Jeep JL Wrangler 3.6L vs 2.0T HP/TQ curve comparison (dyno chart)

[Sean L]

The gap between Rubicon and Sport is like 300 lbs, or about 7%. That should mean a roughly 7% impact on city MPG, for a 1-2 MPG city MPG penalty. Not to mention the increased aero drag due to lift/fenders/tires/etc probably causes a similar or greater highway MPG penalty.

And also add in your 4.10 gears and bigger tires to the mix as well. Your engine will be running about 15% higher RPMs at an equivalent speed with a sport or Sahara.

I get the fact that the Rubicon will get less per gallon than a Sport will but not by as much as you're thinking.

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[The_Phew]

And also add in your 4.10 gears and bigger tires to the mix as well. Your engine will be running about 15% higher RPMs at an equivalent speed with a sport or Sahara.

I get the fact that the Rubicon will get less per gallon than a Sport will but not by as much as you're thinking.

The gearing is less of a big deal than most people think; here is BSFC map for a modern V6 (same family as the one in the new Taco):

If you go from say 2000 RPM to 2300 RPM (the effect of 15% shorter gearing) along an iso-power line (not plotted, because this plot is a hot mess thanks to Toyota trying to show a comparison between two different engines, but you can do the math in your head using the torque and RPM), you're looking at maybe a 3% increase in fuel consumption. The tires, aero, and weight are a bigger deal than the gearing difference.

People wrongly assume gearing is to blame when they go from ~17 MPG to 13 MPG after they put on 37" tires, a massive lift, and shorter gears. No bud, it's those tires and lift that got you WAY worse than the re-gear.

P.S.-It's not relevant to this discussion, but the Toyota plot above shows the improvement due to adding Atkinson cycle cam lobes to their V6. It's basically a ~10% MPG improvement at lower engine loads (i.e. cruising), with virtually no downside. It doesn't really manifest in the Taco, which has the same or worse MPG as the JL, but that's the fault of lousy aero, weight gain, and a transmission and drivetrain from like 15 years ago. FCA probably should have invested in Atkinson operation for the Pentastar, but they are focusing on BSG instead. I'd like both, please.

 

[Sean L]

The gearing is less of a big deal than most people think; here is BSFC map for a modern V6 (same family as the one in the new Taco):

If you go from say 2000 RPM to 2300 RPM (the effect of 15% shorter gearing) along an iso-power line (not plotted, because this plot is a hot mess thanks to Toyota trying to show a comparison between two different engines, but you can do the math in your head using the torque and RPM), you're looking at maybe a 3% increase in fuel consumption. The tires, aero, and weight are a bigger deal than the gearing difference.

People wrongly assume gearing is to blame when they go from ~17 MPG to 13 MPG after they put on 37" tires, a massive lift, and shorter gears. No bud, it's those tires and lift that got you WAY worse than the re-gear.

They still all add up together, Shorter gearing, heavier weight, and the poor aerodynamics of a wrangler.

4+5=9 shall we discuss if 4 or 5 is to blame still?

 

[Rockmaninoff]

...and jet engines are what?

It's always expected from the reader to do their homework prior to joining in to an educated debate but I'll side track to give you a primer... the turbo isn't the problem as long as you make sure it's cooled. It's the engine that's put under a lot more mechanical stress due to a turbo is the point of concern when people say turbos reduce reliability.

 

[Rockmaninoff]

No experience with the FCA 2.0L turbo but I've owned two others: 2.0L Subaru boxer and 7.0L Ford diesel. Lag? Yes, but only about 0.5 sec if that. In other words, about as long as it takes to downshift - manual or auto - and drop the hammer.

Lag you get used to because we can learn to react to the need of power a bit early. There's also non-linear power deliver or as some call it the "sling shot" effect and it's an unsophisticated design outcome. If you don't feel it, the turbo in that vehicle is just an under hood ornament.

 

[WXman]

What I'm saying is neither. People's physical strength is classified in weight (e.g. in boxing, etc.).

When comparing the max power, the 2L with a turbo is like a 5'3" guy on drugs doing the job of a 7' guy with a similar build.

We have forgotten just how much these little engines are pushed. Build and build quality can vary but if they put the 2L turbo's build quality in to a larger, naturally aspirated engine, we'd have an immensely more reliable engine.

The guys on the F-150 forums have been fighting about this for 8 years now.

Here's the analogy I used in those discussions: The EcoBoost is like the little dude at the gym who is on juice and has veins popping out everywhere. He benches 500 lbs. The Coyote V8 is the big dude at the gym who benches 450 lbs.

The little guy is technically stronger, but he thrashes his body to do it and he's going to die at 38.

The big guy still lifts plenty heavy, doesn't even break a sweat, and will go hard for years.

 

[WXman]

P.S.-It's not relevant to this discussion, but the Toyota plot above shows the improvement due to adding Atkinson cycle cam lobes to their V6. It's basically a ~10% MPG improvement at lower engine loads (i.e. cruising), with virtually no downside. It doesn't really manifest in the Taco, which has the same or worse MPG as the JL, but that's the fault of lousy aero, weight gain, and a transmission and drivetrain from like 15 years ago. FCA probably should have invested in Atkinson operation for the Pentastar, but they are focusing on BSG instead. I'd like both, please.

I test drove a 2018 Taco TuRD Offroad before getting my JL, and the engine was horribly non-linear. Especially under throttle. Lots of noticeable hesitation. The salesman said it was the engine ECU switching back and forth between modes. I don't know if he's correct, all I know is the engine is horrible. It's weak, makes even less torque than the outgoing engine, and has very non-linear power. Thank God FCA left Atkinson cycle, direct injection, etc. off the Pentastar.

 

[Sean L]

The guys on the F-150 forums have been fighting about this for 8 years now.

Here's the analogy I used in those discussions: The EcoBoost is like the little dude at the gym who is on juice and has veins popping out everywhere. He benches 500 lbs. The Coyote V8 is the big dude at the gym who benches 450 lbs.

The little guy is technically stronger, but he thrashes his body to do it and he's going to die at 38.

The big guy still lifts plenty heavy, doesn't even break a sweat, and will go hard for years.

Seems like everyone thinks your turbos will always be pushing maximum boost all the time.

Imagine both your short guy on roids and tall guy both take a moderate walk on the treadmill, as that will be what your average user will be for a drive on a country road or cruising on the highway. Your analogy really only takes effect when you're at wide open throttle and if you're the type that drives only with the pedal all the way down then of course you're going to burn out your Jeep early. Moderate Throttle with a turbo motor provides moderate boost and will not constantly want to strip your head bolts and blow up your motor.

 

[The_Phew]

I test drove a 2018 Taco TuRD Offroad before getting my JL, and the engine was horribly non-linear. Especially under throttle. Lots of noticeable hesitation. The salesman said it was the engine ECU switching back and forth between modes. I don't know if he's correct, all I know is the engine is horrible. It's weak, makes even less torque than the outgoing engine, and has very non-linear power. Thank God FCA left Atkinson cycle, direct injection, etc. off the Pentastar.

That's ALL in the throttle mapping (in the ECU) and has nothing to do with the engine itself. There are already aftermarket tunes for the Taco that make the throttle snappy and responsive, and folks love 'em. Over 6000 replies to this thread, and this is just the manual transmission version of the tune:
https://www.tacomaworld.com/threads...anual-transmission-engine-ecu-reflash.515734/

Atkinson cycle can be activated/deactivated just as fast as any other variable valve timing tech, and isn't at all responsible for the terrible throttle response in the Taco. Mazda and Audi use the same tech, and their throttle response is snappy as heck.

 

[RubiconGaby]

Lag you get used to because we can learn to react to the need of power a bit early. There's also non-linear power deliver or as some call it the "sling shot" effect and it's an unsophisticated design outcome. If you don't feel it, the turbo in that vehicle is just an under hood ornament.

Drive a Porsche Cayman and see if you can spot/feel turbo lag. It is so linear it's ridiculous.

 

[Rockmaninoff]

Drive a Porsche Cayman and see if you can spot/feel turbo lag. It is so linear it's ridiculous.

You must not have driven something that has linear power then. Turbos are non linear by design.

 

[RubiconGaby]

You should probably do some research before throwing out blanket statements, and I own a 718 Cayman for comparison, it’s powerband is linear to the extreme, much better than my old 350 Z’s naturally asperated 3.5.

 

[Rockmaninoff]

You should probably do some research before throwing out blanket statements, and I own a 718 Cayman for comparison, it’s powerband is linear to the extreme, much better than my old 350 Z’s naturally asperated 3.5.

I have done the research... it's called having an education in physics. Turbos are non-linear by design. Rules of physics don't walk up to a porsche and say "whoops! my bad... let me send you a gift basket" :cwl:

 

[WXman]

Seems like everyone thinks your turbos will always be pushing maximum boost all the time.

Imagine both your short guy on roids and tall guy both take a moderate walk on the treadmill, as that will be what your average user will be for a drive on a country road or cruising on the highway. Your analogy really only takes effect when you're at wide open throttle and if you're the type that drives only with the pedal all the way down then of course you're going to burn out your Jeep early. Moderate Throttle with a turbo motor provides moderate boost and will not constantly want to strip your head bolts and blow up your motor.

In order for a smaller engine (with less volume in the cylinders) to push the same amount of air (power) as a larger engine with more cylinder volume, it has to compensate for the reduction by using higher pressures. Which mean that even cruising at 70 with the cruise control set, the smaller turbo motor is working harder and is under greater cylinder pressures so that it can flow the same volume of air out the exhaust and produce the same power.

The analogy is spot on whether at 1,500 RPM or 6,000 RPM. A tiny turbo motor is going to have a shorter life, on average. That's just how it is. The fact that they saddle them with DI compounds the issue.

Again, go to any Ford, MINI, Subaru, Nissan, etc. dealership and talk to a seasoned technician and ask him which engines he sees the most often, turbo or naturally aspirated. He'll tell you turbo every time.

 

[Sean L]

In order for a smaller engine (with less volume in the cylinders) to push the same amount of air (power) as a larger engine with more cylinder volume, it has to compensate for the reduction by using higher pressures. Which mean that even cruising at 70 with the cruise control set, the smaller turbo motor is working harder and is under greater cylinder pressures so that it can flow the same volume of air out the exhaust and produce the same power.

The analogy is spot on whether at 1,500 RPM or 6,000 RPM. A tiny turbo motor is going to have a shorter life, on average. That's just how it is. The fact that they saddle them with DI compounds the issue.

Again, go to any Ford, MINI, Subaru, Nissan, etc. dealership and talk to a seasoned technician and ask him which engines he sees the most often, turbo or naturally aspirated. He'll tell you turbo every time.

I know how turbo motors work, and the higher pressures involved, but honestly you're making it seem like you'll need a new motor at 40,000 miles.
Let time tell how well these engines last.

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