why is it that in re the 04 Durango the hemi has significantly less payload and towing capacity than its less hp and torque v8 counterpart?

 

detuned to meet EPA requirements.

 

detuned?

the hemi has the most hp and torque of the V8 options but the least payload and towing capacity of them....

how is that from detuning? if it were detuned wouldn't the hemi have LESS hp and torque?

 

My bad missunderstood your question...The Durango as compaired to the other vehicles may have less of a curb weight?? I dunno..I would need to do some research.

 

wrong section.

 

the hemi is just a merketing name for dodge

 

Towing capacity has nothing to do with teh motor in a truck, everything to do with the fram that the vehicle is built on, and the suspension used with teh vehicle. A Ford F-250 SD and 350 SD have the same choices for motors, but the 350 can tow more weight, only becuase it has an extra leaf on the rear axle.

 

No, its not. The Hemi motor has a hemispherical combustion chamber, like the original Hemi motors, used by Chrysler in the 60's. That shape for the combustion chamber produces more power than any other that is currently known about, since it has the most even combustion.

 

If that is the case then how come it isn't used more?

 

they got the best ad campaighns on TV, I crack up every time I see that hill billy white boy, " is that a hemi?," "your bout to find out..."

 

riiiight

its a marketing name for dodge

they were never as well known as they were when the hemi motors were in their cars. now we all know dodge's suck so they have to somehow keep their name alive. therefore re-inventing the hemi name

thank you drive thru

 

what do you guys think of the new Durango...I think its kind of wierd

What other comparable V8 counterpart were you talking about?

 

Gilgamesh's explanation is correct!

As far as marketing: You use what you can can to sell your product. You may not like MoPar products, but that doesn't change the fact that hemi refers to the engine's head design.

If the Dodge engine didn't have hemispherical combustion chanbers, it's wouldn't be called a Hemi.


BTW: Chrysler has been producing hemi's since 1951: http://www.classichemi.com/index1.shtml

MoPar has ALWAYS been known for their Hemi engines. Ask any muscle car fanatic "who produces the hemi." They'll tell you without hesitation. Keep in mind that hemi engines were purposely limited in production. Not like today's engines.

 

haha, you are such an idiot

 

riiiiiight......

 

:noob: God some people ....it refers to the head design, as dustbuster (and I) said. More people don't produce it becuase Chrysler Corp. (or DiamlerChrysler if you will) has ALWAYS owned the rights to that head design, since they patented it when they invented it. It is far more than just marketing, my friend, they simply choose to use that design to market the motor. That motor will be in many forthcoming cars from DC...they already have it planned to go into the Dodge Magnum, if it makes it into production, and they have other plans for the car as well.

NEXT!!

 

Hemi's are also frequently called "elephants" .Back when I was in high school a buddy had one of these things in a Challenger .Back then the muscle cars were just old used cars and his was a bit rusty and the badges were gone .When he showed up with it I was like WTF is this POS rust bucket .He grinned told me to get in and drive .Hemis have a weird noise to them ,hard to descibe but to a novice set of ears the engine (not the exhaust note) sounds broken .Well I drove the monster without knowing what was under the hood though the pistolgrip Hurst shifter should have been a dead giveaway. To put things mildly after revving this thing to 3 grand and sidestepping the clutch there was absolute pandemonium under the hood and at the rear axle as the rear tires evaporated into billowing white clouds .The bellowing exhaust note and ensuing rush of acceleration was enough to convince me that even though it was tinged with rust this Challenger was special indeed .Well we drove around for a bit and finally i had to go look under the hood .All you can see is wall to wall engine .The valve covers are big enough to qualify as small houses .It was an amazing piece of machinery from a time long ago .We had a lot of laughs with that monster .I never saw my friend or the car after high school again but the memory of that rocket ship is still clear as a bell .

Jens

 

sounds like an episode of "the wonder years"

 

are you reminiscing(sic) wayne?

 

They may own the rights to "hemi" but everybody makes a hemispherical shaped head as opposed to a wedge.

Every DOHC is a hemi. Even toyotas 20r that came out in 1975 was a hemi.

Looking at the bottom of the head a wedge looks like OoOoOoOo all valve in line. a hemi looks like
0 0 0 0
o o o o

In the muscle car days Hemi meant you had the baddest car on the road, today it means almost nothing. True it has a hemi but I agree it's a marketing thing.

 

The 426 Hemi is a magnificent engine. My grandfather has a HemiCuda (not original) that I've gotten the pleasure to drive some. I'm supposed to inherit the car, altho I'm in no hurry. Jens is right about the sound. It's just different. The white cloud can't be mistaken either. I don't know a damn thing about the new Hemi's, but I doubt they are the same. They are too emissions friendly to be as much fun. Not to mention it's in a damn heavy ass truck.

Gilgamesh is partially right. The hemispherical combustion chamber produced more power that was actually concievable at the time. In the 50s, most motors were of the flathead design. This limited valve size and the flow of air as the valves were parallel to the combustion chamber. The Hemi had larger valves, pushed more air in and out and kept all of the heat right where it should have been - it didn't allow cooling like the flathead did as there was a much smaller surface area inside the cylinder. It was simply a more efficient engine. It started as a 331 in 1951 and had 180hp, which was unheard of at the time. By the mid 60s, the 426 was out and made the Hemi quite famous, winning 1st, 2nd, and 3rd in the 1964 Daytona 500. The main reason that this design isn't used widely today is because there are simply better designs. Most engines today use a pentroof design. Hemi engines CAN NOT have more than two valves per cylinder. The angles would be nutz, you just can't make the heads. In race appications this isn't as much of a limitation as it is on the street. The pentroof design is based on straght angles and can handle as many valves as can be stuck into it's size. Pentroofs still follow the reasoning behind the Hemi, and actually can become more efficent due to the fact that they can be made very small and allow even less heat loss.

 

Nope, most are pentroofs, the angular cousin of the hemispherical.

The wedge design is a flathead that just has a triangle shape on top so the valves can migrate to the top instead of the sides. Many truck engines and OHV pushrods are still like this. All two valves per cylinder.

It's def a marketing thing now.

 

You must have read "how stuff works"! LOL. OK DOHC's are pent roof but they even call it a "pentroof hemi".

A wedge and flat head are two totaly different designs. I was talking about B-series, smallblock Chevy's and similar engines having wedge type heads (which are OHV).

Those pictures a very exagerated. They make it seem like the "Hemi" combustion chamber is half a sphere. Dodge 426 Hemi was not a true hemi, the new magnum is even less of a hemi.

 

Um no.

It's because it uses hemispherical heads & pistons to match...

 

I see others have already hit the technology side

 

dodges suck? Don't they have that new SRT4 and SRT10 (Ram and Viper) models out this year?

I suppose everyone else has already explained the hemispherical chamber concept to you so I'll save my breath.

For a noob you sure do have a lot of dumbshit comments to make.

 

to you and Siggy.

Talk shit if you want, and I personally do not like the Dodge trucks (the new ones are nice thoug) I am a Ford man...they are good trucks, and I lust after either SRT-10 model.

 

o yeah and the tow capacity has everything to do with the frame and the suspension setup and how strong it holds up. The new Ford F150s seem really impressive so far as tow capacity goes.

 

um whatever cant wait until the srt -10

 

God I'm terrible when I try and type fast.

 

Don't forget the slightly heavy duty-er (? lol) axle and the two extra wheels/tires. That's how it handles the extra weight, as they both tow the same amount from the hitch.

 

'preciate all the info people. i understand the role the frame design and suspension have to play in towing capacity. but my qustion is (sorry for being unclear thus far), the 04 durango with HEMI {5.7L V8 / 335HP / 370lb/ft of torque} has less towing and payload capacity than an 04 durango with just the basic V8 {4.7L V8 / 230HP / 290lb/ft of torque}....can they change the chassis set up that much to much such a difference?

but it hink jens answered my question...i suppose the hemi is heavier than the 4.7L thus reducing payload capacity

 

Actually you can only really use a true hemispherical designe combustion chamber on a 2 valve head. BMW used to use it in all their 2v engines. and may still if they have any 2v engines. Once you go to a 4v engine, you can not get the hemi chamber without extremely complicated valve gear. Honda did it in some of their dirt bikes in the 80's. They could angle 4 different valves at 4 different angles in to create a hemi chamber by using a series of oddly angled rocker arms etc. So now engine design has evovled to using intricate port and runner shapes to creat turbulance in the intake charge to get efficient combustion with valves set at just 2 angles and a low included angle for a flat, compact chamber.

End of lesson

 

Very Well put...

 

Haha! Beat ya to it!

 

I was talking about the single Wheel 350...with Ford, you can get the 350 with only a single rear wheel, which does tow less than the duallie 350, so yes that does add some capacity as well.

 

"SWEEEEEEET"

 

yes

 

I don't know about Dodge trucks but I know that Chevy blazers can have either leaf or coil springs depending on whether they have 4wd or rwd. Also Ford pickup & Expedition vary by suspension setup (live axle vs. indep rear suspension). If there are two suspension setups the leaf spring setup usu can handle more weight same goes for a live rear axle. that's why all eighteen wheelers have live axle & leaf springs.

 

Here is a good article on the Hemi Engine:

http://auto.howstuffworks.com/hemi.htm