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 Post subject: 3.7L vs 3.8L...... What's the deal???
PostPosted: Tue Dec 25, 2012 11:35 pm 
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Location: Lake County, Illinois
So.....

Caught an episode of "Truck U" this morning, and they installed this awesome Magnuson supercharger system
on a 3.8L V6 Wrangler. The system came complete with tuner, new injectors, the works.

The best part was the torque and horsepower curves after install were incredible...
90% of available torque and HP at 1900 RPM, with peaks below 3500 RPM.

To me, this was the ultimate Jeep upgrade.

I understand there was something similar available for the 3.7L a while ago, but the engine couldn't handle
the boost, so the manufacturer stopped making it.

So what makes the 3.8L so much "better" ????
I know it's been a staple in the minivan line since the mid 90's, but what's the difference really??

This has seriously got me looking into a 3.8L swap for my Libby!!
Hell, doing a full engine, tranny, T-case swap from a Wrangler to a Libby should be easier
than a V-8 swap IMHO...... especially if I can bolt on this supercharger and have torque and HP
numbers equal to a small V-8.

Any thoughts?????

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 Post subject: Re: 3.7L vs 3.8L...... What's the deal???
PostPosted: Tue Dec 25, 2012 11:52 pm 
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Why?

It's a 30+ year old engine design,hence why it can handle boost.


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 Post subject: Re: 3.7L vs 3.8L...... What's the deal???
PostPosted: Wed Dec 26, 2012 12:06 am 
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If you are going to go to all that expense, why not just get a turbo diesel? More power and better fuel efficiency.


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 Post subject: Re: 3.7L vs 3.8L...... What's the deal???
PostPosted: Wed Dec 26, 2012 2:27 pm 
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Location: Lake County, Illinois
Just kinda wondering why the 3.8L wasn't used in the Liberty as well as the Wrangler.
Seems it's a much stouter engine overall, is able to handle the weight of said vehicles
with better initial performance and mileage than the 3.7L, and has more available in the
way of upgrades.

My wife's Caravan weighed in roughly the same as a stock Liberty, and she got 23 - 28 MPG with the 3.8L,
whereas my Liberty with the 3.7L gets 14 - 20 MPG.

IMHO... if you're gonna do an engine swap, this would be the ideal candidate.
The fitment issues would be nearly non-existent, wiring and ECU problems pretty much gone as well,
and the availability of inexpensive performance upgrades is a definite plus.
The Magnuson supercharger gives the best of both worlds with increased torque and horsepower
readily available from idle to 3000 RPM, and increased fuel economy.

Just thinking out loud....

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Brad
International Man of Mystery, Singer of Sentimental Ballads,
Soldier of Fortune, Guardian of the Holy Hand Grenade of Antioch,
Bass Player Extraordinaire, Keeper of the Eternal Flame
of the Immortals, Master Swordsman, The "5th" Beatle,
Expert Marksman, Stand-up Comedian, Martial Artist,
Jeep owner, and all around swell guy.


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 Post subject: Re: 3.7L vs 3.8L...... What's the deal???
PostPosted: Wed Dec 26, 2012 11:08 pm 
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X2 on buying a CRD :SOMBRERO:

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2005 Blue KJ Sport CRD, GDE, Magnaflow muffler, Destination AT, Amsoil filters, Fumoto, Timing belt and waterpump @ 99,600, 11 blade nylon fan, 2905 hayden fan clutch, EURO TC




Arguing about whether the glass is half full or half empty misses the point: the bartender cheated you.
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 Post subject: Re: 3.7L vs 3.8L...... What's the deal???
PostPosted: Tue Jan 08, 2013 2:23 pm 
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Having first hand use of the 3.7 in the KJ and the 3.8 in the JK (even a supercharged 3.8) let me say the 3.7 was a much better engine. Even after the blower and 5.13 gears, I still was wishing for the KJ engine in the JK... Now the 3.6 Pentastar... thats a different story altogether!

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 Post subject: Re: 3.7L vs 3.8L...... What's the deal???
PostPosted: Fri Jul 13, 2018 1:16 pm 
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The 3.7 engine was designed for the Liberty, saw that in the advertisements!


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 Post subject: Re: 3.7L vs 3.8L...... What's the deal???
PostPosted: Fri Jul 13, 2018 8:02 pm 
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Jindosjeep wrote:
The 3.7 engine was designed for the Liberty, saw that in the advertisements!

The 3.7/4.7 was designed in the 1980's but shelved since the market was not ready for a SOHC engine in a pickup/SUV.

AMC actually designed it.


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 Post subject: Re: 3.7L vs 3.8L...... What's the deal???
PostPosted: Sat Jul 14, 2018 2:35 pm 
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x3 for the CRD! In US gallons I average 38mpg, which is 45mpg in UK gallons!
The 3.8 gas guzzler is simply no match for the fuel economy of the 2.8 CRD.
The 3.8 started out with 150hp and just 213 ft-lbs of torque in 1991, which was steadily increased over the years up to 2007, when the the most powerful version was produced with 215hp and 245 ft-lbs of torque.
The CRD may only have 161hp but it has a whopping 296 ft-lbs or torque, so averaged out, it should have near indentical performance to the 3.8, but all the while using a lot less fuel!


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 Post subject: Re: 3.7L vs 3.8L...... What's the deal???
PostPosted: Sat Jul 14, 2018 6:50 pm 
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jeepsterkj wrote:
x3 for the CRD! In US gallons I average 38mpg, which is 45mpg in UK gallons!
The 3.8 gas guzzler is simply no match for the fuel economy of the 2.8 CRD.
The 3.8 started out with 150hp and just 213 ft-lbs of torque in 1991, which was steadily increased over the years up to 2007, when the the most powerful version was produced with 215hp and 245 ft-lbs of torque.
The CRD may only have 161hp but it has a whopping 296 ft-lbs or torque, so averaged out, it should have near indentical performance to the 3.8, but all the while using a lot less fuel!

3.8 timing chain = $550 repair at a shop,average life span is 250,000+ miles

2.8 CRD timing belt = $1500-$2000 at most shops and a must every 100,000 miles


I'll stick with piss poor mpg's.


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 Post subject: Re: 3.7L vs 3.8L...... What's the deal???
PostPosted: Sat Jul 28, 2018 6:52 am 
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[quote]
2.8 CRD timing belt = $1500-$2000 at most shops and a must every 100,000 miles


I'll stick with piss poor mpg's./quote]

That's what you tell the guy you buy your CRD from. Then do it yourself. Parts ARE $400.00 still. Then GDE tunes are over 700.00 and back at $1200. But now it's 180 hp and 330 lb/ft.

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Now have GDE full torque eco tune and eco transmission tune. Used an 02 liberty trans computer for my new trans tune.


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 Post subject: Re: 3.7L vs 3.8L...... What's the deal???
PostPosted: Tue Jan 15, 2019 10:35 am 
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Location: Kennewick, wa
So... To get the actual story... One of my friends is a euro mechanic and I am a diesel mechanic, that said he filled me in, when the diamler Benz and Chrysler merger happened they got rid of a fiew designs that were crap and guess what we got them. We got the 2.7, 3.7, and 4.7, they were all old Mercedes designs that they didn't want so we (Chrysler) got them, so we would have ohc technology. All the ohc 4bangers are from Mitsubishi and the 3.8 is based on an old Mitsubishi design I believe. If you look at the problems with all the mercedes designs you will see why they didn't want them, valve guide issues, timing chain issues, cracking heads ect. It costs MILLIONS to develop new engines and thats why there is so much design sharing as they buy other designs from each other to save. Look at rover, they have used old jag and BMW engines for years, and the new supra will have BMW engines.


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