Go Back   Jeep Garage - Jeep Forum > Jeep Platform Discussion > Grand Cherokee - WK > Engine Performance/Intake/Exhaust

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #1  
Old 03-04-2013, 04:20 PM
Member
 
Join Date: May 2011
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1323
TyBauz is on a distinguished road
Best fuel for 87 Tune? 87 pure or 89 w/ ethanol - Jeep Hemi

I have a 2005 Jeep Grand Cherokee with a 5.7L Hemi with MDS. I have a cold air intake and a Flowmaster muffler. The manual recommends 89 octane. I have the Superchips 87 tune installed.

I am trying to decide what fuel to use. I am pretty sure the 91 octane won't provide any benefit with this tune. I am mostly considering 89 w/ 10% ethanol or 87 with no ethanol. The only pure gas (non-ethanol) I can easily get is 87.

With the Superchips 87 tune installed I am wondering which fuel would provide the best power and fuel economy between these options:

87 w/ 10% Ethanol
87 w/ NO Ethanol (pure gas)
89 w/ 10% Ethanol

Any ideas or feedback would be appreciated.
__________________

__________________
Reply With Quote
  #2  
Old 03-04-2013, 06:09 PM
Senior Member
My Jeep: 2006 5.7L WK
 
Join Date: Dec 2009
Location: Home of the Mountain Blue Bird
Posts: 1,061
Thanks: 0
Thanked 26 Times in 24 Posts
Rep Power: 155084
jeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond repute
Re: Best fuel for 87 Tune? 87 pure or 89 w/ ethanol - Jeep Hemi

Generally, the ethanol blends will get you up to ~20% less fuel economy than the "straight gasoline". Also, I have found, with the SC 91 tune (running 91 straight gasoline), that I get some knock retard at WOT. Don't know if that would be true with the 87 tune or not, since I have never tried it.

IMO, the best thing to do is try them all, making sure to run several tanks of each through the system (and hand calculate results) before you make your final decision. Remember, all fuels are not created equal. Different brands of the same octane may deliver better or worse fuel economy. If your ride is basically stock, running 91 won't do a thing for you with the 87 tune. It might actually deliver less FE than the 87/89 would. Again, give it a try though Also, if you're at altitude (above ~2000 ft.) you may be able to get away with using lower octane....i.e. with my mods., if I am at altitudes above ~4000 I can run 87 without issue. Where I live (~3000 ft.) I can
"get away with" running alternate tanks of 87/91 (non-ethanol) in the winter, but I must run all 91 in the summer. No matter what, with any of the fuels, at any time of the year, I still get a little KR with the SC tuner. With the Diablosport tuner, running the 93 tune (using the same fuels) I don't get any KR. The DS tuner also delivers slightly better FE, but doesn't allow for complete adjustment of the transmission which is, IMO, essential.
__________________

__________________
05 LX/RT & 06 WK/GCO, modded similarly, MDS "ON" Light, Vortex Gens, Debadged, DashHawk, BT Catch Can, SRT CAI W/Add Air Inlet, K&N Filter, Sonnax Trans Press Booster, SC Tuner W/Adv Trans Tuning App, DS Tuner, Cust tube headers w/3 in. catback, Bilsteins, SRT frt/rear bumpers, Eibach SRT Lwr Sprgs & Sways, FRI Sidewinder Cam Adv 2*, 6.1 valvetrain, SLP 25% UD Pulley, BBK 90mm TB, SOS Coils/.060 plug gaps. 20 in. SRT Reps.
Reply With Quote
  #3  
Old 03-04-2013, 06:31 PM
SvenskaJeepGuy's Avatar
Let's Roll
My Jeep: 2005 4.7L WK
 
Join Date: Dec 2009
Location: Scranton PA
Posts: 13,091
Thanks: 140
Thanked 163 Times in 153 Posts
Rep Power: 1255470
SvenskaJeepGuy has a reputation beyond reputeSvenskaJeepGuy has a reputation beyond reputeSvenskaJeepGuy has a reputation beyond reputeSvenskaJeepGuy has a reputation beyond reputeSvenskaJeepGuy has a reputation beyond reputeSvenskaJeepGuy has a reputation beyond reputeSvenskaJeepGuy has a reputation beyond reputeSvenskaJeepGuy has a reputation beyond reputeSvenskaJeepGuy has a reputation beyond reputeSvenskaJeepGuy has a reputation beyond reputeSvenskaJeepGuy has a reputation beyond repute
Garage
Re: Best fuel for 87 Tune? 87 pure or 89 w/ ethanol - Jeep Hemi

if you have no ethanol fuel available in your area then go for it, i dont have that option
__________________
Reply With Quote
  #4  
Old 03-04-2013, 06:39 PM
Lucas J's Avatar
natural born world shaker

My Jeep: 2005 5.7L WK
 
Join Date: Aug 2011
Location: Mass
Posts: 2,692
Thanks: 127
Thanked 84 Times in 76 Posts
Rep Power: 996690
Lucas J has a reputation beyond reputeLucas J has a reputation beyond reputeLucas J has a reputation beyond reputeLucas J has a reputation beyond reputeLucas J has a reputation beyond reputeLucas J has a reputation beyond reputeLucas J has a reputation beyond reputeLucas J has a reputation beyond reputeLucas J has a reputation beyond reputeLucas J has a reputation beyond reputeLucas J has a reputation beyond repute
In my experience with a similar setup. I get the best MPG with the 91 tune running 93 octane. Then the 87 tune running 89 octane.
__________________


Beatrix "The Black Mamba" Build Thread
http://www.jeepgarage.org/f14/beatri...ead-42874.html
Reply With Quote
  #5  
Old 03-04-2013, 07:05 PM
Member
 
Join Date: May 2011
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1323
TyBauz is on a distinguished road
Re: Best fuel for 87 Tune? 87 pure or 89 w/ ethanol - Jeep Hemi

Thanks for the detailed reply. I really appreciate it. I tried the 91 tune with 91/ethanol but my MPG decreased when compared to the 87 tune. The performance may have only been slightly better, but the MDS would surge and that was annoying. The surging and poorer fuel economy is the only reason I am running the 87 tune now. I am at 2700 Ft in Boise, ID so maybe the 87 octane pure gas will work better than the 89 with ethanol. Like you said though, I think I will have to give both a try and see what works best. I hope I can find some 89 and 91 octane gas without ethanol some day. It's sad that they add ethanol to our gas now.
__________________
Reply With Quote
  #6  
Old 03-04-2013, 10:16 PM
Senior Member
My Jeep: 2006 5.7L WK
 
Join Date: Dec 2009
Location: Home of the Mountain Blue Bird
Posts: 1,061
Thanks: 0
Thanked 26 Times in 24 Posts
Rep Power: 155084
jeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond reputejeepgcoman has a reputation beyond repute
Re: Best fuel for 87 Tune? 87 pure or 89 w/ ethanol - Jeep Hemi

I don't think you'll have any problem finding non-ethanol fuel where you live. Try the Baird Oil (CFN) place on Chinden. They have both 87 and 91 non-ethanol fuel. It's a card lock system, so you'll have to sign up with them first.
__________________

__________________
05 LX/RT & 06 WK/GCO, modded similarly, MDS "ON" Light, Vortex Gens, Debadged, DashHawk, BT Catch Can, SRT CAI W/Add Air Inlet, K&N Filter, Sonnax Trans Press Booster, SC Tuner W/Adv Trans Tuning App, DS Tuner, Cust tube headers w/3 in. catback, Bilsteins, SRT frt/rear bumpers, Eibach SRT Lwr Sprgs & Sways, FRI Sidewinder Cam Adv 2*, 6.1 valvetrain, SLP 25% UD Pulley, BBK 90mm TB, SOS Coils/.060 plug gaps. 20 in. SRT Reps.
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
2009 5.7L Hemi - Suggestions for Better Fuel Economy?? mlsmith3344 Engine Performance/Intake/Exhaust 11 04-09-2012 12:07 AM
Hemi Predator CMR Tune Questions Omegax1 Performance Modifications 21 02-15-2012 08:35 AM
Hemi Fuel Economy Comparison After Mods. jeepgcoman Grand Cherokee - WK 0 05-06-2011 03:11 PM
Fuel economy 5.7 hemi DanD2124 Grand Cherokee - WK 48 05-06-2011 02:00 AM
Diablo 5.7 hemi 87 tune CAI option? charteroak_2000 Performance Modifications 21 02-15-2010 08:25 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 05:45 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.