Engine swap advice

[adamrich33]

first things first im new to jeep wranglers, but it didnt take me long to realize my 94 with a 2.5L 4cyl is under powered. i want to put the 4.0L motor in but im not sure about all the details as to what axles, mounts, trans and ecu to go with. I want to get the 4.0 b/c i assume it would be easier than doing a v8 swap and my brothers 94 w/ a 4.0 moves along pretty good. Im not power hungry but like to be able to use 5th gear below 70 mph.lol.
I will be leaving it a 5 speed, so im guessing just buy a 4.0 motor and trans, transfer case, axles, (driveshaft???) and ecu out the same generation of my jeep.
im sure it looks like i just answered my own question, but would like some opinions and advice
thanks

 

[SteelHeadz]

Have you considered re-gearing the axles?. that would be less headaches IMO.

 

[Bounty__Hunter]

I regeared my axles and my 2.5L holds 5th on hills just fine.

And swapping a 4.0L isn't any easier or cheaper than a v8 swap, and you end up with another run of the mill 4.0L jeep but with a hacked up install.

You need the motor, transmission, and transfer case combo as the transmission behind the 2.5L won't handle any more power, or bolt up to the 4.0L engine.

 

[adamrich33]

what gears did you use?
And im a little confused about you second reply, are you saying a 4.0 will bolt to a 2.5 trans.
And i can assure you anything i do to any of my vehicles would not be a hacked up install.

I regeared my axles and my 2.5L holds 5th on hills just fine.

And swapping a 4.0L isn't any easier or cheaper than a v8 swap, and you end up with another run of the mill 4.0L jeep but with a hacked up install.

You need the motor, transmission, and transfer case combo as the transmission behind the 2.5L won't handle any more power, or bolt up to the 4.0L engine.

 

[Utah_jeepster]

For the amount of work, and money its going to take to swap your 2.5 to a 4.0, your better off dropping a Chevy V-6 or V-8. The costs is considerably cheaper than trying to drop in a 4.0. Keep in mind even after the motor, electrical, ECM, radiator, and fuel pump then comes the axles, even with a 4.0 your still going to need to regear your axles to your tire size or its still going to be a dog on hills and steep climbs.
By all reports from several magazines your better off selling off your 2.5 and finding a TJ (97-06) with a 4.0 if you want a 4.0 inside your motor bay.

 

[Bounty__Hunter]

what gears did you use?
And im a little confused about you second reply, are you saying a 4.0 will bolt to a 2.5 trans.
And i can assure you anything i do to any of my vehicles would not be a hacked up install.

I run 5.38 gears, but 4.88 is as low as you can go with the stock axles.

No, the 4.0L will not bolt to the 2.5L trans.

I'd consider any non-factory install to be 'hacked up', but I'm sure there's a few exceptions to that rule.

 

[adamrich33]

i guess i will try the gears, first. Im running a 31" tire on a 10x15 rim, this ride is a daily driver. I havent even been off roading and if i do it will be for lite trail riding. so with that in mind what would size gears would i benefit the most from and what brand of gears?

 

[Bounty__Hunter]

Go with 4.88 gears, as 4.11 to 4.56 isn't enough of a change to make it worth the cost and trouble. 4.88 will give you a lot of performance back.

 

[adamrich33]

i seen a set on ebay, he recommends a ring master install kit for intallation with the gears. is that b/c he is just trying to sell something or b/c its just a good idea to replace these parts while you already in there. id post the sale link but admin wont let me.

 

[jps4jeep]

a 5.3L swap is probably the easiest swap right now for a jeep.

 

[Bounty__Hunter]

i seen a set on ebay, he recommends a ring master install kit for intallation with the gears. is that b/c he is just trying to sell something or b/c its just a good idea to replace these parts while you already in there. id post the sale link but admin wont let me.

You should use an install kit with a ring and pinion set as it includes all new bearings and shims.

 

[adamrich33]

thanks for the input

 

[adamrich33]

forgot to ask if i have to regear front diff as well, i assume if im not in 4x4 it would not matter but thought i should ask

 

[Bounty__Hunter]

Yes, you have to regear the front, unless you remove the front driveshaft. With the front driveshaft installed and mismatch gear ratios front/rear, you will ruin the transfer case.

 

[jfrabat]

Go with 4.88 gears, as 4.11 to 4.56 isn't enough of a change to make it worth the cost and trouble. 4.88 will give you a lot of performance back.

X2; I regeared to 4.88 when I had 31's (planning ahead for my 33's), and I just loved how it handles! I know all charts will say the right gear is 4.56, but forget that and go to 4.88. I could cruise down the highway at 70mph (speed limit in the FL turnpike) on 5th no problem (the engine would turn a bit over 3K RPM, but that's just normal for the 4 banger, and you can drive all day there without issues).

I now wish I could go to 5.13's for my 33's, but that means 2 new axles (and 2 new lockers, which would be almost as much as the axles if not more), so I'm kind of stuck at 4.88...

My advice, go for 4.88 and you will forget all about the 4.0L... Oh, and by the way, when I went to 4.88 with 31's (from 4.10), my fuel efficiency actually went up about 1 mpg.

Felipe