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View Full Version : Help talk me out of it (going back to the I6)


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shawn
05-02-2008, 05:52 PM
I really like my 304, it's mild but it has served me very well and still does (eddel performer and truck avenger and TFI).

But gas prices are killing me and I like to go wheeling when I can. I drive to the trails getting 10 (maybe 11) mpg's doing 70 mph (4.10's on 35's).

I've been toying with the idea of getting a 4.0L fuel injected and putting that in. I would hopefully get 15 mpg then (maybe? ya think?), and even on the trail I may not have to carry an extra jerry can!

Is it worth it? What if I put a Howell EFI kit on, what would I really gain out of this?

Ibby
05-02-2008, 06:40 PM
I'm in the same boat, I cooked my 304 over the winter. Oil pressure piston problem. Nice thing is, the engine still seems to be running well, but I do plan on replacing it sooner rather than later. I've narrowed it down to 2 choices, another 304 (and I'll move to the Howell or Powerjection systems) or the new diesel engine Jeep Performance will be putting out (if it will fit without a ton of mods).
I have a newer 2000 XJ with the I6, and with a few small engine mods and programming the computer I get similar mileage to my CJ with the carbed 304. Both Jeeps are set up with the same size tires, gearing, and similarly geared trannies.

dan58
05-02-2008, 07:42 PM
Keep the 304 and slow down to 60. You'd be amazed at how much better it'll do. Do you have an overdrive tranny?

Blown7
05-02-2008, 07:44 PM
A good V8 well done, with the latest fuel and timing systems will be just as good as a straight 6 for economy or consider this, a 5.7 Hemi with MDS that can give you 25 miles to the gallon.


Jeff

1980_Cj7
05-02-2008, 09:02 PM
I've narrowed it down to 2 choices, another 304 (and I'll move to the Howell or Powerjection systems) or the new diesel engine Jeep Performance will be putting out (if it will fit without a ton of mods).


If this is for fuel economy, have you looked at the price of diesel fuel lately?

shawn
05-02-2008, 09:24 PM
A good V8 well done, with the latest fuel and timing systems will be just as good as a straight 6 for economy or consider this, a 5.7 Hemi with MDS that can give you 25 miles to the gallon.


Jeff

HAHA! A hemi? Cost is still a factor here you know :razz:

I do live in Michigan, so keeping a job here is quite the challenge right now. I just recently lost my job with Pfizer, but I am working but for much lower wages. Thus, I have to consider ways to get me to the trails. The goal was to sell the 304 for enough to get me a 4.0L installed without much extra money involved.

I DO NOT have OD, I run a Ford T18. I do have a 4500 sitting on the garage floor but I sure as hell don't have the money to put that thing in.

There is another GLFWDA ( www.glfwda.org and gl4x4.com )member that was running a newer Chevy 6.0 and 4L60E tranny getting 20-21 mpg at 70 or 75 with Prorock 60's with 5.13's and 37"s (IIRC), but that was loads of cash put into that setup.

shawn
05-02-2008, 09:26 PM
Keep the 304 and slow down to 60. You'd be amazed at how much better it'll do. Do you have an overdrive tranny?

Yeah, I know you are right. It just makes it a little tougher when you are traveling 200-300 miles with a number of other rigs (mainly TJ's) that are running at least 70 to the trail when on 35's. I hate being the slow guy.

Goose
05-03-2008, 03:41 AM
Well, being the slow guy beats being the guy that couldn't go because he couldnt afford it..

And the fuel mileage wont get much better with a 4.o.. you are going to be pushing it harder to go down the road.. Slow down and oyu will be amazed..

happyhoppy
05-03-2008, 05:52 AM
When I purchased my CJ with an AMC 360, 3,54:1 and 31 inch tires I got about 15 mpg - with tons of power.
When it went bad I put in an AMC 258 from a 1976 CJ with 58000 miles. My gas mileage decreased to just over 11 mpg with regular, 13.5 with premium.
I've done all the math and research for going to propane and when the winter heating system is over prices drop I'm going to make the conversion.
Certainly not a conversion for everyone but with two tanks and the propane filling station on the way to work I can drop a tank off and have it filled. (Three miles to work)
Bottom line - I can lose 2 mpg on the AMC 258 and break even with propane at current costs. With the correct timing, etc. I hopefully will gain a few miles per gallon.......

ironman_gq
05-03-2008, 01:52 PM
I think you gotta bring your compression up quite a bit. I think propane likes 12:1 or there abouts.

Ibby
05-03-2008, 02:53 PM
If this is for fuel economy, have you looked at the price of diesel fuel lately?

Yes, up here in Canada it's still slightly cheaper than gas depending where you go. The diesel motor they're offering is the common rail 2.5l that the Liberty had a couple years back. It's pretty efficient. The major downside to the diesel is that they're damned hard to start during our winters here.

1980_Cj7
05-03-2008, 07:02 PM
If this is for fuel economy, have you looked at the price of diesel fuel lately?

Yes, up here in Canada it's still slightly cheaper than gas depending where you go. The diesel motor they're offering is the common rail 2.5l that the Liberty had a couple years back. It's pretty efficient. The major downside to the diesel is that they're damned hard to start during our winters here.

That's good. Here in Pennsylvania, diesel is the most expensive thing you can buy right now. It's $4.20 a gallon. 93 octane gas is only $3.79. I've heard it is because of having gone to the low sulphur, and all the extra processing that requires. Who knows?

dwg86
05-03-2008, 07:09 PM
What about a stroked 4.0. Kieth black is making a new stroker piston. Its supposed to be out in a couple of weeks. Use a 4.0 block .030 overbore and 4.0 rods with a 258 crankshaft = 4.6L. Or you can use a 4.0 block with jeep 4.0 pistons with 258 crank and rods. With this combo the pistons sit down in the bore a little.
Check out www.jeepstrokers.com. There is alot of info on the web also.

shawn
06-23-2008, 11:00 AM
So, I think I have other things to worry about right now. I am going to hold off on any drivetrain modifications for now :smile:

http://i175.photobucket.com/albums/w156/shawnscj/Jeep%20Pics/SV100660.jpg

fifesjeep
06-23-2008, 01:56 PM
That IMO is one of the best looking newer "Jeeps" that I have seen in a while.... But, that slanted grill is definitely reaching a little to far... the same with the windshield... :idea: aerodynamics and fuel efficiency must have been on the agenda :-|
Where's the front hoop of the rollcage??? There's Nothing like removing or disquising a unibrow with a big gash/windshield impression... :!:
So how did that happen... anymore pics or footage?

shawn
07-01-2008, 10:22 PM
Uh, rollcage you ask......................

Yeah, stupid me, I'm the guy that is always the "easy" wheeler. And although I have had plans to get the front hoops in and a grill hoop on, I kept putting it off so I could do other things in this rig.

Well, look where it got me. I'm just very thankful that I didn't get more hurt. And I hope everybody that sees this is a little more serious than I was about getting a full cage done.

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