Hemis

[v10_viper]

Are the new Hemi's real hemi's like the old 426's?? give your explanations as to if they are or aren't. In the way that a hemi is a hemi, because of it's hemispherical combustion chamber i agree, but with that the spark plugs were smack dab in the center of it i believe and with the new ones being dual spark plugs per cylinder they can't be in the center. i had a few other reasons i think but can't think of them now.

[Polygon]

The plugs are still smack dab in the cylinder like the old ones, just an extra one this time around. Big differences, the aluminum head on the truck version and an all aluminum version in the cars. The extra plugs. Lower compression ratio. I am not sure what the compression in the car versions of the Hemi will be.

All in all, it is a good old Hemi with some better technology, so I would say partially.

[Neutrino]

I agree with poly on what he said. Of couse though the new hemis will not be indentical with the old ones and i don't even want them to be cuz now we have better technology. So the question -if you ask me- should be do the new hemi's deserve the name hemi or not cuz they are obviously different. I say Yes.

[72DEMOLITION]

The valve angles are different by about 26 degrees or around that anaway Iread it in hot rod magazine one time. Theres something with the way the Plug wires still go through the VC but differently too

[Chris1337]

The new Hemi's Still kick major ass though :sun:

[911GT2]

It's all in the marketing.

Porsche (among other companies, can't remember which) have been using hemispheric combustion chambers for years.

[Neutrino]

ok this is the millionth post i do askig this. I want to hear which engines in particular have this configuration and some photos or documentation to attest this. Every single time i asked for this nobody replied this makes me think that those engines do not exist.

And please don't bring the cammer into this.

[Polygon]

As far as I know, the Hemi was engineered by Chrysler, so if other people want to use Hemi combustion chambers that is fine by me. Imitation is the most sincere form of flattery. There is also more to a Hemi than the hemispherical combustion chamber. I too would love to see some proof that other cars are using them, if they are; they are doing a poor job of it and should be getting a hell of a lot more power.

[911GT2]

Originally posted by Polygon
As far as I know, the Hemi was engineered by Chrysler, so if other people want to use Hemi combustion chambers that is fine by me. Imitation is the most sincere form of flattery. There is also more to a Hemi than the hemispherical combustion chamber. I too would love to see some proof that other cars are using them, if they are; they are doing a poor job of it and should be getting a hell of a lot more power.

Note my namesake.

911 GT2 - 456 hp out of 3.6 liters. Not too bad.

And the hemispherical shape is an obvious development. Energy flows better.

[Polygon]

Originally posted by 911GT2


Note my namesake.

911 GT2 - 456 hp out of 3.6 liters. Not too bad.

And the hemispherical shape is an obvious development. Energy flows better.

That is a turbocharged engine. I am talking naturally aspirated. And like I said, there is more to Hemi than hemispherical cumbustion chambers.

[911GT2]

Alright, point taken.

Then what's so different about a Hemi than the naturally aspirated GT3 motor? Or the Carrera 4?

Both are approaching 100hp/L (3.8L/380hp, 3.6L/320hp), which seems to be the standard we've set here.

Explanation?

[Polygon]

Well, the spark plug is directly in the cylinder, there is also something to do with the valves. I am not saying that Porsche engines aren't impressive, because they are.

There is only one thing about the Hemi which I wish they would change. I wish they would move from pushrods to a DOHC design and they would so much more power, but for some reason they stick with the damn pushrods.

[FYRHWK1]

Originally posted by Polygon
As far as I know, the Hemi was engineered by Chrysler, so if other people want to use Hemi combustion chambers that is fine by me. Imitation is the most sincere form of flattery. There is also more to a Hemi than the hemispherical combustion chamber. I too would love to see some proof that other cars are using them, if they are; they are doing a poor job of it and should be getting a hell of a lot more power.

yep, the hemi chamber was first designed for aircraft engines in WW2, I believe Zora Duntov had something to do with it as well. they stuck it in their cars later on.

Other then the very sharp valve angle & shape, and the obvious spark plug in the center of the chamber, what could the difference possibly be? the LS1 is basically a hemispherical design as well, just not a "true" hemi.

[v10_viper]

Originally posted by 911GT2
Alright, point taken.

Then what's so different about a Hemi than the naturally aspirated GT3 motor? Or the Carrera 4?

Both are approaching 100hp/L (3.8L/380hp, 3.6L/320hp), which seems to be the standard we've set here.

Explanation?

yes, but are they square engines?? meaning do they have the same bore and stroke?? Everybody is saying how they want hp per liter such as their damn Hondas, well how much torque do they have??. When any engine is sqared it most likely wont be 100 hp per liter. they could be with as much technology as we have but i'm kinda doubtin that.

[FYRHWK1]

Originally posted by v10_viper


yes, but are they square engines?? meaning do they have the same bore and stroke?? Everybody is saying how they want hp per liter such as their damn Hondas, well how much torque do they have??. When any engine is sqared it most likely wont be 100 hp per liter. they could be with as much technology as we have but i'm kinda doubtin that.

dquare or undersqueare engines CAN make equal hp/liter but noone bothers to make them do that because they don't HAVE to. the porsche people are working with a decently sized engine and are working as much power as they can from it in order to be faster, hondas and toyotas are extacting 100 hp/liter from a 4 cylinder because if they didn't it wouldnt even run the 15's it does.
they make it oversquare in order to help the engine last, if you dont need 8 & 9000 RPM you can build it better to its range, its cheaper then using higher quality internals.