OK, you two, I finally found a good deal on what is supposed to be an unlocked Superchips 3874, should be here later this week...

 

OK, got a little behind the wheel time this past weekend, took the fam on about a 3hr drive to the big D and I was really considering stopping at Summit to pickup a Superchips but before I did, I took one more look on ebay and found a slightly used one, supposed to be unlocked for about half price so I nabbed it.

I took the opportunity to try a little experiment and filled it up with 93 from Texaco before we headed out and then 87 on the way back. I can't say I noticed any difference with either fuel, either with performance or by watching the fuel mileage estimator on the dash. Gets about 16mpg and struggles to maintain highway speed either way, spent the whole trip taching between about 65 and 80. I really hope this tuner will let me use cruise control, but if not, I still have Yukon 4.56 kit!

 

Having owned what turned out to be a reconditioned 3.8 (which I sold for $700CDN at the time condition unknown) I can honestly say you are expecting way too much from your Jeep trying to cruise at 80mph. My 6 speed man at 110kph (68mph) was not able to pass a semi on flat ground running into a headwind. Problem solved with Chev/auto conversion and more economical.
I would recommend spending the money on HP Tuners as that is good for almost any vehicle on the road, resides in your laptop of the day (IE new laptop transfer over) and accesses almost all parameters of your drivetrain on easily understood tables, graphs etc. Cost in US is about $299 plus $100 for 2 connectivity credits. Change vehicle just simply buy more access credits. Only warning is you get a license to kill with it and by that, I mean, you can destroy your engine or tranny if you do not understand what you are doing. I use this system for both the Jeep side and the Chev side on my vehicle and has a fantastic diagnostic scanner for use while you drive down the road. Check it out and you might see it as a good fit.

 

Sixty, thank you for your response, seriously. If an LS swap were something my wife would even remotely consider, I might look into it. I have no doubts whatsoever that yours makes power to spare and will run circles around anything powered by a 3.8 V-6. Its just not on the table right now, ours is not really using oil or showing any signs of age and fatigue, I'm just not ready to give up on it. I might have been misleading in my post previously, I'm not trying to maintain 80 on the highway, 75 would be great I just want O/D to be useable anywhere but downhill. I don't think that's asking too much, the little motor just needs a little help, a little more RPMs to carry that load at speed and it should do fine.
I will say this, if I put the 4.56 gears in it and the Superchips and it still won't cruise down the highway in O/D, then I will be talking about a repower!

 

OK, its finally here, yes as several of you warned, it was still VIN locked to the previous owner, downloaded some updates, a few minutes and $100 later its unlocked and now its VIN locked to my Jeep

So the 91 Performance tune, doesn't really seem to do much on its own, Maybe I'll revisit with a tank of 91 fuel in it, but I programmed it in a couple of times and it felt really flat on performance and power.

The 87 Octane tune definitely woke it up, better acceleration and easier to hold highway speed, very nice, not sure if its perfect but its hard to judge, there was still quite a bit of traffic on the interstate and the wind was blowing like crazy but its definitely better.

I let my wife try the 93 Performance tune first, and I could feel the difference from the passenger seat, but she didn't say anything at first, just had like a half grin on her face so I asked her after we got to highway speed, "Well, can you tell the difference now?" She said "Yeah! It drives like a Ferrari!" She was of course exaggerating slightly, but yeah, it definitely made an improvement!

The transmission does seem to make more appropriately timed shifts now, much easier to get it to settle into OD Lockup, but so far it STILL will not lockup even at 50mph downhill in 3rd. I'm still planning to regear it, although this does make me think perhaps I could get away with 4.10s instead of 4.56s....
I'm going to have to play with it some more and see how it goes.

 

I own a 3.8L auto but don't have any ideas about how the torque converter inside the trans is suppose to work or the reason you would want to attempt to lock it up.

 

The app ties a license to a vehicles vin so if you had an open license you could read your friends car, but it would then lock that license to that car.

 

Late to the party, but I'm glad you got the same satisfaction out of the tuner that we did. It seems to make the vehicle more normal. I'm thinking I'll have to try another tune now that I'm doing more highway. The only two I've stayed away from are the Eco and Crawl. Nobody wants to wait 5-10 mins to apply a tune that only changes 4lo as far as I know.

 

I could explain... but this will be faster I've skipped to the part that describes the clutch, but I recommend watching the whole thing.