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  #49  
Old 09-29-2012, 12:58 AM
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Re: Possible trade for a WK2 Hemi, need advice from hemi owners

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The part I'm not so sure about though was, look at all the great new tech on the V6, the Hemi looks like a dinasour next to it. Yes, it produces more HP and torque then the V6, but, the V6 has alot more potential still, and if they used the same new tech on the V8, then maybe it could be a 4.5 liter V8, and produce 400 HP and 400 FT, AND get over the 20 MPG hump, share the same maintenance schedule the current 3.6 liter does, AND Then I would buy one!
Again you are mistaken. Displacement != size. They could absolutely produce a lower displacement engine that makes more horsepower. But that engine would not be lighter and it would not be cheaper and because of the smaller dispalcement it would have less low end torque.

It's just a different solution to a problem - of how to motivate a truck. There is nothing magical about DOHC engines - they had them in the 1920s. Peugot had a DOHC engine in 1925.

With a big pushrod engine it will make more power all through the rev range - only in the high revs will a DOHC pull ahead. You don't want or need a high reving engine for a truck. From a strictly mechanical point of view a pushrod engine is a great choice for a truck.

ICE engines have been around for a very long time now. Yes pushrod engines are antiquated - but so are DOHC - and so are electric ones as well. They had electric cars in the 1800s!

Calling Pushrod engines antiquated just means you are victim of marketing.
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  #50  
Old 09-29-2012, 11:09 AM
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Re: Possible trade for a WK2 Hemi, need advice from hemi owners

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Originally Posted by Smooth1 View Post
The part I'm not so sure about though was, look at all the great new tech on the V6, the Hemi looks like a dinasour next to it. Yes, it produces more HP and torque then the V6, but, the V6 has alot more potential still, and if they used the same new tech on the V8, then maybe it could be a 4.5 liter V8, and produce 400 HP and 400 FT, AND get over the 20 MPG hump, share the same maintenance schedule the current 3.6 liter does, AND Then I would buy one!
I'm not quite sure what you're getting at here.

The 3.6L is an OK engine, but its totally lacking in torque. It truly makes the Jeep feel sluggish and cheap, it's not able to move around with authority like the Hemi allows it to. Going up hills with the 3.6L is a VERY demeaning affair to what's supposed to be a higher end vehicle.

And that's due to its construction. While not as bad as GM's absolutely TERRIBLE new V6s, the Pentastar isn't as torquey down low as Ford's V6s, and so you have to spin it up to make your power. Yes it allows for higher fuel economy when driven in a precisely controlled manner, but in average driving you won't see much if any benefit to economy.

I'm not sure where you're getting the idea that the Hemi is expensive to maintain. Yes, the plugs get changed at 30k miles and there's 16 of them. But, they're cheap copper plugs that can be bought anywhere for like $1. The plugs on my old car were $16-25 each, there were 6 of them, and they lasted 100k miles. I'll let you do the math on which one costs more to put plugs in.

As others have alluded to, DOHC engines make power up top, and are typically lacking down low, making them feel less powerful in normal driving. I don't think I would have bought my Overland with a DOHC engine, unless it was one of those fwe DOHC Turbo mills that actually produce prodigious torque down low. Having to rev your engine to 3-4000 rpm just to get up a hill isn't luxurious at all, and that's what would have had to happen with any pentastar derived mill.

I think the Hemi is a great engine, it's powerful around town, and quite fuel efficient as well. I got 24mpg highway when I was down in Florida, and mine's as heavy and high drivetrain loss as they come. IMO, it's VASTLY superior to the Pentastar, despite being older.
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  #51  
Old 09-29-2012, 12:22 PM
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Re: Possible trade for a WK2 Hemi, need advice from hemi owners

Man, what you guys are saying isn't anything near what I'm studying at Mid Florida Tech. Do you guys have real mechanical backgrounds or are you just opinion punching?
Here's a small cut and paste of the intro out of one of the course studies:

07 May 2010 | JDavis
Mercedes-Benz is setting previously unachievable efficiency standards in the premium segment with completely newly developed V6 and V8 engines. The new V8 engine has a displacement of 12 percent more than its predecessor despite less overall displacement. Torque has also increased fby no less than 32 percent while fuel consumption has been reduced by 22 percent.

With the same displacement as its predecessor, the new V6 engine develops 306 hp. Torque has increased by 20 Nm to 370 Nm. As with the V8, the improvement in fuel efficiency is remarkable, the S 350 equipped with the new V6 engine consumes 24 percent less compared to its predecessor. Mercedes-Benz has achieved this considerable leap in efficiency with the use of features such as newly developed, third-generation direct petrol injection with spray-guided combustion, multiple injection and multi-spark ignition.

(In case there are some conversion challenged readers, 370 Nm converts to 273 Feet Pounds of Torque. That's only 17 less than a motor twice it's size.) And then look at what you get in a real V8 motor further below.

While the new V8 is based on its predecessor and has the same distance between the cylinders, it has undergone substantial reengineering in every respect. For example, it has a 15-percent smaller displacement (4663 cc rather than 5461 cc) but generates 429 hp and therefore around 12 percent more output than the preceding unit (382 hp). It’s estimated that this new engine will achieve a fuel economy improvement of 22 percent. CO2 emissions have likewise fallen by 22 percent – an outstanding improvement for this performance class. At the same time torque has been raised from 391 lb-ft to 516 lb-ft – an increase of 32 percent.

(Translation: They took a 5.5 liter and made it a 4.6 liter, and the fuel efficiency went up by 22%, and now makes 429 Hp instead of 382 hp, (How much does the 5.7 liter make again?), and creates 516 feet pounds of torque from 1800 rpm, which is up from 391 feet pounds of torque, which is still 100 feet pounds more than the current Hemi in the old version!)

Key figures for the new V8 engine

No. of cylinders V8
Displacement (cc) 4633
Bore (mm) 92.9
Stroke (mm) 86
Compression ratio 10.5:1
Output (hp at rpm) 429 at 5250
Torque (lb-ft at rpm) 516 from 1800-3500

Also, the factory authorized maintenance schedule on this motor, is 15,000 miles or 1 oil change per year intervals. Lifetime spark plugs, and lifetime transmissions. So it's cheaper to own also.

This is an under 5.0 liter motor. Same people that designed the rest of the Jeep. And why the Jeeps are only $50K. Now if this motor was in the Jeep, I'd get it, and the lifetime warrentee, and I think I'd just drive it until they put a gold plate on the hood with "Here lies the dearly departed....." and buried me in it.
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  #52  
Old 09-29-2012, 12:47 PM
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Re: Possible trade for a WK2 Hemi, need advice from hemi owners

And you guys should see the new tech coming from Japan! What they are doing with direct injection and cooled cylinder sleeves to create high compression turbo charged systems, man...... a V6 motor, FROM THE FACTORY!>>>Nissan GTR. That motor and drivetrain is engineering excellence, and you can have one for under $80K. Realistic technology that could be used in a Jeep like ours, and the SRT version wouldn't be much more than the price they are asking now....and I would get one.
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  #53  
Old 09-29-2012, 01:35 PM
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Re: Possible trade for a WK2 Hemi, need advice from hemi owners

Guys...all of this is moot. The MB engines are very nice, but I drove a nice new MB 450 with the smaller V8 and so what? The Overland was nicer and felt stronger with more torque and a more capable 4X4 system.
Almost all of the competition CAN'T go offroad. Most SUVs are just big AWD cars, but the Jeep, Land Rover and Toyota Landcruiser are different. So even the V6 jeep Overland is more capable that most any SUV.

I agree 100% though that the GC feels hampered by the V6. Many of us who bought expensive SUV's did not buy them to worry much about MPG. 20-23 MPG highway for a 5300 lb truck is pretty darn good and it needs the Hemi.

Enjoy what you got!


Robert
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  #54  
Old 09-29-2012, 01:58 PM
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Re: Possible trade for a WK2 Hemi, need advice from hemi owners

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Originally Posted by Smooth1 View Post
. The new V8 engine has a displacement of 12 percent more than its predecessor despite less overall displacement.

What does that mean? How can it have more and less displacement at the same time. My education must be lacking.
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  #55  
Old 09-29-2012, 02:58 PM
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Re: Possible trade for a WK2 Hemi, need advice from hemi owners

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Originally Posted by Smooth1 View Post
Man, what you guys are saying isn't anything near what I'm studying at Mid Florida Tech. Do you guys have real mechanical backgrounds or are you just opinion punching?
Here's a small cut and paste of the intro out of one of the course studies:
I've got an actual engineering degree

What you're missing in that whole article is the turbos. The new MB mills are turbocharged, with very small turbos not unlike the EcoBoost tech that Ford has licensed, and BMW's turbo mills. That allows them to spool up nearly instantly, and be in boost ALL THE TIME. This is great for marketing, you get high hp numbers and high mpg numbers when driven to achieve them. But on the road, when you're in boost, you're using gas. It's very easy to not get near EPA estimates with an engine like this, as the amount of fuel used is very dependent on how much power you're requiring.

When you drive those cars, and stay out of the boost, they're sluggish. It's difficult to do though, because the turbos are very small and spool up nearly instantly.

Take anything "lifetime" with a grain of salt. What is the "lifetime" they're referring to? Is it the typical 3 year lease most MBs live with their first owner? Is it a 3 year lease followed by a 5 year loan? Is it 12k a year, 25k a year, 35k a year? Are these magical "lifetime" spark plugs a lifetime of 100k as other manufacturers have? And is that 15k oil change because it takes 12 quarts of synthetic oil?

There's definitely some cool tech out there, but the cost is insane. The GTR is creeping ever closer to $100k. The MBs are a $15k+ premium over a Jeep. And those new tech ideas don't always work out so great. Ask anyone who had one of the first 335i about their HPFP, it was a big ordeal.

FWIW: The Pentastar has none of that cool new tech you were talking about.
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  #56  
Old 10-01-2012, 06:54 AM
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Re: Possible trade for a WK2 Hemi, need advice from hemi owners

^^
a very convenient forget of the turbos at that. People forget that turbos go bad (and quick) if maintenance is not followed correctly and they are not cheap to replace. Seems like smooth1 got himself caught up in the marketing mumbo jumbo from MB.

Could chrysler get hemi #s from the 3.6 with turbos, probably pretty close, it depends on how much you want to do the engineering ($$). A hemi option doesn't add that much to the base price, in a business case, it does an admirable job.

DOHC/variable timing only lets your engine do different things, it might widen a power band but how often do you run your jeep at 5K+?

Lifetime spark plugs, I'd prefer to remove/replace them now and again so you can get them out when you have to.
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Old 10-01-2012, 09:27 AM
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Re: Possible trade for a WK2 Hemi, need advice from hemi owners

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Originally Posted by neiltb View Post
^^
a very convenient forget of the turbos at that. People forget that turbos go bad (and quick) if maintenance is not followed correctly and they are not cheap to replace. Seems like smooth1 got himself caught up in the marketing mumbo jumbo from MB.

Could chrysler get hemi #s from the 3.6 with turbos, probably pretty close, it depends on how much you want to do the engineering ($$). A hemi option doesn't add that much to the base price, in a business case, it does an admirable job.

DOHC/variable timing only lets your engine do different things, it might widen a power band but how often do you run your jeep at 5K+?

Lifetime spark plugs, I'd prefer to remove/replace them now and again so you can get them out when you have to.

Ford is getting better than Hemi numbers from the 3.5L EcoBoost. Granted, Jeep engineers will seriously jack up the programming and make it useless, but it is possible.

Turbo's are reliable now, they used to have a short life but I ahve not seen that lately. There are a ton of factory cars runnign around with turbo's and not having any issues.

I do like my V8 though, I think Jeep should turbo the Hemi, that would be fun.
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  #58  
Old 10-02-2012, 11:11 AM
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Re: Possible trade for a WK2 Hemi, need advice from hemi owners

The turbos are only on the V8. And the technology and life of the turbo systems they are using far exceed what they were able to achieve just a few years ago. Which brings me to my point again. They used a state of the art chassis, and then put a dinasour motor in it to keep it cheap. So can the engineers here explain the V6 numbers that just about match the Hemi numbers? That was really my point. Chrysler only has a V8 Hemi to compete with just about everyone else's V6's today.
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Old 10-02-2012, 11:49 AM
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Re: Possible trade for a WK2 Hemi, need advice from hemi owners

Pushrods v6 < DOHC v6 < pushrods v8 < DOHC v8

</thread>
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Old 10-02-2012, 12:48 PM
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Re: Possible trade for a WK2 Hemi, need advice from hemi owners

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Originally Posted by 77rednecktruck View Post
Ford is getting better than Hemi numbers from the 3.5L EcoBoost. Granted, Jeep engineers will seriously jack up the programming and make it useless, but it is possible.

Ford can jack up the numbers at will with the stroke of a pen, and often have. Its called marketing, not engineering. As I've mentioned before, my neighbors 3.5 ecoboost is a POS gutless toy, useless off road. He will gladly trade up to a V8 Hemi.
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