2.5 4-cylinder upgrades

[Neumeyer]

The oil feed line I used a 1/8" Tee and came off the sending unit and drained it back in to the oil pan. The AEM FIC controller I had to figure that out myself AEM has no tune for the Jeep. What is nice is that the Jeep acts totally stock when you have no boost. It runs on the original ecm controller programming. The Aem has an internal MAP sensor that when in boost it see the amount of boost and controls it to your rpm and psi pressure to your setup.

 

[StG58]

The oil feed line I used a 1/8" Tee and came off the sending unit and drained it back in to the oil pan. The AEM FIC controller I had to figure that out myself AEM has no tune for the Jeep. What is nice is that the Jeep acts totally stock when you have no boost. It runs on the original ecm controller programming. The Aem has an internal MAP sensor that when in boost it see the amount of boost and controls it to your rpm and psi pressure to your setup.

What grade of gas are you running?

You may just get a "Hero of the Revolution" award for working this out.

 

[Neumeyer]

You will need a 1/8" Tee to tap in where the oil sending unit is, and drain it back into the oil pan. The AEM controller is cool, because it uses the original ecm computer fuel set up when not into boost. You control the amount of fuel you want by either adding or subtracting the percentage of fuel at the exact rpm and boost level that you but in. The software you can download from AEM and play with it a little bit , but will need to set up your own tune. I'm no tuner but I believe I have a good starting point, My jeep runs really good.

 

[Neumeyer]

91 octane

 

[Neumeyer]

What I Forgot to add was I'm running 20% bigger injectors, 19lbs is stock and I put in 24lbs injectors. So from 500 rpms to 5000 rpms I run 20% less fuel through the AEM controller which it believe it running stock amount of fuel. Then from 1 psi to 10 psi, I've just stared adding fuel with boost and rpm's. I run 5% over the 24 lbs injectors at 10 psi at 5000 rpm. Hope I didn't confuse anybody. So in reality from base line to 10 psi and 5000rpm's I'm running 25% more fuel than a stock 19 lbs injector. Without over loading the injector pulses of the 24 lbs injector.
I've played with the timing and found that you don't have to take out any more timing. I felt the difference in 2 degrees of taking timing out and stock timing and stock runs better. Only way to really find out is dyno.

 

[Neumeyer]

Here is the Pictures of the yj with turbo

 

[StG58]

Wow. That's a clean install! Thanks for taking the time to share that.

So, was it worth the $800? I'm guessing that it was. Now to stare at those pictures some more...

 

[Chris]

Wow, that is indeed a nice install. I'm impressed!

 

[Neumeyer]

Wow. That's a clean install! Thanks for taking the time to share that.

So, was it worth the $800? I'm guessing that it was. Now to stare at those pictures some more...

It was worth every penny. very easy install. Hardest part was tuning.

 

[Kevin Snyder]

I know that the best upgrade for any 2.5 4 cyl is to replace it with a 4.0. That's not really in the budget for me right now and I'm sure there are people wheeling 2.5s. Short of the 4.0 swap, are there any modifications that you have made to your 2.5 motors to give them a little more pep and make them more street friendly?

Specs:
1997 Wrangler 2.5 4 cyl 5 speed
Stock ride height and stock wheels and tire size (for now)

i put a turbo on my 2.5 a true difference on the highway,, but with low compression numbers and still needing a little more i am rebuilding motor and using a mitsubishi turbo, but need to learn about changing gearing for highway and changing geraring for low 4x4 grinding

 

[Neumeyer]

Here is an equation that will help with the tire and gear size. Take the tire size that you are wanting to run and multiply by the gear ratio and divide by the original tire size. Tha will give you the gear size needed to run your jeep like the stock jeep came.
Example 33 x 4.10/29=4.66. So the gear you would run is a 4.66 gear. Jeep don't make that gear so you choices are either a 4.55 or the 4.88. Hope this helps.
I run 4.88 in my jeep with 33x12.5 and it get down the highway just fine. Runs just alittle bit high rpm's but the 4 banger doesn't mind it.

 

[TimboSlice]

This needs a true step by step write up lol. This is revolutionary

 

[SSTJ]

So I'm seeing a lot of encouraging comments here. @Neumeyer, I don't think you're on the forum any more, but does anyone have more of a write-up about this?

 

[Bill W.]

I know that the best upgrade for any 2.5 4 cyl is to replace it with a 4.0. That's not really in the budget for me right now and I'm sure there are people wheeling 2.5s. Short of the 4.0 swap, are there any modifications that you have made to your 2.5 motors to give them a little more pep and make them more street friendly?

Specs:
1997 Wrangler 2.5 4 cyl 5 speed
Stock ride height and stock wheels and tire size (for now)

Roller rockers from Harland Sharp . And a header. Will increase your HP by 25 to 30hp. The wife and just got back from a road trip .In my 1997 Wrangler 2.5L. Anaheim Calif. To Georgia to Maine to Las Vegas and home. Had no problem.
Bill W.

 

[Daviddnv]

My intended use of the Jeep is 90% as a beach Jeep. So for me, I guess that tire contact patch should be first. Then maybe a little more height to keep me from bottoming out in the ruts.

Any other Jeepers use their Jeeps in the sand a lot?

I'm in the same boat, just down the road in Daytona. I have the same 97 SE 5spd. I have 33s and it's fine with the stock 4.11 gears. I take it to the beach and around town. I probably only have had in 5th gear few times, lol. I rarely go above 50mph. My biggest improvement was using non-ethanol fuel. It's a little expensive, but if you don't drive it much (I drive mine pretty much on the weekends), you will have a lot less build up on the throttle body.

I suggest driving it some and then looking for what specifically you want improved, if anything.

Have fun!

 

[Wildman]

Roller rockers from Harland Sharp . And a header. Will increase your HP by 25 to 30hp. The wife and just got back from a road trip .In my 1997 Wrangler 2.5L. Anaheim Calif. To Georgia to Maine to Las Vegas and home. Had no problem.
Bill W.

I'd like to see some dyno sheets proving this as I believe some of the 4WD mags have tested this stuff before and didn't come up with those kind of numbers.

 

[Foxhound67]

Roller rockers from Harland Sharp . And a header. Will increase your HP by 25 to 30hp. The wife and just got back from a road trip .In my 1997 Wrangler 2.5L. Anaheim Calif. To Georgia to Maine to Las Vegas and home. Had no problem.
Bill W.

I declare shenanigans. You're talking 20-30% gain over stock from rockers and a header. Without dyno proof I think those are seat of the pants numbers.

 

[roverhi]

FWIW, built an even more anemic 4 cylinder for my '65 Series Land Rover. Bored the cylinders to max with new pistons. Figured out how much the head could be shaved to raise compression to 9-1 and used a slightly hotter later model cam shaft. Made a major difference in road performance. A hill I had to climb every day on the way home went from a. 3rd gear 35mph grind to a 45mph speed limit. cruise in 4th gear. With Overdrive could cruise easily at Speed Limit on flatish terrain. Think the greatest benefit was from shaving the head. I had several blocks laying around so was able to do the work at my leisure. worked out great as it was my first complete engine build and probably did the assembly three or more times to be sure I'd gotten things right. Pistons were the big expense as Ebay and my other Yard Sculptures were my friend on most of the other new(er) parts.

Shaving the head to raise compression is mostly a reasonable cost machine shop deal for a valve job. Would consider trying that as the R&R of a head is pretty much straight forward and within the ability of even the least mechanically inclined.

 

[ArmyRN]

I'm in the same boat, just down the road in Daytona. I have the same 97 SE 5spd. I have 33s and it's fine with the stock 4.11 gears. I take it to the beach and around town. I probably only have had in 5th gear few times, lol. I rarely go above 50mph. My biggest improvement was using non-ethanol fuel. It's a little expensive, but if you don't drive it much (I drive mine pretty much on the weekends), you will have a lot less build up on the throttle body.

I suggest driving it some and then looking for what specifically you want improved, if anything.

Have fun!

GEARING!!! OMG - GEARING!!!!!

Stock SE TJ's came with 4.10 gears and dinky tires. Now you're up to 33" tires. You need either 4.88 or 5.13 gears.

Not only will you get your 5th gear back, but you'll also enjoy easier take-offs from standing still in first gear with lower gears. It will be a lot more "peppier" off the line and around town. You will notice a huge difference, and you'll wonder why you didn't do it a long time ago.

Other than forced induction, there's really not much you can do to the 2.5 engine itself to make more power. Lots of folks and magazines have tried to no avail. I put a heavier flywheel in my 98 TJ (think inertia ring) and it may have helped maintain speeds, but that's about it.

My Jeep: 98 TJ, 2.5/five-speed. Dana 30 front with Aussie locker/Dana 44 rear with Detroit locker. 4.88 gears (don't know if 5.13 was an option in 2008 - sometimes I wish I had 5.13), 33" tires (285/75/16), 3.5' RE lift. Lots of other stuff too. I have fun with my TJ. That's what I've got it for. Fun and adventure.

Sometimes I pull a little trailer.

 

[Daviddnv]

GEARING!!! OMG - GEARING!!!!!

Stock SE TJ's came with 4.10 gears and dinky tires. Now you're up to 33" tires. You need either 4.88 or 5.13 gears.

Not only will you get your 5th gear back, but you'll also enjoy easier take-offs from standing still in first gear with lower gears. It will be a lot more "peppier" off the line and around town. You will notice a huge difference, and you'll wonder why you didn't do it a long time ago.

LOL... yeah, I know it would be much better, but the bank account would not be much better. But seriously, I put less the 1000 miles on this a year, probably less the 500 miles. It goes to the beach and the gas station, then back to the garage (after getting a rinse... most times).