why did Jeep put v8s in the Grand Cherokees?

[titan]

As I do research there is one thing that puzzles me. Depending on the recipe strokers are comparable or even better than the 5.2l, 5.9l, and 4.7l v8s in power fond in the ZJ/WJ yet I've also I read comments like "Gas mileage remained the same despite the higher HP/TQ outputs thus reflecting the engine's greater efficiency."

They sound great in every way. So what am I missing? Emissions? Reliability? Why didn't Jeep just build the 4.0 as a square engine from the factory instead of putting v8s in the Grand Cherokee?

[Cheromaniac]

Why didn't Jeep just build the 4.0 as a square engine from the factory instead of putting v8s in the Grand Cherokee?

That's a very good question! If hundreds of us managed to easily put together the raw materials needed to build a 4.6L stroker (a truly square one like mine is actually 4563cc), it does make you wonder why Chrysler couldn't do it.

[Missourian]

The funny thing is because of folks here like; "Cheromaniac", "SilverXJ" and "Muad'Dib" supporting the STROKER interest, MOPAR is now offering a 4.6L STROKER motor through the dealerships.

[Cheromaniac]

The funny thing is because of folks here like; "Cheromaniac", "SilverXJ" and "Muad'Dib" supporting the STROKER interest, MOPAR is now offering a 4.6L STROKER motor through the dealerships.

Yeah that's funny. Considering that the 4.0L engine went out of production nearly 6 years ago, MOPAR shut the stable door long after the horse had already bolted.

[SilverXJ]

That, the price, and lack of any real info on them. ATK makes them, but that is about all we know. I would love details on their roller cam setup, and I am sure Mopar would do well selling the cam setup as a kit.

On the V8 vs the stroker issue, I think a lot has to do with the perceived image of a V8 vs a I6. Also, the 4.0L wasn't exactly emissions friendly and an old design. The new 4.7L V8 is a lot more emissions friendly and is a newer design. Aluminum heads, over head cams, etc.

[Missourian]

Knowing how much torque is created in a inline design versus a V design. You would have thought Chrysler would have tried to develop a inline 6 with an overhead cam, four valves per cylinder using an aluminum block and head or perhaps just aluminum head. It would have outperformed many V-8's and could have taken advantage of newer emission techniques.

I do realize they made the decision to use the crappy little underpowered Caravan 3.8L V6 engine into the next generation Wrangler. It took them five years of hearing the customer complain about it before they made a change to dump it for the 3.6L Penstar. I am still trying to understand why they have not offered a HEMI yet? You would think the 5.7L HEMI would be a no-brain-er for at least the 4-door Wrangler.

I don't think these guys are really trying all that hard to sell new Jeep Wranglers or you could buy a 5.7L HEMI equipped, Dana 60 F&R w/lockers, and aggressive tire package Wrangler at the dealership.

[titan]

I don't think there is anything inherent about I vs. V or H piston layouts that mean more or less power. The only advantage an i6 has over other piston configurations is it is balanced so you don't need balance shafts or anything for a smooth engine.

If they appear to produce more torque it is because you have 6 in a row vs. 4 in a v8 the engine's pistons are 50% longer! So to get large displacement a longer stroke vs. bore may be favored to keep the engine as short as possible. e.g. the GM 4.2l Atlas was 93 mm bore and 102 mm stroke, the 4.2l Jeep i6 was 95 mm bore and 99 mm stroke, and the famous Cummins ISB is 102/107 bore and 120/124 stroke. Of course the 4.0 had a larger bore than stroke proving this doesn't mean its a rule.

You would have thought Chrysler would have tried to develop a inline 6 with an overhead cam, four valves per cylinder using an aluminum block and head or perhaps just aluminum head. It would have outperformed many V-8's and could have taken advantage of newer emission techniques.

GM did that with the Atlas and was on Ward's best engine list from 2002-2005. 270hp/275lbft when it was introduced and 291/277 four years later. You have to build quite a stroker to compete with that! Heck, that's comparable hp to the 2008 refreshed 4.7l v8!

I guess, to be fair, when you're on the verge of bankruptcy all you can do is toss in a minivan motor and hope the pentastar comes quick.

[gonridnu]

I'd take a 5.9 Limited Grand in a heartbeat if I could find a nice one. I could have all kinds of fun with one of those:)

[SilverXJ]

You would have thought Chrysler would have tried to develop a inline 6 with an overhead cam, four valves per cylinder using an aluminum block and head or perhaps just aluminum head. It would have outperformed many V-8's and could have taken advantage of newer emission techniques.

That would have been nice. A 4.7L (or smaller) with a cross flow alminum head (maybe a aluminum block too), 4 valves per cylinder, DOHC, direct injection, etc. Just look at what BMW does with their inlines.

I do realize they made the decision to use the crappy little underpowered Caravan 3.8L V6 engine into the next generation Wrangler. It took them five years of hearing the customer complain about it before they made a change to dump it for the 3.6L Penstar. I am still trying to understand why they have not offered a HEMI yet? You would think the 5.7L HEMI would be a no-brain-er for at least the 4-door Wrangler.

And there is plenty of room for the two extra cylinders. There is like a foot, maybe more, between the front of the engine and radiator. They probably want you to buy a larger Jeep with a V8 so they can make more profit.

I'd take a 5.9 Limited Grand in a heartbeat if I could find a nice one. I could have all kinds of fun with one of those:)

I'd like one too, I even like the 4.7L HO WJ.