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

rubileon

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I'm not an automotive engineer but I'm an aerospace systems engineer so complexity vs. reliability vs. cost vs. performance and weight vs. size is what I do. I'll offer my thoughts, however much they're worth.



Stress, yes, but every modern engine manufacturer will design their components to handle it. There has been a huge leap forward in terms of stress analysis, materials science, and manufacturing technology since turbos were slapped onto everything without much accommodation. The 1980's era logic where manufacturers tended to just slap low-compression pistons in the same engine long block to add a turbo or supercharger to. Maybe adjust the cams, too. And that's about it.

Modern 4-cylinder turbocharged engines are designed with the turbocharger in mind from the very beginning. Metallurgy, engine tuning, heck, even the air flow sensors have seen huge improvements in capabilities since the 80s. That was 40 years ago. Think of how much computation power is available in that iPhone in your hand vs. how massive even the simple calculators were back then. Engine control systems to eliminate/avoid preignition under boost are ubiquitous and effective, even on naturally aspirated engines.



If it's not acceptable continuously they wouldn't rate it for towing or put it in an application where it would run low/medium boost levels nearly continuously. Higher stress doesn't matter if it was designed with adequate material strength.

Using a turbocharger's boost in a turbocharged engine doesn't defeat the purpose. Staying out of boost all the time defeats its purpose - you never, ever use its potential. It's like never revving up a DOHC engine above 3,000 RPM because you're worried about your bearings or something. They're designed to use the boost and they're designed to control the level of boost to protect the engine from excessive torque.

I might have a V6 but it's because that was the only engine offered with the manual transmission. If I could have chosen the 2.0T as well, it would be a tough call. I'd have to drive both, but I think the extra torque from the 2.0T above ~1,500 RPM would be very, very useful. I find the V6 torque lacking and have to downshift more than I thought I would. But, I still like the drivetrain overall.

I don't think a high-technology V6 like the new Pentastar is any more or less complex than a well-designed turbocharged I4. You get an extra 2 cylinders, an extra head and pair of cams, as well as the oil systems and chains, guides, and tensioners to worry about with the V6 over the I4. The I4 might have a turbo but those are pretty well understood at this point being an extremely widespread presence on modern cars from subcompact through midsize. It's honestly probably a wash.
Before you go that far, if we take the two vehicles with the exact same engine, isn't the one that works harder the one that's more likely to fail first? Now imagine if the one that works harder is smaller in displacement and still outputs more? You're burning a candle from both ends.

Also, isn't steady state operation better for engine longevity? A turbo engine goes through a massive range of cylinder pressures thanks to there being no boost at low engine speeds.

Aircraft piston engines are also a very relevant example to this discussion. They are made simpler, they have big displacement, low CR even on avgas... a 6 liter engine with CR of 9 might produce 200 hp. There are people here wanting to use turbos in high altitude areas and you're saying they're perfectly fine but why aren't their used in modern aircraft piston engines more widespread then?

Why do piston aircraft engines with turbos have lower TBO (time before overhaul, for others) than naturally aspirated ones?

Finally, why are we all lying to ourselves by saying manufacturers want us to have reliable things that last longer? Manufacturers are making things more complex to the point self maintenence is increasingly more difficult, they're adding defeat devices and planned obsolescence is not a conspiracy theory anymore but somehow, according to the turbo i4 buyers here, the introduction of highly stressed little turbo engines in recent times is a sign of manufacturers doing things for the greater good and world peace :CWL:
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AnnDee4444

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Before you go that far, if we take the two vehicles with the exact same engine, isn't the one that works harder the one that's more likely to fail first? Now imagine if the one that works harder is smaller in displacement and still outputs more?
I'm not really concerned with longevity of the 2.0 or 3.6, as any new motor should go +250,000 miles if maintained properly. I can also think of a few instances where the smaller 'overworked' engine has a reputation of being 'un-killable' (Slant 6, Ford 300, Chevy 292).

This isn't to say that I disagree with your thoughts, but as of right now it's all speculation. Every engine will have it's own unique set of issues, and comparing some other manufacture's turbo 4-cylinder, or an airplane engine, or old reliable inline 6s... it's is all just a guess right now. Nobody (besides FCA) knows if the 2.0 will have carbon on the valves at 100,000 miles, just like we couldn't guess that the simpler 3.6 would have passenger-side head failure issues, or that the old-school manual transmission would be blowing up clutches.
 

OnlyOne

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The V6 is a fine motor. A damn good one. It just doesn’t have the power to turn bigger tires comfortably. Especially at altitude. My V6 JL on 37s made a lot of noise but never wanted to move. It was fine around town but an utter dog on the highway. My turbo barely needs to downshift on a long 7% grade.
 

tfinnell

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they revised the spec - you can run 87, just get a bit lower performance.
I'm running 87 on my '20 Recon, got 28.3 mpg on a 300 mile round trip partially thru the Smokey mountains and it has way more pep than my '18 Rubi with the 3.6 that I traded in.
 

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Kyanche

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3.6 owner checking in again. Guess I was wrong about the premium gas!

In that case, the 2.0T sounds like a better engine all the way.
 

FireWorxFire

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We run a 3.6 and the 2.0. Both have been amazing. I personally drive the 2.0 daily which is used for work, personal, play, good amount of off road, and towing my 2.5k pop up. Zero issues and it is a pleasure to drive! Just have to learn how to drive it off road on the rocks and the rest is downhill
 

Tyderian

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Man I really need to find out why my 3.6 vibrates at idle lol.

Anyway, the only downside I can think of with the 2.0 is that you have to use premium gas.
I have 15k miles on my 2.0 and have never once put premium gas in it. I regularly fill up at Safeway and Costco, I see no difference in mileage/performance vs Chevron or Shell gas. 87 octane all day! 89 if I feel like spending the money.
 

zrickety

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I heard someone say carbon buildup. If the 2.0 is direct injection, that will be it's Achille's heel. If they are not driven hard to burn it off (3000+ rpm for 30 min), or walnut blasted, you will see driveability problems in the future. Other forums are full of these horror stories.
 

FireWorxFire

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I heard someone say carbon buildup. If the 2.0 is direct injection, that will be it's Achille's heel. If they are not driven hard to burn it off (3000+ rpm for 30 min), or walnut blasted, you will see driveability problems in the future. Other forums are full of these horror stories.
^^^^^^^ This is extremely true of any direct injection engine. I will say with some relief that fuel is not the concern, hence why some, including myself, do not see much if any performance difference with different octanes. The key to keeping these engines as clean as possible, while heat is a great cleanser, is the oil used and how often. Tow? Change oil even more frequently. Drive like Ricky Bobby coming back to racing? Change it frequently. Use higher octane, drive it like you mean it, get it hot enough on the intake side, and then you can do regular oil change frequencies. Just my .02 after building and owning way to many turbo engines with direct injection.
 

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oceanblue2019

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Does anyone who actually owns a 2.0 have any complaints or engine failures related to the 2.0? I don't really count the first 500 miles, as assembly & manufacturing defects happen to all motors. BSG/eTorque isn't 2.0 specific anymore, just wondering if there are actually any issues besides speculation.
19,000 miles. 14,000 miles with a JB4 tune on MAP2. 2.5" Lift. LOD destroyer front and rear bumpers and side skids. 35" tires. Goes off road at least two weekends a month, and often more - mostly blue and some black trails. 2.5 hour road trip each way to the off road park at 75mph.

Absolutely zero issues. Love the 2.0L and would not change a thing.

I've yet to meet someone with a 2.0L who wishes they went 3.6L.
 

IdahoJOAT

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Man I really need to find out why my 3.6 vibrates at idle lol.

Anyway, the only downside I can think of with the 2.0 is that you have to use premium gas.
Except it doesn't.
 

oceanblue2019

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I heard someone say carbon buildup. If the 2.0 is direct injection, that will be it's Achille's heel. If they are not driven hard to burn it off (3000+ rpm for 30 min), or walnut blasted, you will see driveability problems in the future. Other forums are full of these horror stories.
Can be an issue, but typically is much worse on normally aspirated DI engines. NA Audi DI engines are a pain as need frequent walnut blasting as they get carboned up pretty quickly.

The turbocharged DI's typically have enough intake velocity to keep the intake and intake valves pretty clear of oil and not as big of an issue. Just run oil to the vendors spec and "put the pedal to the metal" when you safely can.
 

zrickety

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Can be an issue, but typically is much worse on normally aspirated DI engines. NA Audi DI engines are a pain as need frequent walnut blasting as they get carboned up pretty quickly.

The turbocharged DI's typically have enough intake velocity to keep the intake and intake valves pretty clear of oil and not as big of an issue. Just run oil to the vendors spec and "put the pedal to the metal" when you safely can.
I've seen some pretty gnarly build up on turbo engines...it really depends on how they are driven. Quality oil at early intervals helps, but is not the silver bullet. It seems anyone that drives like an old lady or tries to save gas, falls victim to buildup.
 

viper88

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You need to test drive both engines and both start stop systems. Buy the one that drives the way you prefer. Then buy a discounted Mopar Max Care Warranty and enjoy.
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