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General Forums => The Mess Hall => Topic started by: keithert on October 20, 2006, 09:19:35 AM

Title: 2.5 vs 2.4 engine
Post by: keithert on October 20, 2006, 09:19:35 AM
I've had my 98 SE for about 6 weeks and am happy enough with it's power.  It is a 5 speed.  It won't win any races but does an ok job otherwise.   I know the 2.4 has more horsepower and is a completely different engine.  What are the pro's and cons of each engine?  Will a 2.4 with an automatic have as much power as a 2.5 with manual trans?  I've also read that the 2.5 has more toreque down low so it actually feels quicker than the 2.4.  I'm wondering because I might get a newer TJ and would like to stay with the 4 cyl due to cost and mpg issues.  I know the mpg isn't much different than the 6 but every bit helps.
Title: 2.5 vs 2.4 engine
Post by: frosty on October 20, 2006, 11:19:14 AM
the 2.5 is a jeep engine designed for a jeep. The 2.4 is a dodge neon engine designed for a car.  The 2.5 has its torque at a much lower rpm where you really need it. its the same as the 3.8 vs 4.0 debate.  The 3.8 produces a little more torque but the 4.0 produces 85% of its torque at idle where you really need it.  With thats said I would take any variant of the two amc engines over a chrysler engine any day of the week.  The are both simple tough strong engines that are made of all cast iron.  Both the 2.5 and the 4.0 are known to go forever I am not so sure about the 2.4 it may be a decent engine as is the 3.8v6  But i will say that the jury is out and they dont match up as far as durability and longevity to the older amc engines
Title: 2.5 vs 2.4 engine
Post by: dunklervogel on October 20, 2006, 12:47:13 PM
I've just heard the 2.4 has to get pretty high revs to reach a good torque that the 2.5 can put out at lower rpms..  in which case on a trail i'd think the 2.5 would be a better engine for a jeep.
Title: 2.5 vs 2.4 engine
Post by: Jeffy on October 20, 2006, 12:55:55 PM
The DC 2.4L is a completely different engine then the AMC 2.5L.  The AMC 2.5L was first designed to replace the GM Pontiac Iron Duke 2.5L that the CJ's had been using for years.  In 1984, the first Jeeps with the AMC 2.5L.  This included the CJ and the new Cherokee (XJ) and Comanche (MJ).  The engine was designed from the 4.2L AMC already had but with some differences.  The engine still uses push rods like the 4.2L.  Stock gearing was 4.10/4.11 for the manuals and 3.73:1 for the automatics generally but when parts ran short, some 3.54 gears were used for the auto's and possibly 3.73 gears were used on the manuals.  The engine has had different ratings over the years but the TJ's has 120hp (down 3hp from the YJ) and 140lbs-ft of torque.  The engine hits peak torque between 2600-3200RPM.  This is pretty low and is in the middle of the power band.

The 2.4L was designed to be used on multiple platforms.  The Neon, Caliber, Liberty, PT Cruiser, etc...  Unlike the 2.5L the 2.4L was designed to be a transverse engine instead of the conventional N-S setup a RWD uses.  The 2.4L also moved away from push rods in favor of OHC.  OHC involve less parts so there is less power wasted in moving the valves.  Typically, this also means that the engine is more balanced and can rev higher.  The down side is there there is less torque down low.  To hit peak RPM with a 2.4L you will need to rev to 6000.  That's 3000RPM more then the 2.5L.  The 2.4L does produce 147hp which is 27hp more then the 2.5L though.

The first 2.4L's came out with the same gearing as the 2.5L, 3.73 and 4.11's.  They were still using a 5-speed manual and a 4-speed automatic 42RLE.  Then they switched from the 5-speed manual and 4-speed auto to the 6-speed box for both. They also regeared the 2.4L to 4.56:1 in both models.  This only lasted a year, I believe.  Then they went back to 3.73 and 4.11's which is where it started till they phased out the 2.4L Wrangler.

As for the 3.8L, this engine was derived from the current 3.8L DC has been using in their Caravan and other cars.  The engine was revamped though.  A friend of mine bought a Rubicon Unlimited JK and drove it from MI to CA with the 3.8L.  He said he likes the engine better then his old 4.0L but not as nice as his 5.7L Hemi.  (His 97 TJ ahd a 4.0L before he swapped in a 5.9L.  His Unlimited had a 4.0L but was swapped out at AEV for a 5.7L Hemi.)

That said, another friend said had owned a 2.5L, and two 2.4L's one with 4.56's.  He never got very good gas mileage compared to his 2.5L.  His Jeeps were all relitively stock.

The biggest advantage of having an engine shared with a bunch of other model vehicles is that many parts are interchangable.  This means there is a higher likelyhood of performance parts especially with the Neon.  There is also the option of a turbo, lower compression rods, etc...
Title: 2.5 vs 2.4 engine
Post by: keithert on October 20, 2006, 02:08:56 PM
Jeff, thanks for the excellent and detailed write up.  Can any 2.4 owners speak up on how they like their engine?  I get about 17-19 mpg with my 2.5 that has 31's and 139k miles.  What are people with the 2.4 getting?
Title: 2.5 vs 2.4 engine
Post by: Liljeepz on October 20, 2006, 03:39:19 PM
Quote
Both the 2.5 and the 4.0 are known to go forever I am not so sure about the 2.4

I never thought about this.... That dose worry me....



Quote
The biggest advantage of having an engine shared with a bunch of other model vehicles is that many parts are interchangable. This means there is a higher likelyhood of performance parts especially with the Neon. There is also the option of a turbo, lower compression rods, etc...


This I like! I need to look into good engine mods for the 2.4L!
Will the 4.0TB work on the 2.4 since its a totally different engine?
Title: 2.5 vs 2.4 engine
Post by: Jeffy on October 20, 2006, 03:58:57 PM
Quote from: "Liljeepz"
Quote
Both the 2.5 and the 4.0 are known to go forever I am not so sure about the 2.4

I never thought about this.... That dose worry me....


I wouldn't worry about it.  The engine's used all over the place.  If the engine does have a problem with the design then it would have come up already.  Rememeber that the engine was used for a few years before the TJ ever got it.  I think it might be evolved from the 2.0L, 2.2L of the Neons.  In any case the engines are plentiful and are probably cheap too.
Title: 2.5 vs 2.4 engine
Post by: Chad on October 21, 2006, 12:08:11 AM
I get like 12-14 mpg with 31's on my 2.5L i've got about 50k miles on the engine what the hell, how come your gas mileage is so much better?
Title: 2.5 vs 2.4 engine
Post by: YJmechanic on October 21, 2006, 05:21:08 AM
jeffy not to kill your write up because as usual you have the insight to more info than i can imagine but one problem and i have heard this many times before.  but the 2.4 in the jeep is not a neon motor.  the 2.4 in the neons and the jeeps are totally different motors.  the 2.4 in the jeeps is actually from the stratus coupe and is actually a mitsubishi motor.  i thought the same thing untill i contacted my dealer reps with questions about using an srt4 turbo setup and found out where the motor came from.  also as a general buying guide.  42rfe is a great trans but if you see the tag 42rle it is a horrible trans.  we have replaced about 200 in the last couple of years with low milage.  jeep doesn't even use the trans any more because of all the problems.  just thought i could give some insight.

now as far as 2.5 vs 2.4  i have driven tons of both and i have to say my opion is that the 2.4 doesn't belong in a jeep. it is flat as day and revs out in two seconds.  it was designed for cars and that is where it belongs.  no offense to 2.4 owners though
Title: 2.5 vs 2.4 engine
Post by: Liljeepz on October 21, 2006, 09:01:07 AM
:sad: I'm stuck with this POS because I didn't know any different when I bought it just over two years ago! Thanks a lot DC!  :angry:
Dose any one know of any good wright ups on this engine? Options, reviews... any thing? Or even good replacements? I already have 50k on this engine and it will be well over 100k by the time its my toy and I can play with it. I don't want to get rid of the 4 cyl but I don't want to keep the 2.4 when it has 35's and all these other great mods. :roll:

I know it dose great for me now... but when I'm more experienced I may want something else and I would like the knowledge before I get to that point.
Title: 2.5 vs 2.4 engine
Post by: Bounty Hunter on October 21, 2006, 11:52:51 AM
Quote from: "Chad"
I get like 12-14 mpg with 31's on my 2.5L i've got about 50k miles on the engine what the hell, how come your gas mileage is so much better?

Shoot, I get 18city and 21hwy with my 2.5L on 32"s, and the speedo has been corrected.

Back down to 225's now while I do a SOA and throw on 35"s and 5.38's.
Title: 2.5 vs 2.4 engine
Post by: Jeffy on October 21, 2006, 12:06:09 PM
Quote from: "Liljeepz"
:sad: I'm stuck with this POS because I didn't know any different when I bought it just over two years ago! Thanks a lot DC!  :angry:
Dose any one know of any good wright ups on this engine? Options, reviews... any thing? Or even good replacements? I already have 50k on this engine and it will be well over 100k by the time its my toy and I can play with it. I don't want to get rid of the 4 cyl but I don't want to keep the 2.4 when it has 35's and all these other great mods. :roll:

I know it dose great for me now... but when I'm more experienced I may want something else and I would like the knowledge before I get to that point.


I'm not sure if Allpar.com would have a good writeup but there should be on there.

Like we always say, gears are your friend.  Properly geared you should be fine even with 35's.  I'm a bit tossed between wanting to run 5.38's or else doing a SC or engine swap.  Going too low with the gears will limit my high end.  Although I doubt I'd want to go over 85mph.  It gets a bit scary at those speeds when a crosswind picks up.  If I was considering an engine swap, I'd probably gear only to 5.13's instead of 5.38's although I could live with 4.56's too.  I'd really like to swap my axles for a pair of Dtrac D60's, I think and keep my 35's.  I'd be able to go up to 37's or 38's but I really like 35's.

When I was mostly stock and ran 32's I would get +21MPG.  My best was 25-27 but back then 60mph was considered fast and so I didn't have to push it hard.  This is the biggest problem.  I think if I was able to drive at 55-60mph without having everyone in this Prius pass me, I'd get into the 20's again.  That's with 35's and 4.56's.  From what I've seen though the 2.5L gets better mileage since most are driven around town and you don't have to rev it up to get enough torque.  3000rpm vs. 6000rpm is a big difference.
Title: 2.5 vs 2.4 engine
Post by: Liljeepz on October 21, 2006, 12:52:28 PM
Saving money now for a axle swap, I was tossing the idea around for a bigger lift fist, but axle's with lockers would help a bit more. I just have to remember I have a 2" lift and can't do the very hard trails with out a lot of damage. I'm running 31's now, I can't complain about the power but it is high rpm power I don't get going tell 3k+.
1K-3K is rough tho.
Title: 2.5 vs 2.4 engine
Post by: JeepersCreepers on October 21, 2006, 06:44:28 PM
The 2.4 engine is supposed to actually be a longer lasting engine than its predecessor...............Time will tell. It works well for me as I use it to get to work. I drive on older state highways about 60 miles round trip & rarely get over 65MPH.When you think about it the Jeep isn't really a good car for interstate travel with it's soft top(mine anyway), solid front axle & VERY short wheel base. Also the peak HP comes long before 6000 RPM(this is where my tach is at extreme redline)more like 5000RPM. I would have to say the two engines are pretty much alike all things said. I have yet to get under 20MPG out of mine & get about 22MPG most of the time. Here is the specs straight from Chrysler..............Enjoy............ :D




The 2.4 L (2429 cc) EDZ engine is very similar to the 2.0, sharing the same bore and DOHC cylinder head, but it has a taller block and longer 101 mm stroke. It also uses balance shafts to smooth vibrations and is built in Saltillo, Mexico. Output was up to 140 hp when production started in 1994 for the 1995 model year. As of 2004, output is 147 hp SAE (110 kW) at 5200 rpm with 165 ft·lbf (224 N·m) of torque at 4000 rpm.

It has a cast iron engine block and an aluminum DOHC cylinder head. It uses SFI fuel injection, has 4 valves per cylinder with roller followers and features fracture-split forged powder metal connecting rods, a one-piece cast camshaft cast, and an aluminum intake manifold.

Applications:

Chrysler PT Cruiser
Dodge Stratus/Chrysler Cirrus/Chrysler Sebring/Plymouth Breeze
Dodge Caravan/Chrysler Voyager
Jeep Liberty
2003-2005 Jeep Wrangler
Title: 2.5 vs 2.4 engine
Post by: keithert on October 21, 2006, 06:55:25 PM
Quote from: "YJmechanic"
but the 2.4 in the jeep is not a neon motor.  the 2.4 in the neons and the jeeps are totally different motors.  the 2.4 in the jeeps is actually from the stratus coupe and is actually a mitsubishi motor.


I don't think it is a Mitsu motor.  The Mitsu 2.4 is a SOHC engine and the Mitsu DOHC heads look a lot different than the one in the SE.
Title: 2.5 vs 2.4 engine
Post by: JeepersCreepers on October 21, 2006, 07:04:43 PM
Quote from: "keithert"
Quote from: "YJmechanic"
but the 2.4 in the jeep is not a neon motor.  the 2.4 in the neons and the jeeps are totally different motors.  the 2.4 in the jeeps is actually from the stratus coupe and is actually a mitsubishi motor.


I don't think it is a Mitsu motor.  The Mitsu 2.4 is a SOHC engine and the Mitsu DOHC heads look a lot different than the one in the SE.



Read my post & here is a link where I got the info:  
http://en.wikipedia.org/wiki/Chrysler_Neon_engine#2.4
Title: 2.5 vs 2.4 engine
Post by: wrangler387 on October 21, 2006, 07:07:59 PM
I'm going to say the 2.4 probably has more potential. just because its peak torque comes higher in the RPM doesn't mean it doesn't make more low end then our 2.5L... SOHC head and an efficient design can make it hold power a lot longer. It has a 101mm stroke, it should be torquier then our 2.5L's 89mm stroke (rod to stroke ratio will play a role here also becuase of piston speeds). I dont know if that 2.4 will last as long though, big stroke is more strain on the bearings, but it is a newer design so it should be better.
Title: 2.5 vs 2.4 engine
Post by: Liljeepz on October 21, 2006, 07:19:25 PM
Good link, explains a lot about it.
Title: 2.5 vs 2.4 engine
Post by: zeitlerusmc on October 23, 2006, 10:50:46 AM
13-16mpg with a 2.4l 6spd and 3:73's turning 33 bfg muds
Title: 2.5 vs 2.4 engine
Post by: YJmechanic on October 24, 2006, 05:10:48 PM
the 2.4 in the jeeps is not the mitsubi motor that you are thinking of with the single cam.  mitsu makes a lot of the dodge and chrysler motors.  the stratus coupe was the original plattform for the motor and the stratus cooupe is entirley mitsu.  we can't even you dc equip to diag the cars. they run their own mitsu controllers and everything.  the motors were just adapted over to the jeeps for emmissions reasons.  the liberty runs a mitsu mercedes combo motor.  dc is using everything they own to make these combo parts for all the vehicles.  and by the way don't worry about the 2.4 being a pos.  there is still plenty of power to be had out of the motor it is just higher up so use deeper gears to compensate the low end and get lots of power from the motor in the high end.  that is pretty much what my setup is.   i spin almost 7k on my motor and rely on gearing on the low end.
Title: 2.5 vs 2.4 engine
Post by: iismet on October 25, 2006, 12:19:53 PM
Quote from: "zeitlerusmc"
13-16mpg with a 2.4l 6spd and 3:73's turning 33 bfg muds


Regear it - you will be happy. That milage is lousy.
Title: 2.5 vs 2.4 engine
Post by: Tall Boy on October 26, 2006, 12:14:59 AM
I tried to race a girl in her 2.4l and she won me in my 2.5l.   :cry: I really wanted her to check my muscles out but she didn't like my ride :cry: .  They are faster off the line, and probably have more torque off the line. I had done an intake, tbs, and flowmaster  muffler and still lost. But I had 30's on and she had the stock 225's I think. I think she had the 373 gears maybe cause i got 4 11's. Her 1st gear wound out further than mine.

Bizatch, showing off her newer 4 banger. If I saw her now a year later it wouldn't surprise me if she had a mullit hair dew.
Title: 2.5 vs 2.4 engine
Post by: YJmechanic on October 27, 2006, 03:31:59 PM
i have no idea what you are talking about but the 2.4 especially with 373 should not even be close off the line as a 2.5 with 410.  you either have a problem or she's hiding something.
Title: 2.5 vs 2.4 engine
Post by: JeepersCreepers on October 27, 2006, 09:58:03 PM
Quote from: "YJmechanic"
i have no idea what you are talking about but the 2.4 especially with 373 should not even be close off the line as a 2.5 with 410.  you either have a problem or she's hiding something.


It could have to do with Tall Boys larger tire size(evens up the gear advantage) & the 30 more HP the 2.4 has?......................... :D
Title: 2.5 vs 2.4 engine
Post by: Tall Boy on October 27, 2006, 10:13:12 PM
Yj mechanic knows. :P   My brother is a Hyundai tech and business is slow right now.  8) Sitting back in the recliner waiting for work shooting the breeze and sipping soda pop  :beer: .

 He's right though, there is always something wrong with a Jeep. Just Empty Every Pocket (J.E.E.P.)
Title: 2.5 vs 2.4 engine
Post by: wrangler387 on October 28, 2006, 11:36:10 AM
I still want to see a dyno of the 2.4, i bet it has more torque across the whole powerband then our 2.5L It has a much larger stroke. Our 2.5L gets its size from it's bore. Not to mention the 2.4 is probably lighter/better balanced, better timing and fuel maps, SOHC experiences less resistance then a push rod motor. The list can go on and on. greaing of the transmissions (both manual?), what each person launched at.
Title: 2.5 vs 2.4 engine
Post by: Jeffy on October 28, 2006, 12:57:37 PM
Quote from: "wrangler387"
I still want to see a dyno of the 2.4, i bet it has more torque across the whole powerband then our 2.5L It has a much larger stroke. Our 2.5L gets its size from it's bore. Not to mention the 2.4 is probably lighter/better balanced, better timing and fuel maps, SOHC experiences less resistance then a push rod motor. The list can go on and on. greaing of the transmissions (both manual?), what each person launched at.


Except for the fact that the inlines produce more low-end torque.  Just looking at the specs, a 2.5L will produce peak at 3000RPM's less then the DOHC 2.4L.  I still haven't driven one but a friend on another board had owned a 2.5L and two 2.4L Wranglers.  He sold all three for other reasons but he always wished he kept the 2.5L because of the low-end torque.

As for Tall Boy's race. There are too many unknowns.  I doubt 30" tires will make that much of a difference over stock 28/29's.  The driver on the other hand can make a big difference.  If you're shifting too low, you won't be in the powerband for the next shift which will really slow you down.  Although if she was driving an Auto, all she's got to do is punch it and let the transmission do all the work.  With everything being unknown, there's no way to tell.

I'd imagine the 2.5L would have better off the line start but the 2.4L would start coming back after they hit around 45mph.  Then the 2.4L would start reeling the 2.5L in.  Although the track would have to be pretty long in which case they might run out of track.
Title: 2.5 vs 2.4 engine
Post by: wrangler387 on October 28, 2006, 01:34:18 PM
Just because the 2.5L hits peak torque earlier doesn't mean that the 2.4L produces less torque in those areas. Engine design and tuning can make a cars torque carry much further into the powerband. With today's techonology smaller motors can easily produce more torque and longer then our 2.5L motors. If our 2.5L motor had a bigger stroke then i think it would be different, but the fact that the 2.5L only has a stroke of 89mm makes me question whether it truely has more lower end. typically a larger stroke pulls the powerband down more, since pistons speeds are generally higher (rod to stroke ratio). My old 2.2-2.3L hondas definately put out more low end torque then my current 2.5L jeep. Bigger stroke, better design, better tuning... Timing makes a world of a difference in how good your motor feels down low. Only good thing i can say about a small stroke (assuming it has decent length rods, which it must since its supposed to be based off the 6 cylinder motor which uses a bigger stroke) is that it's nice for forced induction since the piston spends more time at TDC, so the smaller jeep stroke isn't bothering me to much.
Title: 2.5 vs 2.4 engine
Post by: Jeffy on October 28, 2006, 02:10:07 PM
I agree that we need to see a dyno of the 2.4L to really be sure.  I only have the official one for the 2.5L.  I still have my doubt on the 2.4L.  Like I said this person owned both variations of the 2.4L Wrangler as well as a 2.5L.  Not only did he not like the power output but be also got lackluster gas mileage.  I don't think they ever got the gearing right for the 2.4L either, which probably hurt it as well.  They jumped from 3.73 in the Auto and 4.11's in the Manual to 4.56 in both and then 3.73 in both till they killed it off.
Title: 2.5 vs 2.4 engine
Post by: mud4feet on October 28, 2006, 03:30:16 PM
6000 rpm?? :shock: !!! My tach ('03 2.4) redlines about 5500. When she's crankin' 4500, I can tell I better be shifting. Where'd that 6000 number come from??

BTW - Wife's '94 2.5 feels like it's got lots more power than my 2.4.............probably the aforementioned low-end torque.
Title: 2.5 vs 2.4 engine
Post by: wrangler387 on October 28, 2006, 04:20:42 PM
Well thats two personal experiences, definately put to shame my hopes  :lol:  its sad that the motor got weaker :( I guess i was just hoping for something better  :cry:  O well, i'm happy with my 2.5L, and later this winter i'll hopefully be a lot happier.
Title: 2.5 vs 2.4 engine
Post by: Jeffy on October 28, 2006, 04:45:06 PM
Quote from: "mud4feet"
6000 rpm?? :shock: !!! My tach ('03 2.4) redlines about 5500. When she's crankin' 4500, I can tell I better be shifting. Where'd that 6000 number come from??

BTW - Wife's '94 2.5 feels like it's got lots more power than my 2.4.............probably the aforementioned low-end torque.


Whoops!  Peak Torque is at 4000 while peak HP is 5,200rpm.  I screwed that one right up. :roll:

In any case the 2.4L probably wasn't used because it's a better engine.  It was used because it was expensive for DCX to keep making the 4.0l and 2.5L which are only used in the Jeep Wrangler line-up only.  The KJ had used the 2.4L from the start so it was fairly easy to swap the drivetrain into the TJ.

I still think the 2.4L will have more options for mods then the 2.5L ever will since it is shared over so many platforms.  Especially the Neon/PT Cruiser.  Although with the Neon replaced with the Caliber only the SRT4 is available now from what I understand.  Although that used the same engine too as well as the Patriot and Compass so hopefully there will be more performance parts for them available.
Title: 2.5 vs 2.4 engine
Post by: wrangler387 on October 28, 2006, 04:55:50 PM
We'll see, i hope there is still a few companies who will be R&D products for the 2.4, but if the motor isn't going to be in any performance vehicles then the products won't get near as much R&D into them.
Title: 2.5 vs 2.4 engine
Post by: Jeffy on October 28, 2006, 05:21:07 PM
Quote from: "wrangler387"
We'll see, i hope there is still a few companies who will be R&D products for the 2.4, but if the motor isn't going to be in any performance vehicles then the products won't get near as much R&D into them.


I don't think finding performance parts for the 2.4L will be a problem at all.  They already have a lot of stuff since the SRT4 is still popular.  I wonder if they'll make a SRT version of the Caliber?

I doubt there will be much for the 2.5L unless people DIY stuff themselves though.  A Turbo 2.5L would be pretty cool though.  Looking for 2.5L parts is almost as hard as looking for a Mac game. :lol1:
Title: 2.5 vs 2.4 engine
Post by: JeepersCreepers on October 28, 2006, 06:33:10 PM
Get this months issue of JP magazine & read the write up :Scrappy The Wonder Jeep The hot rod 'banger TJ  . Neat little Turbo on a 2.4L ................................................ :D
Title: 2.5 vs 2.4 engine
Post by: Tall Boy on October 28, 2006, 07:35:55 PM
She had a stick as well. It was right after they came out with the 2.4L so I guess it was a 2003 model. I was kind of messing with her a bit to get her attention , but she took off pretty fast, fast enough where I figured she was faster than I anyway. She was good and pissed I suppose , or just scared of my size. I don't know, it may have been the superhuman strength thing. I may have had the crack on my manifold then, not too sure about it. But I figured since she had the 3:73's , she would get the longer shifts and red line out slower than me. So all the time she was faster. Mind y'all this was in the dead center of downtown where many cops hang out. So I was not too serious, but I did want to witness her gearing stretch opposed to mine.
    One thing I don't do anymore is race my Jeep. The shifting is smoother now, less wear on my pistons and such. I have lost too many races to know where I belong in my Jeep. For the most part I just antagonize the race cars on the road every so often.  It's kind of funny when I pull up to a Corvette or something like that and rev my motor a few times. I even challenged some ricers once and they took me seriously, passed me up like I was standing still. :roflol:
Title: 2.5 vs 2.4 engine
Post by: dunklervogel on October 28, 2006, 08:06:53 PM
My 2.5 has a nice kick to it at the start.. obviously the faster things get the slower the jeep becomes but I've learned to live with it .. its a jeep not a racecar.  

While I had my jeep in the shop I got to drive an 03' chevy tahoe with the 5.3l vortec v8 .. man is that thing quick for being a 6500 lb monster

I'd like to drop that engine into my 3200 lb TJ and see how it goes!
Title: 2.5 vs 2.4 engine
Post by: Jeffy on October 28, 2006, 08:33:28 PM
Quote from: "Tall Boy"
She had a stick as well. It was right after they came out with the 2.4L so I guess it was a 2003 model. I was kind of messing with her a bit to get her attention , but she took off pretty fast, fast enough where I figured she was faster than I anyway. She was good and pissed I suppose , or just scared of my size. I don't know, it may have been the superhuman strength thing. I may have had the crack on my manifold then, not too sure about it. But I figured since she had the 3:73's , she would get the longer shifts and red line out slower than me. So all the time she was faster. Mind y'all this was in the dead center of downtown where many cops hang out. So I was not too serious, but I did want to witness her gearing stretch opposed to mine.
    One thing I don't do anymore is race my Jeep. The shifting is smoother now, less wear on my pistons and such. I have lost too many races to know where I belong in my Jeep. For the most part I just antagonize the race cars on the road every so often.  It's kind of funny when I pull up to a Corvette or something like that and rev my motor a few times. I even challenged some ricers once and they took me seriously, passed me up like I was standing still. :roflol:


If it was a '03 she had 4.11's and with stock tires, they are quick.  Still, a 2.5L manual with 4.11's and 30's shot not have been left behind.  Maybe you were grabbing for the wrong stick. :uhoh:  :whistle:
Title: 2.5 vs 2.4 engine
Post by: Tall Boy on October 28, 2006, 09:24:11 PM
Purple Haze.
Title: 2.5 vs 2.4 engine
Post by: wrangler387 on October 28, 2006, 11:15:16 PM
Quote from: "Jeffy"

I don't think finding performance parts for the 2.4L will be a problem at all.  They already have a lot of stuff since the SRT4 is still popular.  I wonder if they'll make a SRT version of the Caliber?

I doubt there will be much for the 2.5L unless people DIY stuff themselves though.  A Turbo 2.5L would be pretty cool though.  Looking for 2.5L parts is almost as hard as looking for a Mac game. :lol1:


Is the caliber going to retain the same motor and everything? i figured it would be more of a whole new car (I really havn't looked into it at all). If they stick with the 2.4L then I do expect a SRT4 version. Even though there is a lot, there is always people out there slowly finding little things that make more of a difference, but if the platform ever gets replaced then the efforts stop. between cams, headers, intake manifolds, pistons, rods, there are a lot of ways to make extra power... If you look at hondas they have TONs of stuff (hundreds of header designs, all of which serve different purposes, same for intake manifolds, cams etc.), but everything has shifted over to the newer K series motors.

I agree that finding stuff for the 2.5L is hard... I'd like to find some forged pistons and rods a little down the road to put into the spare motor i picked up. The amount of people who have boosted the 2.5L is very small, and the ones who have dont seem to be pushing it to much. I'm going to be starting at 6psi, that is what the spring in my tial is... I'd be further along in my efforts but work, school and my girlfriend have me tied up too much. I'm hoping this winter break to start fabricating stuff. I've pretty much collected everything I need now.
Title: 2.5 vs 2.4 engine
Post by: YJmechanic on October 29, 2006, 07:47:57 AM
the caliber does not use the same motor but i think it is a variation of the same motor.  also the srt4 is no longer produced but they are making a srt4 caliber.  again not the same motor.  although the compass does use the same motor as far as i know.  so you may be able to rely on that for aftermarket support.  



forged pistons for 2.5- York tool warehouse  York,PA
its where i got mine
Title: 2.5 vs 2.4 engine
Post by: wrangler387 on October 29, 2006, 08:56:30 AM
I figured they would change the motor since it's a whole new car. wonder how similar it is.

but does york they have forged rods too? I'd hate to buy forged pistons and then increase the boost and have my rods go. I know i could get custom forged pistons pretty easily, i've gotten custom wiseco ones before. I'll check out that york tool warehouse though.
Title: 2.5 vs 2.4 engine
Post by: Jeffy on October 29, 2006, 11:30:40 AM
Hmm, that's weird.  You're right on them being different.  The engine is part of their 'World Engine' series and looks to have VVT, too.  Having VVT would have made the 2.4L Jeep a lot better.  The flow control in the intake is kinda neat too.  Sure uses a lot of plastic though.

http://www.allpar.com/mopar/world-engine.html

http://www.allpar.com/mopar/24.html
Title: 2.5 vs 2.4 engine
Post by: YJmechanic on October 30, 2006, 05:17:31 AM
i don't know about the rods.  i sanded the casting edges and had them shot peaned and balanced to get what i wanted.  i don't think you need forged rods inless you are going to very high boost which you shouldn't with a 2.5 cause the compression is already too high for that.


yeah the vvt would help i think but still the compasses and calibers are still dogs if you ask me.  i wouldn't pull out in traffic in either.
Title: 2.5 vs 2.4 engine
Post by: wrangler387 on October 30, 2006, 03:36:37 PM
The compression isn't to high. Obviously it isn't a honda, so running 10+ C/R and then 15+lbs out of a t3/t4 won't happen. But getting 15 out of a 14b is possible.
Title: 2.5 vs 2.4 engine
Post by: iismet on October 30, 2006, 05:50:12 PM
Found this somewhere. Please correct if 2.5 data is incorrect. Graphs would be interesting.

2.5L, 120 HP SAE @ 5,400 rpm, 140 ft lb @ 3,500

2.4L, 147 HP SAE @ 5,200 rpm, 165 ft lb @ 4,000
Title: 2.5 vs 2.4 engine
Post by: Jeffy on October 30, 2006, 05:52:12 PM
Quote from: "iismet"
Found this somewhere. Please correct if 2.5 data is incorrect. Graphs would be interesting.

2.5L, 120 HP SAE @ 5,400 rpm, 140 ft lb @ 3,500

2.4L, 147 HP SAE @ 5,200 rpm, 165 ft lb @ 4,000


The 2.5L info you have is for a +'97.  Most specs and general info can be found in the FAQ.
Title: 2.5 vs 2.4 engine
Post by: iismet on October 30, 2006, 06:00:58 PM
Right On - Thanks.
Title: 2.5 vs 2.4 engine
Post by: keithert on November 01, 2006, 12:57:46 PM
Does the 2.4 do any better at maintaining expressway speeds than the 2.4?  In my 2.5 5th gear is pretty much useless if you have to accelerate at all.  With the 6 speed is 5th a lower ratio than in the 5 speed?
Title: 2.5 vs 2.4 engine
Post by: Jeffy on November 01, 2006, 01:08:33 PM
Quote from: "keithert"
Does the 2.4 do any better at maintaining expressway speeds than the 2.4?  In my 2.5 5th gear is pretty much useless if you have to accelerate at all.  With the 6 speed is 5th a lower ratio than in the 5 speed?


Typically, when you add more gears to a transmission, they do not add another gear past 5th.  The last gear is almost always an overdrive gear.  This is used for cruising at a steady pace and not for passing or hills.  When you add 6th gear it's usually added between 3-4.  So 3rd is lowered a bit and 4th is raised.