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Unread 08-08-2011, 03:37 PM   #16
Xpress
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^Depends on your junkyard. Around here they want something like $60 for the throttle body

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-1989 Jeep Wrangler 2.5L, soon to be 5.2L
-1996 Jeep Grand Cherokar 5.2L, donor and rainy day driver
-2004 Kawasaki KLR650 sunny day driver
[QUOTE=mudsweatNgearz;21162729]Leave em off and weld an I beam on. Bumperetts just scream homo.[/QUOTE]
"A well regulated Militia, being necessary to the security of a free State, the [B][I]RIGHT[/I][/B] of the people to keep and bear Arms, [B][I]SHALL NOT BE INFRINGED[/I][/B]."
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Unread 08-08-2011, 05:06 PM   #17
sbsg2005
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Quote:
Originally Posted by Xpress View Post
Honestly it's not going to work on a system that uses multi-port injection.


Not to hi jack someones thread but throttle body injected or multiport fuel injection does not matter. You may see more gains on tbi set up but any time make a change to the intake volume and the distance the air has to travel you are gonna see some kind of change. They may in the form of performance loss or gains it just depends on how the engine is set up and the condition it is in.
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Unread 08-08-2011, 05:18 PM   #18
TheNewbie
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Quote:
Originally Posted by Xpress View Post
^Depends on your junkyard. Around here they want something like $60 for the throttle body
They wanted around $180 for one at the junkyard here.

But I ended up getting mine for like $12. I wouldn't spend too much on one.
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Unread 08-08-2011, 05:42 PM   #19
Xpress
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Whoops, forgot to mention that was just the throttle body itself. No injector.
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[URL="http://www.jeepforum.com/forum/f12/another-5-2l-yj-thread-1503048/"]My 5.2L Build thread[/URL]

-1989 Jeep Wrangler 2.5L, soon to be 5.2L
-1996 Jeep Grand Cherokar 5.2L, donor and rainy day driver
-2004 Kawasaki KLR650 sunny day driver
[QUOTE=mudsweatNgearz;21162729]Leave em off and weld an I beam on. Bumperetts just scream homo.[/QUOTE]
"A well regulated Militia, being necessary to the security of a free State, the [B][I]RIGHT[/I][/B] of the people to keep and bear Arms, [B][I]SHALL NOT BE INFRINGED[/I][/B]."
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Unread 08-09-2011, 09:41 PM   #20
jonzjeepyj
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This isn't rocket science. You need Spark, Fuel and Air for combustion. With my 2.5L I did all of
the above and noticed a hugh difference. But that's the key, you have to do them in conjunction
with each other. Doing one will only net small changes and you might notice a small gain but
you still have choke points in the complete system.

1) Open up your air intake by getting rid of your stock air box. There are two choke
points or restrictors in your stock air box. By doing so you will greatly increase the air
flow and temp of the air being mixed. This is where a cold air intake comes into play and
allow cooler, more dense air into your system.

2) Open up your throttle body and port your intake to match. If you just throw
your 4.0L (larger)TB on your intake, there is a restriction of the Intake being smaller. If you
look down through it, you will see the extra surface area that has to be ground down to
match the TB. A TB spacer doesn't do much to the equation but I have found that it does have
a cooling effect with the helix design and therefor does increase the HP upgrade a bit.

3) Increase your fuel delivery to match your larger air flow This is where you upgrade
your stock 17lb fuel injectors to a better 4 pintle Bosch Type III EV1 19lb injector. This
allows more fuel to be mixed and atomized with the cooler, more dense and higher air flow
volume. Stock injectors have only one pintle or jet hole. Bosch type III EV1 19lb injectors
have 4 pintles or jet holes for a better spray pattern and mist. Depending on how you drive,
this equates to a more efficient burn for better gas mileage or a hotter burn for better
power and throttle response at the top end.

4) Hotter spark to burn the mixture. By upgrading your coil-wires and plugs, you allow your
system to burn off the better spray for more power. I used a super coil (Screamen
Deamon) coil, Live wires and Champion Plugs gaped to .080 for a much hotter burn.

5) Open up your exhaust for your new system to breath. Getting rid of the stock muffler
and cat and replacing them with high flow units allows your system to aspirate
(breath) much better and allows your system to move the exhausted gases out at a
quicker rate.

I also went to an 14 " electric fan. By eliminating the belt powered fan, it reduces drag
on your little 2.5L 120Hp motor. Here are a few things to think about. Approximately
for every year old your motor is, you loose 1 hp due to age wear and tear. Stock your
new 2.5L motor is only 120Hp. My YJ is 19 years old. Theoretically, i'm around 101 HP.
small gains of 4-5 HP is noticeable on this size motor. Someone that has the 4.0L at 265Hp
probably won't notice a 5 Hp gain. I have not tested my motor but I think I'm in the 143 Hp
range for power. Not bad for a stock tired motor.

You may or may not notice a difference when you only do one of these upgrades.
Unless you do them in conjunction with each other, there will always be a choke point
in your system and it will not work up to it's capacity. In my experience, all of these
upgrades done together really do make a much peppier 2.5L motor. Will it ever be a
4.0L NO. But it is much better then a stock 2.5L will ever be.

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Unread 08-10-2011, 12:48 AM   #21
CRASHNDENT
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JonzJeepYJ,
very nice post, very well written. Makes a lot of sense
Don
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Unread 08-10-2011, 06:35 AM   #22
nzpete
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No doubt there are things to make the 2.5 run a bit better, but are they huge gains? All of those listed mods are standard fare on web sites, but you may be spending too much money on very little in return.
And that is where the rubber meets the road. While one can do all of those things listed, I don't think anyone will make huge gains by implementing "snake oil" components or techniques. Can we alter responsiveness? Sure. Smoothness? Sure. However, I don't think you can turn a sow's ear into a silk purse.
Of course, I would love to see a bonafide writeup with dyno'd results to see just how much of a difference a holistic approach to the 2.5 would make. Heck, it just might convince me to turn over some of my hard earned cash!
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Unread 08-10-2011, 03:35 PM   #23
jonzjeepyj
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Food For Thought

Here is an article from 4banger.com which specializes in 2.5L motors. I cut and pasted the article so you wouldn't have to join the forum to see the link.

Enjoy.




Yesterday a 4.0L TB from a '98 Cherokee arrived by UPS -- to be installed on a 2000 2.5L TJ. With the help of a neighbor who teaches auto mechanics at the local high school (absolutely cool woman who decided to make it a day project for some of her students), I dyno-ed everything in stages. Checked the air flow, too.

Results, with stock (2.5L TB & no spacer)as baseline:

(1) Poweraid spacer only -- +2 HP, 8% less airflow (Evidently, the helix bore, lips of which extends beyond intake & TB opening, actually cuts down on airflow. But the spacer does "cool" and extend air volume, hence horsepower increase.)

(2) 4.0L TB only -- + 6 HP, 16% more airflow (no surprise here)

(3) 4.0L TB & grind out intake opening to match lower TB opening -- + 13 HP, 29% more airflow (Wow! Grinding out the intake opening did make a difference!)

(4) 4.0L TB & Poweraid helix spacer & grinded-out intake opening -- +16 HP, 2% less airflow from #3 above(overlapping helix bore is still cutting off airflow, but spacer is still cooling & increasing air volume)

(5) 4.0L TB & grind out helix bore in Poweraid spacer to match lower TB opening & grinded-out intake opening (the Big Kahuna) -- + 24 HP, 39% more airflow (Wow again; the optimal configuration, obviously)

It should be noted that grinding out the helix in the Poweraid spacer still leaves a partial helix in the walls -- the main difference being that the helix now has rounded edges rather than sharp ones. My auto mechanics-teacher neighbor suggests that these rounded edges are actually more aerodynamic than the original sharp ones, and will still "spin air" -- so perhaps the "pulse-organizing" effect I mentioned in an earlier post will be retained, if in fact there is such an effect.

So, to reiterate, I ground out on the helix bore of the Poweraid spacer, and ground out the intake opening, both to match the lower opening of the 4.0L TB I swapped in. Dyno-ed & tested airflow, results: +24 HP, 39% more airflow.

Seat-of-the-pants impression: idles smoothly, more torque on the low end, smoother accleration through the midrange, and better performance above 2700 RPM. No hesitation, no engine codes.

One MAJOR suggestion: if you grind out your intake opening, be VERY CAREFUL about aluminum filings in the intake manifold. We stuffed everything with tack cloth -- sticky cloths which can be purchased at a hardware store -- rather than shop towels. The tack cloth caught about 95% of the filings, but there was still a small mess in the intake. We vacuumed a lot of the leftover out with a shopvac, but we still had to use tack cloth attached to a long, thin screwdriver to "mop out" the runners. On the TJ there are also four open plugs/hoses attaching to the intake below the TB -- you'll have to clean those, too. It took longer to clean out the intake than it did to bore out the opening, but it can and needs to be done.

Finally, should say that the TJ has a two-stage K&N filter system, an MSD ignition system & coil, high-gapped Champion truck plugs, a Flowmaster delta-40 catback, and a case-full of Mobil 1 synthetic oil. All or part of which may have a synergistic effect on my results, since mods usually affect each other.

Cheers, GP http://www.forumco.com/jeffy/topic.a..._ID=6&CAT_ID=1

More Info: (1) The intake is soft aluminum, so we used a medium tungsten rasp, followed by a fine fluted grinder bit, followed by a fine polisher. I'll admit it's not even -- hard to get consistency around the runner walls which are nearly flush to the intake opening. The spacer is a harder grade of metal, and trickier, even when clamped in a vise. Doesn't look pretty anymore, at least on the inside.

(2) Tested at 1800 RPM and 2800 RPM with an average between the two -- but the results were fairly similar.

(3) We figured the following: At 2800 RPM, torque was up by about 16% with #5 option above. At 1800 RPM, torque was up by about 14%.

Again, folks, consider the mods and the synergistic effects -- your numbers may be different depending on what you have your rig, mileage, mechanical conditions, altitude, etc. I give this just as a general indication.

Ambient air temperature: 74 degrees Humidity: about 35%



First, let me say hello to the group. I am a tech for Jeep and Chrysler, electrical and drivability are my areas of expertise. Now I'm going to add my .02

1. I have done this mod on my own 92 wrangler with a 2.5L engine with incredible results. The 2.5L has a K&N stock replacement air filter w/ a stock air box... the restrictor in the air box cover removed, a tri-y design header (manufacturer unknown, was given to me), stock exhaust minus the cat, an Accel super coil (direct OEM replacement) w/ Belden spiral core wires and factory plugs gapped at .035". I have 4.10 gears w/ 35x12.50 General MT's and I can say this motor screams. The motor in stock form would not pull the jeep w/ 33" tires. I did all the mods except the throttle body and put the 35's on. At 65 mph into a 15mph headwind, I would have the throttle pushed to the floor just to maintain speed in 4th gear, with the throttle body swap, it was like putting a 4.0L under the hood. Under the same conditions,I could maintain speed w/ 1/4 to 1/3 throttle opening, and my DRB III confirmed it. It felt like I added 15 to 20 hp., bottom end torque improved and overall drivability improved. Fuel milage remained constant, or slightly better depending on how heavy my foot was.

2. Now on to the AIS motor. If you look at the AIS motor and housings on th 2.5 and 4.0L engines, you will notice tha the idle air passage seat where the AIS needle seats is considerbly smaller on the 2.5L than the 4.0L, so is the needle on the AIS motor itself. You must transfer the AIS motor and housing from the 2.5L throttle body to the 4.0L throttle body, if you don't and you use the 4.0L housing and motor, you may not get your idle speed down to where it should be. Your AIS motor will be fully closed or close to it (0 to 2 steps). On TJ's this can be a problem with the OBD II, since it can trgger a code in the PCM (target idle not reached), so be sure to transfer it to the 4.0L throttle body. Be careful with the gasket it is not available separately. If done right and you have access to a DRB II or DRB III or a code scanner your idle steps should be around 14 to 18 steps in neutral, air off, if not you can fine tune to get it in that range by adjusting the throttle stop screw, if you turn it more than a 1/2 turn in either direction, you better check your installation.

3. Yes you do have to trim the intake manifold opening, mine had a 1/8 lip around the base and it does have a profound effect on air flow, enough to cancel the gains of doing the conversion. I used a die grinder with a wide fluted aluminum bit, on the vehicle wuth rags stuffed in the intake runners. A shop vac to remove the filings was used and make sure all filings and rags are removed. I trimmed the hole to the size of the gasket (4.0 and 2.5L gaskets are the same).

4. The PCM's adaptive memory after 100 miles of driving was practically unchanged after the swap meaning the PCM saw no ill effects from the swap. Keep in mind that the MPI fuel injection is a speed/ density based system and does not see an increase in airflow like other systems that use a mass air flow sensor, instead it sees changes in MAP value and intake temperature (density in the intake manifold) crankshaft speed and throttle position, coolant temperature in all modes plus the O2 sensor at idle and part throttle and then using complex alogrythims calculates the injector pulse to provide the correct fuel/air raio. For all practical purposes you do not need to worry about it, the computer seems to compensate for the swap with no problems.

5. For those of you who still feel the need for more fuel, you can try injectors from a 4.0L engine. These run approx. 10% richer, single cylinder displacement is about 10% larger on a 4.0L, so these will work good if you need more fuel delivery without screwing around with the pressure regulator on the fuel rail (91-95 only, TJ's regulator is in the fuel pump). The PCM will only compesate for the added fuel in closed loop operation only (idle and part throttle)!

I did this swap months before I even came across this site (my own idea) in search of more power, knowing what it would take to install a 4.0L in my Jeep, even with the resources available, and I can tell you I am very satisfied with the results. I hope the information I posted is useful and can be used to your advantage.
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Unread 08-10-2011, 03:46 PM   #24
Xpress
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Wow 24hp from adding the 4.0 throttle body and a spacer then grinding out the intake and spacer to match the 4.0 TB?

What injector? Just the stock 2.5L?

24hp from a couple hours work seems completely worth the effort...

What about gas mileage? I can only imagine with added air and fuel flow that it would go down.
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[URL="http://www.jeepforum.com/forum/f12/another-5-2l-yj-thread-1503048/"]My 5.2L Build thread[/URL]

-1989 Jeep Wrangler 2.5L, soon to be 5.2L
-1996 Jeep Grand Cherokar 5.2L, donor and rainy day driver
-2004 Kawasaki KLR650 sunny day driver
[QUOTE=mudsweatNgearz;21162729]Leave em off and weld an I beam on. Bumperetts just scream homo.[/QUOTE]
"A well regulated Militia, being necessary to the security of a free State, the [B][I]RIGHT[/I][/B] of the people to keep and bear Arms, [B][I]SHALL NOT BE INFRINGED[/I][/B]."
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Unread 08-10-2011, 04:07 PM   #25
jonzjeepyj
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The injector used is a . . . . .
Bosch type III EV-1 19lb injector. Commonly know as a ford 19lb
injector

Most all of the mods are very inexpensive to do. These are all of
the mods that I have done which include

1) Bosch Type III EV-1 19lb injectors
5 injectors for $$12.00 and some change off Ebay

2) 4.0L TB was $28.00 off Ebay

3) High flow cone filter from local auto shop $25.00

4) 14" Electric Fan from pick and pull yard (Ford Taurus) $20.00

5) Champion Plugs gaped to .080 $2.69 each local parts store

6) Super coil and Live wires were 200.00 from quadratec



John
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Unread 08-10-2011, 04:11 PM   #26
Xpress
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I can't really remove my airbox, the emissions equipment in it are required. Unless you've figured out how to place the pre-heater inlet and pre-heater valve inside of the intake tube?
__________________
[URL="http://www.jeepforum.com/forum/f12/another-5-2l-yj-thread-1503048/"]My 5.2L Build thread[/URL]

-1989 Jeep Wrangler 2.5L, soon to be 5.2L
-1996 Jeep Grand Cherokar 5.2L, donor and rainy day driver
-2004 Kawasaki KLR650 sunny day driver
[QUOTE=mudsweatNgearz;21162729]Leave em off and weld an I beam on. Bumperetts just scream homo.[/QUOTE]
"A well regulated Militia, being necessary to the security of a free State, the [B][I]RIGHT[/I][/B] of the people to keep and bear Arms, [B][I]SHALL NOT BE INFRINGED[/I][/B]."
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Unread 08-10-2011, 09:24 PM   #27
jonzjeepyj
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I used a 97-05 TJ's TB Piping and hooked up all required lines. Mine flew through inspection
with flying colors at our DMV. Here are a few pics of how I used a TJ's TB intake tubing.










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Unread 08-10-2011, 10:05 PM   #28
nzpete
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I have done all of those mods minus the spacer and the 200 dollar ignition upgrade. I'm nowhere near a 24hp gain, but have noticed the aforementioned throttle response/smoothness.
The mods were simple enough and inexpensive enough to try, and part of the fun is simply wrenching on the vehicle. I wouldn't expect too much though. I would like to try the ignition upgrade, but can't convince myself to part with the 200 bones to experiment with.
Personally, the 2.5 is what it is, and I simply enjoy driving within the capabilities that it possesses.
I've decided the best course of action, and best bang for the buck with regards to power increases, is to put money into a gear swap, (4.88). It is a proven method with little impact on engine longevity.
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