The quest for a better KJ for the wife

patracy · **Joined:** Tue Apr 07, 2009 8:50 pm **Posts:** 115

Well we purchased a 05 CRD for the wife two weekends ago. We've managed to put a few miles on it since. The wife is ok with me modding it to improve mileage, reliability, and slightly power. Right now it's at a hair over 50K miles. First thing I wanted to do was get a mileage baseline. Ugh, not impressed. She drives about 40% city / 60% hwy. We saw 22 mpg out of that tank.

So the first "mod" I did was raise the tire pressures from 30psi to 40psi. I also loaded a dose of Diesel Kleen (Silver bottle). That returned us 24mpg. It appears that the mileage is about 4% low, so I have taken that into consideration.

I've ordered a PML trans pan. I'll also be installing a transgo shift kit. (And servicing the trans of course) The Liberty has been F37'ed. But power is still fine for what we use it for. I hope that maybe this will help mileage a .25 of a mile possibly? If not, so be it. I'm only doing this to help the transmission.

I want to replace the heavy and restrictive muffler as well. But it has to remain unoffensive to the wife. I installed a 3" glasspack on my cummins, and it helped uncork it. I was thinking about a 2.5" for hers? The CAT will remain since we're still under war. How would the sound be? Or is there a better muffler for it?

She also doesn't want a dash full of gauges. But I'd like to be able to monitor EGT, Boost, and Trans temp. (Oil pressure too) Anyone know of an all in one that can do that? I'm thinking about a quadzilla commander.

Also whats the best "chip" for it. From what I gather, there are only a handful of options for the CRD (Edge, MP-8, and a few others). Just looking for a little bit of power, but more of a MPG gain.

chrispitude · **Posted:** Sat Apr 18, 2009 10:55 am

patracy wrote:

I want to replace the heavy and restrictive muffler as well. But it has to remain unoffensive to the wife. I installed a 3" glasspack on my cummins, and it helped uncork it. I was thinking about a 2.5" for hers? The CAT will remain since we're still under war. How would the sound be? Or is there a better muffler for it?

The Magnaflow stainless steel catback worked out very nice for my wife's daily driver. The comment she made was, "It sounds like it went through puberty" with the new exhaust. It wasn't really louder, just a little deeper and fuller. It has no drone at all on the highway.

- Chris

patracy · **Joined:** Tue Apr 07, 2009 8:50 pm **Posts:** 115

Did your MPG improve? And by how much?

CRDMiller · **Posted:** Sat Apr 18, 2009 4:02 pm

I gained around 1-1.5 mpg when went from stock to a super 44.

But save your money and go straight pipe (if it's legal and you have no inspections) MY straight pipe is quieter than the super 44 and it cost 20 bucks to DIY. Again, its not loud (and i have a gutted cat, you should too :P).

I honestly think it's quieter than stock. Cant even hear it on the freeway with the windows up.

warp2diesel · **Posted:** Sat Apr 18, 2009 4:18 pm

Also check your odometer. Mine is 10% shy on miles and reads 5% fast on the speedo. You can have the body module flashed to correct it, but I don't trust dalers.

patracy · **Joined:** Tue Apr 07, 2009 8:50 pm **Posts:** 115

Ok, we're currently at 1/2 a tank and have 300 miles on the clock. I just installed a glasspack muffler on it. So we'll see what improvement that makes.

I have the shift kit here, but I'm waiting on the PML pan to come in. I'm thinking the next mod will be for the air intake? Anyone have any ideas?

chadhargis · **Posted:** Wed Apr 29, 2009 10:46 am

22mpg is pretty good mileage.

I get about 20mpg in the city and I've seen as high as 30 on the highway but most of the time I get about 28mpg because I have a heavy foot.

Compared to the PT Cruiser I had which got 19mpg city and about 26 highway....the CRD is amazing!

patracy · **Joined:** Tue Apr 07, 2009 8:50 pm **Posts:** 115

Actually 22mpg is what we got the first time. I got 24 by upping the air pressure in the tires, and adding diesel kleen. I hope after the next tank we'll break 25mpg. I'd like to hit 30mpg someday with more work.

JL Rockies · **Posted:** Wed Apr 29, 2009 1:12 pm

I recently got the best HWY MPG of my modified career on my last trip to Jackson Hole, WY: 23MPG.

ribbon · **Posted:** Wed Apr 29, 2009 3:02 pm

some say a glasspack will hurt the mpg. unplug the maf also. that upped my power and mpg noticeably. http://www.lostjeeps.com/forum/phpBB3/vie ... hp?t=24961 check out that link for more things. You may want to look into a suncoast and a new pump if your going through the trouble of doing the shiftkit

nursecosmo · **Posted:** Wed Apr 29, 2009 5:36 pm

JL Rockies wrote:

I recently got the best HWY MPG of my modified career on my last trip to Jackson Hole, WY: 23MPG.

Ouch.

UFO · **Posted:** Wed Apr 29, 2009 6:58 pm

patracy wrote:

Ok, we're currently at 1/2 a tank and have 300 miles on the clock. I just installed a glasspack muffler on it. So we'll see what improvement that makes.

I have the shift kit here, but I'm waiting on the PML pan to come in. I'm thinking the next mod will be for the air intake? Anyone have any ideas?

You won't see any gains from intake modification. But it is still worth it to replace the air box with a 3.7L unit, it keeps the water out.

JL Rockies · **Posted:** Wed Apr 29, 2009 7:16 pm

nursecosmo wrote:

JL Rockies wrote:

I recently got the best HWY MPG of my modified career on my last trip to Jackson Hole, WY: 23MPG.

Ouch.

I don't know many with anything close to me mileage-wise who have an off-road rig and I don't believe many of the claims of MPG people post here. Especially if they're using the OEM trip computer.

When my KJ was bone stock I got 26 MPG. I don't think that 3 MPG (normally 22 MPG) is too much loss for all this sexy!

patracy · **Joined:** Tue Apr 07, 2009 8:50 pm **Posts:** 115

ribbon wrote:

some say a glasspack will hurt the mpg. unplug the maf also. that upped my power and mpg noticeably. http://www.lostjeeps.com/forum/phpBB3/vie ... hp?t=24961 check out that link for more things. You may want to look into a suncoast and a new pump if your going through the trouble of doing the shiftkit

I'm not buying the "glasspack hurt my mpg" thing. It most certainly will if you romp on it all the time to hear it. IMO that's what happened to those people. They then put a straight pipe on, got more noise for less throttle, so mileage improved. Kind of a placebo effect coupled with a real life "drive like a egg is under the accelerator". I know the glasspack I put on my CTD in the dodge helped mileage.

I've got to convince the wife to live with the CEL to do the ORM. She had to live with a CEL on her honda accord, so I'm not sure I want to approach her with that proposal yet. :lol:

Thanks for the heads up UFO on the intake. I'll skip that then.
As for the transmission. I'm still under warranty for another 24K. So the shift kit is all I'll be doing. I'm not about to lug the transmission/tcase out to put a TC and pump in. If I'm "fortunate" enough to kill the TC while under warranty, I'll spring for the better TC. I doubt I'll have any issue though since it's just a soccer mom mobile. (Don't tell the wifey! :wink:

)

mrkake · **Posted:** Thu Apr 30, 2009 1:58 am

JL Rockies wrote:

nursecosmo wrote:

JL Rockies wrote:

I recently got the best HWY MPG of my modified career on my last trip to Jackson Hole, WY: 23MPG.

Ouch.

I don't know many with anything close to me mileage-wise who have an off-road rig and I don't believe many of the claims of MPG people post here. Especially if they're using the OEM trip computer.

When my KJ was bone stock I got 26 MPG. I don't think that 3 MPG (normally 22 MPG) is too much loss for all this sexy!

My best ever mileage was on a trip from Vegas up to see the family in Utah. I had just changed out all the fluids 30 miles before we left. 3 adults and luggage for a week. I got 29.8 on the way up and 29.2 on the way back. Calculated by GPS and my laptop. I have never made it close to that since I put the MT/R's on it though. I was running BFG ATA's on the aforementioned trip. Believe it or not, I know it's true.

nursecosmo · **Posted:** Thu Apr 30, 2009 11:52 am

JL Rockies wrote:

nursecosmo wrote:

JL Rockies wrote:

I recently got the best HWY MPG of my modified career on my last trip to Jackson Hole, WY: 23MPG.

Ouch.

I don't know many with anything close to me mileage-wise who have an off-road rig and I don't believe many of the claims of MPG people post here. Especially if they're using the OEM trip computer.

When my KJ was bone stock I got 26 MPG. I don't think that 3 MPG (normally 22 MPG) is too much loss for all this sexy!

Agreed. I hadn't looked at your sig line featuring lift, tires, and especially the 4,10's.

patracy · **Joined:** Tue Apr 07, 2009 8:50 pm **Posts:** 115

Our liberty also has the 4.11 gearing as well.

mrkake · **Posted:** Fri May 01, 2009 3:18 am

I'm confused here. Doesn't everyone say that 4:10's will get you back to your original mileage. Is that not the case? I average right around 19.5 now and I was right around 21.5 before putting on the MT/R's. That was the only change that I made, so I can only assume that the heavier tires are the culprit. Is this logic on the right track?

patracy · **Joined:** Tue Apr 07, 2009 8:50 pm **Posts:** 115

mrkake wrote:

I'm confused here. Doesn't everyone say that 4:10's will get you back to your original mileage. Is that not the case? I average right around 19.5 now and I was right around 21.5 before putting on the MT/R's. That was the only change that I made, so I can only assume that the heavier tires are the culprit. Is this logic on the right track?

With a taller tire, lower gearing will help get the RPM's back up to where they were with the shorter tire. However, you'll always be against the heavier wheel/tire combo.

nursecosmo · **Posted:** Fri May 01, 2009 12:23 pm

patracy wrote:

Our liberty also has the 4.11 gearing as well.

You should update your sig line.

The quest for a better KJ for the wife

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