I hope this will help. I have been told by a local shop this will be good up to 35 horses.

takeda54 is offline  
Sponsored Links
Advertisement
 
post #2 of 103 Old 07-19-2010, 08:04 PM
fernjack
Registered User
2007 JK Wrangler 
 
Join Date: Apr 2009
Location: Winnipeg
Posts: 1,031
Most guys on here will tell you to save your cash and use it for gears .....the intake & exhaust thing just doesn't make ponies on this engine . Probably would need a cam and a retune to be able to use the intake & exhaust . Are you auto or 6spd. ?
fernjack is offline  
post #3 of 103 Old 07-19-2010, 08:08 PM
stanware
Registered User
2008 JK Wrangler 
 
Join Date: Jun 2010
Location: Los Angeles
Posts: 36
I went to 35" from stock and also got a Volant Exhaust and intake and there is power loss, it was only after my Superchips tune that I got some real power back.
stanware is offline  
post #4 of 103 Old 07-19-2010, 08:17 PM
fan45acp
Registered User
2010 JK Wrangler 
 
Join Date: Mar 2010
Location: Texas
Posts: 307
Really save your money and REGEAR...
fan45acp is offline  
post #5 of 103 Old 07-19-2010, 08:25 PM
GPV
Registered User
2008 JK Wrangler 
 
Join Date: Jul 2008
Location: Maine
Posts: 933
Yep regear it and be done with it.

Sean

2008 Jeep JK Rubicon Unlimited (Bought for Wife)
2007 GMC 2500HD Duramax (Work Horse)
1982 Honda CB 900F Supersport
2001 Honda RC51
GPV is offline  
post #6 of 103 Old 07-19-2010, 08:32 PM
Benderff
Web Wheeler
 
Benderff's Avatar
2006 TJ Wrangler 
 
Join Date: Apr 2007
Posts: 5,264
You will not lose any engine power by changing tires. (So why would you waste money fixing something that's not broken?) Changing tire size affects the rate your drivetrain can turn your tires. If you want to be able to turn the tires the same as before you need to regear the axles.
Benderff is online now  
post #7 of 103 Old 07-19-2010, 08:33 PM
MilitaryJK4455
Web Wheeler
2010 JK Wrangler 
 
Join Date: Mar 2009
Location: Ft. Detrick MD
Posts: 2,624
about a 20% power loss in take off and about a 5% loss in mid speed (2500 rpms runnin up to about 65) and then about a 15% loss in anything over 70-75mph. Thats about the best I can describe it in terms that ppl on the interwebz can understand.
MilitaryJK4455 is offline  
post #8 of 103 Old 07-20-2010, 01:10 AM
Armycop
Registered User
2014 KL Cherokee 
 
Join Date: Jul 2007
Location: Fort Lewis, WA
Posts: 126
The Superchip can give you a couple more HP and a better throttle response, but regearing is the best way to get the engine in the sweet spot for power.

2014 KL SPORT BILLET SILVER l 9-SPEED l 25% TINT l MB ICON WHEELS l OEM SPLASH GUARDS
Armycop is offline  
post #9 of 103 Old 07-20-2010, 01:16 AM
1222
RIP John
 
1222's Avatar
2012 JK Wrangler 
 
Join Date: Jul 2007
Location: Henderson
Posts: 13,239
Yup, re-gear first. If itís an auto go with 5.13ís. Maybe even 5.38ís.
1222 is offline  
post #10 of 103 Old 07-20-2010, 01:37 AM
JLC08JK
What was I thinking?
 
JLC08JK's Avatar
2008 JK Wrangler 
 
Join Date: Sep 2009
Location: Los Angeles
Posts: 6,082
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!
JLC08JK is offline  
post #11 of 103 Old 07-20-2010, 02:08 AM
MilitaryJK4455
Web Wheeler
2010 JK Wrangler 
 
Join Date: Mar 2009
Location: Ft. Detrick MD
Posts: 2,624
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!
With my 3.73's I just got back from a trip with 35's also... 4th gear at 65 im running 2500 rpms, I did have power to accelerate and I was getting about 18.5 mpg and I could go up to 5th gear and run about 2k rpm unless I was going up hill, then I would drop into 4th.... That shows you the change just up to 3.73's... I only have to hit 3rd gear when traffic got slow or I was decelerating.
MilitaryJK4455 is offline  
post #12 of 103 Old 07-20-2010, 02:12 AM
Warlord2
Registered User
2007 JK Wrangler 
 
Join Date: Jul 2007
Location: Bakersfield, California
Posts: 1,952
screw gears, just buy a hemi and call it good

07 JK 2D X model with 6 speeds. Full Traction 3" ultimate lift kit. 315x75x16 Toyo Open Country M/T on Rock crawler procomp rim. Ruby dana44's front sleeved inside/outside C truss and rear with 5.13's gears. Homemade rock guards, rear bumper w/tire carrier, oilpan/tranny skid, evap canister skid, light bar, switch pod. Riddler diff covers, Cobra 75 w/wilson antenna, Polk speakers, 10" sub, 2x Amps, Lightforce 240 drive light, backup lights, rock lights.
Warlord2 is offline  
post #13 of 103 Old 07-20-2010, 01:20 PM
1222
RIP John
 
1222's Avatar
2012 JK Wrangler 
 
Join Date: Jul 2007
Location: Henderson
Posts: 13,239
Quote:
Originally Posted by Warlord2 View Post
screw gears, just buy a hemi and call it good
Ok, but Iíll have to sell my kids first. Ooh, this is starting to sound better already.
1222 is offline  
post #14 of 103 Old 07-20-2010, 01:27 PM
Rafi
Registered User
2010 JK Wrangler 
 
Join Date: Apr 2010
Location: Boston
Posts: 331
Quote:
Originally Posted by MilitaryJK4455 View Post
With my 3.73's I just got back from a trip with 35's also... 4th gear at 65 im running 2500 rpms, I did have power to accelerate and I was getting about 18.5 mpg and I could go up to 5th gear and run about 2k rpm unless I was going up hill, then I would drop into 4th.... That shows you the change just up to 3.73's... I only have to hit 3rd gear when traffic got slow or I was decelerating.
i just got back from a 400 mile round trip on 35's with 3.73's too. I was only able to really put it in 6th gear down hill. but most of my time was spent in 5th and needing 4th up hills. You think you would get better gas milage in 4th gear revving higher than 5th? Probably what a 300-400 rpm difference? just because it would be "trying less" even though the rpm's were higher? i was at 15.8mpg's or so. but i was going up to the moutains...
Rafi is offline  
post #15 of 103 Old 07-20-2010, 03:54 PM
MilitaryJK4455
Web Wheeler
2010 JK Wrangler 
 
Join Date: Mar 2009
Location: Ft. Detrick MD
Posts: 2,624
Quote:
Originally Posted by Rafi View Post
i just got back from a 400 mile round trip on 35's with 3.73's too. I was only able to really put it in 6th gear down hill. but most of my time was spent in 5th and needing 4th up hills. You think you would get better gas milage in 4th gear revving higher than 5th? Probably what a 300-400 rpm difference? just because it would be "trying less" even though the rpm's were higher? i was at 15.8mpg's or so. but i was going up to the moutains...
It just depends on how you drive man... I try to run about 65-70 in fifth gear where I can and I drop to 4th for inclines to keep the motor from working too hard... good mpg's and giving it hell dont go together

Not to mention I was driving to the beach... Not too many hills, I was able to run 5th pretty much the whole way unless traffic lights or idiots ended up in front of me.
MilitaryJK4455 is offline  
Reply

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



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
loss of power... Shinitenshi TJ Wrangler Technical Forum 17 12-30-2007 12:16 AM
Serious power loss shinigami YJ Wrangler Technical Forum 14 09-01-2007 03:29 PM
loss of power echoes TJ Wrangler Technical Forum 11 07-31-2006 06:58 PM
a/c on big power loss KKiowaTJ TJ Wrangler Technical Forum 2 07-30-2006 08:10 PM
4.2L power loss COSourdough YJ Wrangler Technical Forum 11 05-13-2006 04:51 PM

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