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-   -   2.5 performance mods (http://www.wranglerforum.com/f218/2-5-performance-mods-177205.html)

Frenz 07-30-2012 03:18 PM

2.5 performance mods
 
After adding a lift and 33 inch tires a 4cyl is pretty heavily stressed and lacking power. short of re gearing, what are some ways to "beef up" my little 4 banger

Thread is not a how to manual.. it's merely to seperate fact from fiction.. and as such will aid me in choosing the next diy project of the week.

feed back:
please rate or place the the various mods in the order 1 - 5 of importance.. which if done first will do the most good. If you have done any of these.. then what was the degree of your success?


Got any other bright ideas?

1. cold air intake

2. 4.0 throttle body spacer

3. exhaust

4. ECU or Chip

5. O2 sensor

Squeeze 07-30-2012 03:43 PM

I can't speak from experience as I'm still building my jeep, but most guys and girls on here will tell you just to regear. At the price you'll be putting out for all the things you listed, you'll be better off regearing to get the most power. Just figured is prepare you for the same answers I got!

Squirrel cage 07-30-2012 04:16 PM

What squeeze said. However I have the intake, 4.0 tb, and replaced the 02 censor and it makes it bearable... Until I hit a hill, or hook up my trailer!

Squirrel cage 07-30-2012 04:17 PM

Quote:

Originally Posted by Squirrel cage
What squeeze said. However I have the intake, 4.0 tb, and replaced the 02 censor and it makes it bearable... Until I hit a hill, or hook up my trailer!

Note: I have the 4.0 throttle body, not a spacer.

XJ Knight 07-30-2012 04:37 PM

Regear Regear REGEAR

VinceTj 07-30-2012 04:41 PM

Stroke it :D

Nickabis 07-30-2012 05:16 PM

You forgot to add swapping in a electric fan for the clutch fan.

mbaseel 07-30-2012 05:21 PM

I have intake, 4.0 throttle body and throttle body spacer, pacesetter header, high flow cat, banks cat back monster exhaust, and mustang 19lb injectors and it gave me 5th gear back... If all of that is worth it to you go for it. But from experiencing the minor differences of all of these things together even after a full rebuild on my top and bottom end I say save for the re-gear.

IndyJeepMan 07-30-2012 05:22 PM

Dont waste 500+ on useless items, put that towards a regear!

P0234 07-30-2012 06:40 PM

Quote:

Originally Posted by IndyJeepMan (Post 2637063)
Dont waste 500+ on useless items, put that towards a regear!

Exactly. The 2.5L is a fantastic motor, durable as heck, good torque curve, fairly reliable. It does not respond well to mods. There is a good idiom that applies, like squeezing blood from a stone.

DasfieldmarshelsYJ 07-30-2012 08:34 PM

Quote:

Originally Posted by mbaseel
I have intake, 4.0 throttle body and throttle body spacer, pacesetter header, high flow cat, banks cat back monster exhaust, and mustang 19lb injectors and it gave me 5th gear back... If all of that is worth it to you go for it. But from experiencing the minor differences of all of these things together even after a full rebuild on my top and bottom end I say save for the re-gear.

How's the banks cat back for you? Does it sound good?

mbaseel 07-30-2012 08:59 PM

The banks cat back is great. Has a nice low rumble. Wasn't the greatest until I put the header and high flow cat on it though. Sounded kind of ricey before that.

kdub 07-30-2012 09:04 PM

I put a intake,4.0 throttle body,and a efan and it helped some.still was not happy.I ended up swaping my engine for a 4.0.

Frenz 07-30-2012 09:25 PM

yup you're right.. and i'm looking now for the fan $25 taurus
Quote:

Originally Posted by Nickabis (Post 2637052)
You forgot to add swapping in a electric fan for the clutch fan.


Xpress 07-31-2012 01:59 AM

Dyno tests have shown as much as 40hp over stock with all of the available mods.. I will say that 19lb injectors that have a multi-ported nozzle do give the engine more umph. Cleaner burn pattern.

lokitim 08-01-2012 08:17 AM

If you haven't yet check out 4bangerJP.com - Index
Alot of good info..

ctlucas93 08-01-2012 10:26 AM

1. 4.0 Throttle body and spacer
2. 19lb Bosch Yellow Top Four Hole Injectors
3. Ford Taurus Electric Fan
4. MSD Ignition Coil
5. 8mm Spark Plug Wires

I have all these mods and I can do 75 MPH no problem running 31-10.50-15s, AND I use 5th gear and get 18 MPG. Fan and throttle body make the most difference right off of the bat.

Frenz 08-01-2012 10:16 PM

I am buying an e fan $40 pep boys. also excited about "tri county gear's.. inertia ring" that is sitting here waiting to be installed. the motor is on the engine stand waiting for the mods. injectors coil & wires yeah baby :thumb: not got my head wrapped around the TB yet.

BlackedOutYJ 08-01-2012 10:27 PM

Quote:

Originally Posted by Frenz
I am buying an e fan $40 pep boys.

do yourself a favor and spend the little extra to buy the wiring harness with the adjustable temp.

Frenz 08-01-2012 10:43 PM

Quote:

Originally Posted by BlackedOutYJ (Post 2645561)
do yourself a favor and spend the little extra to buy the wiring harness with the adjustable temp.

gotchya ty

IndyJeepMan 08-05-2012 10:20 AM

Quote:

Originally Posted by ctlucas93
1. 4.0 Throttle body and spacer
2. 19lb Bosch Yellow Top Four Hole Injectors
3. Ford Taurus Electric Fan
4. MSD Ignition Coil
5. 8mm Spark Plug Wires

I have all these mods and I can do 75 MPH no problem running 31-10.50-15s, AND I use 5th gear and get 18 MPG. Fan and throttle body make the most difference right off of the bat.

I can do 75mph in 3rd no problem with a stock 4cyl on 31"s too!

Also, think about what the Jeeps throttle body does, it has no fuel injection at the throttle body, thus no reason at all for a spacer.

Xpress 08-05-2012 07:43 PM

TB spacers supposedly make the air more turbulent. In theory, it doesn't matter where the fuel is mixed, more turbulence throughout the intake means a better mix.

IndyJeepMan 08-06-2012 07:44 AM

Quote:

Originally Posted by Xpress
TB spacers supposedly make the air more turbulent. In theory, it doesn't matter where the fuel is mixed, more turbulence throughout the intake means a better mix.

While that would make sense, a spacer also allows the air to heat more causing lese dense mixture atleast I would think so

Irongrave 08-06-2012 08:02 AM

1 e-fan
2 lose the AC
3 4.0 throttle body
4 gear the hell out of it, 4:56 or 4:88

mike22 08-06-2012 09:19 AM

Do any of yall have a p/n on the Bosch 19lb injectors

Xpress 08-06-2012 10:28 AM

Here's a list of parts for 1991-1995 MPFI 2.5L engines:

-19lb injectors
-Electric fan
-4.0 throttle body
-Throttle body spacer
-High flow intake
-Borla headers
-Full exhaust system
-Hotter running ignition coil
-Regear for your tires

Like I mentioned, some advocates of this setup has seen as much as 40hp over stock in engine output, and some 35ft lbs of torque. That's plenty to make your humble 2.5L into an engine that can roll with a bit more authority. 123hp vs 163hp, modern 4 cylinder engine territory.

Of course if you really want to get power out of a 4 cylinder then I suggest stroking to a 2.9L and turbocharging, ontop of the above power upgrades.

And for those who whine about parasitic drag increases on the alternator from the e-fan, it's not present while the fan isn't running. Above 25mph there's really no need for a fan, as the air flow through the radiator is adequate to keep everything cool. 25mph+ = no electric fan on, which in turn = no additional parasitic drag on the alternator.

Quote:

Originally Posted by IndyJeepMan (Post 2657324)
While that would make sense, a spacer also allows the air to heat more causing lese dense mixture atleast I would think so

Not really, no. Your intake manifold isn't really HOT in the first place. Plus, more spooling air inside means that it will cool down more before it gets sent in. NOT THAT a 10* temperature difference is going to make your engine run any better or worse. The turbulent air is what you're after.

Ibuildembig 08-06-2012 10:53 AM

You can throw all kinds of parts at it, but when the day is done a gear swap is the only thing that will make a real difference.

denisbaldwin 08-06-2012 01:58 PM

Quote:

Originally Posted by mike22 (Post 2657516)
Do any of yall have a p/n on the Bosch 19lb injectors

I'm curious of this myself, as I believe the 0280150943 Bosch/19 pound yellow tops I have are the WRONG part number.

Babasnoopy 01-09-2013 04:47 PM

Does any of this apply to the 90 2.5l TBI? Not the exhaust, but the 4.0 TB, 19lb injectors, etc?

Nickabis 01-09-2013 11:28 PM

Quote:

Originally Posted by Babasnoopy (Post 3205667)
Does any of this apply to the 90 2.5l TBI? Not the exhaust, but the 4.0 TB, 19lb injectors, etc?

Unfortunately no, you and I have the same motor. I only did the header and e fan. Most everything else is for the mpi motor.


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