hasten3

Chrysler wrote “The new Phoenix of V6 engines will feature cylinder deactivation (MDS)...the engine will operate efficiently on three cylinders when less power is needed, and in V-6 mode when more power is needed. This optimizes fuel economy when V-6 power is not required – without sacrificing vehicle performance or capability."


I am kinda worried about the cylinder deactivation in this engine as well.........this is going to be worse than an overdrive for the Wrangler.....with the NON-aerodynamics of the Wrangler, I don't ever see a time it could switch to 3 cyl......maybe at a redlight

highoctane

That's probably true for those who would plan to stay stock. My Jeep, with the heavy LoD bumpers, 18' beadlock wheels, heavy Nitto Mud Grappler 35" tires, and a few other small things, bring the weight on my Unlimited Rubi with a full tank of gas to 5700lbs. And I haven't even added a winch, the heavier 37" Toyo tires, PSC Brawler rockers, or any aftermarket skid plates. I'm sure those would bring it to 6100 or so. And that's w/o me in there.



As for the pushrod vs ohc/dohc cam argument. My Cobra with a 4.6L DOHC modular engine made 671lbs of tq at 3400 rpm, from 2200 rpm and up, it was making at LEAST 500ft/lbs, granted that's with a twin screw compressor. The same engine with the belt bypassing the blower pulley made 340lbs of tq at 2600rpm. Low enough in the rpm band for me. But my peak power was made at 6700 rpm, both NA and boosted, quite lofty rpms for a caveman pushrod GM LS motor. I never had any issues with the local cammed/tuned '08 ZO6.

highoctane

That's probably true for those who would plan to stay stock. My Jeep, with the heavy LoD bumpers, 18' beadlock wheels, heavy Nitto Mud Grappler 35" tires, and a few other small things, bring the weight on my Unlimited Rubi with a full tank of gas to 5500lbs. And I haven't even added a winch, the heavier 37" Toyo tires, PSC Brawler rockers, or any aftermarket skid plates. I'm sure those would bring it to 6100 or so. And that's w/o me in there.



As for the pushrod vs ohc/dohc cam argument. My Cobra with a 4.6L DOHC modular engine made 671lbs of tq at 3400 rpm, from 2200 rpm and up, it was making at LEAST 500ft/lbs, granted that's with a twin screw compressor. The same engine with the belt bypassing the blower pulley made 340lbs of tq at 2600rpm. Low enough in the rpm band for me. But my peak power was made at 6700 rpm, both NA and boosted, quite lofty rpms for a caveman pushrod GM LS motor. I never had any issues with the local cammed/tuned '08 ZO6.

goaterguy

~( 8^(I) Doh! My sarcasm meter was off for some reason! I agree completely, and want to add the ability for it to drop the top, and an incredible turning ratio (on the 2 door at least).

OMG! Quick call Bentley because they just designed a brand new pushrod V8 for their $285,000 2011 Mulssanne flagship!

Seriously, every engine has an application. I prefer the simplicity and reliability of an pushrod engine.

For example, I rarely read of a GM LS engine having reliability issues even when owners beat on them like a redheaded stepchild or when doubling or tripling their original power outputs but new DOHC engines with variable timing have to be treated more carefully and better mantained because of all the oil passages in the cams used to phase them that can clog and cause problems, more moving parts, more expensive, etc.

goaterguy

That's true but the Cobra/Lightning/GT DOHC engines are forged and handbuilt, hardly comparable to the mass produced Pentastar.

My nephew's Lightning had the dissapearing oil problem and it had to be rebuilt. The cost of rebuilding that OHC engine was more than enough to buy a complete and new LS.

tpm152

I have to disagree with the pushrods being less reliable. If something goes wrong with a valve on a pushrod engine, that cylinder will not work anymore, but the rest of the engine will continue to run. God help you if anything goes wrong with the valvetrain of an OHC engine

I know a lot of Toyota owners and most of them have had their timing belts break on them at least once and all have had to pay ~$2000 when their timing belts broke and they had to replace the entire top end of the engine. Also they were all stranded on the side of the road when their OHC engine went and their engine completely stopped working (as is expected when none of the valves work)

On the other hand my father has a ram with the 5.7 hemi, he had a valve break on him once at ~150K miles (he now has over 200K miles on his hemi btw) and he drove it to the dealer because the engine was stumbling and it didn't have the same power as before. About ~$400 and 2 hours of work later and he drove it out of there after having the valve replaced.

No worries about the cylinder deactivation. The only thing that they do to deactivate the cylinders is that they just tell the fuel injectors for those 3 cylinders to not inject for given conditions. So there is nothing mechanically different about engines with MDS compared to without it, just slightly different programming. You don't worry about dying because a glitch in the superchips programming on a power programmer do you? Then you shouldn't worry about the MDS

EzK

Since I already have a Jeep, that engine will be in there until it bites the dust. Not sure I'd buy into the Pentastar thing but I do despise everything about this 3.8L. None of which make me not want my Jeep because I love Jeeps but:

-Doesn't sound good.
-Doesn't run smooth at high rpm.
-Responsiveness to the pedal is about 0.

Clearly I enjoyed my 4.0L more because when I tapped the pedal it actually revved up. Problems 1 and 2 are about the same and the mileage was worse so I suppose it evens out for me since I commute with it. Maybe the new engine will be a large upgrade in these areas.

I'd love just a simple 5.3L Chevy, dropped down to its old 285hp rating power this thing(maybe one day). With that engine a Suburban can get 17-18mpg highway pretty. As far as engines go, nothing about Chrysler excites me.

ronjenx

There must be a wide difference in these engines, because I can't say any of the three things you mention, about my engine.

drschem

as I readthrough these posts, there seems to be a little confusion about what different people are calling "push rod" engines. I think, the difference being compared is overhead cam vs a camshaft below the cylinders. The overhead cam is driven by a chain or belt and directly operates the valve lifters. A "V" designed engine will need at least 2 camshafts. The traditional cam position is driven off the crankshaft by a gear and operates the valve lifters either with a push rod or a hydrolic link. One camshaft can operate both banks of cylinders. Thus, what someone is calling a "push rod" engine might not have pushrods as it could have hydrolic lifters. The difference in engine design is considerable and is what everyone is talking about, not how the valves open and close.

EzK

Possibly, my friends '10 is a much more peppy engine. Maybe I got a dud.