Good 4.0 performance ECU?

[Milford Cubicle II]

Oh, and also...I pray you've got damn sticky tires and a stiff suspension going that fast...and you never hit a pothole or variation in the road surface...I know that by the time I hit my 116mph gov' it's squirrly as hell...I would NOT want to be in an XJ going anything more than 120 without serious suspension mods...

I've topped mine out on 31's and it felt very stable, surprisingly. Don't get me wrong, I was very focused and conscious of my speed, but it didn't feel the least bit out of control.

OP: I've used Unichip's piggyback and it worked very well. It has some programs already available for the 4.0 and you can always get a custom tune for it down the road if you'd like.

 

[sidewaysstarion]

I had Christune.com do a +4 timing cal on my stock ecu along with removing the speed limiter and lowering the cruise engagement. I also had them bump the extended idle from 1000 rpms to 1300 rpms. They also replaced the fuel map with an export XJ fuel map and set it to run open loop on cruise to save fuel.

 

[GrimmJeeper]

Check the post dates...

OP: I've used Unichip's piggyback and it worked very well. It has some programs already available for the 4.0 and you can always get a custom tune for it down the road if you'd like.

I don't think he's going to see this, profile says:

Last Activity: October 9th, 2006

:gee:

 

[streetxj]

I had Christune.com do a +4 timing cal on my stock ecu along with removing the speed limiter and lowering the cruise engagement. I also had them bump the extended idle from 1000 rpms to 1300 rpms. They also replaced the fuel map with an export XJ fuel map and set it to run open loop on cruise to save fuel.

Were you running regular 87 octane fuel?

What export tune are you running? Reason why I asked that question is because the European 4.0's had less hp and torque than the U.S models. I think it's due to stricter emission requirements.

 

[sidewaysstarion]

I'm still running 87 octane, I also have a +6 timing cal if I want to run it on 91.

 

[streetxj]

I'm still running 87 octane, I also have a +6 timing cal if I want to run it on 91.

Cool. I edited my post and added another question. Thanks.

 

[sidewaysstarion]

The fuel map is out of a Mexican jeep calibration.

 

[streetxj]

I had Christune.com do a +4 timing cal on my stock ecu along with removing the speed limiter and lowering the cruise engagement. I also had them bump the extended idle from 1000 rpms to 1300 rpms. They also replaced the fuel map with an export XJ fuel map and set it to run open loop on cruise to save fuel.

The link sends me to a musical instrument website. lol

 

[O-Gauge Steamer]

I believe he is referring to Chris Jensen who has better than 20 years in the ECM business... I know the folks a F&B sure like him.

 

[CobraMarty]

Who's F&B?

I have a new never used Superchips Flashpaq Tuner #3875 I want to sell.

 

[sidewaysstarion]

Sorry the website is christuned.com, the way I contacted him was sending and email to [email protected]

 

[streetxj]

Sorry the website is christuned.com, the way I contacted him was sending and email to [email protected]

No problem. Thanks.

 

[GSequoia]

I'm a little confused at how cruising at open loop is going to save you fuel. That's just the ECU dumping in a pre-set ration of fuel to make it run, it's ignoring certain sensors so not running at peak economy / performance.

 

[sidewaysstarion]

In closed loop the ecu is constantly switching from rich to lean to keep kitty cat happy and emissions lower, this doesn't net the best economy / performance. Running it in open loop at 15-16:1 will net better performance but will also raise NOX on cruise and net better fuel economy. This is exactly what Chrysler did on the Mexican jeeps since Mexico doesn't really have any emissions laws.

 

[O-Gauge Steamer]

Who's F&B?

I have a new never used Superchips Flashpaq Tuner #3875 I want to sell.

They make new, from billet, Throttle Bodies.

 

[CobraMarty]

62mm to 68mm ? What is the real difference? almost $400, ouch. Will probably use the 62mm for a while now.

 

[Talyn]

I had Christune.com do a +4 timing cal on my stock ecu along with removing the speed limiter and lowering the cruise engagement. I also had them bump the extended idle from 1000 rpms to 1300 rpms. They also replaced the fuel map with an export XJ fuel map and set it to run open loop on cruise to save fuel.

x2 on Christune.com

 

[kastein]

wow I read this thread and 'xuv-this' has absolutely no idea what he's talking about, about anything he talked about. Glad he already SPOBI...

 

[WAZZUXJ]

Looks like a good place for this.

Jeep 4.0L performance upgrade myths

 

[Talyn]

Looks like a good place for this.

Jeep 4.0L performance upgrade myths

Yeah.. no. We aren't talking about those crappy one-size all flash packs that just adjust the timing and fuel. If you actually read the thread there is a lot more that can be done and gains to be had on a custom tune.