plac

it comes down to this for me..

buy a 2011 JK with the new interior and 3.8L engine, and supercharge it. wont pass smog in cali, but would be a fun machine.

or buy a 2012 JK with probably 3.6L engine, keep it stock, have more power then the previous year, and keep it smogable.

the question since i havent bothered to check anything.. is how does a 3.8L w Ripp compare to a stock 3.6L Pentastar power and torque wise. I guess no one knows, since it isn't out yet.

tpm152

If I were you, just from the smog legal aspect, keeping it stock might be better. I have actually debated the same thing since we have CA emissions here in PA now and have come to the conclusion I just don't feel like paying the government more of my money just to have something that isn't smog legal...

However I will say this:

Looking at the pentastar versus the current 3.8, it has more power, but the TORQUE (which is the important thing) is fairly similar to the 3.8. The best way to describe what the pentastar would be like in the JK would be like having our current 3.8 with a redline of 6400 rather than 5500 RPMs. That is how it gains the extra ~80HP over the 3.8. It has an advertised ~10% increase in torque compared to the 3.8 which would be nice in the JK but it would by no means make a huge difference that everyone is hoping for (like shoving a hemi in the JK). We can probably get that same 10% boost in torque by having the JK tuned better (by superchips or what have you) and adding less restrictive intake and exhaust.

I am guessing this is why all of the reports that I have heard to date have panned the new pentastar in the grand cherokee and durango. We thought we had it tough having the 3.8 in our JKs that weigh in the neighborhood of 3800 - 4300 pounds (stock depending on the trim, whether its an unlimited, etc). Imagine expecting this nicely tuned engine that does wonders only to have about 10% more torque than our 3.8s in a new grand cherokee that weighs 4700 - 4900 pounds (10 - 30% more weight than the JKs) Driving a new grand cherokee with the pentastar (even with the best refinement and shift points possible) would be AT BEST just like driving a JK with the 3.8 and automatic

outside316

Well Plac I have to agree with waiting for the new engine. I have a s/c 3.8 & while it does run great it gets crap for mileage (nothing close to what Ripp claims) the computer mpg readout doesn't read properly now after their programming (this seems to be an issue with other owners as well) not that its a big issue but after spending that much $ it should still work accurately, as it did before the install. I am to the point now that I am going to put mine up for sale & wait on or see what the new 2012's/engine is like & go that route. I would just take the s/c off & sell it but ater originally buying the Gen1 & converting it to the Gen2 I have so much invested I couldn't get anything for it compared to what they are selling them for now. Just my .02

plac

thanks for the thoughts. i still gotta compare the hp/tq engine to engine. i keep forgetting to look it up. I didnt think the 3.8L torque was anything near the Pentastar either..

plac

thanks for the unusual stance on this, and real world thoughts. its rare you hear the other side on this S/C. I dont like modifying my cars, but i like the results. Stupid, but true. I like keeping my cars factory original if at all possible.

plac

2007-2011 3.8L
205hp/240tq

2012+ 3.6 Pentastar
280hp/260tq

I dont know about anyone else, but thats a pretty huge difference to me.. The extra 20tq is just a bonus.

tpm152

The 3.8 is quoted at 237 lb-ft whereas the pentastar is 260 lb-ft (in the grand cherokee which I would guess would be the version that would go into the JK) on the Jeep webiste. From what I can gather through various online sources (wikipedia, etc) it looks like the peak torque for the 3.8 is around 4,000 RPM whereas the pentastar peaks at 4,800 RPM so I am guessing the low RPM performance for the pentastar would likely be just about equal to the 3.8

plac

still, you ask anyone which engine they would rather have with both in front of them, the choice is obvious. 80hp is massive. now, is it worth it to trade in the 3.8L for the new engine, thats pretty debateable.. prob not worth it.

tpm152

I guess the way that I look at it is that either way (pentastar or RIPP SC) is that I very rarely exceed 3000 RPMs on my current 3.8 so neither would do me any good. Both of them make an additional ~80 HP over the current 3.8 by redline, but if you never come anywhere close to redline that extra power does you absolutely no good.

I currently get good fuel economy (23 pure highway and 17 pure city driving) which is the same as the fuel economy ratings of the new grand cherokee with the pentastar and from what I have read many people get worse fuel economy when getting the RIPP SC (expected since more air = more fuel needed at same RPM). So for me I see no reason to spend more money (to either buy a brand new JK in 2012 or supercharge my current rig) to have the engine perform exactly the same at low RPMs just like the pentastar will or to get more power at high RPMs that I never reach just like the RIPP SC does.

BOOGY

and .... iron block vs aluminum block = weight savings