Originally Posted By: 440Magnum
Originally Posted By: GMBoy
I'm glad the Jeep Wrangler finally got a more powerful engine. The previous V6 engine was not exactly a good replacement for the very good and durable 4.0L straight-6.
I'm not sure why you would say that... the 3.8 v6 had almost exactly the same torque curve as the 4.0, but had more horsepower too. It goes back almost as far in terms of design, and has racked up just as many reliable miles in even more vehicles over the years. It was the absolute best possible replacement for the 4.0... assuming you want to replicate the 4.0. The real problem is that tractor engines like the 3.8 and 4.0 both feel a bit outdated when competing with newer engines with variable valve timing and more gears in the gearbox. Especially since the Wrangler was already heavier than the Cherokee in 2000, and has only gotten heavier since. The Pentastar is being asked to fill some big shoes and haul a lot of weight (too much, really, but you gotta meet safety regs).
Originally Posted By: GMBoy
People have been saying how this new 3.6L like to rev and makes good power up high....I wonder how it behaves at low RPM like you would see in a off road trail?? Hopefully, it has good torque off idle like it has power up the RPM band.
The last offroading magazine I read asked the same question, and loved the answer. The combination of available gearing (both in the WA580 and the available 6-speed stick) works great for crawling. IN fact I think that's one of the primary reasons for pairing the Pentastar with the WA580 instead of the 545RFE - better gear ratios for a smaller engine instead of optimized for big v8s. The other (bigger, probably) reason is that the Pentastar and W580 already go together in the LX/LC platform cars.
Originally Posted By: GMBoy
I still would rather have a 4.0L or good old 258 for Jeep Wranglers. But, given that most never see off road, the new engine probably is a very wise move.
As for the "built in exhaust manifold", I agree that is no real concern....unless you prefer headers... Which you cannot do anymore with that design
Headers would probably reduce power on a modern, computerized, and optimized engine... unless you also did a complete computer re-tune also. My only possible concern would be more about excess heat transferring from the exhaust passages into the engine cooling system, or heat warpage of that part of the head. But its not a real concern, they've been doing this type of design long enough to figure it out.
And why would anyone ruin a Jeep with a Chevy engine???
Excellent post, thank you. I can agree with all you said and appreciate the feedback.
As for ruining the Jeep with a Chevy motor, well, I can laugh with you on that one.
But seriously, I got that CJ7 in highschool (a LOOONG time ago lol) all worn out. I completely rebuilt it and restored it...2 times lol. The second time I replaced the body with a new steel tub (hate fiberglass).It is really nioe, custom paint, hardtop and soft tops, Dakota digital dash, Corvette seats, 4" softride lift, all the goodies etc... but the old 258 even with true dual headers and exhaust and the popular Weber carb set up was lucky to push maybe 160hp and with like 11mpg tops. Add that it has the T150 3-speed and the power on road is not too good. Off-road is fine. I had a buddy who had a crate 350 that he was going to install in a Nova but he went LS1 instead. So I bought the engine and the Advance Adaptor kit and took the 258 out. I now get around 17-18mpg average..with SCARY power in such a small truck, lol!
Originally Posted By: GMBoy
I'm glad the Jeep Wrangler finally got a more powerful engine. The previous V6 engine was not exactly a good replacement for the very good and durable 4.0L straight-6.
I'm not sure why you would say that... the 3.8 v6 had almost exactly the same torque curve as the 4.0, but had more horsepower too. It goes back almost as far in terms of design, and has racked up just as many reliable miles in even more vehicles over the years. It was the absolute best possible replacement for the 4.0... assuming you want to replicate the 4.0. The real problem is that tractor engines like the 3.8 and 4.0 both feel a bit outdated when competing with newer engines with variable valve timing and more gears in the gearbox. Especially since the Wrangler was already heavier than the Cherokee in 2000, and has only gotten heavier since. The Pentastar is being asked to fill some big shoes and haul a lot of weight (too much, really, but you gotta meet safety regs).
Originally Posted By: GMBoy
People have been saying how this new 3.6L like to rev and makes good power up high....I wonder how it behaves at low RPM like you would see in a off road trail?? Hopefully, it has good torque off idle like it has power up the RPM band.
The last offroading magazine I read asked the same question, and loved the answer. The combination of available gearing (both in the WA580 and the available 6-speed stick) works great for crawling. IN fact I think that's one of the primary reasons for pairing the Pentastar with the WA580 instead of the 545RFE - better gear ratios for a smaller engine instead of optimized for big v8s. The other (bigger, probably) reason is that the Pentastar and W580 already go together in the LX/LC platform cars.
Originally Posted By: GMBoy
I still would rather have a 4.0L or good old 258 for Jeep Wranglers. But, given that most never see off road, the new engine probably is a very wise move.
As for the "built in exhaust manifold", I agree that is no real concern....unless you prefer headers... Which you cannot do anymore with that design
Headers would probably reduce power on a modern, computerized, and optimized engine... unless you also did a complete computer re-tune also. My only possible concern would be more about excess heat transferring from the exhaust passages into the engine cooling system, or heat warpage of that part of the head. But its not a real concern, they've been doing this type of design long enough to figure it out.
And why would anyone ruin a Jeep with a Chevy engine???
Excellent post, thank you. I can agree with all you said and appreciate the feedback.
As for ruining the Jeep with a Chevy motor, well, I can laugh with you on that one.
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