4.7 vs 5.7

[kntr]

Is the extra 25 hp worth it?

2008 4.7 305hp

vs

2008 5.7 330hp

Has anyone driven the new 4.7/305 hp and 5.7 hemi.

[marcram]

You won't be saving too much on gasoline costs with the 4.7 due to the Hemi MDS (at least if you are a highway driver).

[JeepinJon]

I think that the 5.7 is also lighter than the 4.7. When I had the 4.7 in my Grand Cherokee I avereaged about 13mpg, and the new 5.7 is doing better than that.

[kntr]

Im talking about the new 08 4.7.

[4.7commander]

does the new 4.7 have MDS now?

i'd say if it does have MDS go with the 4.7L and save yourself some money.

i have the older 4.7L in my commander. it gets up and goes pretty good. i have driven a dodge 1500 with a hemi and i was not impressed. i'm not sure if it was the gearing or what.

[JeepinJon]

I don't think the 4.7 has MDS yet. The new one has been uprated on the power, but I think that the 5.7 is still rated with better power, and milage

[TRZ]

I have an '08 WK with 4.7L Gen II engine. If memory serves, this engine is 50 lbs lighter than the Hemi. I only have 850 miles on the vehicle (so it may not be fully broken in yet) and have pretty much gotten 14.5 mpg in city driving (not too many quick starts) from the start.

It's a smooth, quiet and powerful package. It does not have MDS. I've not driven an '08 Hemi, so I can't really compare to that, but compared to my 4.0L ZJ, it's got tons more power.

[kntr]

With only 25 hp difference, I can't see that you would feel much more power.

[TRZ]

With only 25 hp difference, I can't see that you would feel much more power.
I kinda feel that way, but some people spend hundreds of dollars upgrading their intake and exhaust systems to get every last bit of power from their engine, so some will opt for the Hemi.

Another point someone made on a different forum - there are more performance mods available for the Hemi than the 4.7L Gen I engine - vendors think people who want performance will have purchased the Hemi. So, if you want to leave open the prospect of future mods, you might want to spring for the Hemi.

[JeepinJon]

Have you tried the diesel yet? It is quiet, smooth, it doesn't take much to get tons of power out of them, and you can still get 20+ miles per gallon.

[4.7commander]

the commander doesn't have the diesel option yet. maybe next year?

one of the 4x4 rags did a test on the new dakota with the 305hp 4.7L, they said they were getting 21mpg going 75 on the highway. thats better then you get with the hemi, the MDS only works between 40-60 mph.

[JeepinJon]

Is this the last year for the Commander, or is it next year? I know I have heard that 2009 is the last year for the Commander, but I never heard if it was the 2009 model year was the last year, or they weren't making a 2009 model year.

[WKJeepster]

I have a 2007 5.7 and I love it. I get around 16 mpg in the city and about 18 - 19 on the highway. I went with the HEMI because I have to tow a 3000 lb boat, which it does quite nicely. The HEMI has incredible pick up between 50-70 mph even with the boat. The MDS is nice for the highway and clicks on un-noticeably when you need the power.

[WohlfordTL]

You will get better gas mileage with the 5.7 if it is lifted because it will drive the bigger tires more efficiently. i recently had a 6.1 put in my grand cherokee, i have a 4 inch inch lift and nitto mud grapplers and believe it or not, i get better gas mileage than the 5.7.

[Fos005]

You will get better gas mileage with the 5.7 if it is lifted because it will drive the bigger tires more efficiently. i recently had a 6.1 put in my grand cherokee, i have a 4 inch inch lift and nitto mud grapplers and believe it or not, i get better gas mileage than the 5.7.

Thanks WohlfordTL... that does make sense. Did your original 5.7 have MDS?

[Jdemonto]

The new 4.7 has very simular power to the hemi:

New 4.7:

305 hp

334ft lbs Vs

5.7 Hemi

330 hp

378ft lbs

Yes, I have driven both and there is not much difference between the two

[Ivanko]

Have you tried the diesel yet? It is quiet, smooth, it doesn't take much to get tons of power out of them, and you can still get 20+ miles per gallon.


I was thinking about a diesel GC before I changed directions and got my JK. The only thing that was holding me back was the fact that VERY soon (the industry was expecting it for the 08 model year) the GC will have a Bluetec diesel available, which has the best diesel technology in the market right now. When the Bluetec comes out, the current GC diesel engines will be much less desirable and inferior.

[TRZ]

I was thinking about a diesel GC before I changed directions and got my JK. The only thing that was holding me back was the fact that VERY soon (the industry was expecting it for the 08 model year) the GC will have a Bluetec diesel available, which has the best diesel technology in the market right now. When the Bluetec comes out, the current GC diesel engines will be much less desirable and inferior.

Eh? Bluetec just means it has urea injection which I believe will make it 50 state legal. In California you can't buy a new CRD, but you can buy one with 7000+ miles on it, so the lack of Bluetec (at least in Cali) should have minimal impact on resale value.

[Ivanko]

Eh? Bluetec just means it has urea injection which I believe will make it 50 state legal. In California you can't buy a new CRD, but you can buy one with 7000+ miles on it, so the lack of Bluetec (at least in Cali) should have minimal impact on resale value.

BlueTec is the way Chrysler is headed when it comes to diesel, not the current motor, which is a "fill-in":


"Diesel fuel sold in the United States contains large amounts of sulfur, and this sulfur content, among other factors, is what causes a diesel engine to run dirty with nitrous-oxide emissions. With Bluetec technology, emissions are reduced through the use of an oxidizing catalytic converter, a particulate filter, and what Mercedes calls a DeNOx nitrogen-oxide reducing system. DeNOx is the key here, a storage catalytic converter designed to treat engine exhaust gases before they are emitted from the tailpipe, and it reduces nitrogen-oxides by up to 80 percent. A reducing agent called AdBlue is injected into the gases contained in the storage catalytic converter, releasing ammonia which converts the nitrogen oxides into harmless nitrogen. The separate tank that stores the AdBlue is refilled whenever the car returns to the dealer for service.

To work properly, Bluetec technology requires the use of low-sulfur diesel fuel, defined as that with a sulfur content below 15 parts per million. This type of fuel will be available in the U.S. starting in the fall of 2006, but may not be widely available. Over time, however, the fuel will become the standard in North America, and DaimlerChrysler will be ready to capitalize on this with a fleet of Bluetec-equipped cars and SUVs wearing Chrysler, Dodge, Jeep, and Mercedes-Benz nameplates.

Bluetec arrives first under the hood of the 2007 Mercedes E-Class, but will be added to three Benz SUVs and the Jeep Grand Cherokee shortly thereafter. In the Jeep, DaimlerChrysler theorizes that the Grand Cherokee Bluetec could achieve a highway fuel economy rating of 25 mpg, allowing the driver to tread lightly with the land and the Jeep to tread lightly with the atmosphere. And in the future, DaimlerChrysler plans to connect Bluetec diesels to hybrid drive systems to create even cleaner, greener, and more efficient vehicles. Clearly, DaimlerChrysler thinks that diesel will power tomorrow’s cars in greater numbers, and Bluetec will be the instrument it uses to ensure success. "

[mikskillz]

has anyone run the 4.7 on E85?

[JeepinJon]

Currently the big debate with Blue Tec is wether or not the vehicle should be able to run when it runs out of the urea. Chrysler doesn't think it should just make the vehicle inoperable, and claims that this should be part of the routine maintenance, like an oil change, but as we all know there are independent shops, and even dealerships that will not complete this, along with the home mechanic. The states such as California do not want the vehicle to be able to run if this gets below a certain point, similar to how a vehicle will not run without gasoline. Until they come to an agreement on this item we will probably not see it released in the American marketplace.

[JeepinJon]

has anyone run the 4.7 on E85?

I know that I have test driven an E85, but I would never run E85 even though the engine could run it. It is only about 20 cents cheaper per gallon around my house, and on an average tank will get you about 100 miles less than normal gasoline. Just not worth it to me, especially with the new studies coming out showing the true enviromnetal impact of E85 when you factor in the production compared to normal gasoline.

[mikskillz]

I know that I have test driven an E85, but I would never run E85 even though the engine could run it. It is only about 20 cents cheaper per gallon around my house, and on an average tank will get you about 100 miles less than normal gasoline. Just not worth it to me, especially with the new studies coming out showing the true enviromnetal impact of E85 when you factor in the production compared to normal gasoline.

yea - i guess its definitely a balance between price and efficiency. Right now I'm looking at about $1.00 to $1.25 or more price difference per gallon. 87 Octane where i live is pushing over $4.05 a gallon and seems to be climbing 5 - 10 cents every couple of days - its insane. i have yet to see the actual price of the E85 near me so my numbers are based on national average on a site i found.

the other side of the coin as you stated is the true environmental impact. I would like to learn more about that - my problem is i never believe anything i hear on Tv or read on the web. You just never know the intentions of the people presenting the information - maybe I'm cynical.

Another factor i consider - which again i would like to learn more about - is where is the money i spend on E85 actually going compared to the money i spend on regular gasoline?

This is how i see it - if the price is equal to or less then gas, the money is staying in this country and the environmental impact is less then regular gas then its worth it. Maybe I'm stating the obvious and again i would like to learn more about these factors. I guess its research time.

[JeepinJon]

I know for regular gas we are importing over 60% from Canada, American's actually get very little from the Middle East.

On another intereseting note I was watching an interview with the CEO of Exxon Mobil and he said that it is all about supply and demand, and he has actually seen a signifigant decrease in demand so far, but that on the world market the demand is getting stronger as other countries such as China become wealthier, and their citizens are able to buy cars, and vehicles that they were unable to in the past. I know many American's including myself only looked within our borders to see what was going on, and not outside of the borders. Also I found it interesting that the oil companies are oftentimes criticised about the profits they make compared to the price, but when compared to other Fortune 500 companies they really aren't making that much money in relation to the expenses. Most companies try to make 30 cents in profit from every dollar of expense, where most oil companies are making less than 10 cents on every dollar of expense. I know this was kind of off topic, but I don't like to see the price at the pump, just like most people, but there are always two sides to the story.

[TRZ]

Interesting (and totally plausible) explanation on what's taking Chrysler so long to come out with the Bluetec version of the CRD. Talk about overregulation!

Regarding E85 - I run it as much as possible. Making ethanol out of corn is a bit wasteful - it takes a lot of fuel to plant, grow, harvest and distill the corn into ethanol and then truck it to the outlets (there are no pipelines for ethanol, so we're stuck with shipping it which is a much less efficient way to distribute). But that's just version 1. Version 2 will be ethanol from biomass which will cost less fuel to produce. Version 3 will be ethanol from enzymes, which is the (current) ultimate goal. There's a pilot project now where biofuel is being created by enzymes in (big) plastic bags in the desert. The enzymes consume C02 (fed to them by a nearby powerplant) and use photosynthesis to produce biofuel. Now THAT'S pretty efficient!

You can find statistics that claim E85 is from 0-50% efficient (creates 0% to 50% more fuel that it uses). Again, that's just based on current technology. I use E85 to spur investment in newer more efficient technology.

[mikskillz]

this is all really good insight and greatly appreciated.

I too also heard that its the worlds demand that is driving the gas prices up - not our countries demand.

Prices aside - w/ the amount of fuel my grand uses running 33" KM2s - i would feel much better if i knew i was burning something that was better for the environment - which was my motivation in getting the flex fuel motor over the HEMI.

Recently i have learned about other impacts that E85 is having not only on the environment but to our economy as well in the form of raising food prices.

I'm have no problems w/ American farmers getting rich as long as its not at the expense of people who can barely make ends meet.

It seems to me like its the same story w/ any (or most) new technology - growing pains in geting it to a real viable form. I agree w/ you TRZ - i think i will try to run it as much as possible to help move the evolution along and hopefully get to that 3rd version you spoke about.

My plan is to start next week w/ a full tank of E85 and compare the milage and price to gas.

[JeepinJon]

I know that the second version of ethanol seems to be just a few years off the horizon. At the moment they have developed a new strain of the ecoli virus that can break down wooded biomasses that currently go into the landfill into an alchohol that can be used to create ethanol. My concern with this is the government and the lobbyists for the farmers since it seems like much of the economy is all about the money, and this is making the grain farmers rich, and driving meat farmers and dairy farmers out of business. I know the technology is rapidly advancing, but farmers will not give up on this without a fight. I think that until the technology is fully there to create the ethanol from the corn husks and stems, the farmers are going to be very resistant.

[somewhereinla]

Ethanol has no long term future whatsoever... It's politicians basically trying to solve a problem and potentially creating a much bigger one. Since ethanol basically rely on our food supply, the result is basically going to lower the cost of gas (slightly...ethanol is still expensive to make) and rising the cost of food and potentially create famine since many country in the world rely on the U.S surplus of corn, rice and soy to eat... Furthermore, the second problem which Brazil is deeply confronted with: the deforestation necessary to maintain an ethanol base economy which in turn contribute a great deal to the warming of our planet. Ethanol is just the stupidest solution for our long term energy. I think our country should follow France's energy model. France produces over 90% of it's energy with nuclear,they also use a different process than the US, which allow them to recycle the waste into more usable energy... Of course solar is a big one as well... And for our cars, until hydrogen can become viable, Diesel is still the best alternative, we have the technology, the Europeans make very efficient engines, and Diesel can be made from coal which is plentiful in the U.S. and doesn't affect the food chain.

[JeepSauce]

Seriously though 4.7/5.7, is there really any difference, guys? :cool:

[JeepinJon]

Seriously though 4.7/5.7, is there really any difference, guys? :cool:

The 4.7 is heavier then the 5.7, and the 5.7 puts out more power, and gets as good of if not better fuel effeciency since it has the MDS, and the 4.7 does not.

[mikskillz]

Ethanol has no long term future whatsoever... It's politicians basically trying to solve a problem and potentially creating a much bigger one. Since ethanol basically rely on our food supply, the result is basically going to lower the cost of gas (slightly...ethanol is still expensive to make) and rising the cost of food and potentially create famine since many country in the world rely on the U.S surplus of corn, rice and soy to eat... Furthermore, the second problem which Brazil is deeply confronted with: the deforestation necessary to maintain an ethanol base economy which in turn contribute a great deal to the warming of our planet. Ethanol is just the stupidest solution for our long term energy. I think our country should follow France's energy model. France produces over 90% of it's energy with nuclear,they also use a different process than the US, which allow them to recycle the waste into more usable energy... Of course solar is a big one as well... And for our cars, until hydrogen can become viable, Diesel is still the best alternative, we have the technology, the Europeans make very efficient engines, and Diesel can be made from coal which is plentiful in the U.S. and doesn't affect the food chain.

This is what i mean by i never believe what i read or see on Tv. How can i know if your right on this? I'm not saying your wrong - i'm just simply possessing the question - what do i believe? and i don't expect an answer

The answer is i need to do my own research and draw my own conclusions but who has the right facts?

What is the correlation btwn ethanol and deforestation? I admit i am not as knowledgeable about this as i would like but i have a hard time making that connection.

Can't ethanol be made from sugar? Isn't that what Brazil is doing? That would greatly reduce the impact on food supply, no? It seems to me that ethanol, if done right, has the potential to be a very viable long term solution because it is renewable - diesel is not. Its up to our elected officials to make sure its done right - and thats the part that scares me.

As far as comparison btwn the 4.7 and 5.7 - i have no experience w/ the 5.7. What i can say is that even running 33's the 4.7 has PLENTY of power. I can cruise at 80 and be well over 90 in no time. My WK hums at 80 on the highway. i feel a difference in performance btwn the new 4.7 and old 4.7 even w/ my old 4.7 running stock sized wheels.

My 1 disappointment right now in the performance of my 08 WK is in throttle response (which i believe is now electronic) - very slow (my wheels could be a contributer - not sure) I have never driven a stock 08 w/ the new 4.7 - i also had the same opinion in my 99 WJ w/ the 4.7.

I would assume the 5.7 has the same throttle response but i am unsure - just an assumption.

[TRZ]

My 1 disappointment right now in the performance of my 08 WK is in throttle response (which i believe is now electronic) - very slow (my wheels could be a contributer - not sure) I have never driven a stock 08 w/ the new 4.7 - i also had the same opinion in my 99 WJ w/ the 4.7.


When new, my 4.7 Gen II seemed to have a wierd throttle response - sometimes seeming to hesitate. After 5 K miles (and installing 33" tires) that problem seems to have gone away. Either I have gotten used to it, or the computer has learned and has taken out the hesitation

One thing to keep in mind - the power curve changed with the 4.7L Gen II, you need higher revs before the power kicks in. Sometimes it almost feels like turbo lag - press the gas, accelleration is slow to begin with, but when you reach 3K rpm, the power kicks in.

[mikskillz]

When new, my 4.7 Gen II seemed to have a wierd throttle response - sometimes seeming to hesitate. After 5 K miles (and installing 33" tires) that problem seems to have gone away. Either I have gotten used to it, or the computer has learned and has taken out the hesitation

One thing to keep in mind - the power curve changed with the 4.7L Gen II, you need higher revs before the power kicks in. Sometimes it almost feels like turbo lag - press the gas, accelleration is slow to begin with, but when you reach 3K rpm, the power kicks in.

that actually explains alot - thanks - i only have 900 miles on it right now

[jared]

i for 1 would prefer the hemi. i work at a dealership as a tech. the 5.7 is quite easy to work on and a very stout engine.

this would be my engine of choice for performance mods and building for power.

but if its a lease vehicle or will remain stock. either is fine.

[mikskillz]

i for 1 would prefer the hemi. i work at a dealership as a tech. the 5.7 is quite easy to work on and a very stout engine.

this would be my engine of choice for performance mods and building for power.

but if its a lease vehicle or will remain stock. either is fine.

With the lifetime warranties now, are there any dealer installed performance mods we can have done to either motor that will keep the warranty intact?

[jared]

With the lifetime warranties now, are there any dealer installed performance mods we can have done to either motor that will keep the warranty intact?

i don't see why not. any mopar accessory is warrentied when installed by a chrysler dealer.