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Out for a couple drinks yesterday and got into a discussion with another customer. They loved my Challenger R/T but told me they are not true Hemis. I told them they are and the engines combustion chamber is hemispherical . Therefore it is a true Hemi.....Am I wrong?

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Paul :scratchhead:
 

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They do not have hemispherical combustion chambers because modern engineering has developed far better designs. HEMI is a famous trademark used for powerful V8 engines and the cars they go in to.
 

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Your friends are technically correct. But I'd argue today's HEMI is as much HEMI as a modern Mustang 5.0 is a "5.0".

As Danner points out, the history and legend of the HEMI name has turned it into such a mythical brand, that inspires much owner pride --and the inevitable envy implicit in your drinking buddies' veiled questions .
 

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Yep...it's a Hemi

Yes its the gen 3 HEMI... No sense in splitting hairs

Read this:
A tale of two Hemis: Chrysler's 5.7 and 6.1 V8 - Autoblog

This argument has proponents on both sides.. The valve angle and layout and combustion chamber shape all have something to do with it....
I was about to post the same link:

Article Quote:

"Squabbling about the chamber shape neglects the most important attribute of the Hemi design - the valve placement. We'll get to the importance of that in just a moment, but suffice to say that this new Hemi deserves to carry the name."
 
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Out for a couple drinks yesterday and got into a discussion with another customer. They loved my Challenger R/T but told me they are not true Hemis. I told them they are and the engines combustion chamber is hemispherical . Therefore it is a true Hemi.....Am I wrong?

Thanks
Paul :scratchhead:
You're not wrong. None of the Chrysler three generations of hemi v8s is a true hemi. They're more like a "quarter-spherical", not a "hemi-spherical". The gen1 (Firepower/Firedome) engines have the widest angle between intake and exhaust so I guess you could call them the "purest" of the hemi's. However, they all have a common (and rare for 2 valve engines) valve layout: Intake and exhaust in a common plane perpendicular to the crankshaft centerline (and twin rocker shafts). In fact the only other 2 valve v8 I know of that shares that valve geometry layout is the 427 SOHC Ford. The gen3 and some gen2 cylinder heads also share a rare trait for 2 valve engines: twin plugs.

Most importantly all three generations share one more trait: extremely high airflow potential for both intake and exhaust ports. At the 2014 NHRA race in Gainsville a 427 COPO Camaro ran a 9.15 in Factory Stock/B class, indicating the engine was making probably more than 800 hp. A very good number and we all admit these LS1 series Chevrolet engines are very good. However at the same race David Barton ran an 8.76 in the same class in a Drag Pack Challenger with a GenIII 7 litre hemi, which indicates the G3 hemi possibly in the 900 hp range. Both engines are allowed essentially the same compression ratio and valve lift.
 

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They do not have hemispherical combustion chambers because modern engineering has developed far better designs. HEMI is a famous trademark used for powerful V8 engines and the cars they go in to.
Correct, new Gen head chamber is more closely related to a 1966 318 Poly head, than a 66 426 Hemi head.
 
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I'd disagree with that.. The 318 poly I think had the plugs on the side of the chamber... On the outside if the exhaust valve. Not at the top between the valves like the HEMI
 

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Correct, SRT Blubyu...the poly is a distinct cross-breed stage between a wedge head and hemi head design. It allows for some offset in the valve orientation, but driven by a standard valve-actuation of a wedge head design. The Gen 3 has nothing to do with that, in the same sense that a Gen 2 has nothing to do with that.

The Gen 3 Hemi shares the valve actuation concept of the Gen 2 Hemi (though not down to the millimeter in physicality, of course). More or less, canted-valves oriented across from each other and actuated using 2 rocker arms as pivot points (one for intake and one for exhaust). Both valves intersect perfectly on an "imaginary" spherical geometry/surface (which does not necessarily correspond to the actual surface of the cylinder head...that's where people get really tangled up on what this is all about). It is that natural orientation of the valves on this surface, combined with the physical spherical surface (whether in whole or part) inside the cylinder head that makes it flow so well...it is essentially bespoken by Nature, herself, the way it all lines up. Of course, it is going to flow good.

I was just going to post in to note that it is good to see many responses here recognizing the updated distinctions that make something qualify as a Hemi. :thumbsup:

My answer was going to be...this is topic has been discussed ad nauseum in the past, and the best answer that can be offered is that they are all marklar. :p Someone above already astutely noted that not even the Gen 2 Hemi (i.e., the legendary 426 from decades past) qualifies as a "true Hemi" under prevailing purist definitions, hence the attempt to make any meaningful distinction that separates the Gen 2 vs Gen 3 is largely moot. Either they both are good enough to be considered Hemi's, or they are both just "trying" to be Hemi's and missing the boat. So the easy answer to it is that they are both good enough to be under the Hemi brand name, and let's be done with it. ;) They are both a distinctly different type of animal from the more common wedge head design. If they were just wedge designs, Dodge could just have called them Magnums, and been done with it.

On the subject of an actual Poly design, I think Dodge does have one in one of their other smaller/older v8's (or is it a v6?). It's some sort of "new-world" sohc engine in the 4.7 L range? Help me out here, guys? The interesting thing about that is that it is in a very unique position to "transition" to become a "sohc Hemi" design, if the designers ever wanted to go that direction. It's already got the ohc in place, and all it really needs is valves arranged in a canted position with finger followers to the cam, and viola!...sohc Hemi. :p It would be a smaller engine on this stage, but it also would be positioned to take a 2-valve/cyl Hemi design into the world of high rpm. Update for aluminum block, vvt, Multi-Air, modern emissions/mpg, and that could be an interesting development, imo...
 
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for some reason I believe dodge owns the term "HEMI" or maybe it's Cuda', I forget and it's not that big a deal.
In the end Dodge calls em a HEMI so that's good enough for me.
If other folks wanna split some technical hair well let em.
 

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It maybe not a "true" hemi. But your friend's " hemi envy" is very real. :)
Exactly! You can brag about your HEMI, while they tell you how fuel efficient their 2.4L Toyota is. Now that'd be real sexy!
 

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I thought the same thing when I got my Challenger. after I got schooled up by Eric at Arrington I saw the light and he showed me a 1970 Hemi vs our Hemi. They have really evolved and today's Hemi is a descendent or the the early Hemi. They are much improved engineering wise and they still have the characteristics of the original Hemi. they are not the same but some of the same ideas from the original are there.
 

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Exactly! You can brag about your HEMI, while they tell you how fuel efficient their 2.4L Toyota is. Now that'd be real sexy!
So true!
 

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Yep....

Every couple months these threads come up.
And every couple months, some "troll" will try and start an internal debate/fight. The "experts" agree that these are Hemi's. The aforementioned posts back the claims up. It will happen again.
 

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I always use this, especially when you get that has the old Hemi powered cars. I say something to the effect that "yea, that's so true. Those original true Hemi's were something in those aircraft ". Then I talk about the original Hemi being an aircraft engine. It usually shuts them up.

Wiki link -

The Chrysler XIV-2220 (XI-2220 from 1944) was an experimental 2,500 hp liquid-cooled inverted-V-16 aircraft engine designed by Chrysler starting in 1940. Although several aircraft designs had considered using it, by the time it was ready for use in 1945 the war was already over. Only a few engines were built during the program, and it retained its 'X' designation the entire time as the XIV-2220, later XI-2220. The IV-2220 is historically important as it was Chrysler's first hemi, a design that would re-appear for many years later and is now a Chrysler trademark.
 

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I always use this, especially when you get that has the old Hemi powered cars. I say something to the effect that "yea, that's so true. Those original true Hemi's were something in those aircraft ". Then I talk about the original Hemi being an aircraft engine. It usually shuts them up.

Wiki link -

The Chrysler XIV-2220 (XI-2220 from 1944) was an experimental 2,500 hp liquid-cooled inverted-V-16 aircraft engine designed by Chrysler starting in 1940. Although several aircraft designs had considered using it, by the time it was ready for use in 1945 the war was already over. Only a few engines were built during the program, and it retained its 'X' designation the entire time as the XIV-2220, later XI-2220. The IV-2220 is historically important as it was Chrysler's first hemi, a design that would re-appear for many years later and is now a Chrysler trademark.
Well, I just printed this out and put it in the glove box. Good info to have for those pesky know it alls I run into from time to time.
 

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Just laugh at them and say "your right, semi-hemi."
 

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The Gen 3 Hemi is a Hemi. It's evolved and is better. It's really that simple. There is a good reason why Chrysler isn't still stuffing Gen 2 HEMIs into our cars...
 
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