2.5 performance? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > 2.5 performance?

Introducing MONSTALINER™ UV Permanent DIY Roll On Bed LineWe have Engo 10k Synthetic IN STOCK!!! Hurry while supplieJeep speedometer gears at rockridge4wd

Reply
Unread 05-03-2010, 10:41 PM   #1
pot_father
Registered User
1993 YJ Wrangler 
 
Join Date: May 2010
Location: seymour
Posts: 8
2.5 performance?

I have a 93 wrangler, it has the MPI fuel delivery. Ive seen a few different forums about this and am kinda confused now. Could I replace my TB with a 4.0TB, and Ive heard something about restrictors in the stock air intake. If so where exactly in the air intake is it?

pot_father is offline   Reply With Quote Quick reply to this message
Unread 05-03-2010, 10:42 PM   #2
provinT13
Registered User
1999 TJ Wrangler 
 
Join Date: Oct 2007
Location: Colorado Springs, Colorado
Posts: 4,632
Yes you can. Swap your 2.5L sensors onto the 4.0L throttle body and it will bolt right up.
__________________
2 Hands Working Do More Than 1000 Hands Praying

94 YJ Build

99 TJ Build
provinT13 is offline   Reply With Quote Quick reply to this message
Unread 05-03-2010, 10:50 PM   #3
moonshinefuel
Registered User
1995 YJ Wrangler 
 
Join Date: Feb 2009
Location: Los Angeles. California. United States.
Posts: 4,911
2.5 performance? That is the eternal quest, to have someone finally figure out how to do it! (Without spending 4k on some turbo or supercharger) it is a daunting task.
moonshinefuel is offline   Reply With Quote Quick reply to this message
Unread 05-03-2010, 10:58 PM   #4
MJMPC
Registered User
1991 YJ Wrangler 
 
Join Date: Nov 2008
Location: Elizabethtown, Ky.
Posts: 3,070
You need to make sure the hole in the intake is the same size as the TB you may have to do a little grinding.
__________________
MIKE

http://www.dav.org/

MJM Powder Coating
Elizabethtown Ky.

http://www.cityprofile.com/
MJMPC is offline   Reply With Quote Quick reply to this message
Unread 05-03-2010, 11:09 PM   #5
pot_father
Registered User
1993 YJ Wrangler 
 
Join Date: May 2010
Location: seymour
Posts: 8
what about injectors? Ive heard that ford injectors would drop right in. I dont care what they come off of as long as they will fit and give more pressure.
pot_father is offline   Reply With Quote Quick reply to this message
Unread 05-03-2010, 11:31 PM   #6
GermantownJeep
Registered User
1995 YJ Wrangler 
 
Join Date: Mar 2006
Location: Louisville, KY
Posts: 148
Quote:
Originally Posted by pot_father View Post
Iand Ive heard something about restrictors in the stock air intake. If so where exactly in the air intake is it?
There's actually two restrictors. One is in the air box at the intake hole. The other is in the tube where it leaves the air box.

I took mine out. Can't tell that much of a difference, but it's so easy might as well.
__________________
1995 Wrangler Rio Grande: RE 4.5" Lift, 33" MT/R's
2010 Grand Cherokee Limited: Hemi, QD II, 30" Nitto Terra Grapplers
GermantownJeep is offline   Reply With Quote Quick reply to this message
Unread 05-04-2010, 07:44 AM   #7
mb1440
Registered User
1995 YJ Wrangler 
 
Join Date: Jan 2010
Location: lexington,nc
Posts: 50
Don't waste your time trying to mod the engine. Been there and done that Just regear and be done with it. It is money well spent.
mb1440 is offline   Reply With Quote Quick reply to this message
Unread 05-04-2010, 08:36 AM   #8
YJake
Registered User
1991 YJ Wrangler 
 
Join Date: Jun 2008
Location: Orlando, FL
Posts: 2,199
Regearing your axles will be your best bet. I've done just about every 2.5L mod tehre is and they do all help when added together, but I plan to regear to 4.88 with 33's down the road. Heck, I may even regear to 4.88s with 31's.

Jake
__________________
/l , [____],
l---L--[]lllllll[]-_
()_) ()_)==@=)_)

Quote:
Originally Posted by clemsonfan16 View Post
The 4banger only whines because it wants more!
Quote:
Originally Posted by Opihi59 View Post
3 Things to know about the forum: Always PB blaster, Always check the FAQ, Always do a search, and if none of that works, ask Mean Max.
YJake is offline   Reply With Quote Quick reply to this message
Unread 05-04-2010, 10:31 AM   #9
moonshinefuel
Registered User
1995 YJ Wrangler 
 
Join Date: Feb 2009
Location: Los Angeles. California. United States.
Posts: 4,911
I still would like to try and put a mild cam and new lifters in, but need to do more research as far as emissions and how the computer would handle that as well. It would not cost much at all and probably has the most potential to increase performance, but again, still have to look into it more.
moonshinefuel is offline   Reply With Quote Quick reply to this message
Unread 05-04-2010, 10:38 AM   #10
dadstoys2
Registered User
1987 YJ Wrangler 
 
Join Date: Feb 2005
Posts: 235
No replacement for displacement. Can't get much out of the 4 banger. Save your money and time and regear it.
__________________
~Rich
87 Wrangler Ford 302
2"bodylift 5"suspension 35" bfg A/Ts
Np435 trans w/ np205
dadstoys2 is offline   Reply With Quote Quick reply to this message
Unread 05-04-2010, 10:38 AM   #11
samsonitesamson
Registered User
1995 ZJ 
 
Join Date: Mar 2008
Location: Bellingham, Washington
Posts: 1,213
Quote:
Originally Posted by moonshinefuel View Post
I still would like to try and put a mild cam and new lifters in, but need to do more research as far as emissions and how the computer would handle that as well. It would not cost much at all and probably has the most potential to increase performance, but again, still have to look into it more.
If you do it, I definitley want to hear your results.
__________________
When thou walkest through the fire, thou shalt not be burned; neither shall the flame kindle upon thee ~ Isaiah 43:2 ~



Quote:
Originally Posted by Bnabb View Post
it bolted right up, except one bolt but i didn't need it anyway
samsonitesamson is offline   Reply With Quote Quick reply to this message
Unread 05-04-2010, 11:23 AM   #12
firebrick43
Registered User
 
Join Date: Mar 2010
Location: Indiana
Posts: 67
I have done the 4.0 throttle body mod on my 91. I didn't do anything to the airbox. It made a huge difference, not straight 6 power but instead of struggling up hills and being limited to 50~ with a strong head wind I now can maintain 60 up hills and 65 on the free way is no longer a problem. You have to change all sensors out and the Idle air speed sensor/bypass housing from your 2.5 to the 4.0 throttle body. Some intake manifolds seem to have a large enough hole, others(such as mine) you need to bore it out. I definitely recommend taking the intake manifold off(its not hard) and using a die grinder bore out the intake where the throttle body mounts onto it so when the throttle body is mounted and butterfly is open you can not see the edge of the manifold. Any edge, no matter how small it may seem will cause turbulence and you will not get the full gain if any. A die grinder works well with a burr bit. Spray out intake with brake or carb cleaner before reinstalling so no metal is ingested into the engine. It takes 2 to 3 hours. Get a felpro full manifold gasket(that does both the intake and exhaust). It will help you keep from having intake or exhaust leaks at the manifold. Torque manifold bolts to 23ftlbs and retorque after a few heat/cool cycles of the engine. I reccomend a copper spray on the gasket as well.

Injectors are from a 4.6 ford mustang v8 but you also need an adjustable regulator and some have had good luck, others have had their engine running to rich so the jury is still out on that one.

Remember, this is for mid range horse power on the road. It does nothing, nor will any other mods really except a regear help turning big tires on the trail. Things such as a cam typically hurt low end off idle performance.
firebrick43 is offline   Reply With Quote Quick reply to this message
Unread 05-04-2010, 11:23 AM   #13
TheRealOldjeep
Registered User
1994 YJ Wrangler 
 
Join Date: Dec 2008
Location: mn
Posts: 1,477
Biggest boost for me was to purchase a TB that had been bored out to 62MM, installed a spacer the same size and then machined out the intake to match the TB bore. Guy had posted dyno results from a similiar setup and was claiming around 28HP. I found it difficult to believe, but after making the change there was a huge difference.




__________________
Chuck P
94 YJ 2.5L/AW4 (Gone)
98 ZJ Limited 5.2 - sons car
97 TJ 2.5L/30RH - daughters car

www.oldjeep.com My site
TheRealOldjeep is offline   Reply With Quote Quick reply to this message
Unread 05-04-2010, 11:41 AM   #14
xdgt03
Registered User
1994 YJ Wrangler 
 
Join Date: Feb 2008
Location: a2, mi
Posts: 160
Ford injectors have made the biggest difference for me. 19lb 4 pin hole. I found some on ebay the other day for about $25 shipped. Used. I did try the 4.0l TB swap but that did nothing whatsoever. I did not bore the intake and that could be all the difference.
__________________
1994 Wrangler YJ
/l ,[____],
l---L--''lllllll''-
()_) ()_)--o-)_)
2.5L
31x10.5x15 BFG MT
xdgt03 is offline   Reply With Quote Quick reply to this message
Unread 05-04-2010, 12:02 PM   #15
djsmith1174
Registered User
1993 YJ Wrangler 
 
Join Date: Mar 2010
Location: minnesota
Posts: 163
I too have done the 4.0L TB and made my own CAI. To make the CAI I used a 3" aluminum tube and a universal conical air filter. It cost less than $50 total. I would say these mods helped the most at highway speeds. It helped slightly with acceleration, but required much less throttle tip in to maintain highway speeds. It increased noise in the form of whooshing air, but not that you notice much because after all it's a YJ.

I have also changed to the Ford 19# injectors, but I only did it due to the better design and because they cost less than $20. I need to change the FPR to take advantage of them anyway. I also made my own cat back system. I did this because I needed a new exhaust and buying a 2 1/4" performance muffler and tail pipe was a lot cheaper than the OEM one piece replacement. The exhaust note is slightly louder, but mainly when you get into the throttle and not really noticeable when maintaining speed. I would say that it helped acceleration slightly, but that may have been due to worn exhaust components that were replaced.

I have the parts to do the Taurus e-fan mod this weekend. I am making this mod to maintain temperature better. Since I replaced the radiator with the universal fit years ago it runs slightly cool. I want to be able to have the fan run only after it has reached operating temp. If this adds any power or mileage, great. If not, that wasn't my intention in the first place.

Sorry for the long winded post. I was just trying to give perspective on where to start through my experience. Start with the TB, then the CAI as most value added and go from there. I'm sure others will flame that it's BS, but that's just my experience. Hope this helps.
djsmith1174 is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.