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

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #25  
Old 02-16-2011, 04:44 PM
Premium Member
My Jeep: 2012 6.4L SRT8
 
Join Date: Dec 2010
Location: Ormond Beach FL
Posts: 1,544
Thanks: 0
Thanked 22 Times in 21 Posts
Rep Power: 2946
mjw930 has a reputation beyond reputemjw930 has a reputation beyond repute
Re: Is anyone running E-85 Gas in their WK2 V6?

Quote:
Originally Posted by vikingdave View Post
There is really no need to do the testing, it's a simple matter of the fact that E85 has significantly less energy than gasoline. Traditional gasoline has an energy rating of 46.4 (MJ/kg), while E85 is much lower at 33.1 (MJ/kg). Fuel economy and power output will suffer significantly if you run E85 in your V6. Yes, you can build/tune an engine to produce fantastic power on E85, basically with very high compression and large fuel flow rates but it is an unavoidable fact that a gallon of E85 has significantly less energy than a gallon of gasoline. Octane and energy are two completely different things. Ethanol can be produced with very high (100+) octane ratings to prevent pre-ignition (knocking), but it is still a lower energy fuel than gasoline.
Everything you say is 100% true but different vehicles have wildly different results. For example, the flex-fuel 2010 Chevrolet Impala equipped with a 3.5-liter V-6 engine gets an EPA-estimated 18/29 mpg (city/highway) on gasoline and 14/21 mpg when burning E85, roughly a 28% reduction in MPG while a 2010 Saab flex fuel turbo motor gets exactly the same MPG on E85, E10 or pure gas. It's all about how the motors are tuned.

All I've been trying to say here is he should give it a try, accurately determine the effects on his fuel economy and do the math to see if it's worthwhile for him.
__________________

__________________
2012 Grand Cherokee SRT8 Black/Black
Reply With Quote
  #26  
Old 02-16-2011, 04:59 PM
Member
 
Join Date: Feb 2011
Posts: 182
Thanks: 0
Thanked 4 Times in 4 Posts
Rep Power: 1499
vikingdave is on a distinguished road
Re: Is anyone running E-85 Gas in their WK2 V6?

Quote:
Originally Posted by mjw930 View Post
Everything you say is 100% true but different vehicles have wildly different results. For example, the flex-fuel 2010 Chevrolet Impala equipped with a 3.5-liter V-6 engine gets an EPA-estimated 18/29 mpg (city/highway) on gasoline and 14/21 mpg when burning E85, roughly a 28% reduction in MPG while a 2010 Saab flex fuel turbo motor gets exactly the same MPG on E85, E10 or pure gas. It's all about how the motors are tuned.

All I've been trying to say here is he should give it a try, accurately determine the effects on his fuel economy and do the math to see if it's worthwhile for him.
Could you point me to the MPG data on the Saab showing similar MPG for gasoline and E85? Everything I could find about that engine shows that Saab tuned it so that it could produce similar power on E85 and gasoline. This is possible because the ECU can control the compression ratio via the turbo. They also had to give it larger fuel injectors to yield similar power on E85, because it has to use more E85 to produce the same amount of power which to me implies less MPG. Anyway, I'm open minded about stuff like this, and I would really like to see that MPG data. Similar power production is very believable with a turbo and high-flow injectors but similar MPG would require overcoming some basic laws of physics.
__________________

__________________
Reply With Quote
  #27  
Old 02-16-2011, 05:08 PM
Member
My Jeep: 2004 4.7L WJ
 
Join Date: Nov 2010
Location: Michigan
Posts: 6
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1415
hondurantaco is on a distinguished road
Re: Is anyone running E-85 Gas in their WK2 V6?

If you're at high elevations, like in the Rockies or anywhere close... then getting E85 or E87 doesnt really matter. With the higher elevations.. the e85 burns just as normal because of the amount of oxygen in the air. But I always put in 87 because its a cleaner fuel. I only put in 85 when I'm down on money but with a gas treatment to go with it
__________________
Reply With Quote
  #28  
Old 02-16-2011, 05:19 PM
Member
 
Join Date: Feb 2011
Posts: 182
Thanks: 0
Thanked 4 Times in 4 Posts
Rep Power: 1499
vikingdave is on a distinguished road
Re: Is anyone running E-85 Gas in their WK2 V6?

I found a detailed SAE certified study of that Saab turbo engine. It's a very complex study that can easily be mistakenly misinterpreted to show that fuel economy is similar on E85 and gasoline. Upon further explanation though, it shows that the engine did suffer significantly in terms of fuel economy on E85. They introduced the concept of "gasoline equivalent fuel economy" to account for the fact that E85 has less potential energy than gasoline. Basically they said that because E85 has less energy than gasoline, lets multiply the E85 MPG numbers to show what it would do on E85 if E85 had the same energy as gasoline. It's a silly exercise, that in the end can't overcome the basic problem with ethanol which is reduced energy capacity.
__________________
Reply With Quote
  #29  
Old 02-16-2011, 05:33 PM
OneCent's Avatar
Premium Member
 
Join Date: Sep 2010
Location: Switzerland
Posts: 134
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1592
OneCent is on a distinguished road
Re: Is anyone running E-85 Gas in their WK2 V6?

at the end, for most of us with flex fuel engines, it will depend on cost, like in Brazil. You fill your tank with the cheaper stuff. Just when "its cheaper for you" is a point we can discus. ;-)
__________________
Grand Cherokee 3.6l Overland, Brilliant Black, Dark/Light Frost Beige
Reply With Quote
  #30  
Old 02-16-2011, 05:48 PM
Member
 
Join Date: Feb 2011
Posts: 182
Thanks: 0
Thanked 4 Times in 4 Posts
Rep Power: 1499
vikingdave is on a distinguished road
Re: Is anyone running E-85 Gas in their WK2 V6?

Quote:
Originally Posted by OneCent View Post
at the end, for most of us with flex fuel engines, it will depend on cost, like in Brazil. You fill your tank with the cheaper stuff. Just when "its cheaper for you" is a point we can discus. ;-)
Agreed, if down the road E85 can be purchased for significantly less than gasoline, than it would be a great option. I guess it's nice knowing that if this ever does happen in the US those that have a V6 will be able to take advantage of it.
__________________
Reply With Quote
  #31  
Old 02-16-2011, 05:48 PM
Premium Member
My Jeep: 2012 6.4L SRT8
 
Join Date: Dec 2010
Location: Ormond Beach FL
Posts: 1,544
Thanks: 0
Thanked 22 Times in 21 Posts
Rep Power: 2946
mjw930 has a reputation beyond reputemjw930 has a reputation beyond repute
Re: Is anyone running E-85 Gas in their WK2 V6?

Quote:
Originally Posted by vikingdave View Post
I found a detailed SAE certified study of that Saab turbo engine. It's a very complex study that can easily be mistakenly misinterpreted to show that fuel economy is similar on E85 and gasoline. Upon further explanation though, it shows that the engine did suffer significantly in terms of fuel economy on E85. They introduced the concept of "gasoline equivalent fuel economy" to account for the fact that E85 has less potential energy than gasoline. Basically they said that because E85 has less energy than gasoline, lets multiply the E85 MPG numbers to show what it would do on E85 if E85 had the same energy as gasoline. It's a silly exercise, that in the end can't overcome the basic problem with ethanol which is reduced energy capacity.
I had just found that same information, that's what I get for quoting someone else from another site without researching their source. Yes, it's a silly play on words and I can see how someone, myself included, could reach the wrong conclusion. It is, however, more likely that a boosted engine, with enough adjustability could narrow the typical 28% MPG gap but until the price difference is more like 40% it's an academic discussion here in the US.

Thanks for keeping me honest
__________________
2012 Grand Cherokee SRT8 Black/Black
Reply With Quote
  #32  
Old 02-16-2011, 05:50 PM
Premium Member
My Jeep: 2012 6.4L SRT8
 
Join Date: Dec 2010
Location: Ormond Beach FL
Posts: 1,544
Thanks: 0
Thanked 22 Times in 21 Posts
Rep Power: 2946
mjw930 has a reputation beyond reputemjw930 has a reputation beyond repute
Re: Is anyone running E-85 Gas in their WK2 V6?

Quote:
Originally Posted by hondurantaco View Post
If you're at high elevations, like in the Rockies or anywhere close... then getting E85 or E87 doesnt really matter. With the higher elevations.. the e85 burns just as normal because of the amount of oxygen in the air. But I always put in 87 because its a cleaner fuel. I only put in 85 when I'm down on money but with a gas treatment to go with it
I think you are confusing E85 (85% ethanol, 15% gasoline) with 87 and 85 octane gasoline.
__________________
2012 Grand Cherokee SRT8 Black/Black
Reply With Quote
  #33  
Old 02-16-2011, 06:00 PM
Member
 
Join Date: Feb 2011
Posts: 182
Thanks: 0
Thanked 4 Times in 4 Posts
Rep Power: 1499
vikingdave is on a distinguished road
Re: Is anyone running E-85 Gas in their WK2 V6?

Quote:
Originally Posted by mjw930 View Post
I had just found that same information, that's what I get for quoting someone else from another site without researching their source. Yes, it's a silly play on words and I can see how someone, myself included, could reach the wrong conclusion. It is, however, more likely that a boosted engine, with enough adjustability could narrow the typical 28% MPG gap but until the price difference is more like 40% it's an academic discussion here in the US.

Thanks for keeping me honest
I'm glad you haven't taken offense here. I'm an R&D guy by trade, so the whole thing just didn't add up to me, not that I have to be right, but I do need to understand things that don't make sense. I hate it when things are studied, and studies are manipulated if they don't show what they wanted to show. The Saab study basically showed that MPG suffered slightly less given the lower energy in E85 than you would expect it to. My suspicion is that they just spent much more time tuning the engine (timing, fuel flow, and compression) for E85 than they did for gasoline. Either way though, it did very poorly on E85 compared to gasoline.
__________________
Reply With Quote
  #34  
Old 02-16-2011, 06:14 PM
Premium Member
My Jeep: 2012 6.4L SRT8
 
Join Date: Dec 2010
Location: Ormond Beach FL
Posts: 1,544
Thanks: 0
Thanked 22 Times in 21 Posts
Rep Power: 2946
mjw930 has a reputation beyond reputemjw930 has a reputation beyond repute
Re: Is anyone running E-85 Gas in their WK2 V6?

NP,

Yep, here's the kicker from the SAE abstract that could confuse many:


Results show that the vehicle's gasoline equivalent fuel economy on the Federal Test Procedure (FTP) and the Highway Fuel Economy Test (HFET) are on par with similar U.S.-legal flex-fuel vehicles.

You could then look and the economy numbers and forget to notice it's represented a MPGe
__________________
2012 Grand Cherokee SRT8 Black/Black
Reply With Quote
  #35  
Old 02-20-2011, 01:22 PM
Member
 
Join Date: May 2010
Posts: 30
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1630
granto3k is on a distinguished road
Re: Is anyone running E-85 Gas in their WK2 V6?

Not that I really want this, but I have noticed several WK2's driving around lately that have the Flex Fuel badge on the back. Mine does not have this. Are all of the V6's flex fuel?

The ones that I have seen with the badge appeared to be rental cars so I'm wondering if the badge is a fleet only feature?
__________________
Reply With Quote
  #36  
Old 02-20-2011, 02:36 PM
Long Live the Graphite Ghost

 
Join Date: May 2009
Posts: 13,418
Thanks: 55
Thanked 132 Times in 114 Posts
Rep Power: 542637
robpp has disabled reputation
Re: Is anyone running E-85 Gas in their WK2 V6?

i can tell you that fot ther wk there was a VIN diff for the 4.7. some were flex and some were not. it adds some cost on as a few of the fuekl system components need to be a bit different IIRC. I have my window srticker if need be.

like ihave a P 7th VIN vs a x whatever the opther one is. my gas cap is yellow and the hole is open diff then a reg gas model.

so point is in 07 not all 4.7 were flex and you can tell by the VIN which is which.

i would assume the same for the 3.6.
__________________

__________________
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
Running board for WK2 wefwef Interior/Exterior/Visual 1 02-14-2011 04:01 PM
If Gas Were $5.00 Would You Still Buy a WK2? blankster Grand Cherokee - WK2 - 67 12-30-2010 09:53 AM
Not A SRT8 WK2 But A WK2 Speed Demon Review! NYCSRTATE Grand Cherokee SRT - WK2 17 12-04-2010 12:37 AM
running new exhaust jdcollins86 Engine Performance/Superchargers/Turbos 2 02-25-2010 12:30 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 02:38 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