How can I get more performance out of my 2.5?

[Jerry Bransford]

I will need to research this! Do you think they will be as strong or even stronger than normal gear sets?

This is from RGA's information, copied verbatim...

• Reduced friction = runs cooler
• Increased durability = longer lifespan and less metal debris
• Better corrosion resistance
• Reduced vibrations and noise = quieter!!!
• Eliminates break in periods = don’t need to baby it right after you get your new gears anymore!

 

[StG58]

I can't find a 5.13 for a Dana 30. If you have a link or reference it would be greatly appreciated! I would prefer 5.13, just because I live to go slow on the trail! No need for speed.

Here ya go!
https://www.amazon.com/dp/B017BW4NN4/?tag=wranglerorg-20

...and a picture thread would be outstanding!

 

[Jake kozlowski]

This is from RGA's information, copied verbatim...

• Reduced friction = runs cooler
• Increased durability = longer lifespan and less metal debris
• Better corrosion resistance
• Reduced vibrations and noise = quieter!!!
• Eliminates break in periods = don’t need to baby it right after you get your new gears anymore!

Sounds great! I'll be looking into them!

 

[Jake kozlowski]

Here ya go!
https://www.amazon.com/dp/B017BW4NN4/?tag=wranglerorg-20

...and a picture thread would be outstanding!

Holy!!!!!!!!!

 

[Jake kozlowski]

Holy!!!!!!!!!

Also, thanks snagging and posting that!

 

[Jerry Bransford]

By the way the REM process is optional, it's something like $60 per gear set. In time and grief savings it's with the extra $120 to not have to worry about breaking the gears in.

 

[Jake kozlowski]

By the way the REM process is optional, it's something like $60 per gear set. In time and grief savings it's with the extra $120 to not have to worry about breaking the gears in.

I've never had new gears or had to break them in, but for the satisfaction of knowing it's done right from the factory is settling.

 

[StG58]

Also, thanks snagging and posting that!

You're welcome.

 

[Rob5589]

The 30 is fine for 33's. Upgrade to Revolution alloy axles for added insurance. For 33's and the 2.5, 5.13 is the way to go. Revolution cuts them. I run 4.88 but on 31's. I'd definitely want lower for 33's.

 

[Jake kozlowski]

The 30 is fine for 33's. Upgrade to Revolution alloy axles for added insurance. For 33's and the 2.5, 5.13 is the way to go. Revolution cuts them. I run 4.88 but on 31's. I'd definitely want lower for 33's.

I think I'll be purchasing the 5.13 for the Dana 30.

Now I'll have to just buy gears for the Ford 9 inch and do the swap!

 

[Jeeper25]

I wish I would have read this thread sooner... instead I read all the threads that told me it was all possible. Now I wont say it was all completely useless... I put in a CAT back exhaust, removed the cat (not required where I'm at), 4.0 Throttle body with spacer, even ported the intake manifold to match. Added the upgraded fuel injectors, installed electric fan, (more of a preference really) and put in a cold air intake. But then I also added about 300lbs of bumpers, armor, lights, and a winch... sooooo!... hahah any performance gains would have been negated by the added weight.

Before I put 33 inch tires on (bought it with 31's) with my 4.11 gears, I was able to easily use 5th gear except when climbing hills. The biggest advantage of a cold air intake over the stock intake typically isn't the actual temperature as much as it is the flow of air to the intake. But with air in, you need air out which requires a better flowing exhaust. either way... for the maybe 30-50 HP gain... if that with all the "upgrades", for the $1500 I spent on everything... I can 100% say, the money would have been better spent towards the V8 swap I'm about to undertake. Don't get me wrong though. the 2.5 is bullet proof and it crawls just as good as any jeep... but with 33's or larger tires, the only way to get more drivability out of it is to do a gear swap, or change to a better engine. I bought a cheaper 2.5L to do just that, but still fell victim to the "HP upgrades" to fill in the space until I saved up for the V8 swap.

I'm not mad that I did it all. I love working on these types of projects even if the gains aren't the best… but I know that the money could have been better spent on other things I may be replacing in conjunction with the V8 later down the road.

 

[Chris]

I'm not mad that I did it all. I love working on these types of projects even if the gains aren't the best… but I know that the money could have been better spent on other things I may be replacing in conjunction with the V8 later down the road.

Live and learn my friend, we've all done stupid stuff before, myself included.

At least now you know, so you can spread good, accurate information as oppose to misinformation.

And for what it's worth, you actually can get a very good amount of power out of a 4.0, it just involves very expensive things such as long tube headers, head work, camshafts, forced inductions, or stroker engines.

The weak point of this engine (and you can ask any 4.0 engine builder this such as Golen) is the cylinder head. It simply doesn't flow well enough from the factory. You can slap on an intake or a bigger throttle body, but that doesn't solve anything. The fact of the matter is the head itself needs to be re-worked, or you need some real long tube headers (not those bullshit Chinese things that Banks likes to call "headers").

EDIT: Crap... I thought we were talking about the 4.0, hence this response. I didn't realize we were talking about the 2.5!

 

[VegasOPM]

I can say for sure that the 2.5l engine is bullet proof and has decent torque but it won't make much power- no matter what you do. The head can't be made to flow, since the inlet to exhaust transition is terrible (cross flow heads work MUCH better). I used to race a 2.5l Jeep Commanche in SCCA Showroom Stock Truck racing series. I picked up the "hacks" from Archer Brothers racing and everything we did (which included everything mentioned above) netted us about 15 hp at the wheels well above the factory redline (the engine was fully balanced and blueprinted, port matched and set up for high RPM use). Suffice to say that the drivability was negatively impacted everywhere else. Enjoy it, and upgrade to a 4.0L if you want more power.

 

[Jeeper25]

Live and learn my friend, we've all done stupid stuff before, myself included.

At least now you know, so you can spread good, accurate information as oppose to misinformation.

And for what it's worth, you actually can get a very good amount of power out of a 4.0, it just involves very expensive things such as long tube headers, head work, camshafts, forced inductions, or stroker engines.

The weak point of this engine (and you can ask any 4.0 engine builder this such as Golen) is the cylinder head. It simply doesn't flow well enough from the factory. You can slap on an intake or a bigger throttle body, but that doesn't solve anything. The fact of the matter is the head itself needs to be re-worked, or you need some real long tube headers (not those bullshit Chinese things that Banks likes to call "headers").

Let me sell my 2.5 engine first... then I'll spread good accurate info!... lol I kid! If I never added the bumpers, winch, rocker armor, side steps, and then the real power killer... the 33's, I'd have no issues with how the jeep drives. but I mean its a Jeep... who doesn't add all that stuff?... I'll tell you!... the ones that don't wave back! haha. but really, the 2.5 wasn't meant for anything other than stock performance, and with out dual overhead cams and the money you could spend on an amazing engine swap... its just not going to provide the gains everyone is looking for.

I can squeeze 400 HP out of a Nissan KA24DE.. but I have to do a full rebuild with forged internals...port and polish the head, add new cams and valve springs, build a custom plenum with individual throttle bodies and boost it like no other... but the KA and SR have a good following with a lot of support so parts are affordable... Jeep 2.5's... not so much lol... I'd love to see it though... its always awesome squeezing every bit of power out of something like that... but the engine itself just wasn't designed for that kind of output in the first place. Maybe the later DOHC 2.4 they came out with but I'm sure that'd cost even more.

I'm sticking with the popular 5.3L Vortec because it has amazing support, its a dime a dozen and you can do a $250 mild cam swap and gain 50 HP... Get a Trailblazer Intake, aggressive cams and upgraded headers and you can easily push close to 100hp gain... the 5.3 is a great upgrade and very capable upgradable engine for just about anything you'd want to throw at it. I've read an article where they only upgraded the top end and boosted the hell out of it (tuned of course and fuel system to support the boost) and were able to pull nearly 1300 HP out of it with stock bottom end internals... not that it'd last very long, but it just goes to show the durability and capability of the engine.

 

[Jeeper25]

I can say for sure that the 2.5l engine is bullet proof and has decent torque but it won't make much power- no matter what you do. The head can't be made to flow, since the inlet to exhaust transition is terrible (cross flow heads work MUCH better). I used to race a 2.5l Jeep Commanche in SCCA Showroom Stock Truck racing series. I picked up the "hacks" from Archer Brothers racing and everything we did (which included everything mentioned above) netted us about 15 hp at the wheels well above the factory redline (the engine was fully balanced and blueprinted, port matched and set up for high RPM use). Suffice to say that the drivability was negatively impacted everywhere else. Enjoy it, and upgrade to a 4.0L if you want more power.

100%. I enjoy building small engines for the sheer fun of seeing what they can do... but like you said, with out a cross flow head, its just not going to breath to its full potential. I'd be curious to see what the 2.4l DOHC can do but with out the support like the V8 swaps or any of the other engines have, it'd be like throwing money into the fire.

Personally I didn't want the 4.0 which was why I got the 2.5 for nearly 3k cheaper with the full intention of doing a V8 swap. with all the info from Novak and advance Adapters, it'd be dumb to do a 2.5 to 4.0 swap instead of just buying a 4.0 in the first place... that's just my opinion though.

 

[TJKarr]

I've enjoyed this read. I agree that most of these mods are useless. The fact that you put new parts, on an old Jeep, makes it better anyway??

The best modification I have done, is re-gearing to 4.88 and going with a Ford 8.8 rear axle. That axle already has the same bolt pattern as the stock Jeep, plus you get LSD, disc brakes, larger axle shafts, etc. I run 285/75/16s on mine. Yes, I drive comfortably at 3000 RPM, 60-65 mph down the highway.

The performance on and off-road, with all the benefits from this mod, is unrivaled in my opinion.

 

[Skulljeep]

Honestly, 505 Performance has an economy stroker kit for 1,100 and that includes the megasquirt piggyback computer pre-tuned. Or, you can send your original CPU to them and they will map it. Or if you have a buddy with HP tuners, you can tune it on a dyno after the mods for 100 bucks for the token. I've been on Jeepz another forum site, and working with some great minds there on the topic. The computer is what it all hinges on, tuning it to run the way you need it to. There's also cost effective stuff like mega-squirt, that you can pick up for a few hundred by itself and then for say 1100 to 2000 you can have the little motor put out some more grunt. You are right, that all those mods will do nothing because the computer compensates. But when you change the way the computer thinks, that's where you see the gains. Just to be a bit more clear on the topic.

 

[Snowkilla73]

Hey Chris love your post very informative. I was just wondering I currently purchased a 1994 Jeep Wrangler YJ bodies in perfect condition unfortunately the previous owners told me that the motor was freshened up a couple years ago and that he was a mechanic so kept up on all the maintenance. Well guess I was suckered fortunately I brought a trailer down to Salem Oregon and trailer it back home to Vancouver Washington. Cleaning it all up making it shine the bodies great nice cherry red interior was good all the gages worked initially I was happy. Took it force a few short drives never had a problem temperature never got high idle great seem to run really good. I decided to start putting a little money into it new taillights new headlights winch 2 1/2 inch lift new wheels and tires new tune up kit just went completely through it and made it look as new as possible. Took it for a drive up to large mountain gravel roads had the top off doing what you do in a Jeep I started to notice to temperature rising to uncomfortable levels so pulled over lifted the hood notice that I had a pinhole leak in the radiator. Sat there for a bit popped off a couple rounds let it cool down topped it off with water drove it home. Took it to my local mechanic asked him to go through it this is where it gets fun. He replaced the water pump upper and lower hosing thermostat thermostat housing the hoses going to the heater core then talk me into pulling the timing chain cover to check the timing chain which entails pulling off the oil Pan. Got the timing chain cover off and the oil pan off and unfortunately he put everything back together then gave me the bad news instead of giving me the bad news before they did all the work. He said there was metal debris in the oil Pan and so much carbon build-up on the timing chain cover and oil Pan that he had to send both of them off to get blasted. The timing chain was so badd that it could have went any day. Well I guess we know that the previous owner didn't do the maintenance he said he did at all. My mechanic told me that everything on the Jeep was all stock not a chance in hell that it had been freshened in any way and that he believes it was overheated and burnt the coating off the rings so now you're getting massive blow by which is causing all of the rust on the dipstick. So now I need a new motor I found some motors from API motors out of Florida they want $1700 plus $250 shipping for a stock 2.5 l motor with a 24 month warranty or I could get a 2.5 l stroker motor bored and stroked to a 3.1 for 2000 dollars and $400 shipping with a 18 month warranty and that's a complete long block with all brand new parts including new block new head and everything is balanced ported and polished. Keep in mind I am not a Wheeler I won't be up in the mountains flinging mud all the time but when I do go up into the mountains I wouldn't mind happen that little tiny bit of extra power to fling that mud a couple extra feet. I was told by my mechanic and multiple people that it is costly and a pain in the ass to do an ls1 swap in that Jeep unless you can do-it-yourself and just as expensive to drop the 4.0 into that Jeep unless again you do-it-yourself. I am no mechanic by any means and would not be comfortable doing a motor swap. I have all the tools and all the equipment to do it just don't have the confidence I'm your basic garage mechanic the can do all the bolt on necessities but never have done a complete motor swap along with a bunch of custom work like motor mounts wiring all the stuff my mechanic will do. My mechanic told me that if I purchased either the stock 2.5 or the stroke or 2.5 it would cost me about 1100 to $1500 to do the swap. Just seeing what your opinion is because I am new to the Jeep world but looking forward to moving up in it. You gotta start somewhere.

 

[Chris]

Hey Chris love your post very informative. I was just wondering I currently purchased a 1994 Jeep Wrangler YJ bodies in perfect condition unfortunately the previous owners told me that the motor was freshened up a couple years ago and that he was a mechanic so kept up on all the maintenance. Well guess I was suckered fortunately I brought a trailer down to Salem Oregon and trailer it back home to Vancouver Washington. Cleaning it all up making it shine the bodies great nice cherry red interior was good all the gages worked initially I was happy. Took it force a few short drives never had a problem temperature never got high idle great seem to run really good. I decided to start putting a little money into it new taillights new headlights winch 2 1/2 inch lift new wheels and tires new tune up kit just went completely through it and made it look as new as possible. Took it for a drive up to large mountain gravel roads had the top off doing what you do in a Jeep I started to notice to temperature rising to uncomfortable levels so pulled over lifted the hood notice that I had a pinhole leak in the radiator. Sat there for a bit popped off a couple rounds let it cool down topped it off with water drove it home. Took it to my local mechanic asked him to go through it this is where it gets fun. He replaced the water pump upper and lower hosing thermostat thermostat housing the hoses going to the heater core then talk me into pulling the timing chain cover to check the timing chain which entails pulling off the oil Pan. Got the timing chain cover off and the oil pan off and unfortunately he put everything back together then gave me the bad news instead of giving me the bad news before they did all the work. He said there was metal debris in the oil Pan and so much carbon build-up on the timing chain cover and oil Pan that he had to send both of them off to get blasted. The timing chain was so badd that it could have went any day. Well I guess we know that the previous owner didn't do the maintenance he said he did at all. My mechanic told me that everything on the Jeep was all stock not a chance in hell that it had been freshened in any way and that he believes it was overheated and burnt the coating off the rings so now you're getting massive blow by which is causing all of the rust on the dipstick. So now I need a new motor I found some motors from API motors out of Florida they want $1700 plus $250 shipping for a stock 2.5 l motor with a 24 month warranty or I could get a 2.5 l stroker motor bored and stroked to a 3.1 for 2000 dollars and $400 shipping with a 18 month warranty and that's a complete long block with all brand new parts including new block new head and everything is balanced ported and polished. Keep in mind I am not a Wheeler I won't be up in the mountains flinging mud all the time but when I do go up into the mountains I wouldn't mind happen that little tiny bit of extra power to fling that mud a couple extra feet. I was told by my mechanic and multiple people that it is costly and a pain in the ass to do an ls1 swap in that Jeep unless you can do-it-yourself and just as expensive to drop the 4.0 into that Jeep unless again you do-it-yourself. I am no mechanic by any means and would not be comfortable doing a motor swap. I have all the tools and all the equipment to do it just don't have the confidence I'm your basic garage mechanic the can do all the bolt on necessities but never have done a complete motor swap along with a bunch of custom work like motor mounts wiring all the stuff my mechanic will do. My mechanic told me that if I purchased either the stock 2.5 or the stroke or 2.5 it would cost me about 1100 to $1500 to do the swap. Just seeing what your opinion is because I am new to the Jeep world but looking forward to moving up in it. You gotta start somewhere.

My personal opinion (and some won't like this) is not to dump any money at all into your 2.5. You'd be better off saving the money and swapping in another engine to be honest. If you plan to only use it for off-road, trails, and in-town city driving, then the 2.5 is more than fine. However, if you plan on lots of long trips that involve highway speeds or lots of hills, you really want to get away from the 2.5 and swap something else in there.

The 4 cylinder engines have their place, I just don't believe they are well suited for much more than in-town driving and off-road use.

That statement will anger some, but it's not meant that way. I can just tell you from experience having driven and owned a 2.5, I know what I personally would and would not use it for.

 

[TJ4Jim]

My personal opinion (and some won't like this) is not to dump any money at all into your 2.5. You'd be better off saving the money and swapping in another engine to be honest. If you plan to only use it for off-road, trails, and in-town city driving, then the 2.5 is more than fine. However, if you plan on lots of long trips that involve highway speeds or lots of hills, you really want to get away from the 2.5 and swap something else in there.

The 4 cylinder engines have their place, I just don't believe they are well suited for much more than in-town driving and off-road use.

That statement will anger some, but it's not meant that way. I can just tell you from experience having driven and owned a 2.5, I know what I personally would and would not use it for.

I have been saying this for years, the 2.5 is a good setup based on those driving parameters. I like mine and although I have the tools and ability for an engine swap she is staying put under the hood.