Author Topic: 2.5 power questions  (Read 3932 times)

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TJZep

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2.5 power questions
« on: February 22, 2006, 11:02:11 AM »
I have a 97 2.5  Currently i run 33x12.5s.  I have the stock 4.10s in the axles, but have the 4.88's sitting in my kitchen waiting for the carrier i have on backorder.  Anyways, the jeep is obviously slow, but, it is not unbearable.  I couldnt use 5th gear at all when i first put the tires on, but since then ive put a 4.0 tb, spacer, aem intake, flowmaster 40 series catback(freebie from a buddy who sold his jeep before he had a chance to put it on) and a custom airt intake sensor mod(something about tricking the ecm into thinking its getting a cooler charge than it is for optimal burn??)  Well now i can use 5th gear on the highway, although any hill means a downshift.  I like to drive 75mph, and it keeps up with traffic alright, although no real passing unless they are doing 55.  Well the point of this is that i am not looking for sick power and speed, just for the best i can do with what i got.  I know the gears are supposed to make a huge difference, putting the engine back into its powerband.  Well What next!!  Does an electric fan really help that much, or is it just another mod people do just to get 2 more hp on the dyno.  Im looking at the flexalite 475 kit, i dont really have time to go to junkyards, plus the one good one we have left is starting to really suck(they wont let up pick parts anymore, too many ricer kids stealing parts for their hondas!!)  Also, how about the ignition?  I know there is that kit (firepower maybe??) but i read somewhere that the stock tj ignition does enough and it isnt necessary to upgrade.  So which power mod should i do next!! Eventually i will pony up for the avenger(or whatever else may be around by then), but not until i do a full build, with an nv4500 and an atlas II to go behind it(and maybe dana 44s too!)  so which is it, fan or ignition, or both!!  any other suggestions?  I can attest from this being my 2nd 2.5 jeep that the 4.0 tb is by far the best cheap mod, for 40 bucks it made decent power gains!!

jwrape

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2.5 power questions
« Reply #1 on: February 22, 2006, 12:10:49 PM »
I would go with the fan next. It is a easy 5-10 HP. You are reducing rotatong mass by 5 pounds. I just got my fan and am going to install it this week. After that the only other thing that I would do is look for a CAM. You can sometimes find a nwq old stock Stage 3 Mopar cam. I have one for mine but haven't installed it yet. I am waiting on my rebuild but I have heard, aside from gears that is the best bang for the buck.
If you can't find that cam you can get on here.
http://www.hescosc.com/shop.asp?action=details&inventoryID=42889&catId=7758

Either of these cams will give you a NICE boost from what I have heard from others that have installed them.

Offline Bounty Hunter

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2.5 power questions
« Reply #2 on: February 22, 2006, 12:30:02 PM »
I've got both the Firepower ignition setup and a Taurus fan, and both are nice additions to the overall power package.  Of the two I think I felt the power improvement the most with the upgraded ignition.  

Even if you can't feel a power increase from the fan swap, it's a nice addition to the overall power improvement of this small engine.

I've got a Mopar Performance cam in mine (256º/.450"), and will soon be installing an adjustible MAP sensor to dial in my own air/fuel ratio.

Offline Jeffy

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2.5 power questions
« Reply #3 on: February 22, 2006, 01:16:30 PM »
You know, I'd maybe consider a 9lbs inertia ring.  More mass will keep the RPM's up while at highway speeds.  The 2.5L really loses speed fast if there's a sudden gust or a hill.
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"If the motor car were invented today, there is absolutely no way that any government in the world would let normal members of the public drive one."

jwrape

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2.5 power questions
« Reply #4 on: February 22, 2006, 02:15:39 PM »
Quote from: "Bounty Hunter"
I've got both the Firepower ignition setup and a Taurus fan, and both are nice additions to the overall power package.  Of the two I think I felt the power improvement the most with the upgraded ignition.  

Even if you can't feel a power increase from the fan swap, it's a nice addition to the overall power improvement of this small engine.

I've got a Mopar Performance cam in mine (256º/.450"), and will soon be installing an adjustible MAP sensor to dial in my own air/fuel ratio.



How did that Cam feel when you installed it?


Also the inertia ring is a nice addition for low end torque. I can stall my Heep down to 200 rpms, basically that little mark at the bottom of your tachometer and recover without any problems. It'sgreat for crawling and fun in traffic. I idle in 1st and hold the brakes to creep through traffic.  :D

One of my favorite mods is that inertia ring. You can get them from Tri-county 4x4. I think it runs $165 shipped.

TJZep

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2.5 power questions
« Reply #5 on: February 22, 2006, 03:44:49 PM »
Quote from: "jwrape"
I would go with the fan next. It is a easy 5-10 HP. You are reducing rotatong mass by 5 pounds. I just got my fan and am going to install it this week. After that the only other thing that I would do is look for a CAM. You can sometimes find a nwq old stock Stage 3 Mopar cam. I have one for mine but haven't installed it yet. I am waiting on my rebuild but I have heard, aside from gears that is the best bang for the buck.
If you can't find that cam you can get on here.
http://www.hescosc.com/shop.asp?action=details&inventoryID=42889&catId=7758

Either of these cams will give you a NICE boost from what I have heard from others that have installed them.

maybe ill get that cam and the roller rockers from quadratec and rebuild my top end!!  I can do that in an afternoon in my driveway!(yes i have plenty of experience with engine rebuilds)  While i am at it, are there any aftermarket heads?  probably not huh.  I was gonna rebuild the whole motor and p&p the head before i dropped in the avenger and the nv4500/atlas.

jwrape

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2.5 power questions
« Reply #6 on: February 22, 2006, 03:51:39 PM »
Quote from: "TJZep"
Quote from: "jwrape"
I would go with the fan next. It is a easy 5-10 HP. You are reducing rotatong mass by 5 pounds. I just got my fan and am going to install it this week. After that the only other thing that I would do is look for a CAM. You can sometimes find a nwq old stock Stage 3 Mopar cam. I have one for mine but haven't installed it yet. I am waiting on my rebuild but I have heard, aside from gears that is the best bang for the buck.
If you can't find that cam you can get on here.
http://www.hescosc.com/shop.asp?action=details&inventoryID=42889&catId=7758

Either of these cams will give you a NICE boost from what I have heard from others that have installed them.

maybe ill get that cam and the roller rockers from quadratec and rebuild my top end!!  I can do that in an afternoon in my driveway!(yes i have plenty of experience with engine rebuilds)  While i am at it, are there any aftermarket heads?  probably not huh.  I was gonna rebuild the whole motor and p&p the head before i dropped in the avenger and the nv4500/atlas.


 I haven't seen any aftermarket heads but I know there is a difference in Valve size betwwen the years of 2.5L. I think The #117 is the head you would want. But basically just polishing and porting would be your best bet.

Offline Jeffy

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2.5 power questions
« Reply #7 on: February 22, 2006, 03:59:01 PM »
Quote from: "jwrape"
Quote from: "TJZep"
Quote from: "jwrape"
I would go with the fan next. It is a easy 5-10 HP. You are reducing rotatong mass by 5 pounds. I just got my fan and am going to install it this week. After that the only other thing that I would do is look for a CAM. You can sometimes find a nwq old stock Stage 3 Mopar cam. I have one for mine but haven't installed it yet. I am waiting on my rebuild but I have heard, aside from gears that is the best bang for the buck.
If you can't find that cam you can get on here.
http://www.hescosc.com/shop.asp?action=details&inventoryID=42889&catId=7758

Either of these cams will give you a NICE boost from what I have heard from others that have installed them.

maybe ill get that cam and the roller rockers from quadratec and rebuild my top end!!  I can do that in an afternoon in my driveway!(yes i have plenty of experience with engine rebuilds)  While i am at it, are there any aftermarket heads?  probably not huh.  I was gonna rebuild the whole motor and p&p the head before i dropped in the avenger and the nv4500/atlas.


 I haven't seen any aftermarket heads but I know there is a difference in Valve size betwwen the years of 2.5L. I think The #117 is the head you would want. But basically just polishing and porting would be your best bet.


You haven't looked at the Mopar Perfromance catalog, I guess.

Race Prepared Head
P4529644 Mildly Ported Cylinder Head Assembly
Youtube Channel: https://www.youtube.com/channel/UCZNlr60GXH5OlKIFrT7P6mg
My Jeep: http://4bangerjp.com/forums/index.php?topic=2783.0
"If the motor car were invented today, there is absolutely no way that any government in the world would let normal members of the public drive one."

snowbrew

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2.5 power questions
« Reply #8 on: February 23, 2006, 01:09:51 AM »
Just last week I added a banks header to my '91 2.5L. It really opened up the exhaust and added quite a bit of hp and torque. I would look into getting a header if you are going to be building the engine.

chrisfranklin

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2.5 power questions
« Reply #9 on: February 23, 2006, 04:41:23 AM »
Sounds good.  But, I still aint sure my ECU is causing enough fuel to be injected to match the air flow in my current setup wth no headers.  I think I need a MAP adjuster and a friend at the local SMOG station.

How's the noise at full throttle?

jwrape

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2.5 power questions
« Reply #10 on: February 23, 2006, 05:22:18 AM »
Quote from: "Jeffy"
Quote from: "jwrape"
Quote from: "TJZep"
Quote from: "jwrape"
I would go with the fan next. It is a easy 5-10 HP. You are reducing rotatong mass by 5 pounds. I just got my fan and am going to install it this week. After that the only other thing that I would do is look for a CAM. You can sometimes find a nwq old stock Stage 3 Mopar cam. I have one for mine but haven't installed it yet. I am waiting on my rebuild but I have heard, aside from gears that is the best bang for the buck.
If you can't find that cam you can get on here.
http://www.hescosc.com/shop.asp?action=details&inventoryID=42889&catId=7758

Either of these cams will give you a NICE boost from what I have heard from others that have installed them.

maybe ill get that cam and the roller rockers from quadratec and rebuild my top end!!  I can do that in an afternoon in my driveway!(yes i have plenty of experience with engine rebuilds)  While i am at it, are there any aftermarket heads?  probably not huh.  I was gonna rebuild the whole motor and p&p the head before i dropped in the avenger and the nv4500/atlas.


 I haven't seen any aftermarket heads but I know there is a difference in Valve size betwwen the years of 2.5L. I think The #117 is the head you would want. But basically just polishing and porting would be your best bet.


You haven't looked at the Mopar Perfromance catalog, I guess.

Race Prepared Head
P4529644 Mildly Ported Cylinder Head Assembly


No I haven't where do I get one? The dealer?

TJZep

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2.5 power questions
« Reply #11 on: February 23, 2006, 10:16:04 AM »
Quote from: "snowbrew"
Just last week I added a banks header to my '91 2.5L. It really opened up the exhaust and added quite a bit of hp and torque. I would look into getting a header if you are going to be building the engine.

dont know about the 2.5s, but my two friendswith 4.0 tj's with banks headers both had them crack.  One lives with the lawn mower sound, one is on his second header, and he thinks it might be cracked.   Those things are just too expensive to crack like that.  I also heard from people that the headers open it up too much and your low end torque goes south in a hurry.  i think i'm gonna do the fan and...shit who am I kidding.  I'm gonna do the ignition too.  I just didnt want a shiny new 300 dollar ignition that performs exactly like stock.  If you guys think it helps than ill do it, i need a tune-up anyways!!  Think ill wait till spring because i hate wrenching when its cold!!(you shoulda seen me bolt on the tb/intake in 28 degree weather, i did the whole thing in 20 min!! It was funny how fast i was runnin back into the shed to get different tools, my landlord was watchin me out the window laughing!!

Offline Jeffy

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2.5 power questions
« Reply #12 on: February 23, 2006, 11:58:27 AM »
Quote from: "jwrape"


You haven't looked at the Mopar Perfromance catalog, I guess.

Race Prepared Head
P4529644 Mildly Ported Cylinder Head Assembly


No I haven't where do I get one? The dealer?[/quote]

The part number is right there.  The dealer would be the best shot at finding one since it is a dealer part number.  But remember they haven't been made for over 10 years.  :roll:  :wink:
Youtube Channel: https://www.youtube.com/channel/UCZNlr60GXH5OlKIFrT7P6mg
My Jeep: http://4bangerjp.com/forums/index.php?topic=2783.0
"If the motor car were invented today, there is absolutely no way that any government in the world would let normal members of the public drive one."

jwrape

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2.5 power questions
« Reply #13 on: February 23, 2006, 12:51:08 PM »
Quote from: "Jeffy"
Quote from: "jwrape"


You haven't looked at the Mopar Perfromance catalog, I guess.

Race Prepared Head
P4529644 Mildly Ported Cylinder Head Assembly


No I haven't where do I get one? The dealer?


The part number is right there.  The dealer would be the best shot at finding one since it is a dealer part number.  But remember they haven't been made for over 10 years.  :roll:  :wink:[/quote]

oh

lrdogg

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2.5 power questions
« Reply #14 on: February 23, 2006, 02:54:00 PM »
What is the 4.0 tb? :shock: