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#11
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Does vortec engine mean good?
Steve Mackie wrote:
>>>(Before this causes a ruckus, look it up. They are no longer true > > "hemi's". > >>>They are as much of a Hemi as my '95 GM 3.4L DOHC is.) >> >>The modern 5.7 Hemi is "more" of a Hemi than any quad-valve DOHC engine, >>though. Quad-valves are pent-roof chambers. > > > True, I should have thought it over before typing. My point was, which I > think was conveyed, is that the new 'Hemi' name is more marketing than > design. And as pointed out by a previous poster this is not 100% true of the > 'Vortec' brand as I stated earlier. > > Steve I wouldn't say it's "more" marketing than design. The big benefit of the Hemi head was never so much the shape of the combustion chamber (in many ways that was a detriment) as it was the bigger valve head size, the valve angles relative to the cylinder bank, and the port size and straightness on both intake and exhaust that the Hemi head allowed. The new "Hemi" still has ALL of that goodness, even though the chamber itself is more hemi-elliptical than hemispherical. And the revised chamber shape gets rid of most of the bad things about a Hemi- high NOX and HC emissions. In that sense, "Hemi" and "Vortec" are both single marketing words that capture a whole lot of subtle engineering features. No harm in that. |
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#12
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Does vortec engine mean good?
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#13
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Does vortec engine mean good?
"Steve" > wrote in message ... > Steve Mackie wrote: > > > > (Before this causes a ruckus, look it up. They are no longer true "hemi's". > > They are as much of a Hemi as my '95 GM 3.4L DOHC is.) > > > > Steve > > If there are "degrees" of Hemi-ness, then the 426 Hemi wasn't a "true" > one either since the spark plug wasn't quite central and the valve > angles weren't symmetric about the axis of the cylinder, and the last > "true" Hemi was the 1957 392 Hemi. > > The modern 5.7 Hemi is "more" of a Hemi than any quad-valve DOHC engine, > though. Quad-valves are pent-roof chambers. The heads off a current Chrysler "hemi" look like Ford Cleveland heads to me, Ed |
#14
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Does vortec engine mean good?
"Steve" > wrote in message news > Steve Mackie wrote: > I wouldn't say it's "more" marketing than design. The big benefit of the > Hemi head was never so much the shape of the combustion chamber (in many > ways that was a detriment) as it was the bigger valve head size, the > valve angles relative to the cylinder bank, and the port size and > straightness on both intake and exhaust that the Hemi head allowed. The > new "Hemi" still has ALL of that goodness, even though the chamber > itself is more hemi-elliptical than hemispherical. And the revised > chamber shape gets rid of most of the bad things about a Hemi- high NOX > and HC emissions. The engine is still marginal from an emmissions standpoint. Check out http://www.allpar.com/mopar/new-mopar-hemi.html : "The Hemi design combustion chamber is one of the poorest designs for emissions - why do you think it took so long to get it into production? It almost did NOT make emissions test requirements even with the modifications. .... Today's Hemi is that (a "Hemi") in name only." As far as I can tell, the only reason for calling it a "hemi" is so they can drag in a few more suckers who think it is somehow better than a current model small block Chevrolet engine - which it isn't. Ed |
#15
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Does vortec engine mean good?
Steve Mackie wrote:
> I doubt it's nothing more than a trade name, period. Like the way GM says > "Ecotech" or Ford says "PowerStroke" or the way Chrysler now uses the term > "Hemi." Doesn't really say anything about the engine, it's just a name. > (Before this causes a ruckus, look it up. They are no longer true "hemi's". > They are as much of a Hemi as my '95 GM 3.4L DOHC is.) > > Steve > But isn't the hemi revival engine still more of a hemi than a wedge? Don't the valves come in on opposite sides of the chamber, instead of being in line like most wedge heads? I am under the impression that MOST engines today are wedges with squish, to add turbulence and lower octane requirement. Don't have one of the new hemis, but I would suspect if it is close to a real hemi shape it would have a higher octane rating that wedges. |
#16
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Does vortec engine mean good?
C. E. White wrote:
> > The heads off a current Chrysler "hemi" look like Ford Cleveland heads to > me, > > Ed Kinda similar, except for valve placement and dual plugs. And again, the main "good" thing about the Cleveland head compared to the Windsor head was the port size/shape. |
#17
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Does vortec engine mean good?
C. E. White wrote:
" > > As far as I can tell, the only reason for calling it a "hemi" is so they can > drag in a few more suckers who think it is somehow better than a current > model small block Chevrolet engine - which it isn't. Actually, its measurably and objectively a lot better than the Gen III (and the Gen III is a VERY good engine- much better than the ancient "small block Chevy" that it replaced). And that's according to the admitted "Chevy guys" at PHR: http://www.popularhotrodding.com/tech/0403phr_hemi/ |
#18
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Does vortec engine mean good?
Don Stauffer wrote:
> Steve Mackie wrote: > >> I doubt it's nothing more than a trade name, period. Like the way GM says >> "Ecotech" or Ford says "PowerStroke" or the way Chrysler now uses the >> term >> "Hemi." Doesn't really say anything about the engine, it's just a name. >> (Before this causes a ruckus, look it up. They are no longer true >> "hemi's". >> They are as much of a Hemi as my '95 GM 3.4L DOHC is.) >> >> Steve >> > > But isn't the hemi revival engine still more of a hemi than a wedge? > Don't the valves come in on opposite sides of the chamber, instead of > being in line like most wedge heads? Yes and yes, which is why it IS technically a Hemi in spite of the elliptical chamber shape. I am under the impression that > MOST engines today are wedges with squish, to add turbulence and lower > octane requirement. Don't have one of the new hemis, but I would > suspect if it is close to a real hemi shape it would have a higher > octane rating that wedges. They worked hard on the details of the head and piston crown shape, as well as adding dual plugs, to allow it to run on regular gas at the same compression as a wedge head. There are many paths to the same destination, more than one way to skin a cat, etc. :-) |
#19
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Does vortec engine mean good?
"Steve" > wrote in message ... > C. E. White wrote: > " > > > > As far as I can tell, the only reason for calling it a "hemi" is so they can > > drag in a few more suckers who think it is somehow better than a current > > model small block Chevrolet engine - which it isn't. > > Actually, its measurably and objectively a lot better than the Gen III > (and the Gen III is a VERY good engine- much better than the ancient > "small block Chevy" that it replaced). And that's according to the > admitted "Chevy guys" at PHR: > > http://www.popularhotrodding.com/tech/0403phr_hemi/ Dodge 6.1L Hemi V-8 Power: 425 horsepower at 6,000 rpm Torque: 420 lb-ft at 4,800 rpm Chevrolet 6.0L V-8 (LS2) Power: 400 hp @ 6000 rpm Torque: 395 lb-ft @ 4400 rpm On a Horsepower per cubic inch basis - not much difference 6.1L Hemi - 425 hp, 370 cu. in - 1.15 hp/cu. in. 6.0L LS2 - 400 hp, 364.3 cu. in = 1.10 hp/cu. in. And even the Ford Mod V-8, which the Popular Hot Roding article disparaged, is similar on a horsepower per cubic inch basis (1.07 hp/cu. in.). Mustang GT 4.6L V-8 Power: 300 hp @ 5750 rpm Torque 240 lb-ft @ 3500 rpm The Chevy has the smallest outside dimension and is the lightest (and certainly cheaper to build than the "hemi"). So, all things considered, I think it is the better engine. Regards, Ed White |
#20
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Does vortec engine mean good?
C. E. White wrote:
> "Steve" > wrote in message > ... > >>C. E. White wrote: >>" >> >>>As far as I can tell, the only reason for calling it a "hemi" is so they > > can > >>>drag in a few more suckers who think it is somehow better than a current >>>model small block Chevrolet engine - which it isn't. >> >>Actually, its measurably and objectively a lot better than the Gen III >>(and the Gen III is a VERY good engine- much better than the ancient >>"small block Chevy" that it replaced). And that's according to the >>admitted "Chevy guys" at PHR: >> >>http://www.popularhotrodding.com/tech/0403phr_hemi/ > > > Dodge 6.1L Hemi V-8 > Power: 425 horsepower at 6,000 rpm > Torque: 420 lb-ft at 4,800 rpm > > Chevrolet 6.0L V-8 (LS2) > Power: 400 hp @ 6000 rpm > Torque: 395 lb-ft @ 4400 rpm > > On a Horsepower per cubic inch basis - not much difference HP/CID doesn't mean anything anyway. > > And even the Ford Mod V-8, which the Popular Hot Roding article disparaged, > is similar on a horsepower per cubic inch basis (1.07 hp/cu. in.). > > Mustang GT 4.6L V-8 > Power: 300 hp @ 5750 rpm > Torque 240 lb-ft @ 3500 rpm > > The Chevy has the smallest outside dimension and is the lightest (and > certainly cheaper to build than the "hemi"). So, all things considered, I > think it is the better engine. Its also got short connecting rods, crummy rod-ratio, and small diameter lifters, so I'd consider it the poorest of the 3- although that's splitting hairs since its clearly quite good. In truth, the Ford Modular (iron block, not the Al version) is closer to using up all that the basic architecture can support in stock form than the other two. PHR's point was that the Hemi has much more growth potential than the others, and with its longer rods its a much sounder basic architecture. |
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