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Fasstdak
Dodge Dakota
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2/10/2007
00:15:01
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 Subject: RE: Hemi going to VVT?
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The MDS system uses solenoids to "lock" the lifters on opposite cylinders - basically keeping the valves closed with exhaust gases in the cylinder to act as an air spring. The injectors for those cylinders are shut off but fire at certain intervals to keep the misfire monitors happy. When does it work, at a steady cruising speed (not when less power is needed) and it works VERY well - you don't feel it kick in/out unless you really know what to look for.
I see Hemi trucks coming in with 19-20mpg on the overhead and 300's getting close to 24mpg. That's not bad at all for a 345HP 5.7L V8 in a heavy vehicle.
No, it's not like the old GM system which was problematic (to say the least)...and the newer system still has complaints with 1/2 the cylinders engaging properly from a stop (northstar engines). DC didn't steal it at all...they perfected it.
Biggest issue with the Daimler MDS system: You MUST run the correct oil. The MDS system is monitored via the solenoids - if 5w30 or a 10w30 oil is used, the solenoids don't open/close quick enough and the MIL is tripped. I have yet to see any driveability issues with them in the engines.
The CVT's are "cute", but definitely don't feel like a real transmission unless you get the 2.4L Caliber with the Auto-Stick - 6 "gears" programmed into the TCM logic when in auto-stick mode...kinda cool and does feel like a conventional transmission.
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Fasstdak
Dodge Dakota
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2/10/2007
00:18:02
| RE: Hemi going to VVT?
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BTW: The new 4.7L engine will be the test bed for the VVT system (hopefully not the DVVT system as on the World Engines - GPEC controlled).
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GraphiteDak
GenIII
2/10/2007
13:20:17
| RE: Hemi going to VVT?
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The funny thing, is the engine still has to be wasting SOME energy simply moving the pistons up and down like the way they are. Maybe the "air spring" effect kind of dampens some of the loss as energy would be going from the movement of the pistons, to the air being compressed, decompressed, etc.
DC should just make a larger displacement of the 4.7 design anyway. Go 4 valve DOHC if they have to.
Otherwise they are going to get passed by :(
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Super bee
GenI
2/11/2007
00:27:15
| RE: Hemi going to VVT?
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CVT is not a bad thing
its the same principal that has been driving snowmobiles for about 40 years
1990 sport RC SB, 1995 318drivetrain, 3.92 gears (came with truck) Powertrax "traction system", 95 dash/steering wheel, hearthrob exhaust, headers, cutout after y-pipe, necessary electric fan add-a-leafs, 30x9.5 mud tires, cranked T-bars, AR 39 15x8 rims, grill guard, roll bars
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Kowalski
GenIII
2/11/2007
07:24:22
|  RE: Hemi going to VVT?
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I wonder why the 4.7 would be considered the "test bed" for this, when Shoe is reporting he is making the parts for the 5.7 ?
Lead, follow, or get out of the way
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Shoe
GenIII
2/12/2007
18:50:46
| RE: Hemi going to VVT?
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I never said that they were still the MDS setup from GM. I said that they are stealing the VVT setup from GM's hyrbid suvs. I do not see it happening on the 4.7. The contract says HEMI, not 4.7 Magnum motor. I will ask one of the engineers for further information.
'97 RC V6, 5spd, soon to be V8, 5spd!
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jayb
Dodge Dakota
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2/12/2007
22:29:48
| RE: Hemi going to VVT?
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"I see Hemi trucks coming in with 19-20mpg on the overhead and 300's getting close to 24mpg. That's not bad at all for a 345HP 5.7L V8 in a heavy vehicle. "
Im not impressed at all. Especially considering all that could, and probably would go wrong with a complex system like this.
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Fasstdak
Dodge Dakota
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2/12/2007
22:44:41
| RE: Hemi going to VVT?
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You wouldn't believe how complex they already are...there's more that goes on in a 10 minute commute than on a decent sized corporate network. Things have come a long was since the archaic GM design of yester-year. Now who did GM get the VVT idea from? (Honda???) ;)
I asked one of the DC engineers that I deal with and he didn't know about the 5.7L VVT system at this time. He did mention the 4.7L though - "it's still being worked on". I'll try to find out more on the alleged 5.7L system from the training grounds - the instructors normally know what's coming down the pipeline even before it's posted for us internally.
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intense blue
Dodge Dakota
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2/16/2007
00:07:00
| RE: Hemi going to VVT?
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The VVT that goes into cam-in-block engines is usually just a cam gear that can advance or retard the cam. It isn't too complex, heck, it's possible to make it all mechanical and simply have the gear twist the cam back a few degrees at high rpm. I'm not sure if the systems currently being used are mechanical or computer controlled. I would guess it's the latter because that seems to be the trend. (ie: drive by wire)
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Shoe
GenIII
2/16/2007
18:22:38
| RE: Hemi going to VVT?
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I talked to one of the engineers and he is not too for sure at the moment. We will know more once we have the contract for sure. It is possible that it might be for the 4.7. Oh well, sorry to get everybody rised up for the occasion.
'97 RC V6, 5spd, soon to be V8, 5spd!
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Shoe
GenIII
6/02/2007
01:37:09
| RE: Hemi going to VVT?
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"When it goes on sale late next summer, there should be four revised engine choices. The base 215-hp / 235 lb-ft 3.7-liter V6 will be replaced with the 260 hp / 265 lb-ft 4.0-liter V6 used in the Dodge Nitro. The Ram's 4.7-liter V8 will get the same makeover as in the Dodge Dakota, boosting power to 300 hp/ 330 lb-ft, and the 5.7-liter HEMI V8 will get a bump in power [Brenda wrote “and displacement” but we believe variable valve timing will be used instead. There have been rumors about an optional 6.1 but that seems to be speculation). A new Cummins V8 diesel motor will also be available [we think this is the lower-power model for 1500, and that the bigger straight-six Cummins will remain on the 2500/3500]. Both gas and diesel V8s will use 6-speed automatic transmissions."
I was telling some truth. We will know more later. Hell yeah.
'97 RC V6, 5spd, soon to be V8, 5spd!
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