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

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #13  
Old 11-06-2013, 10:41 PM
Dan JGC's Avatar
Premium Member
 
Join Date: Dec 2010
Posts: 2,006
Thanks: 3
Thanked 72 Times in 59 Posts
Rep Power: 4373
Dan JGC has a reputation beyond reputeDan JGC has a reputation beyond reputeDan JGC has a reputation beyond reputeDan JGC has a reputation beyond reputeDan JGC has a reputation beyond reputeDan JGC has a reputation beyond reputeDan JGC has a reputation beyond reputeDan JGC has a reputation beyond reputeDan JGC has a reputation beyond reputeDan JGC has a reputation beyond reputeDan JGC has a reputation beyond repute
Re: 87 vs 89 octane in 2014 V-8

FYI - My previous GC (WK) with V8 I ran 87 for five years and as great.....then thought I would try 89 on the next fill up after near empty. A few miles later and without question I noticed a difference especially in acceleration. After five years of driving it on 87, I could readily notice the improvement. From then on I kept using 89 and still do in my new WK2. I was surprised at the difference. For some people, the difference may not be worth it but for me it was a no brainer.
__________________

__________________
||||||| 2014 Jeep Grand Cherokee Summit 4x4 V8 in Bright White Clear Coat exterior with Grand Canyon Jeep Brown interior. |||||||
Reply With Quote
  #14  
Old 11-07-2013, 03:31 PM
Member
My Jeep: 2014 5.7L WK2
 
Join Date: Jul 2013
Location: Beech Mountain, NC
Posts: 193
Thanks: 13
Thanked 6 Times in 6 Posts
Rep Power: 646
2014RedHemiGC is on a distinguished road
Re: 87 vs 89 octane in 2014 V-8

I use 89 - a 5000 pound vehicle needs all the help it can get!
__________________

__________________
2014 Jeep GC Limited 4X4 V8 QD2
2012 Cadillac CTS-V Coupe
2011 Chevy Corvette Z06/07
Reply With Quote
  #15  
Old 11-07-2013, 08:47 PM
Member
 
Join Date: Feb 2013
Location: Clifton NJ
Posts: 42
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 639
1rawZ06 is on a distinguished road
Re: 87 vs 89 octane in 2014 V-8

To be honest with everyone, i would never put 87 octane in my 50k truck. Im sorry i just wont do it. I have owned plenty of "beaters" in my day and of course i used 87. My 2004 4.7l v8 i always used 89, as do i with my 2014. During cold months im sure it is OK to use 87, but i wouldn't chance it during warm months (better chance of detonation) Hey when you pay 50k for a truck whats a few extra cents at the pump. Just my 2 cents
__________________
2014 Jeep Grand Cherokee Overland 5.7L
2006 Corvette Z06 7.0L
Reply With Quote
  #16  
Old 11-08-2013, 10:37 AM
Member
My Jeep: 2012 5.7L WK2
 
Join Date: Nov 2011
Location: perry hall, maryland
Posts: 420
Thanks: 0
Thanked 3 Times in 3 Posts
Rep Power: 1653
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: 87 vs 89 octane in 2014 V-8

Quote:
Originally Posted by NavyDoc View Post
So, do you think that the MPG is higher with 89?
Octane does nothing for gas mileage.
__________________
Reply With Quote
  #17  
Old 11-08-2013, 10:43 AM
Member
My Jeep: 2014 5.7L WK2
 
Join Date: Jul 2013
Location: Beech Mountain, NC
Posts: 193
Thanks: 13
Thanked 6 Times in 6 Posts
Rep Power: 646
2014RedHemiGC is on a distinguished road
Re: 87 vs 89 octane in 2014 V-8

Quote:
Originally Posted by peckmv View Post
Octane does nothing for gas mileage.
If the ECU is programmed to handle higher octane (say 89 like the V8) then 89 will raise mpg's some. However, as others have said, the small increase in mpg's is usually not worth the price difference between 87 and 89. I use 89 to get all 360 horses.
__________________
2014 Jeep GC Limited 4X4 V8 QD2
2012 Cadillac CTS-V Coupe
2011 Chevy Corvette Z06/07
Reply With Quote
  #18  
Old 11-08-2013, 12:27 PM
Member
My Jeep: 2014 5.7L WK2
 
Join Date: Aug 2013
Posts: 28
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 428
NavyDoc is on a distinguished road
I suppose that I'll be sticking with 87 for now. Thank you, everyone for the advice.
__________________
Reply With Quote
  #19  
Old 11-08-2013, 12:48 PM
The Evil Twin's Avatar
Member
My Jeep: 2011 5.7L WK2
 
Join Date: Jan 2013
Location: Gainesville, VA
Posts: 341
Thanks: 0
Thanked 12 Times in 10 Posts
Rep Power: 361122
The Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond repute
Garage
Re: 87 vs 89 octane in 2014 V-8

Regarding pump fuel, higher octane (actually AKI, or anti knock index) fuel contains less energy per unit of measure. Especially when the fuel is an E10 mix. Technically, to make the most power one would use the LOWEST possible octane rating that does not cause the engine to pre detonate. A gallon of pure gasoline (no ethanol) with an AKI of 87 contains about 114,000 btu of energy. In contrast, pure ethanol is around 76,000 btu. Most formulations use ethanol, among other reasons, to increase the AKI of the fuel. Ethanol is rated at 113 octane. What does all that mean? Well, it takes energy to produce motion. There is more energy in a gallon of 87 than in 91 or 93. A gallon is a gallon, so if there is ethanol, MTBE or ETBE in it then it is no longer a gallon of gas it is (in random numbers) 100 oz gasoline/ 14 oz ethanol/ 14 oz MTBE. For comparison sake, per gallon:
Summer blend gasoline= 114,000 btu
Winter blend gasoline= 112,000 btu
Reformulated with 10% ethanol= 111,000 btu
Reformulated with MTBE/ ETBE= 111,000 btu
Ethanol= 76,000 btu
My race bikes all have used 87 AKI pump fuel. I have no ignition advance module or O2 sensors. I have consistently seen 4-6% HP gains over using 91 AKI. With advance and increasing compression I could eek out more power on a higher AKI fuel. Seeing as most modern cars can to an extent adjust timing and injector duration for conditions, the gains in power and economy are going to be nominal. The car doesn't know what octane it has, only how clean the burn is as it is told by the O2 sensors. As long as there is no knock the ECU only dumps as much fuel in as is can without emissions exceeding set parameters. Even in "lab" conditions it is hard to squeeze out more than 1-2% gain. For an interesting read on this: Fuel Rating - Octane Comparison - Dyno Tests Graphs - Hot Rod Magazine
Now, do I run 89 in my rig? Yes. Only when I am towing during the summer months. Other than that, 87 it is.
As a side note, I try to use top tier fuels as well. There definitely IS a difference there.
__________________
#132-CCS Racing

2014 Sponsors: Amsoil, www.DC-MOTO.net, Manassas Honda Kawasaki Suzuki, www.MARRC.org
Amsoil 5w-20 synthetic meets Chrysler MS-6395 for my Jeep!
Reply With Quote
  #20  
Old 11-08-2013, 01:34 PM
silvermax04's Avatar
Premium Member
My Jeep: 2014 5.7L WK2
 
Join Date: Feb 2013
Posts: 1,134
Thanks: 38
Thanked 84 Times in 65 Posts
Rep Power: 2167
silvermax04 has a reputation beyond reputesilvermax04 has a reputation beyond reputesilvermax04 has a reputation beyond reputesilvermax04 has a reputation beyond reputesilvermax04 has a reputation beyond reputesilvermax04 has a reputation beyond reputesilvermax04 has a reputation beyond reputesilvermax04 has a reputation beyond reputesilvermax04 has a reputation beyond reputesilvermax04 has a reputation beyond reputesilvermax04 has a reputation beyond repute
Re: 87 vs 89 octane in 2014 V-8

Quote:
Originally Posted by The Evil Twin View Post
Regarding pump fuel, higher octane (actually AKI, or anti knock index) fuel contains less energy per unit of measure. Especially when the fuel is an E10 mix. Technically, to make the most power one would use the LOWEST possible octane rating that does not cause the engine to pre detonate. A gallon of pure gasoline (no ethanol) with an AKI of 87 contains about 114,000 btu of energy. In contrast, pure ethanol is around 76,000 btu. Most formulations use ethanol, among other reasons, to increase the AKI of the fuel. Ethanol is rated at 113 octane. What does all that mean? Well, it takes energy to produce motion. There is more energy in a gallon of 87 than in 91 or 93. A gallon is a gallon, so if there is ethanol, MTBE or ETBE in it then it is no longer a gallon of gas it is (in random numbers) 100 oz gasoline/ 14 oz ethanol/ 14 oz MTBE. For comparison sake, per gallon:
Summer blend gasoline= 114,000 btu
Winter blend gasoline= 112,000 btu
Reformulated with 10% ethanol= 111,000 btu
Reformulated with MTBE/ ETBE= 111,000 btu
Ethanol= 76,000 btu
My race bikes all have used 87 AKI pump fuel. I have no ignition advance module or O2 sensors. I have consistently seen 4-6% HP gains over using 91 AKI. With advance and increasing compression I could eek out more power on a higher AKI fuel. Seeing as most modern cars can to an extent adjust timing and injector duration for conditions, the gains in power and economy are going to be nominal. The car doesn't know what octane it has, only how clean the burn is as it is told by the O2 sensors. As long as there is no knock the ECU only dumps as much fuel in as is can without emissions exceeding set parameters. Even in "lab" conditions it is hard to squeeze out more than 1-2% gain. For an interesting read on this: Fuel Rating - Octane Comparison - Dyno Tests Graphs - Hot Rod Magazine
Now, do I run 89 in my rig? Yes. Only when I am towing during the summer months. Other than that, 87 it is.
As a side note, I try to use top tier fuels as well. There definitely IS a difference there.
Agree with you completely, If you are towing a heavy load up a mountain in high heat 89 can give some benefit but for tooling around the suburbs in average temperatures 87 is fine and you may get a little better mileage out of it depending on your situation. The high octane is not better unless your car can make use of the high octane. the detergent in 87 and 93 is the same all you are paying for is more octane. Sticking to Top tier fuel important also, no unknown minimart gas. The other thing is understanding the difference between the words "recommended" and "required" If I had the SRT I would not put anything in it but premium because it is "required" and can cause issues if you don't. My last car consistently got better mileage on 87 even though it "recommended" 91 for best performance. Was there a very slight increase in performance with 91 maybe slightly in certain conditions but worth it? not even close.
Its not a one size fits all and just my opinion but if you drag race your truck all the time or always towing you may see some benefit with 89 if you are a normal driver in a normal climate 87 is likely just fine. Its not really as much about cheapness as it is just being necessary or not.
__________________
Reply With Quote
  #21  
Old 11-08-2013, 01:54 PM
Premium Member
My Jeep: 2014 5.7L WK2
 
Join Date: May 2013
Location: Colorado
Posts: 2,366
Thanks: 31
Thanked 80 Times in 73 Posts
Rep Power: 43812
lstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond repute
Re: 87 vs 89 octane in 2014 V-8

Quote:
Originally Posted by NavyDoc View Post
That's more or less what I was thinking. We've been getting around 15 MPG. Maybe a tank or 2 or 89 may give me an idea if the cost would be worth it.
15 seems awful low unless you have a lead foot or always drive in sport mode or do a lot of very low speed stop/go.

I wouldn't expect a bump in octane to do much for that unless your local suppliers are loading the regular up with more alcohol than premium, where the alcohol simply has worse inherent mileage.

The Hemi will dial it back a bit if you use the lower grade, but as the owners manual notes, the Hemi is designed for 89, but premium has no benefit.

"This engine is designed to meet all emissions
regulations and provide satisfactory
fuel economy and performance when using
high-quality unleaded gasoline having
an octane range of 87 to 89. The manufacturer
recommends the use of 89 octane for optimum
performance. The use of premium gasoline is not recommended,
as it will not provide any benefit over regular
gasoline in these engines."


You might want to change brands and see if that helps IF the other brand is from a different depot.

I could swear I saw a driveability TSB for a flash over on Milous site for the Hemi when running the lower octane, but can't find it now.

Too bad the manual doesn't just indicate regular to midgrade as at altitude regular is about 85 mixed method and midgrade is about 87 and is all you need.
__________________
Reply With Quote
  #22  
Old 11-08-2013, 01:56 PM
Premium Member
My Jeep: 2014 5.7L WK2
 
Join Date: May 2013
Location: Colorado
Posts: 2,366
Thanks: 31
Thanked 80 Times in 73 Posts
Rep Power: 43812
lstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond reputelstowell has a reputation beyond repute
Re: 87 vs 89 octane in 2014 V-8

Quote:
Originally Posted by 2014RedHemiGC View Post
I use 89 - a 5000 pound vehicle needs all the help it can get!
Then strap on a JATO and call Mythbusters.
__________________
Reply With Quote
  #23  
Old 11-08-2013, 02:37 PM
The Evil Twin's Avatar
Member
My Jeep: 2011 5.7L WK2
 
Join Date: Jan 2013
Location: Gainesville, VA
Posts: 341
Thanks: 0
Thanked 12 Times in 10 Posts
Rep Power: 361122
The Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond reputeThe Evil Twin has a reputation beyond repute
Garage
Re: 87 vs 89 octane in 2014 V-8

Quote:
Originally Posted by lstowell View Post
Too bad the manual doesn't just indicate regular to midgrade as at altitude regular is about 85 mixed method and midgrade is about 87 and is all you need.
That is an excellent point, sir! I completely forgot to mention that too. As altitude increases, the required AKI is reduced. Folks in Denver are wasting $$ if still running 89.
__________________

__________________
#132-CCS Racing

2014 Sponsors: Amsoil, www.DC-MOTO.net, Manassas Honda Kawasaki Suzuki, www.MARRC.org
Amsoil 5w-20 synthetic meets Chrysler MS-6395 for my Jeep!
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
Tuners! What octane is best kapytan83 Engine Performance/Intake/Exhaust 28 01-28-2014 01:53 PM
87 vs 89 octane Golgo13 Engine Performance/Intakes/Exhausts 3 07-26-2012 05:05 PM
Which Octane just4fun Export Grand Cherokee 2011+ 6 11-15-2011 03:48 AM
87 or 89 octane jp467 Engine Performance/Intakes/Exhausts 46 08-16-2011 10:03 AM
What Octane? THEPRFCT10 Grand Cherokee - WK2 - 18 11-27-2010 10:31 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 12:29 AM.


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