Performance chip/module???

jeepzilla · **Posted:** Tue Feb 26, 2008 4:50 am

Hey all ... I did a little searching around for power mods for my KJ, an wanted to know if anyone has used the JET performance module on there 3.7L?? What results have you found from using the stage 1 or 2?

tommudd · **Posted:** Tue Feb 26, 2008 9:47 am

talk to KYLiberty hes been there done that I think,

sleeve84028 · **Posted:** Tue Feb 26, 2008 10:08 am

My question: Since the ECM is a learning computer - wouldn't it automatically adjust itself back to stock settings after a while? Or at least as close to stock as the adjustment range would allow?

Based on this theory - the performance chip seems a bit wastefull.

ATXKJ · **Posted:** Tue Feb 26, 2008 11:12 am

search for KYLiberty posts
he had one of the modules reprogramed to allow the extra power or it would autoadjust it down

tjkoen01 · **Posted:** Tue Feb 26, 2008 11:40 am

Here's the deal. I have used both Jet Stage 1 & Stage 2. Stage one is worthless. KYLiberty will agree. Don't waste your money. If you are serious about making some more HP, go with a B&G flash. KYLiberty will agree.

Here's my two cents: I currently run the Stage 2 Jet Chip. It is not a night and day difference, but the extra power is noticable. To make the biggest difference, I need to run the high octane fuel. Gas mileage also improved slightly as well. If you can find one cheap (I found mine used for $50), I'd go for it. Having said all that, I am looking to upgrade to a B&G flash when money permits.

As far as the learning/adaptation ability of the computer, Jet says they alter the fuel and timing tables, so instead of the factory tuned for emission reduction, you get Jet's table tuned for power. So when the computer is "learning" it is basing it off of the Jet table. I have no way to idea how to verify that, take it for what it is worth.

What I can tell you is if you install the Jet Chip and don't reset the computer, it will do funny things. After resetting the computer, you need to let it idle for 10 minutes before driving it, otherwise it will stall at a red light. The first time it happened to me I didn't even realize the engine stopped b/c it just stopped, no sputtering or vibration. Scared the crap out of me. However, once I reset the computer and let it idle for 10-15 minutes before driving it, I have had no problems at all.

Hope this helps.

ATXKJ · **Posted:** Tue Feb 26, 2008 2:27 pm

The reason we refer to KY is that he's the only guy I know who's Dyno'ed, Nitrous'ed and blown up a Liberty engine.

his comment on Jet
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?p=271523&highlight=#271523

and mod's list
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=17536&postdays=0&postorder=asc&start=0

(#1 thing is stop the computer from limiting power)

cmohr · **Posted:** Tue Feb 26, 2008 8:09 pm

I know I have read that a few guys here have had the B&G flash don eto their ECU..

http://www.bgperformancepcm.com/ scroll down about 3/4 down to find the Liberty.

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

I've dyno'd the stage 1 and it doesn't work on the 3.7 in the KJ. I haven't dyno'd the stage 2, but would think you would run into the same problems with the torque management. You may get a little more power in certain areas of the power curve, but the torque management kicks in and limits the power even with the stock settings, so it should definately kick in with the advanced timing of the stage 2 and retard the timing back down and richen up the mix. If you go with the stage 2, I would highly recommend not doing any dyno runs as you are probably going to be very disappointed. Just use the seat of the pants dyno and you should be ok as it will shift and drive differently. If you actually want to upgrade your power, I would recommend the B&G. I have the first flash they did for the 3.7, and I have dyno'd it. I know that it actually works. You can actually get some pretty good power out of the 3.7 without blowing it up. Of course, accidentally tuning it to make close to 400 hp will blow the snot out of it. Still have a 3.7 short block with 2 scorched cylinders sitting in my garage just begging to be rebuilt.

cmohr · **Posted:** Wed Feb 27, 2008 3:47 am

I'm really really interested in this whole reflash thing, but, very hard to really find out much down here in Australia, main problem realy is the logistics of it, trying to organise another ECU from over here and then getting it set with my VIN and then reflashed all thats hard when you 12 hrs behind. :wink:

Saw something on their site about a little unit you can use to flash the ECU whilst its in the car, but, did not see it as an option for the Libery flash. Do you know anything about that?????

cmohr

jeepzilla · **Posted:** Wed Feb 27, 2008 5:04 am

I never really heard much about the power improvments of the JET chip on any engine, my thoughts where mostly about the shift points an MPG's I could get... I guess my next question would be is the B & G flash really worth the extra money if the power aspect isn't my biggest concern? I was hoping to get 1-2 mpg's an smoother ( less bog ) shifts out of the Jet...

tjkoen01 · **Posted:** Wed Feb 27, 2008 9:30 am

jeepzilla wrote:

I never really heard much about the power improvments of the JET chip on any engine, my thoughts where mostly about the shift points an MPG's I could get... I guess my next question would be is the B & G flash really worth the extra money if the power aspect isn't my biggest concern? I was hoping to get 1-2 mpg's an smoother ( less bog ) shifts out of the Jet...

I believe the Jet Chip changes the line pressure of the transmission which will firm up the shifts. When I installed my transgo shift kit, the last thing on the install list was to install a resistor across the terminals of the pressure sensor on the side of the tranny. Things were fine until about the 2nd day when out of the blue, the 2-3 shift was so hard you could almost chirp the tires at 25 mph! So naturally I called transgo and talked to their tech support. As soon as I removed the resister, the hard shift went away. The tech asked if I had any engine management software running. It took a minute of trying to figure out what he was talking about, but then the Jet Chip came to mind. He said the combination of the chip and resister was probably causing the problem. I have since tweaked the value of the resister to firm up the shifts to the way I think it should be.

If you are looking to change the shifting, go with the shift kit. Deleting the torque management with the B&G flash would definately be a plus too.

tjkj2002 · **Posted:** Wed Feb 27, 2008 11:21 am

The Jet stage II chip may be more for WOT apps,well that is what I need since my 5500lbs beast needs all the help it can getting going here in CO which isn't flat anywhere.In town it's normal for me to bounce off the rev limiter every shift until O/D just to keep up with traffic.
How anybody can not be a hazard to everybody else if you don't let the tach go ubove 2000rpm,it would take me 30 miles to get to 40mph at that rate.

The Jet stageII chip also helps with the tranny also,firms up some of the shifts but to take full use of that part the shift kit should be installed,got mine sitting here waiting for a nice non-windy day to install it.

Performance chip/module???

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