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Discussion Starter · #1 ·
Ever wonder why the 5.0 runs so good for such a small motor? Its because it's intake and exhaust lobes on its cams are independent. The lobe separation can change on engine demand as well as the intake and exhaust opening events (centerline's) Dodge already has this technology and it is used in the viper, but instead of 4 overhead cams it uses a pushrod design with "one" or two (depending on how you look at it) cam in the block that can change lobe separation (cam in cam). Come on dodge, give us a pushrod hemi with hp per ci of the ford db's!
 

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Our Hemis are more truck-like. They don't rev as high as the 5.0L but they do have better low end torque. Personally I really like that! Also for longevity, my money is on the Hemi (although maybe I'm biased)

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I would like to see cam-in-cam tech migrate to the Hemi, for sure! Hell, just the SRT8 cam migrated to the 5.7 would be pretty sweet (but I suspect the SRT8 customers would frown on the prospect of 440 hp coming from a 5.7, if that ever happened ;) ).

Just fyi...the Coyote hits the hp rating it does, not simply because of twin variable timing, rather because it is tuned for a hotter top end and has the extended redline to accomodate it (along with higher compression ratio). If you limited it to, say, 5800 rpm, it would suddenly rate at substantially less hp. Even less known to most people, at every rpm below that 5800 rpm, the Hemi is producing more output than the Coyote, comparing hp or torque at rpm to rpm. It should though...because it is a bigger engine. ;)
 

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To me the simplicity of a cam in block, push rod V8 with only 16 valves is more impressive. 5.0 mustang V8 are awesome technology, but I do not want 10 feet of timing chains. Look at the LS. line of engines. All cam in bock, push rod V8 with only 16 valves. So what is more impressive, 400 plus Hp from a 16 valve engine or 400 plus Hp from a 32 valve engine. Preferences is all it comes down to. IMO less parts the better.
 

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The cam-in-cam technology goes right in the place an ohv cam goes. There is no substantial change to the chain that would drive it. It is essentially independently variable intake/exhaust timing for ohv engines. ;)
 

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The cam-in-cam technology goes right in the place an ohv cam goes. There is no substantial change to the chain that would drive it. It is essentially independently variable intake/exhaust timing for ohv engines. ;)
Correct me if I am wrong, don't the cams have to be connected to the crank, some thing needs to turn them. I thought that the new Coyote engine was just a 4.6 bore with some new technology? There seems like to me that is a lot of timing chains?

 

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Correct me if I am wrong, don't the cams have to be connected to the crank, some thing needs to turn them. I thought that the new Coyote engine was just a 4.6 bore with some new technology? There seems to me like that is a lot of timing chains?

That's a lot of moving parts. Dodge is having trouble with 1 timing chain per engine,they don't need anymore.
 

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Yep...

Ever wonder why the 5.0 runs so good for such a small motor? Its because it's intake and exhaust lobes on its cams are independent. The lobe separation can change on engine demand as well as the intake and exhaust opening events (centerline's) Dodge already has this technology and it is used in the viper, but instead of 4 overhead cams it uses a pushrod design with "one" or two (depending on how you look at it) cam in the block that can change lobe separation (cam in cam). Come on dodge, give us a pushrod hemi with hp per ci of the ford db's!
But I think the bottom line is Valves. I believe they have 4 valves per cylinder vice 2? More valves means MORE AIR.
 

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But I think the bottom line is Valves. I believe they have 4 valves per cylinder vice 2? More valves means MORE AIR.
He's on the money ^^^.

Example GM 3.4 V6 (two examples):

Pushrod / 2 valve/cyl was 160hp/194ft.lb. - 9.0:1 CR

DOHC / 4 valve/cyl was 210hp/215ft.lb - 9.25:1 CR (manual trans)

slight increase in CR, but the heads were the key item that made more power.
 

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He's on the money ^^^.

Example GM 3.4 V6 (two examples):

Pushrod / 2 valve/cyl was 160hp/194ft.lb. - 9.0:1 CR

DOHC / 4 valve/cyl was 210hp/215ft.lb - 9.25:1 CR (manual trans)

slight increase in CR, but the heads were the key item that made more power.
Not disagreeing in anyway, yes D.O.H.C seem to make more power. I just like the simplicity of the hemi engines. Less moving parts, less things that ware out. But that is my preference, nothing else. I posted that pic because I was called out, I just said that is a lot of timing chains.
 

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Correct me if I am wrong, don't the cams have to be connected to the crank, some thing needs to turn them. I thought that the new Coyote engine was just a 4.6 bore with some new technology? There seems like to me that is a lot of timing chains?
Yes, it is, but I don't think we are connecting on our points, though.

When someone proposes cam-in-cam technology on an ohv engine, they aren't talking about a 4-valve/cyl setup. Cam-in-cam refers to there actually being a concentric cam assembly right in the same place as the cam is in the ohv. The cam isn't relocated to the heads, and it is an entirely different thing from dohc (which is what I think you thought it meant). It stays in the heart of the block, and the engine is still a 2-valve/cyl setup. Cam-in-cam technology is already in the ohv v10 of the Viper, as someone has already noted earlier.

One large valve with aggressive lift can still accommodate a whole lotta flow, as opposed to 2 small valves. The large valve profile just takes more design to get it to run high rpm. The silver lining to that is...if you can make all the hp you want w/o scathing hp, then the rpm-sensitivity of a large valve is a non-issue. That is exactly what the classic ohv v8 does...you get the fireball of power at modest rpm, using sheer displacement and the flow of large-sized valves that can then fit in those large bores (not to mention the excellent low rpm torque, which small NA engines cannot duplicate, at all, even if they were 6-valves/cyl or some ridiculous number). Smaller ohc engines cannot do the same thing whether they have more valves or not...they make their big hp only when you ride those rpms at the top. It's not that they flow more air...it's that they can move the valves more rapidly (at higher rpm) which also builds up a hp number.
 

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Yes, this is true!...'bout time for some trickle down technology like that to hit the Hemi, eh?
 

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Discussion Starter · #14 ·
It's not about the number of valves it's the flow that counts. For example, the 4 valve 5.4 ford engines make much less horsepower than the 4 valve coyote motors. They also don't have twin independent variable cam timing. Hemi heads flow just as much if not more air than the coyote heads.
 
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