3.6L vs 2.0 turbo?? Pros and cons of both??

[limeade]

I don’t think anybody argued turbos guaranteed reliability, but if you don’t think there’s a massive difference in power loss between NA and forced air you’ve clearly never driven both at elevations above 10k feet. Living at nearly sea level and regularly wheeling in the high Sierra Nevada’s in dozens of different rigs for the last 20 years, I can honestly say that the 2.0t wrangler is the only Jeep I’ve driven that still feels like it wants to pull in 2wd, loaded with camping gear, on steep grades. Off road, in low range, any engine is sufficient, even the garbage 2.8L v6 in my old xj. My wagoneer was a dog at altitude (carb mostly to blame there). The v6 xj couldn’t maintain 40mph on a steep grade. The 89 xj with the 4.0 was better, but still struggled to maintain 55 mph pulling a grade. The 09 2 door jk with the 3.8 was a dog even at sea level, often forcing down shifts pushing 6k rpms just to pass someone on the highway. The 3.6 was a massive improvement over that pos, but still feels sluggish on steep grades at altitude. Even the v8 in the 01 grand Cherokee would struggle to maintain 60mph on a steep grade in the mountains. I’ve yet to find a grade at any elevation that the jl won’t accelerate while climbing, let alone maintain speed. Is it the end all be all of engines, of course not. For my use is it superior to the only other option in 2019? By a mile (or more than that depending on elevation). Having driven the ecodiesel in ram trucks, I’d go with that over the 2.0t if I was buying today, but the 3.6L would still be my last choice. Not that it’s a bad choice, or a terrible engine, but I like the way the 2.0 drives. Not worried about reliability so much when I’m buying a brand new rig that is going to be under warranty for years.

This is the exact reason why I chose the 2.0T over the 3.6. For higher elevation/mountain driving, the 2.0T is a little rocket ship while the 3.6 was a dog. Test drove both in the Sierra Nevada mountains and the 2.0T was an easy decision.

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[Crusifix]

I'm arguing for physics and not against physics so I never said a turbo isn't beneficial in creating power over N/A when the air density is low But the point about a turbo creating higher cylinder pressures and not easily letting the engine operate in a reliable steady state because of boost coming in and going out every time the accelerator is used, still is true whether you're at high altitudes or not.

Now if you somehow can control the boost so that turbo is used when air density falls below sea level, it won't be creating higher pressures than what naturally aspirated is about at sea level. Still, because of the nonlinearity of the boost curve, you don't get the benefits of steady state operation even if you're driving around in a completely flat town in the mountains. To put it differently, if there are no other issues, a naturally aspirated engine will probably last even longer at altitude (vs. sea level) but the turbo might actually fail sooner because now there's a greater difference between boost and no boost states.

Pleasant dreams boosters *evil laugh*

You are overthinking it and inaccurate. I've built more race engines than I can remember, but I can probably count my invoices and figure it out.

 

[PavementWarrior]

4 turbo is not gonna last, not much to talk about.

 

[limeade]

4 turbo is not gonna last, not much to talk about.

I'd love to hear the science and reasoning behind this statement......

 

[Crusifix]

Yeah, I was pushing 430 wheel hp through my 2.0 Evo X for 60K miles before I sold it. FWIW, it put down 267 wheel hp when it was stock on my Dynojet before upgrading the cams, injectors and turbo. The guy that has it now is still racing it and street driving it. I never went into the engine other than to change out the cams. Still on the stock bottom end. It's at around 130K miles now. When you build an engine with boost in mind, then it will last. The black eye that they get is when people throw a turbo on an engine that wasn't designed for it and don't change anything else out to make it work like it should.

 

[Zandcwhite]

4 turbo is not gonna last, not much to talk about.

These guys sound like the carb guys in the late 80's. It's not what I'm used to so it's not going to last. Your fuel injection can't be reliable. I can tune my truck with a screw driver and a pair of pliers. Blah blah blah.

 

[PavementWarrior]

These guys sound like the carb guys in the late 80's. It's not what I'm used to so it's not going to last. Your fuel injection can't be reliable. I can tune my truck with a screw driver and a pair of pliers. Blah blah blah.

No..., its nothing to do with the reliability of the efi or turbo. Its about a small high compression engine that has to work very hard to push a heavy vehicle

its gonna wear out sooner, and its not really a debate, jsut a really bad design

 

[Crusifix]

No..., its nothing to do with the reliability of the efi or turbo. Its about a small high compression engine that has to work very hard to push a heavy vehicle

its gonna wear out sooner, and its not really a debate, jsut a really bad design

I could understand your argument if the engine had to turn more RPM to make the same power as the 3.6. That isn't the case. I would argue that the 2.0 isn't working as hard as the 3.6 per lb of load it has to carry. But what do I know, I'm just an engineer.

 

[PavementWarrior]

I could understand your argument if the engine had to turn more RPM to make the same power as the 3.6. That isn't the case. I would argue that the 2.0 isn't working as hard as the 3.6 per lb of load it has to carry. But what do I know, I'm just an engineer.

Cs get degrees, turbo charging a small engine puts it under alot of stress. As a young engineer I learned to talk to service people to learn how designs hold up over time, they are not engineers but the smart ones see the patterns on what works and what does not work.

I dont know any decent mechanic that will tell you a small turbo engine is gonna last... cause they dont last. For the trade it in every 3 years crowd it will not matter.

 

[AnnDee4444]

I'd love to hear the science and reasoning behind this statement......

Ooo ooo I got this! "TRIED & TRUE"

 

[Zandcwhite]

Cs get degrees, turbo charging a small engine puts it under alot of stress. As a young engineer I learned to talk to service people to learn how designs hold up over time, they are not engineers but the smart ones see the patterns on what works and what does not work.

I dont know any decent mechanic that will tell you a small turbo engine is gonna last... cause they dont last. For the trade it in every 3 years crown it will not matter.

Define last? 100k, 200k? My warranty covers me to the first one and with my usage that’s likely to be 7-8 years out (dealer threw in 100k unlimited time power train). I’m of the mindset that after 100k, it’s all gravy anyway. If I want to keep this rig beyond that it will likely get a Hemi swap if/when the engine fails.

 

[Crusifix]

Cs get degrees, turbo charging a small engine puts it under alot of stress. As a young engineer I learned to talk to service people to learn how designs hold up over time, they are not engineers but the smart ones see the patterns on what works and what does not work.

I dont know any decent mechanic that will tell you a small turbo engine is gonna last... cause they dont last. For the trade it in every 3 years crown it will not matter.

But they do last. At least those designed in the last decade do. There is actually data to back that up.

 

[DadJokes]

Well, real world feedback? Until I see crankshaft flexing signs like images of bearing wiping (usually in high rpm loads in short bursts) or cracks in between journals during a magnaflux, I’ve no additional concern over a 3.6.

Now my old school, years ago opinion on 4cyl’s in heavy vehicles or 4cyl’s in general was simply more wear from having to downshift more (less power down low) to keep rpms higher (more wear) and not being able to upshift under heavy load or inclined roads. Which is simple, more R’s, more wear. Today’s many gear ratio transmissions have negated that extensively. Less downshifting. Less rpms.

So if that 3.6 doesn’t have the torque down low to prevent a downshift that will increase rpm’s... that’s more wear than another engine with more power/cyl pressure/torque in the normal operating range.

 

[emptyminded42]

Cs get degrees, turbo charging a small engine puts it under alot of stress. As a young engineer I learned to talk to service people to learn how designs hold up over time, they are not engineers but the smart ones see the patterns on what works and what does not work.

I dont know any decent mechanic that will tell you a small turbo engine is gonna last... cause they dont last. For the trade it in every 3 years crowd it will not matter.

You can put anything under any amount of stress and if designed properly it will last.

There are plenty of durable turbocharged engines out in the world. It all comes down to the specific engine and if it was designed to handle its use case.

Nobody in this thread knows how much was or wasn't changed between the Jeep 2.0T and the Alfa for the different applications. Therefore, nobody can say anything decisively on how durable the 3.6 Pentastar Upgrade engine is vs. the Hurricane 2.0T.

Throwing around platitudes based on anecdotes is a waste of time. And there's nothing inherently unreliable about a turbocharged engine over a naturally aspriated engine beyond additional part count. However, if you actually consider how many more moving parts the V6 has over an inline 4 turbo, I'd actually expect the V6 to have more things to go wrong. And the Pentastar upgrade was a pretty big redesign over the earlier version based on publicly available information so who knows if they got it right?

 

[Windshieldfarmer]

4 turbo is not gonna last, not much to talk about.

This is opinion, not truth. Not seeing wear related failures of any type yet.... All I know is that I’ve personally witnessed 3 relatively low mileage failures of the 3.6 in the jk.

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