Sweet, thanks! I'll check that out. lol an XJ is never finished!

 

lol I'm on this dang computer all day long! I will try the Youtube method

 

Sorry, this one isn't great since I never took it off idle. I have another one on my phone but left the cord to connect to my computer at work, more to follow tomorrow:


https://www.youtube.com/watch?v=nwTH...ature=youtu.be

 

I looked up the 252h and the info I found on summit was that it isn't for fuel injected vehicles. Is there truth to that or is it just a disclaimer?

 

To answer the header question I don't know, but I had it off, cleaned it up and I would say it's the standard run-of-the-mill $115 jobber. If I had to guess based off what other things I've fixed that the previous owner had 'fixed' I would say the factory manifold cracked and he replaced it with a combination of least expensive/easiest available. I couldn't justify spending money on a header when I already had a functioning one
I'll add a pic in my 2016 folder that shows the header post paint, pre full-wrap.


video isn't great but for the taste please see below:

 

I am in the same bucket as the OP,

I have done nearly all the "bolt on" upgrades for a 4.0, and only felt a slight gain in hp. More in the Butt Dyno department. However they have helped driveability. Had i not lifted, added weight, tires, etc. I am sure it would be more noticeable. Biggest improvement i noticed was with the 4 hole injectors and 2.5" exhaust. That really helped her off idle torque and pep. Not much to be had in the higher RPMS as the 4.0 is a low rpm torque motor.

 

I agree about drivability with the four hole injectors. I'm still at pre-lift height, so the last real solid test I have is checking the mpg. The last highway distance trip I took will all the bolt ons but still factory exhaust yielded 22+ mpg. I have a 300 mile round trip and a 1000 mile round trip this month so I'm hoping for even better mpg numbers. Then on to the lift kit!

 

It will work with fuel injection and factory computer with no problem. I don't know why they say it doesn't work.

 

Sweet! Thanks for the info. lol I will add that to the project schedule.

 

MPG update: Round trip to southern Missouri this weekend was 320 miles of highway but no interstate, hilly for half the trip. On the way down there were many cases of beverage on the roof rack that weren't there on the way back. I really didn't want to run the A/C but I got vetoed by my sweetheart. MPG was just over 23, I can live with that.

 

I noticed 0 improvement regarding everything after swapping to 703 injectors. I thought it possibly idled smoother and what not but honestly I don't think anything at all changed vs the stock ones. I saw virtually the same fuel mileage on mine. mine came out to 23.9 after traveling to the event, chimping around all weekend and then driving back home. 76 mph with the ac on when we were on the interstate.

I lifted it ~2.5" and added bigger tires. still bone stock now it gets dead on 20 mpg almost all city driving. not that it's a big deal. I'll be trading the stock exhaust for a better flowing setup soon, I don't expect much if any loss in mpg.

 

Did you do anything with your rear ratio?

 

nope. I put 235s on it and use a +4% modifier when figuring mileage.

 

Without dyno or real drag strip runs seat of the pants feel means absolutely nothing, I'm sorry.

 

That's what's cool about us all being entitled to have our own opinion. Dynos and Drag Strips aren't common where I'm at in small town Missouri, in hindsight I wish I would have made multiple trips to the city so that I could see the numbers for myself and to share with other for their benefit. lol but I wouldn't have done it just to defend myself on the forum.