Hemi just says that the cylinder heads are hemispherical in a way
basically means the spark plug its on the middle of the combustion chamber, and that the combustion chamber is shaped as a hemisphere
back then the heads where quenched to one side only causing back air fuel mixtures and poor gas scavenging, well after changing it to the HEMI design, they fig out they get more power , better gas mileage and better combustion

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Howstuffworks &raquo;</TD></TR><TR><TD CLASS="quote">In 1951, Chrysler introduced a 180-horsepower HEMI V-8 engine on several models. The Chrysler HEMI engine had a displacement of 331 cubic inches (5.4 liters), so it is known as the "331 HEMI."</TD></TR></TABLE> WOW, and they are proud of that?? that what my SOHC Honda makes at the wheels... BOOOOO

anyways go here and read about it, and u will get it all clear on ur head

http://auto.howstuffworks.com/hemi2.htm

http://auto.howstuffworks.com/hemi5.htm &lt;&lt;&lt; Disadvantages of HEMI

they all scream "Its that a HEMI Boy?!! " well next time u yell, "Its that a VTEC boy?! "





Modified by USDM 4G VTEC at 12:21 PM 12/28/2004

 

nice info in here.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by USDM 4G VTEC &raquo;</TD></TR><TR><TD CLASS="quote">and that the combustion chamber is shaped as half a hemisphere </TD></TR></TABLE>

Half a hemisphere huh?

 

the dodge hemi is only superior over standard push rod engine but OHC is still far more superior than the push rod hemi. the new dodge hemi is not even true hemi because they added quench are on the head which doesn't make it hemispherical. they just use the term as a marketing tool. dodge didn't invent hemi either, it was used on most european sports car way before it was popular in the US. almost all modern engine with OHC have some sort of hemispherical chamber. so next time someone ask you "THAT THING GOT A HEMI", just say "hell yeah BIACH"

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by UberTeg &raquo;</TD></TR><TR><TD CLASS="quote">

Half a hemisphere huh? </TD></TR></TABLE>

Lol, that I didn't catch on to that until you posted that.

 

You've been here a month and a half and you got a title. Impressive!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by @lbert &raquo;</TD></TR><TR><TD CLASS="quote">You've been here a month and a half and you got a title. Impressive!</TD></TR></TABLE>

lol looks like someone else wants one

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by USDM 4G VTEC &raquo;</TD></TR><TR><TD CLASS="quote">WOW, and they are proud of that?? that what my SOHC Honda makes at the wheels... BOOOOO</TD></TR></TABLE>

dude, that was in 1951. nothing was fast in 1951.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rice4life &raquo;</TD></TR><TR><TD CLASS="quote">the dodge hemi is only superior over standard push rod engine but OHC is still far more superior than the push rod hemi. the new dodge hemi is not even true hemi because they added quench are on the head which doesn't make it hemispherical.</TD></TR></TABLE>

look at the pictures in the link i posted.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rice4life &raquo;</TD></TR><TR><TD CLASS="quote">tdodge didn't invent hemi either, it was used on most european sports car way before it was popular in the US.</TD></TR></TABLE>

i believe they came from aircraft.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rice4life &raquo;</TD></TR><TR><TD CLASS="quote">almost all modern engine with OHC have some sort of hemispherical chamber. so next time someone ask you "THAT THING GOT A HEMI", just say "hell yeah BIACH"</TD></TR></TABLE>

and you'll look like a tool.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by O3DigitalBath &raquo;</TD></TR><TR><TD CLASS="quote">

lol looks like someone else wants one </TD></TR></TABLE>

I hope I can get a really rediculously gay title

 

nice information there.. din't know or care before, but still good to know!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">its a hemispherical cumbustion chamber.......just like a honda...and pretty much most all newer automobiles. They found out that if the make the cumbustion chamber a hemi shape, it gets a more complete burn on the air fuel mixture.</TD></TR></TABLE>

I agree. There is very little difference between a "hemi" and a pent-roof chamber. Nothing to write home about anyway. The location of the valves, angle of the valves, and location of the spark plug are the same. The "hemi" was different because it actuated those valves with pushrods... And not very well, either. The 426 Hemi was world-renouned for being an unreliable engine that was difficult to fix. More mopar mechanics prefer the simplicity of the 440 wedge.

With the advent of OHC engines, the basically hemispherical chamber was a gimme. It was easy to do and more efficient that wedge chambers. The problem was that the term "hemispherical chamber" was already patented.

 

damn i'm not gonna explain what a 'Hemi' is because everyone has already done a good job of doing so. i just wished i could of been there to chirp my little bov in their faces as well. man, i never get anyone who wants to mess with my stock looking teg.

 

It might just be me, but WTF is so great about a 40 year old cylinder head technology?

So it has a Hemi...whoopdy ****.

 

That's exactly it. There is nothing great about the Hemi. If anything, it is a step back in technology.

But people are stupid. They buy the Hemi just because they have heard the word "Hemi" before associated with high performance.

 

the hemi motors that dodge is putting out aren't even considered real true hemi's by even the hot rodders. even the V8 mags all agree from motor build ups that they have done, that todays' dodge hemi is not true to the original dodge hemi's of the 60's. it a total marketing joke that every clueless punk out there falls for. the good old hemi bandwagon.
the other post is right about the hemi heads not having any real overall advantage over any of the other combustion chamber designs in use today. technology and todays better efi systems have made the hemi no big deal.
if it was the hands down only head/ combustion chamber design then why doesn't all of motorsports use it? seems to only have a real place in top fuel and funny car drag racing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SCR ZC-T &raquo;</TD></TR><TR><TD CLASS="quote">
if it was the hands down only head/ combustion chamber design then why doesn't all of motorsports use it? seems to only have a real place in top fuel and funny car drag racing.</TD></TR></TABLE>

i'm sure if a dohc 4-valve/cyl setup were better top fuel would be using it.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SCR ZC-T &raquo;</TD></TR><TR><TD CLASS="quote">
the other post is right about the hemi heads not having any real overall advantage over any of the other combustion chamber designs in use today. technology and todays better efi systems have made the hemi no big deal.</TD></TR></TABLE>

it has it's advantages. just not so much compared to 4-valve/cyl motors. remember, those werent around in the 60's. in the 60's, compared to standard style paralell valve pushrod v8's, the hemi was king. and still is amongst large V8's. the only manufacturer i know of to offer a V8 with a dohc setup in 5+ liters is ford. and it still doesn't come near the power output of the hemi unless it's blown.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bryson &raquo;</TD></TR><TR><TD CLASS="quote">WTF is so great about a 40 year old cylinder head technology?</TD></TR></TABLE>

it's like aerodynamics. flow and combustion are the same, it doesn't matter what decade your in. what works works. and a good deal of it was figured out a long time ago. now it's just being refined.

 

i love my honda's.. but i have to stick up for the good old V8

i've never seen 5000+ hp out of a OHC V8

i will agree that the "hemi" name is all marketing

the hemi really is the wholy grail of V8's.. (like DD subs) most of the big dogs run them..

i'd give my left nut for this 572 cube monster

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GLHS895 &raquo;</TD></TR><TR><TD CLASS="quote">i'm sure if a dohc 4-valve/cyl setup were better top fuel would be using it.
</TD></TR></TABLE>

top fuel cars don't have a power problem, they have a traction problem. when they can make upward of 10k hp with large displacement, force induction and nitro methane, why add the complication of 4 valves and 4 cams when these engines are already unreliable. head design on a force induction engine is not as important as a NA car. most of the power from a force induction engine comes from the efficiency of the force induction system itself (as long as the engine can handle the power) where as on a NA car, power depends on head design. no one builds a purpose NA race engine with push rod technology unless restricted like NASCAR.

 

dodge built the pushrod viper V10... its raced.. corvettes use the same old 350 design that has been around since forever.. its just been improved upon..

ford did use a 550hp supercharged DOHC v8 for the new Ford GT.. its the navigator engine... the 4.6 Dohc cobra NA v8's were 320hp i think

those all run in power limited classes i think.. the F1 engines are just insane




Modified by Zakar at 5:57 AM 12/29/2004

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Zakar &raquo;</TD></TR><TR><TD CLASS="quote">dodge built the pushrod viper V10... its raced.. corvettes use the same old 350 design that has been around since forever.. its just been improved upon..
</TD></TR></TABLE>

those engine are still design to be mass produce and have to meet emission regulation and street reliability. they use push rod to reduce production cost, not because it's a better design than OHC.
8.3L to make 500hp . don't get me wrong i would take 500hp anyday.

 

Hemi is for hemispherical head... hemi= half i think and spherical obvisly means circle... it was a head mopar designed to aid in combustion by using there half circle design... as far as i know...

 

Don't make the mistake of comparing power output from an engine in the 60's to power output now... Recall that manufacturers completely changed the way they measure horsepower, and that you should remove 25% of the rated output of motors older than 1972 to compare them to modern engines. (Which is inexact, but better than claiming 450 hp when they really made 375 in the car)

 

Too bad 99% of the guys that owned Hemi equipped Mopars back in the old days probably did not realize that Ford (of all companies) actually produced the baddest motor around.



http://www.geocities.com/infieldg/v8sohc427.html

An SOHC with two cams I guess that means new Mustangs have dual cam motors with 4 cams

At the very least, with this crate motor you didn't get made fun of by anybody for only having an SOHC!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rice4life &raquo;</TD></TR><TR><TD CLASS="quote">top fuel cars don't have a power problem, they have a traction problem. when they can make upward of 10k hp with large displacement, force induction and nitro methane, why add the complication of 4 valves and 4 cams when these engines are already unreliable.</TD></TR></TABLE>

good point. it's a simplicity issue. hemi = simple motor. less **** to take apart after each run. they only last that long anyway. btw, they only get 6 or 7k hp max, and thats just an estimate.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rice4life &raquo;</TD></TR><TR><TD CLASS="quote">head design on a force induction engine is not as important as a NA car.</TD></TR></TABLE>

but flow is. more air = more power. and with more valves, you get more air. but the hemi still does a pretty damn good job of getting lots of air in the cc quickly, compared to engines of similar size and valvetrain.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rice4life &raquo;</TD></TR><TR><TD CLASS="quote">no one builds a purpose NA race engine with push rod technology unless restricted like NASCAR. </TD></TR></TABLE>

ignorance is bliss i guess?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rice4life &raquo;</TD></TR><TR><TD CLASS="quote">
8.3L to make 500hp don't get me wrong i would take 500hp anyday. </TD></TR></TABLE>

ditto.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Zakar &raquo;</TD></TR><TR><TD CLASS="quote">
i'd give my left nut for this 572 cube monster

</TD></TR></TABLE>

mopar engines west?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">87 Shelby Charger GLH 2.5T..... always a busted axle</TD></TR></TABLE>