The 3.7 will reward you mpg-wise if you are patient, or it will get 14 if you dip into it. It's not a muscle car-- it's a 4400 lb brick, so hwy driving, well, you have to know how to dip into it to get it to kick down and go. The autostick can help, get the gear you want ahead of time.
If you lift it, you WILL lose mpg.
If you put larger rubber on it, I found that to be frustrating with the 3.7 and standard gearing because it still tries for that higher gear but can't quite get into lockup.
If you are scared of a full lift, just get the leveling kit from rusty's off road. it's $50 and an easy install if you are mechanically inclined. that alone, and a more aggressive tire, makes a subtle but very nice difference.
Congrats on the jeep-- you'll like it.
Back On Topic: Glad to see some good ole' real reports on headers. There's a lot of "rice" with CAIs that often times just don't offer much over the oem plumbing when it comes to actual numbers. But proper headers always make better gains than intake, they are just more involved so people avoid them.
Shorties are better for high rpm range, long tube headers better for torque. I personally thing long runners would balance out the 3.7 better, but the space doesn't allow for it.
I'll tell you what, if those JBA's could come waay down in price it'd be a no-brainer here. The original post on how they feel is Exactly what I have experienced with headers on previous cars. A header with stock cat-back is a noticeable difference. A cat-back.... meh it varies. Headers, and then an open Cat-back... YEA!
Thanks for the report. I want a pair!
Hey Osd1--- how is the noise in the cabin? Does it growl any?
I think these are going on my wish list for 2012... this is a good, proven, old-school mod.
Hey Osd1..... let us know what you see in mpg change after it all settles in.
Keep a look out, I was able to find a "Used" pair of the silver ceramic for $300. By used, I mean I got them from a Liberty guy that bought them a while ago but never put them on and needed to get rid of them. Check craigslist, ebay, etc. for some deals. I'm thinking I just got lucky, right place, right time.
The short headers do exactly what you describe, long headers would be much better, still there is an improvement.
Still working on the gearing, that is taking a while to figure out.
06 Red Jeep Commander 3.7L V6 "Manual QT2", and many more upgrades
Don't let anyone tell you headers aren't worth the money. I had custom ones made for my Hemi WK (http://www.jeepforum.com/forum/f67/h...-hemi-1161475/) and it made a 3-4 mpg improvement in fuel economy and almost a half second off my 1/4 mile ET at the drags. In the next couple weeks I am going to throw a cam in it that is suppose to further increase performance and economy. There aren't too many vehicles that come from the factory with a top notch exhaust system, and there's almost always room for improvement. You can see on my header post how inefficient the stock Hemi system is, even compared to the Hemi LX vehicles (http://www.jeepforum.com/forum/f67/b...-7-wk-1174042/). I hoped someone would try this setup, but I haven't heard of anyone doing it. Glad to see you 3.7 guys found something that was bolt on. Sure is a lot less $$$ than having custom ones built. Props to you for experimenting. My continuing theory is, if you want to know if something works....try it yourself and draw your own conclusions. Keep on tinkering!!
06 GCO, Dk Khaki, QDII, Flshing Hi 3rd Bk Lt, MDS "ON" Lt, Airtab Vortex Gens, Debadged, Fumoto Drain Valve, BT Catch Can, Chopped EGR Tube, SRT8 CAI, K&N Filter, Sonnax Trans Line Press Booster, SC Tuner W/Adv Trans Tune App, DS Tuner, Cust tubular hdrs w/3 in Magnaflow/Xlerator AP Exh Sys, Bilsteins, SRT Springs/Sways, Cust Eng Cvr, SRT8 frt/rear bumpers, FRI Sidewinder Cam/6.1 valvetrain, SLP 25% UD Pulley, BBK true 90mm T-Body, SOS Ign Coils w/.060 spark plug gaps, SRT Reps with 265/45&295/40X20's.
This is my first post, I've just been reading up on things over the last month and a half since I got my 05 wk. As you mentioned the 3.7l is affordable, which is why it's what I've got. Just figured I'd give a little tip.
I can't say that I regret getting the 3.7, but I wish I would have looked at the 4.7 for sale about an hour away from where I live. I passed on even looking at it because I figured the 3.7 was all I needed. It's definitely capable for my average driving (live in a small town so it's either 25mph or 55mph two lane highways).
However, I just recently took it on a 1300 mile round trip long weekend, and it definitely lacks for highway use. My girlfriend think's I'm crazy, but if I wanted to drive like I have a little four cylinder I would have bought one. I don't really know how to explain it besides just being underpowered. Sure it cruises along at 65, 75, 85, but if you need to merge or pass it's just not really up to the task.
Just my opinion. And if you're thinking 3.7 for gas mileage the first fill up I got almost 21mpg. From then on it worked its way down to about 18.5. (Actual calculations, not onboard reading. Probably had to do with my becoming impatient after hours of driving.) I usually get around 17-18 each tank, but a lot is 2 lane highway 65 cruising with my daily drive to work and back (a whopping 1.5 miles round trip). However these numbers will change when I grab a 2" rc and new tires. Honestly though, I'm intimidated by lifting it, but I really like the look of it and need new tires anyways, might as well do it while I'm buying tires instead of buying two sets. All the pinch weld, speedo being off, tranny shift points, cutting bolts, just sounds scary to me. I'm a self supporting college student working my way through and needed a new car. Nicest car I've ever had so I don't want to jankify it.
I hear ya! I feel exactly the same way. My last long trip I did see 23.3 calculated, but I had to keep it under 70. I'm doing well if I see 18 around town and going back and forth to work. I love my Jeep though!!!
Yeah my buddy has a set of there headers(had them in a box for 2 years) and ran into a issue finding a flange to bolt up to them,he called them and they said they scraped the whole 3.7 header thing due to to many issues and not selling well.
Hey guys. With the price being so low on eBay for the JBA headers I might pull the trigger. Anyone for sure know if they fit on the 3.7l 2006 wk? Any feedback would be great.
It would be nice if someone would ring in here with a definite answer for you, but you may be the first in a 2006 WK. I was the first 2006 XK to install them. I research the heck out if it. Talked to JBA (no answer), checked exhaust manifold numbers between the XK, WK and Liberty. Everything said they would fit so I took a chance with the install and they fix.
Sometimes you have to step up and be first if you really want something, just saying.
06 Red Jeep Commander 3.7L V6 "Manual QT2", and many more upgrades
150bux is tempting, and maybe the OP on this resurrected thread had very positive results... but in all my years tinkering with cars I've never seen shorties do anything good down low. I did look around in the hood this weekend.... I mean $150 is nothing for headers... but the drivers side looks like a LOT of aggravation to work on. As cool as it would be (!!) I think I'm going to save my pennies.
If you go for it, please post! it would be interesting to know!