On the way home today it occurred that the grand Cherokee will not have the 4.0 anymore and if they put the 3.7 in it why not the jk?so i looked it up and the grand gets the 3.7.3.7 hp 210@5200 235@4000 the 3.8 202@5000 237@4000.the torq curve is flatter on the 3.8.so why would jeep spend all the money to turn the 3.8 into a jeep power plant and not use the 3.7?they was/is allot of talk about jeep saddling us with a inferior engine but jeep worked the 3.8 for a reason any one know what the advantage are?the disadvantages to jeep are huge(new line of parts for jeep and jeep dealer to stock and so-on.

 

I wondered the same thing .I have a 05 Grand with the 4.7 and that thing moves good. My Sister has the Commander and it to received the 3.7 sooooooooooooo I to would like to hear why they went with the 3.8?

 

my local jeep dealer argued with me that my truck didnt have a 3.8, and that it had a 3.7, and how i must have heard wrong...

 

It says 3.8 on top of the intake manifold, in big black numbers. Tell him to just open the hood.

 

I read somewhere that the 3.8 is a shorter engine which they needed to meet front end crash requirements.

 

A friend was busting my stones saying that the Liberty 3.7 was the same engine that was being put into the Wranglers. So I asked my dealer about it and he told me that the 3.8 was built specificly for the Wrangler, and it's not the same engine at all.

I really don't know what to believe at this point.

 

Based on what I have read, the 3.8 was chosen because they had extra manufacturing capacity so they could supply it. The 3.7 was being used in other Jeeps and capacity was close to maxed out, so they didn't want to risk engine shortages by also putting it in the Wranger. The 3.8 is supposedly just a "transitional" engine until they can have new ones designed and tested.

 

The 3.8 wasn't specifically built for the Wrangler. It's been in the Caravan minivans for 10+ years. Some modifications yes, but not specifically designed for the Wrangler.

 

Maybe that's what he was talking about...Maybe what ever mods were done on the engine were done specificly for the Wrangler. Or maybe he was throwing a little spin in there to make the sale, but he did also say that the 3.8 was by no means a brand new engine configuration. He seemed to want to just make it clear to me, that the engine in the Wrangler was not the same one that's in the Liberty

Before I had asked anybody about it my original assumption was that it may be a Liberty engine, but with a little different bore size and stroke length.
Or possibly just different cylinder hesds.

Basicly I was just taking a wild guess:toung:

 

OK so why the 3.8 and not the 3.7? They use the 3.7 in the Nitro and the liberty.
Personally i think the 3.8- 60 degree is a little smoother than the 3.7-90 degree.