4.0L Pushrod Inline 6 vs 3.6L DOHC V6

Qball

Qball

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This video shows the difference. I can personally attest to the fact that the 4.0L is the better engine. I have a 2006 Wrangler Rubicon that I handed down to my son. I now drive a 2016 Wrangler Rubicon with the 3.6L Pentastar DOHC engine. This Pentastar engine has 285 hp @6400 rpm and 260-lb-ft of torque @4800 rpm.

My old TJ with the 4.0L has 190 hp @4600 rpm and 230-lb-ft of torque @3200 rpm. Both Jeeps have the same 4.10 final drive ratio.

I have driven the mountains of WV and Virginia on I-77 countless times since 2006 in my old 2006 4.0L powered Rubicon and several times in my 2016 3.6L Pentastar powered Rubicon.

There's no comparison. My old TJ can pull the hills at 70 mph with no effort at all and the cruise control will stay at 70 mph. If I have to let off the cruise control while going uphill and then accelerate to get back up to speed, the TJ does so with no effort whatsoever. Both Jeeps are 6 speed manuals btw.

My 2016 Rubicon sucks when traversing the mountains up in VA and WV. When I have it on cruise control, it can't hold 70 or 65 depending on the speed limit, while on a steep grade. It always creeps down about 5 - 8 mph depending on the length of the climb. My old TJ can hold the speed with ease.

When I have to hit the brakes going uphill due to a slower vehicle in front, therefore cutting off the cruise control, my old TJ with the weaker 4.0L was very easy to get back up to speed. My 2016 struggles horribly to get back up to the previous speed and usually can't get there until it reaches the top and starts back down the other side of the mountain.

The lesson here as far as normal off-road passenger vehicles is concerned, in my opinion of course, is that lower revving pushrod engines rule, and higher revving OHC engines suck. If you want me to prove it, take a ride with me in both Jeeps up I-77 sometime. I'll let you drive.

 
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Those 4.0 were good engines and dang near bullet proof and hated when jeep moved away from it. Had one in a 88 cherokee and gave it grief and it always pulled threw. If you look at the torque curve of both that will be the answer. Its peak should be lower in the rpm range where you need it.
 
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I had a '00 Cherokee 2wd with a limited slip rear end that was very fun to drive. Loved that thing. My old '95 YJ with the 4.0 was stout as well. I 'wheeled the hell out of that thing & it never let me down.
 
SPST said:
What kind of gas mileage do they get?
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Both are about the same. The sticker on the '06 says 15 city/19 highway. The 2016 says 16 city/21 highway. But when going to WV from here, it takes a whole tank to get there. That's around 15 mpg. Coming back is not quite as bad because you're going downhill more than uphill. But they're Jeeps and most people that have them aren't concerned about mpg.
 
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Jp8819 said:
Those 4.0 were good engines and dang near bullet proof and hated when jeep moved away from it. Had one in a 88 cherokee and gave it grief and it always pulled threw. If you look at the torque curve of both that will be the answer. Its peak should be lower in the rpm range where you need it.
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Yep.
 
The Pentastar engine isn't a bad engine. It's just not the right engine for a Wrangler. For the life of me I don't understand why they would put a car engine in a Wrangler.
 
Qball said:
The Pentastar engine isn't a bad engine. It's just not the right engine for a Wrangler. For the life of me I don't understand why they would put a car engine in a Wrangler.
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My guess fuel mileage game and cheaper lighter engine option. That was one down side to the 4.0 it was never great on gas.
 
My first was a '48 model with a 4 bolt main hi po 289 Ford. Followed by a 70s Levi Edition V8 and then A Golden Eagle V8. Then a L O N G time without a Jeep. 2009 a V6 Wrangler. Drove it 5 years without a single issue of any kind. Sold it for Exactly what I paid for it 5 years earlier. Then came a 14 4 door, a 15 4 door, a 16 4 door, a 17 2 door converted to a pickup, and then a 18 4 door and now a 18 2 door. I missed the 4L engine but I'm sure it was a good one. I've never had a bad Jeep.
 
The old 4.0 was generally good for 250k+ miles just so you changed the oil and didn't abuse it. Theres a guy at work with a 96?? Grand Cherokee 4.0 with 320k on the ODO. It burns some oil now, but the engine has never been broken down. I think it was pretty much the same basic design engine for over 50 years.

Speaking of.... I have a factory service manual for a TJ in the buy sell trade area.
 
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BatteryOaksBilly said:
My first was a '48 model with a 4 bolt main hi po 289 Ford. Followed by a 70s Levi Edition V8 and then A Golden Eagle V8. Then a L O N G time without a Jeep. 2009 a V6 Wrangler. Drove it 5 years without a single issue of any kind. Sold it for Exactly what I paid for it 5 years earlier. Then came a 14 4 door, a 15 4 door, a 16 4 door, a 17 2 door converted to a pickup, and then a 18 4 door and now a 18 2 door. I missed the 4L engine but I'm sure it was a good one. I've never had a bad Jeep.
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Dang man. You need to do commercials for Fiat Chrysler. I'm sure they would pay you some good money.:D
 
Wrangler could use a small block option!
 
My guy at the dealership has tried to get me to get the Hemi option. The 385 HP Hemi option. He has actually ordered 1 for another customer. It comes with all kinds of great stuff. I'm not sure if it is still available on the new JL series. It was a $12,500 option on the JK. That added to a base Jeep would put you in about $36K. Not bad really. The new JLs went up $3K across the board on all models. Sticking with the last 2018 JK I just got.
 
BatteryOaksBilly said:
My guy at the dealership has tried to get me to get the Hemi option. The 385 HP Hemi option. He has actually ordered 1 for another customer. It comes with all kinds of great stuff. I'm not sure if it is still available on the new JL series. It was a $12,500 option on the JK. That added to a base Jeep would put you in about $36K. Not bad really. The new JLs went up $3K across the board on all models. Sticking with the last 2018 JK I just got.
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Dats a lotta power in a jeep........i wouldnt hit the has too much unless she was pointed straight!
 
I had a 2010 Rubi 4dr with the 3.8.
Added around 700 pounds to the stock weight. Relaxed at the plastic with steel, lift, skid plates, 37's, and 5.13 gears. Rev' d higher than stock. Still got the same 17mpg that it got bone stock I the highway. Had no problem holding 80 with cruise. Traffic was moving pretty quick that night in VA on 81.

The 4.0 achieves peak at lower revs.
The 3.8 liked running higher.
I'm guessing the 3.6 does too.

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My last one is bone stock with 33s. I had them remove the doors, carpet, sides, and spare for delivery. The shop manager said it was only the second one delivered from them that way. I asked..who got the other one, he said...YOU. I remember back to the Fox Mustangs and we thought 225 HP was really good. The 285 HP in these really push them along. My gets 50 miles a day 5 days a week. ALL weather. I have other ways to go and I usually don't leave in it if it's pouring rain but barring a deluge, I drive it daily. In it's current shape it weighs about 3800 pounds and keeps up with traffic on HW 22 where the norm is 70+. You are EXACTLY right about the milage, at least for the ones I've had.
 
BatteryOaksBilly said:
My first was a '48 model with a 4 bolt main hi po 289 Ford. Followed by a 70s Levi Edition V8 and then A Golden Eagle V8. Then a L O N G time without a Jeep. 2009 a V6 Wrangler. Drove it 5 years without a single issue of any kind. Sold it for Exactly what I paid for it 5 years earlier. Then came a 14 4 door, a 15 4 door, a 16 4 door, a 17 2 door converted to a pickup, and then a 18 4 door and now a 18 2 door. I missed the 4L engine but I'm sure it was a good one. I've never had a bad Jeep.
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Yeah that's all fine and dandy but you left the door open on my mailbox again and my mail got wet.
 
Jp8819 said:
Those 4.0 were good engines and dang near bullet proof and hated when jeep moved away from it. Had one in a 88 cherokee and gave it grief and it always pulled threw. If you look at the torque curve of both that will be the answer. Its peak should be lower in the rpm range where you need it.
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This. At legal speeds in top gear/overdrive you are operating way below the power curve in the new jeep.
 
I've always been a fan of inline 6 engines. Wish they were more common, but the new V6's are more car friendly and fit in a smaller space. Despite its low numbers on paper, its always suprised me how strong the old 300 straight 6 in the ford trucks was.
 
Qball said:
The Pentastar engine isn't a bad engine. It's just not the right engine for a Wrangler. For the life of me I don't understand why they would put a car engine in a Wrangler.
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Yep, this. My commuter car is a Chrysler 200 with the 3.6. The thing is a rocket, and still gets 33mpg on the highway. No business is a truck or truck like vehicle though


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thbassin said:
Yep, this. My commuter car is a Chrysler 200 with the 3.6. The thing is a rocket, and still gets 33mpg on the highway. No business is a truck or truck like vehicle though


Sent from my iPhone using Tapatalk
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My wife's 2015 Charger has the 3.6. That thing is faster than the 72 mustang my neither had with a 302.
I call it her race car. She discovered another benefit the fist time she drove it. Some people thought she was popo and got out of her way.

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BatteryOaksBilly said:
Having had all they have to offer, including having a truck made from a 2017, this is the configuration "I" like best.
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So, and Im trying to make sure I understand correctly - you bought a car with NO DOORS AT ALL, or just not shipped with them and they were given to you later or something?
 
HMP said:
So, and Im trying to make sure I understand correctly - you bought a car with NO DOORS AT ALL, or just not shipped with them and they were given to you later or something?
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I take it that he had them remove all the parts before he took delivery of the Wrangler, so the dealership has them in their parts dept or on a sales mgrs Wrangler :)
 
I didnt know that was possible.
And then I got to wonder if the price they take off for you not getting doors etc is the same as they'd charge you for the same items...
 
HMP, can you really not understand that when you buy a new vehicle, you can have it delivered like you want it? I walked on the lot...I pointed to a Jeep...I said I will give you XXXXXX for that...I told them to remove the doors, carpets, sides, spare tire and to put a set of 33 inch M/Ts on it. I came back in 2 hours...I paid them....I left and went home. Later that day they brought all the take-offs and I put them in the barn. I have purchased a 14 4 door, 15 4 door, 16 4 door, a 17 2 door converted to a pick up, a 18 4 door and a 18 2 door. All from this dealer. I have been doing business with him for 35 years. Hope this helps to make sure you understand correctly [your words]. I can't imagine what's so hard to get but, please, let me know if you have more questions.
 
BatteryOaksBilly said:
HMP, can you really not understand that when you buy a new vehicle, you can have it delivered like you want it? I walked on the lot...I pointed to a Jeep...I said I will give you XXXXXX for that...I told them to remove the doors, carpets, sides, spare tire and to put a set of 33 inch M/Ts on it. I came back in 2 hours...I paid them....I left and went home. Later that day they brought all the take-offs and I put them in the barn. I have purchased a 14 4 door, 15 4 door, 16 4 door, a 17 2 door converted to a pick up, a 18 4 door and a 18 2 door. All from this dealer. I have been doing business with him for 35 years. Hope this helps to make sure you understand correctly [your words]. I can't imagine what's so hard to get but, please, let me know if you have more questions.
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I get what youre saying now, but when you said "delivered" I figured you meant you ordered one from the factory and they had to 'build' it and then ship it to dealership, not that you had bought it on the lot and then had the items taken off.
Then when fsj said what he said it seemed more like you did NOT get those items at all, so that made me think you could order a jeep minus doors

Right on man.
Keep buying them Jeeps, I bet they love seeing you walk up once a year
 
Back to the engine thing. The inline six pushrod engine is definitely better than the overhead cam V-6 for hills regardless of speed.

I could run my JK up the mountains on I-77 on cruise control in 5th gear and I'm sure it would do fine.

But the purpose of this thread is to illustrate that an inline 6 cyl. pushrod engine that has 95 less horsepower and 30-lbs-ft less torque can run the mountains in VA and WV, both running the same 4.10 final drive ratio, better than a DOHC V-6 in 6th gear all day long and then some.

If you own a JK, you shouldn't have to downshift to 5th gear just to get up a hill on the interstate to avoid having your speed to creep down.

Basically it comes down to this: The 4.0L performs better on the road and off-road, at about the same fuel cost, than the OHC car engine. It doesn't make sense to me why they chose to ditch the 4.0L.

It certainly wasn't because of efficiency, reliability, or ease of and more economical maintenance.
 
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SPST said:
Because 99% of them are used like cars. Just like pick up trucks.
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If I drive my son's 4.0L TJ like a car and I drive my 3.6L JK like a car, on the interstate in the mountains, which one do you think I would rather drive based on my comments in this thread?
 
Flashpoint said:
This. At legal speeds in top gear/overdrive you are operating way below the power curve in the new jeep.
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"At legal speeds". That says it all. It's a Jeep. Jeeps are supposed to be driven at or below the legal speed limits.

Jeep Wranglers shouldn't be equipped with engines that produce HP or torque curves similar to passenger car engines.
 
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I hate that they got rid of the 4.0 inline. It really pisses me off. I miss my 2004 Jeep Wrangler Unlimited. I should have never sold her. Only vehicle I ever bought new. I do currently have a 2000 Jeep Grand Cherokee with the 4.0L. Love that thing.
 
Qball said:
"At legal speeds". That says it all. It's a Jeep. Jeeps are supposed to be driven at or below the legal speed limits.

Jeep Wranglers shouldn't be equipped with engines that produce HP or torque curves similar to passenger car engines.
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That why I geared my 2010 a little lower than the straight ration change from 32 to 37 inch. 5.13 gears. RMPs ran a little higher than stock. Reprogrammed with an AEV Procal. Got the same Highway MPG as bone stock even though it weighed at least 700# more than stock when I was done replacing all the plastic with metal plus under armor.
 
Lord of War said:
I hate that they got rid of the 4.0 inline. It really pisses me off. I miss my 2004 Jeep Wrangler Unlimited. I should have never sold her. Only vehicle I ever bought new. I do currently have a 2000 Jeep Grand Cherokee with the 4.0L. Love that thing.
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It's a common story I hear all the time. It used to be a story about "I will forever regret selling my Jeep CJ." Now it's a story of: I will forever regret selling my CJ/TJ and buying a JK.

If I had the time, I'd correct this blasphemy and yank that car engine out of my JK and install a real Jeep engine in it.

Maybe down the road it will happen.
 
Qball said:
It's a common story I hear all the time. It used to be a story about "I will forever regret selling my Jeep CJ." Now it's a story of: I will forever regret selling my CJ/TJ and buying a JK.

If I had the time, I'd correct this blasphemy and yank that car engine out of my JK and install a real Jeep engine in it.

Maybe down the road it will happen.
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My Lottery version would be dropping in a 5.7L HEMI. Not much heavier than the 4.0L. Plenty of room under the hood for it or the 6.4L. [emoji3][emoji16]

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I have a 96 Cherokee 2 door 4X4 5speed manual 4.0 I-6 and its a beast now if it never had "death wobble" again I would be happy
 
The 3.8 in my 07 JKU Rubicon 6-spd couldn’t get out of its own way on 35’s. Had to put that thing in 4 low just to pull my old boat out of the water! I’ve since upgraded to the in-line world with a 6.7 Cummins which allowed me to upgrade my boat as well lol. Current boat weighs 7800 dry without the trailer (over 2x the jeeps tow rating just at that) and I can’t tell the thing is back there most of the time. Apple and oranges I know, but it also explains why all the duramax and power stroke guys get butt hurt when talking about Cummins....;)
 
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