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Old 11-20-2012, 11:14 PM   #61
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2.5 Liter drama

I have an 87 with the 2.5 and I drive it about 60 miles a day round trip. I wouldnt say I love it or hate it but I can get 5 days out of a tank of gas if I dont drive like an idiot. I have 235s on it and the drive train is stock. She does just fine. Now as far as off road I dont do anything crazy with it. I will say that if I was going to offroad heavily then I would have to really think about some serious or moderate mods. I can tell you that my dana 35 axle, and AX5 tranny are bigger concerns to me than my 2.5 liter. Lets not forget that most of them average 350,000 miles or better before they flop. While I dont love my motor it gets me where I'm going and besides I dont want to go fast I would spill my coffee. I am intrigued with the cummins 3.9 idea although what I have found so far is they are hard to find and cost more than what my Jeep is worth. If anyone knows where one can be had for cheap throw me a bone. I will probably do the regear just because I want 33s and its likely I wont do an engine swap for some time. Oh another user on hear told me to ignore the shift light as its quite conservative. I usually shift around 3500 or so winding it out as they say and she does just fine!

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Old 11-20-2012, 11:22 PM   #62
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Oh since we have so many 2.5ers on this thread what are the ods a 2.5 would work out with some nice dana 44s? Just a though I have been having. Can't seem to find much on it. Guess its maybe dumb to put big ole honkin axles like that into a vehicle with such a "light duty" drive train. JP magazine has really bad things to say about the AX5 and NP205 combo that was in the 4 banger 87 and might I add that my front drive shaft is the most feable looking thing I have ever seen. Sorry I know I am segwaying into another subject but I thought it would be better than all of the 2.5 drama of the lovers and haters going back and forth. BY the way to the toyota guy is that really a feasile swap? I mean that seams like a bad ass idea and a donor vehicle would be really readily available. Older tacomas can be had for cheap.

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Old 11-21-2012, 10:44 AM   #63
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Don't mistake the 2.5L for a boat anchor, it has plenty of guts for 4x4ing. I know of a handful of guys running it with a D44/8.8 combo, or a HPD30/8.8 combo spinning 35's.

A lot of people like 4 cylinders offroad, better fuel economy.
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Old 11-21-2012, 11:16 PM   #64
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Nice to know that. I am assuming that you would have to upgrade drive shafts to but if I do the axle swaps I am going to do a SOA. I mean might as well right I have to take the axles off to do that anyway. I am also thinking about 8.8. Just trying to give myself junk yard options. I really don't do any crazy wheeling so I dont want to go nuts with it but I want to go up in tire size. My 2.5 is like brand new so won't be canning it any time soon.
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Old 11-22-2012, 09:32 AM   #65
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To get more power out of the 2.5 lower gears are the only thing that makes sense. I wouldn't spend any money on any motor mods, keep it stock and dependable.
I have 4.88's and 33's and mine is getting much better mileage and 5th gear is useable. Although it is still a 2.5 it is much more driveable
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Old 11-22-2012, 12:30 PM   #66
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Just to add my .02 in, the 2.5 is a very durable engine. A cold air intake, 2.25 exhaust( with straight thru muffler) and 4.88 gears. Those few mods and my 94 runs great. Even with 32" BFG MT's, I get in the upper teens in fuel mileage with enough power to hold 5th gear on the highwayat 65mph. Thinking of upgrading to a 4.0 throttle body with either #703 injectors or 2.0 Neon injectors, I will report back with the results.
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Old 11-23-2012, 03:36 PM   #67
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RB26DETT

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Old 11-23-2012, 04:20 PM   #68
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RB26DETT
R34 motor?
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Old 11-23-2012, 04:39 PM   #69
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LOL cute turbos
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Old 11-23-2012, 04:56 PM   #70
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So, based on this thread, I need to upgrade the entire drive train from behind the engine through the tires to get decent performance on the highway as well as off road with the 2.5l.

Well, I wanted to do that anyway, just so I can run 33's. It is nice to know that my highway performance will actually improve.
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Old 11-24-2012, 05:43 AM   #71
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R34 motor?
Sure why not. It's no more crazy than anything anyone else has suggested. LOL
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Originally Posted by Ibuildembig View Post
LOL cute turbos
They are aren't they. I might put one on my JK one of these days.

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Originally Posted by Pukeolicious View Post
So, based on this thread, I need to upgrade the entire drive train from behind the engine through the tires to get decent performance on the highway as well as off road with the 2.5l.

Well, I wanted to do that anyway, just so I can run 33's. It is nice to know that my highway performance will actually improve.
Depends on how much power you plan on putting out. You can put in an SRT4 engine in and it will bolt up to the stock jeep transmission. The 2003 had 215hp and the 04-05 had 230hp which should be fine behind the stock drivetrain.
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Old 11-24-2012, 12:10 PM   #72
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Depends on how much power you plan on putting out. You can put in an SRT4 engine in and it will bolt up to the stock jeep transmission. The 2003 had 215hp and the 04-05 had 230hp which should be fine behind the stock drivetrain.
So an AX-5 will hold up to a SRT-4 engine? come on, I call shenanigans, the AX-5 blows up behind the stock 2.5L!
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Old 11-24-2012, 05:10 PM   #73
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My bad. Your right. I was thinking AX-15 for some reason.
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Old 11-24-2012, 06:30 PM   #74
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Originally Posted by Jeepfreak94
Just to add my .02 in, the 2.5 is a very durable engine. A cold air intake, 2.25 exhaust( with straight thru muffler) and 4.88 gears. Those few mods and my 94 runs great. Even with 32" BFG MT's, I get in the upper teens in fuel mileage with enough power to hold 5th gear on the highwayat 65mph. Thinking of upgrading to a 4.0 throttle body with either #703 injectors or 2.0 Neon injectors, I will report back with the results.
I added bosch yellowtop injectors,4.0 throttle body,& cold air intake today. I seriously can tell a difference and i have 33's, no elec fan,and i have an a/c compressor to turn. Its still not a 6 cyl,but was worth it. Shopped ebay for 2 wks for parts,all for 120.00 . Injectors were the hard find. Will be gearing it next. I just like tinkering and getting the most out of the smaller stuff,if for no other reason just for the hell of it.
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Old 11-24-2012, 07:40 PM   #75
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So, based on this thread, I need to upgrade the entire drive train from behind the engine through the tires to get decent performance on the highway as well as off road with the 2.5l.
Nope....... I personally feel that a ring and pinion is the best up grade for the 4 cylinder if driven on the road much at all. If you want to have a dual purpose YJ and have a 2.5, that is what I would recommend from my own experience.
Before last Nov. I had only owned 4.0's and v-8 Jeeps. To say I was dissappointed in the 2.5 in the beginning is an understatement.

Mine did great in 4 low and bearable around town under 55mph before the gear swap. I just couldn't use 5th gear.
Keep in mind, mine is a 90 TBI and not direct fuel injection. There is a difference in power between the two.

I guess what I am saying, is you can spend a lot of money doing this and that to the motor, and maybe be able to use 5th gear and drink a bunch of fuel, or gear it correctly for the tires you want, and keep the stock dependability and get your gas mileage back. I am currently getting 20+ mpg with 33's and 4.88's.
The biggest question is do you eventually plan to change to an 8.8 rear and ditch the Dana 35? If so don't waste money on the gears for it now.
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Old 11-24-2012, 10:28 PM   #76
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I just spent a great day wheelin my 2.5 LO highway and trail and I guess I am getting old but enjoyed the whole day. It is a little slow on highway hills but managed 70 on the I-15 right through Vegas to the house. No issues love the torque and on the trail today it was great.
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Old 11-25-2012, 09:36 AM   #77
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I don't have issues with my 2.5L, except that it blows oil from whatever issue is going on inside. It happily rolls down the highway doing 65, and I'm still getting some 18mph average. Climbing hills isn't that big of a deal, just downshift to 4th and roll on some more coals.

Keeping your gears in check is the best thing though, I've found the 2.5L likes ot be between 2700rpm and 3000rpm crusing on the highway.
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Old 11-25-2012, 11:25 AM   #78
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Nope....... I personally feel that a ring and pinion is the best up grade for the 4 cylinder if driven on the road much at all. If you want to have a dual purpose YJ and have a 2.5, that is what I would recommend from my own experience.
Before last Nov. I had only owned 4.0's and v-8 Jeeps. To say I was dissappointed in the 2.5 in the beginning is an understatement.

Mine did great in 4 low and bearable around town under 55mph before the gear swap. I just couldn't use 5th gear.
Keep in mind, mine is a 90 TBI and not direct fuel injection. There is a difference in power between the two.

I guess what I am saying, is you can spend a lot of money doing this and that to the motor, and maybe be able to use 5th gear and drink a bunch of fuel, or gear it correctly for the tires you want, and keep the stock dependability and get your gas mileage back. I am currently getting 20+ mpg with 33's and 4.88's.
The biggest question is do you eventually plan to change to an 8.8 rear and ditch the Dana 35? If so don't waste money on the gears for it now.
Upgrading to 4.88's is fairly expensive isn't it? Also, I thought 33's would be too large for the stock axles. I guess I need to know if I can get away with upgrading to 4.88, installing 33's (and regearing the speedometer to match) on a light off road use '93 Wrangler. Right now it is completely stock.

Edit: A quick search shows the gears are only $200 or so. I might pursue this if you guys think the Wrangler can handle it.
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Old 11-25-2012, 12:44 PM   #79
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Lots of folks have upgraded to 4.88s and love the difference from 4.10s. I got an estimate for $1400 to regear at a local shop but I am not to motivated. If you have someoen who can do it pparts are relatively cheap. I would jump on it if I had someone to do it free. As for the speedo gear mine is great at 35 teeth matches GPS so I guess I am good.
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Old 11-25-2012, 04:50 PM   #80
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Doesn't upgrading from 4.10 to 4.88 get nullified by putting 33's on? Don't you end up with the same ratio relative to 4.10 and stock wheels?

Gearing is a mystery science to me.

I am comfortable with working on vehicles so I am researching what it takes to swap the gears myself. I would rather pocket $1200 if I can do the work.
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Old 11-25-2012, 05:17 PM   #81
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Gearing it to 4.88:1 with 33's is more to return your overall ratio.

Your engine is designed to run at a certain rpm.
When you add bigger tires you fall out of that rpm.
Thus adding more gear reduction you return to your power range.

Think of the tire as the final gear.
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Old 11-26-2012, 10:03 AM   #82
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Quote:
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Doesn't upgrading from 4.10 to 4.88 get nullified by putting 33's on? Don't you end up with the same ratio relative to 4.10 and stock wheels?

Gearing is a mystery science to me.

I am comfortable with working on vehicles so I am researching what it takes to swap the gears myself. I would rather pocket $1200 if I can do the work.
Installing a ring and pinion is not for the average joe home mechanic. Heck, some full time regular mechanics won't do the job. It is a tedious and very precise job that takes special tools and a VERY good knowledge of what you are doing. If this is something you have not been trained on and have hands on experience, I would highly recommend that you take it to a shop and have them do it. There is a very good reason why shops charge $800-$1200 for just labor on a ring and pinion install. It takes about 8-10 hours to install a set of gears in an axle. And that does not even include the time it takes to remove the axle from the jeep and do all the prep work to include making the setup bearings.
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Old 11-26-2012, 11:23 AM   #83
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Gearing it to 4.88:1 with 33's is more to return your overall ratio.

Your engine is designed to run at a certain rpm.
When you add bigger tires you fall out of that rpm.
Thus adding more gear reduction you return to your power range.

Think of the tire as the final gear.
Right, so a stock Wrangler and a Wrangler with 33's and 4.88 gears will perform the same on a highway.

Quote:
Originally Posted by Coyote_94YJ View Post
Installing a ring and pinion is not for the average joe home mechanic. Heck, some full time regular mechanics won't do the job. It is a tedious and very precise job that takes special tools and a VERY good knowledge of what you are doing. If this is something you have not been trained on and have hands on experience, I would highly recommend that you take it to a shop and have them do it. There is a very good reason why shops charge $800-$1200 for just labor on a ring and pinion install. It takes about 8-10 hours to install a set of gears in an axle. And that does not even include the time it takes to remove the axle from the jeep and do all the prep work to include making the setup bearings.
Thanks for the info.
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Old 06-21-2013, 12:18 AM   #84
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I got a gas mileage swap idea. besides my 95 YJ 2.5L ive also got a 96 5.6L Bronco and an old Dodge 440 big block. pull the 2.5L put the 5.6L in the jeep, the 440 in the bronco and buy a Prius rip everything out and put the 2.5L in it with a bumper sticker that says "my 3 cars COMBINED dont get 35mpg"
oh and i have an old blower sitting around somewhere that should go on one of those too.

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