Go Back   Jeep Garage - Jeep Forum > Jeep Platform Discussion > Grand Cherokee - WK2 -

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #1  
Old 02-05-2012, 07:20 PM
Member
 
Join Date: Jun 2011
Posts: 44
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1336
Jimbo is on a distinguished road
2012 WK2 Grade of gas

Could the 2012 3.6l V6 WK2 run on 91 octane fuel to increase mpg? Or would 91 octane gas create performance loss and is harmful to the engine?
__________________

__________________
Reply With Quote
  #2  
Old 02-05-2012, 07:27 PM
xJoshxx's Avatar
Premium Member
My Jeep: 2012 6.4L WK2
 
Join Date: Mar 2011
Location: Burlington,KY
Posts: 866
Thanks: 34
Thanked 40 Times in 31 Posts
Rep Power: 72796
xJoshxx has a reputation beyond reputexJoshxx has a reputation beyond reputexJoshxx has a reputation beyond reputexJoshxx has a reputation beyond reputexJoshxx has a reputation beyond reputexJoshxx has a reputation beyond reputexJoshxx has a reputation beyond reputexJoshxx has a reputation beyond reputexJoshxx has a reputation beyond reputexJoshxx has a reputation beyond reputexJoshxx has a reputation beyond repute
Re: 2012 WK2 Grade of gas

the 3.6 was designed to take 87 and has no gains from using a higher octane.
__________________

__________________
Reply With Quote
  #3  
Old 02-05-2012, 07:54 PM
77Cherokee's Avatar
Member
My Jeep: 2012 3.6L WK2
 
Join Date: Jun 2011
Location: NY State
Posts: 652
Thanks: 0
Thanked 21 Times in 19 Posts
Rep Power: 2239
77Cherokee has a reputation beyond repute77Cherokee has a reputation beyond repute77Cherokee has a reputation beyond repute77Cherokee has a reputation beyond repute77Cherokee has a reputation beyond repute77Cherokee has a reputation beyond repute77Cherokee has a reputation beyond repute77Cherokee has a reputation beyond repute77Cherokee has a reputation beyond repute77Cherokee has a reputation beyond repute77Cherokee has a reputation beyond repute
Re: 2012 WK2 Grade of gas

+1. You would be throwing away good money for nothing.
__________________
2012 Overland, Deep Cherry w/black/saddle interior, V6, ACC pkg.

My 77 Cherokee- Long gone but not forgotten
___
____________________________________
Reply With Quote
  #4  
Old 02-05-2012, 10:55 PM
Member
 
Join Date: Nov 2010
Posts: 220
Thanks: 0
Thanked 3 Times in 3 Posts
Rep Power: 1717
UNCjeepWK2 is on a distinguished road
Re: 2012 WK2 Grade of gas

one of the biggest fuel myths ever... using a higher octane NEVER achieves higher MPG. If it calls for 87, then use 87. If it calls for something else, use the something else. Just go by the manual...
__________________
Reply With Quote
  #5  
Old 02-06-2012, 06:47 AM
Premium Member
 
Join Date: Jan 2011
Posts: 318
Thanks: 0
Thanked 1 Time in 1 Post
Rep Power: 1762
Breitling65 is on a distinguished road
Re: 2012 WK2 Grade of gas

It is safe to drive regular based on book and no power loss based on driving of WK2. Normally higher octane protects against of very harmful detonation, V6 ignition and compression ratio adjusted to run on regular without.
__________________
2013 Jeep Wrangler Unlimited Sport S, White
2012 Mercedes Benz C350 coupe, White
Reply With Quote
  #6  
Old 02-06-2012, 08:51 AM
Member
My Jeep: 2012 5.7L WK2
 
Join Date: Nov 2011
Location: perry hall, maryland
Posts: 428
Thanks: 0
Thanked 3 Times in 3 Posts
Rep Power: 1755
peckmv has a reputation beyond reputepeckmv has a reputation beyond reputepeckmv has a reputation beyond reputepeckmv has a reputation beyond reputepeckmv has a reputation beyond reputepeckmv has a reputation beyond reputepeckmv has a reputation beyond reputepeckmv has a reputation beyond repute
Re: 2012 WK2 Grade of gas

Quote:
Originally Posted by Jimbo View Post
Could the 2012 3.6l V6 WK2 run on 91 octane fuel to increase mpg? Or would 91 octane gas create performance loss and is harmful to the engine?
Octane does nothing for mileage. It is an anti-knock additive.
__________________
Reply With Quote
  #7  
Old 02-07-2012, 12:10 PM
JTS97Z28's Avatar
Premium Member
My Jeep: 2012 3.6L WK2
 
Join Date: Jan 2011
Location: Plainfield, IL
Posts: 1,466
Thanks: 0
Thanked 32 Times in 20 Posts
Rep Power: 25288
JTS97Z28 has a reputation beyond reputeJTS97Z28 has a reputation beyond reputeJTS97Z28 has a reputation beyond reputeJTS97Z28 has a reputation beyond reputeJTS97Z28 has a reputation beyond reputeJTS97Z28 has a reputation beyond reputeJTS97Z28 has a reputation beyond reputeJTS97Z28 has a reputation beyond reputeJTS97Z28 has a reputation beyond reputeJTS97Z28 has a reputation beyond reputeJTS97Z28 has a reputation beyond repute
Send a message via AIM to JTS97Z28
Re: 2012 WK2 Grade of gas

Wow are people still seriously stuck on thinking that just because the fuel is a higher octane that it could deliver better performance and fuel economy.

Like others have said above if your engine is designed to burn regular grade 87 octane, there will be NO benefits of burning premium 91 octane or greater.

Use what the manual says to use and nothing else!!!
__________________
Reply With Quote
  #8  
Old 02-07-2012, 02:50 PM
Jeep_addicted's Avatar
Premium Member
My Jeep: 2012 3.6L WK2
 
Join Date: Nov 2011
Location: St. Thomas US. Virgin islands
Posts: 1,128
Thanks: 16
Thanked 57 Times in 47 Posts
Rep Power: 1332172
Jeep_addicted has a reputation beyond reputeJeep_addicted has a reputation beyond reputeJeep_addicted has a reputation beyond reputeJeep_addicted has a reputation beyond reputeJeep_addicted has a reputation beyond reputeJeep_addicted has a reputation beyond reputeJeep_addicted has a reputation beyond reputeJeep_addicted has a reputation beyond reputeJeep_addicted has a reputation beyond reputeJeep_addicted has a reputation beyond reputeJeep_addicted has a reputation beyond repute
Garage
Re: 2012 WK2 Grade of gas

I have used both 87 and 93 and for me think the sweet spot would be 89 for the 3.6

But me personally I get better mileage when I use the 93 because the engine feels like it produces more torque in the lower rpm. If you can run the tank down to practically empty and do your own seat of the pants calculations you will know which one is right for you.

The 3.6 does not require high octane fuel, as the VVT and knock sensors quickly compensates for the lower octane but advancing the timing a bit.

For my Hilly(mountainous) driving conditions the torque at lower rpm also helps with my stop and go moring traffic...
__________________
Reply With Quote
  #9  
Old 02-07-2012, 07:24 PM
BManz's Avatar
Member
 
Join Date: Oct 2011
Posts: 85
Thanks: 0
Thanked 4 Times in 3 Posts
Rep Power: 1490
BManz has a reputation beyond reputeBManz has a reputation beyond reputeBManz has a reputation beyond reputeBManz has a reputation beyond reputeBManz has a reputation beyond reputeBManz has a reputation beyond reputeBManz has a reputation beyond reputeBManz has a reputation beyond reputeBManz has a reputation beyond repute
Re: 2012 WK2 Grade of gas

I could never tell a difference running 87 or 89 in the Hemi. The Hemi is tuned for 89 but mine's been filled with 87 a few times, full tank too, and I honestly couldn't tell a difference. Still run 89 anyway for most all of my fill ups. But -- about 2 weeks ago I had to fill mine up with 91 at my regular station when they ran out of 87. Since 89 is just a blend of 87 and 91 or 93 as you fill, I just took the premium rather than drive out of my way.

Immediately after that fill up, when I got on my usual I-294 on ramp, I noticed a significant amount more of butt-dyno power. Sure, I would've said to anyone else it was just in their head, but I wasn't expecting any difference at all so I was surprised. There was no fuel economy difference that tank full, mostly highway and got 22+ winter fuel & all.

So, I think my station and some others are cheating on the 89 because after that 91 octane tank got used up that weekend I went back to 89 on the next fill -23gal- at another station and the butt-dyno immediately said "less power" when I got back on the road. I'm about done with that 89 tank now and EVIC says 22.1mpg so again no change in economy. But, actually "butt", I sure felt a difference in power 91 vs the, ahem, 87 er 89, like an engine would do when pulling timing back. Anyone else think some stations might be a little slim in the 91/87 blend to give us "89"? That may be why I could never tell a difference before.

It's possible it was a weather anomaly giving some high pressure but I'm still suspicious.
__________________
Reply With Quote
  #10  
Old 02-09-2012, 06:21 AM
JGCCAYENNE's Avatar
Member
 
Join Date: Oct 2011
Location: Dallas
Posts: 100
Thanks: 4
Thanked 11 Times in 3 Posts
Rep Power: 12667
JGCCAYENNE has a reputation beyond reputeJGCCAYENNE has a reputation beyond reputeJGCCAYENNE has a reputation beyond reputeJGCCAYENNE has a reputation beyond reputeJGCCAYENNE has a reputation beyond reputeJGCCAYENNE has a reputation beyond reputeJGCCAYENNE has a reputation beyond reputeJGCCAYENNE has a reputation beyond reputeJGCCAYENNE has a reputation beyond reputeJGCCAYENNE has a reputation beyond reputeJGCCAYENNE has a reputation beyond repute
Re: 2012 WK2 Grade of gas

The difference between 87 and 91 on a Hemi is at most 10 HP. If your butt can measure that, you have a very sensitive butt.
__________________
2012 JGC Limited
4x4, V8, Trail Rated
Reply With Quote
  #11  
Old 02-09-2012, 11:34 AM
BManz's Avatar
Member
 
Join Date: Oct 2011
Posts: 85
Thanks: 0
Thanked 4 Times in 3 Posts
Rep Power: 1490
BManz has a reputation beyond reputeBManz has a reputation beyond reputeBManz has a reputation beyond reputeBManz has a reputation beyond reputeBManz has a reputation beyond reputeBManz has a reputation beyond reputeBManz has a reputation beyond reputeBManz has a reputation beyond reputeBManz has a reputation beyond repute
Re: 2012 WK2 Grade of gas

Quote:
Originally Posted by JGCCAYENNE View Post
The difference between 87 and 91 on a Hemi is at most 10 HP. If your butt can measure that, you have a very sensitive butt.
You mean 20+hp. It's more like a 6%-8% reduction in power if the engine has a tune to take advantage of a higher octane and you run a lower one. If the change is more than 10-15hp, oh yeah, a car guy like me will feel that on full honk acceleration. While I'm not an engineer, I built, dyno'd and raced a few engine/chassis combos over the years which involved working alongside some powertrain engineers from various manufacturers who were also racers on the weekends and it's what we saw. One of those guys introduced me to this forum as a matter of fact.

This very octane discussion, and torque/horsepower debating, was had many times over beer and brats. The -8% power reduction number matched what we typically saw on dyno testing changing nothing but the fuel and timing to reduce detonation -- I liked trying to build street-gas friendly race engines when money was tight. Modern engines retard timing quickly at the hint of detonation even running the designated octane fuel. So on a hot day while running your engine hard you'll feel a power loss too even running the optimal gas, 87, 89, 91, whatever, as the computer retards timing. It would be a pain to do a controlled test for this on the Grand without disconnecting the fuel tanks, but it'd be interesting.
__________________
Reply With Quote
  #12  
Old 02-09-2012, 11:39 AM
SW03ES's Avatar
Premium Member
My Jeep: 2014 3.6L WK2
 
Join Date: Jun 2011
Location: Gaithersburg, MD
Posts: 1,857
Thanks: 17
Thanked 62 Times in 50 Posts
Rep Power: 1303588
SW03ES has a reputation beyond reputeSW03ES has a reputation beyond reputeSW03ES has a reputation beyond reputeSW03ES has a reputation beyond reputeSW03ES has a reputation beyond reputeSW03ES has a reputation beyond reputeSW03ES has a reputation beyond reputeSW03ES has a reputation beyond reputeSW03ES has a reputation beyond reputeSW03ES has a reputation beyond reputeSW03ES has a reputation beyond repute
Re: 2012 WK2 Grade of gas

Quote:
Originally Posted by Jeep_addicted View Post
I have used both 87 and 93 and for me think the sweet spot would be 89 for the 3.6

But me personally I get better mileage when I use the 93 because the engine feels like it produces more torque in the lower rpm. If you can run the tank down to practically empty and do your own seat of the pants calculations you will know which one is right for you..
Thats totally in your head. Seriously, they have done study after study, using a higher octane gas than what is recommended does nothing for performance.
__________________

__________________
~Steve~
2014 Jeep Grand Cherokee Overland V6 4X4. Maximum Steel w/ Vesuvio Jeep Brown/Indigo Blue. Advanced Tech Pkg.
2013 Lexus GS350 AWD, Liquid Platinum w/ Flaxen. Luxury & Cold Weather Pkg
Previous Jeep: 2011 Grand Cherokee Laredo X w/Nav, QT1 & Trailer Tow
Reply With Quote
Reply

Thread Tools
Display Modes

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Gas mileage on lifted WK2 tswol541 Suspension/Driveline/Brakes/Wheels/Tires 5 02-18-2012 03:06 PM
V8 --- what grade of gas to use? Dan JGC Grand Cherokee - WK2 - 32 09-21-2011 12:34 PM
Hurricane Season -- Syphoning Gas from a WK2 Celly Grand Cherokee - WK2 - 16 08-23-2011 12:30 PM
Is anyone running E-85 Gas in their WK2 V6? WK24ME Grand Cherokee - WK2 - 40 04-14-2011 11:56 AM
If Gas Were $5.00 Would You Still Buy a WK2? blankster Grand Cherokee - WK2 - 67 12-30-2010 09:53 AM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 09:33 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community

JeepGarage.org is in no way associated with or endorsed by Chrysler Group LLC.