W5A580 transmission, any good?

[UNC017]

Originally Posted By: demarpaint
Well we went a bit OT but with some great info, keep it coming. From what I've read about the Pentastar 90% of torque is available from 1,600 to 6,400.


If they can pull that 90% figure down to 1100 RPM, then it will be a good offroading engine. Its definitely possible, but will they?

You also have to remember that many Wranglers are going to have manual transmissions, and torque-monsters like the 4.0 and 3.8 work far better with a stick (especially offroad) than high-winders do. Frankly, offroading is one place where even with a 4.0, the automatic had an advantage over the stick (torque multiplication and not having to ever slip a clutch) so I really hope they keep offering the stick at all.

 

[demarpaint]

I've always liked the I6 engine for making power.

At what rpm range does the 3.8L make its power? I was reading on the Jeep Forums a lot of people complaining that the 3.8L is a real oil burner when used for serious off road driving.

 

[meep]

I fussed about the loss of the 4.0 in the wrangler... until I drove the 3.8 with a manual. They did a good job with it, and it will walk up anything within reason. now-- I drove one with 4.10's, which not everyone gets, but there was no 3.8-bashing to be heard from me. delightful to play in.

I'm surprised none of 3.8 bashers haven't mentioned the wider bodies on the newer wranglers. it's getting fatter, which is great AFA stability and passenger comfort but starts to get a little testy on-trail.

I hated to see the 4.0 go, it was a great start to a great powertrain. But I understand why, and they did good with the 3.8. As long as they tune it right, the pentastar will be a good engine to live with.

As with any chrysler, engines are generally not their problems. electronics and the rest of the car will fall apart around it. The wrangler, still has a LOT of steel and a great frame underneath. I doubt they'll screw it up.

M

 

[demarpaint]

Today is the first day of taking orders for the 2012 Wrangler, lots of talk about it on some of the Jeep forums. I'm in no hurry to be first in line. I won't order anything until prices are posted and I actually see the vehicle, colors, and options. I think the Penastar engine and a 5 speed AT will be an improvement for those seeking a Wrangler with an AT.

 

[UNC017]

Originally Posted By: demarpaint
I've always liked the I6 engine for making power.

At what rpm range does the 3.8L make its power? I was reading on the Jeep Forums a lot of people complaining that the 3.8L is a real oil burner when used for serious off road driving.


Its very, very similar to the 4.0, but will rev a bit higher. The 4.0 has a reputation for doing Very Bad Things if operated above 3500-4000 RPM for extended periods, even though that's still below "redline." Peak torque on the 3.8 is around 4000, but that's true on the 4.0 also. In both cases the ramp up to that peak is pretty flat and starts low. Hadn't heard about it burning oil offroad, but different engines respond differently to operating at strange angles.

Did you know that the 3.8 isn't really that much newer than the 4.0? The 4.0 started out at AMC in roughly 84-85. Contrary to myth, its not "derived from" the older 258, but it shares so many dimensions (bore center spacing, bearing saddle diameter and spacing, etc.) so that it could be built on the same assembly machines. The result is you can swap parts between them and make a 4.7L stroker engine with a 258 crank in a 4.0 block. The 3.8 is a bored and stroked 3.3, which started out at Chrysler around 88 or 89 and hit production in 90 with the 3.8 coming along in 91. More trivia- the 3.5L SOHC v6 has a different block casting than the 3.3/3.8 (even in its original iron block form in '93) but is so related to them that it has the bore of a 3.3 combined with the stroke of a 3.8. It all goes back to dimensions of the machines used to build them being the same to save cost.

 

[Hokiefyd]

Originally Posted By: 440Magnum
Peak torque on the 3.8 is around 4000, but that's true on the 4.0 also. In both cases the ramp up to that peak is pretty flat and starts low. Hadn't heard about it burning oil offroad, but different engines respond differently to operating at strange angles.


Peak torque on a 4.0L is 4000rpm? I wouldn't believe that unless I saw the number. I wouldn't even think the horsepower peak is that high, let alone the torque.

The 3.8L has a reputation for oil consumption in the minivans as well. It's a good motor, but some just simply consume oil. The 3.3L never gained that reputation, just the 3.8L.

 

[demarpaint]

It will be interesting to see the torque and HP #'s for the 3.6L Pentastar in the Wrangler application. I've read on another board one member ordered one today, the dealer doesn't have an info on the HP or torque ratings for the 3.6L Pentastar in the Wrangler just yet. It should be interesting to see if they tuned it for off road use. I'm just happy DI hasn't found its way into the Pentastar yet.

 

[UNC017]

Originally Posted By: Hokiefyd
Originally Posted By: 440Magnum
Peak torque on the 3.8 is around 4000, but that's true on the 4.0 also. In both cases the ramp up to that peak is pretty flat and starts low. Hadn't heard about it burning oil offroad, but different engines respond differently to operating at strange angles.


Peak torque on a 4.0L is 4000rpm? I wouldn't believe that unless I saw the number. I wouldn't even think the horsepower peak is that high, let alone the torque.



I said "about" 4000 ;-p. Now you've done it, you made me go and look it up. See http://www.allpar.com/mopar/40.html and scroll to the bottom for 2003 figures. Torque peak 3200 in the Wrangler (the Cherokee was gone after 2001 and it had a slightly higher torque peak RPM due to a different exhaust system) and horsepower peak at 4600 RPM, redline 5300. But like I said... never let it run >4000 for extended periods if you want it to live long...

 

[UNC017]

Originally Posted By: demarpaint
It will be interesting to see the torque and HP #'s for the 3.6L Pentastar in the Wrangler application. I've read on another board one member ordered one today, the dealer doesn't have an info on the HP or torque ratings for the 3.6L Pentastar in the Wrangler just yet. It should be interesting to see if they tuned it for off road use. I'm just happy DI hasn't found its way into the Pentastar yet.


My other secret worry about the Pentastar design is the "cast into the head" exhaust manifold. Its all nice and neat just bolting the exhaust downpipes to a single outlet on the cylinder heads, but the long exhaust passages inside the head casting mean that a fair amount of extra heat goes into the metal of the head. Gonna have to see how that pans out in the long run. Anyone else remember Pontiac v8 cylinder heads from the 60s and 70s, and how the elongated exhaust passages would burn all the paint off the heads in 3 places on each side?

 

[demarpaint]

Good point ^^^. No headers for the Pentastar.

 

[Hokiefyd]

Originally Posted By: 440Magnum
I said "about" 4000 ;-p. Now you've done it, you made me go and look it up. See http://www.allpar.com/mopar/40.html and scroll to the bottom for 2003 figures. Torque peak 3200 in the Wrangler (the Cherokee was gone after 2001 and it had a slightly higher torque peak RPM due to a different exhaust system) and horsepower peak at 4600 RPM, redline 5300. But like I said... never let it run >4000 for extended periods if you want it to live long...


You had the 4,000 rpm point dead-on for the 3.8L. With experience with both engines, though not both in Jeeps, the 4.0L is definitely a stump-puller compared with the 3.8L. My neighbor has an '07 Rubi with the 3.8L and it's almost always above 2,000 rpm just driving around town. I haven't driven it, but I've ridden with him a number of times. All that said, I prefer the 3.8L to the 4.0L, mostly for NVH issues. I'm sure the Pentastar will be real nice in the Wrangler, if they can keep engine width in check to continue the tradition of easy maintenance and an open engine bay in the Wrangler (spark plug changes, etc).

Regarding the exhaust collector integral to the head, I don't think it'll be a problem. Although it's a first for Chrysler, Honda has been doing that for over a decade now. In fact, now that I traded off my Camry for a CR-V, I officially don't own a single exhaust manifold anymore, on anything. The MDX's J35A5 engine and the CR-V's K24Z4 both use cylinder head designs with exhaust collectors integral. The only thing that bolts to the cylinder head is the collector cup at the top of the catalytic converter.

 

[demarpaint]

Now to take this thread slightly OT again, which BTW was a good thing, a lot of good info has come from this thread, thanks!

Here's another question: Since this is year two for the Pentastar engine, and several years for the W5A580 transmission is it advisable to wait a year since the combo is new to the Wrangler? Or is it GTG now? My only fear is the Pentastar 3.6L becomes DI which is something at this point I'd rather not own. Or they try and jam an 8 speed AT in it, which would probably be a mistake.

OTOH there is a possibility if/when DI reaches the Pentastar they'll have learned from Ford and GM, but it will be totally new to the Jeep product line.

Thanks!

 

[SteveSRT8]

The head directly into the header provides emissions benefit, mostly quicker converter light up. Anytime they can lose a part they are usually doing the right thing.

Expect to see more of it.

 

[meep]

Originally Posted By: demarpaint
Now to take this thread slightly OT again, which BTW was a good thing, a lot of good info has come from this thread, thanks!

Here's another question: Since this is year two for the Pentastar engine, and several years for the W5A580 transmission is it advisable to wait a year since the combo is new to the Wrangler? Or is it GTG now? My only fear is the Pentastar 3.6L becomes DI which is something at this point I'd rather not own. Or they try and jam an 8 speed AT in it, which would probably be a mistake.

OTOH there is a possibility if/when DI reaches the Pentastar they'll have learned from Ford and GM, but it will be totally new to the Jeep product line.

Thanks!


I think chrysler is going to be ok with DI. The pentastar is already designed to accept it, but they are not implementing it yet. rumor is they know DI has some flaws and are delaying their implementation until they can work the bugs out-- tho the engine was designed with it in mind. Kudos to Ford for being first to market-- it was a great move and we need this tech. But also kudos for chrysler for being so careful given their "quality" reputation.

Even if DI just ends up requiring cleaning services every 30k, that's really not such a big deal... lots of folks here do it anyway... Remember the northstar--- known for carbon deposits if it wasn't run hard? And folks kept them and cleaned them as a matter of course- it was in it's own way still a very nice powerplant.

I think DI is a good thing. Even if Chrysler had it out today-- I'd be ok with it, knowing it may require a bit more TLC. What car doesn't need maintenance? I'd be much more leery of an engine known for mechanical failures... cracking blocks (civics), warped heads (some subaru 2.5L), t-chain tensioners (?), weird cam wear (VW), etc....

M

 

[Hokiefyd]

Originally Posted By: demarpaint
Here's another question: Since this is year two for the Pentastar engine, and several years for the W5A580 transmission is it advisable to wait a year since the combo is new to the Wrangler? Or is it GTG now? My only fear is the Pentastar 3.6L becomes DI which is something at this point I'd rather not own. Or they try and jam an 8 speed AT in it, which would probably be a mistake.


In either case, if you didn't want direct injection or an 8-speed automatic transmission, you'd have plenty of lead time to know if that technology is coming to the next model year. If something is coming down the line for 2013, for example, you'd likely know it well enough in advance to find a new 2012 that you wanted to buy.

In other words, I don't think you'd put yourself in a corner by waiting.

 

[demarpaint]

Originally Posted By: Hokiefyd

In either case, if you didn't want direct injection or an 8-speed automatic transmission, you'd have plenty of lead time to know if that technology is coming to the next model year. If something is coming down the line for 2013, for example, you'd likely know it well enough in advance to find a new 2012 that you wanted to buy.

In other words, I don't think you'd put yourself in a corner by waiting.


That was my thinking exactly. I could just as easily buy a 2011 now, vs. order a 2012. I'm in no hurry, time is on my side. I just like to get feedback from others. I think DI is here to stay, I just don't want to be too early into the game, and have the headaches as the problems are ironed out. JMO