2.5 performance? - Page 3 - 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?

Stainless Steel Door Hinge PinsPoly Door Hinge BushingsSave at JeepHut on Smittybilt Soft tops

Reply
Unread 05-06-2010, 12:12 AM   #31
moonshinefuel
Registered User
1995 YJ Wrangler 
 
Join Date: Feb 2009
Location: Los Angeles. California. United States.
Posts: 4,911
I know, I have heard all of the terrible stories and evils of alcohol. 3 years later, 287,000 miles original block. And when I am onword towards 400,000 miles, people will warn and try to protect me of it again. . Thank you, please continue.

moonshinefuel is offline   Reply With Quote
Unread 05-06-2010, 06:02 AM   #32
Area.3.Fiftyone
Registered User
1996 ZJ 
 
Join Date: Sep 2009
Location: Kingston, Pa. 18704, Pennsylvania
Posts: 3,469
Quote:
Originally Posted by xdgt03 View Post
I'm guessing that we can do no better than gain 15hp (freeing) and 15ftlb torque with exhaust, intake, and fan mods.
A roughly 10% increase in power for those little mods is pretty substantial any day of the week.

I'm not looking to ultimate power out of this little motor, but +15 hp would make a noticeable difference IMO and definitely help on the highway.

__________________
79' CJ7 - 82' CJ8 - 94' YJ - 96' ZJ
Diagonally parked in a parallel universe.......
Area.3.Fiftyone is offline   Reply With Quote
Unread 05-06-2010, 07:26 AM   #33
xdgt03
Registered User
1994 YJ Wrangler 
 
Join Date: Feb 2008
Location: a2, mi
Posts: 160
Quote:
Have you even done this mod along with opening the intake manifold to match? Doesn't sound like it?
Nope. I think I said (maybe it was in another thread) that I did the 4.0L tb swap but did not do the porting of the inlet. The porting of the inlet is the important part here. More air is good, but less velocity is bad. For me, it was the first mod I did and it didn't work at all. I think it was even a little worse. However, since then I have done a few other things including swapping to clean ford 19lb injectors. It is running fantastic right now. Unless there is a strong headwind or I have to go up a hill on the freeway, I can maintain a true 70 to 75 mph (adjusted for tires) pretty easily. These injectors are great IMO. So, putting the 4.0L tb back on might work better now. Porting the inlet would be even better.

I was only attempting to point out as it relates to hp that sometimes in the pursuit of raising hp you can lower tq. This is not good.

Quote:
A roughly 10% increase in power for those little mods is pretty substantial any day of the week.
Agreed. For other cars you talk about $ per HP/Tq For our 2.5L the cost per HP/Tq is higher than many other cars, but we have a lot less options. So 10% increase for electric fan, exhaust, injectors, etc... cost is pretty good.
__________________
1994 Wrangler YJ
/l ,[____],
l---L--''lllllll''-
()_) ()_)--o-)_)
2.5L
31x10.5x15 BFG MT
xdgt03 is offline   Reply With Quote
Unread 05-06-2010, 07:31 AM   #34
sloan74
Registered User
2013 JK Wrangler 
 
Join Date: Apr 2010
Location: Charlotte NC
Posts: 606
Quote:
Originally Posted by YJake View Post
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
I am going to regear end of summer. 4.11 now and with these 33" I can barely go past 60 MPH on the interstate....unless I am going downhill of course..LOL

I 100% agree, regearing to 4.88 is the way to go and will help the most.

BTW how much work is involved? Do I just need to purchase the gear/pin? Or are their other parts needed. I just did the rear differential fluids and installed a new seal, so I can get to the gears, etc. But I have not gone any further than that.
sloan74 is offline   Reply With Quote
Unread 05-06-2010, 07:40 AM   #35
Area.3.Fiftyone
Registered User
1996 ZJ 
 
Join Date: Sep 2009
Location: Kingston, Pa. 18704, Pennsylvania
Posts: 3,469
Quote:
Originally Posted by sloan74 View Post
BTW how much work is involved?
A lot.

It's not just a matter of swapping in a ring and pinion.

You need master install kits for both axles, new seals, etc. Plus a bit of work to get the contact pattern within spec using a dial indicator and some grease.

It is not a typical remove and replace kind of deal. You really have to know what you are doing for them to last.
__________________
79' CJ7 - 82' CJ8 - 94' YJ - 96' ZJ
Diagonally parked in a parallel universe.......
Area.3.Fiftyone is offline   Reply With Quote
Unread 05-06-2010, 07:58 AM   #36
xdgt03
Registered User
1994 YJ Wrangler 
 
Join Date: Feb 2008
Location: a2, mi
Posts: 160
Here is the thread about porting the head, etc...http://www.jeepforum.com/forum/f12/2...e-look-457885/

He said he dyno'd at 140bhp after increasing the displacement by .2 liters (.060 over), porting the head, header, and exhaust. The stock HP number is 130HP but that is engine hp not bhp. Roughly, the stock bhp number should be around 105bhp. This means his mods actually gained him 35bhpish. He never did post his tq numbers but most certainly they must be higher at least some. Plus, he had not done the injector swap, nor a 4.0l tb swap, and is running with the stock airbox. Hmmm
__________________
1994 Wrangler YJ
/l ,[____],
l---L--''lllllll''-
()_) ()_)--o-)_)
2.5L
31x10.5x15 BFG MT

Last edited by xdgt03; 05-06-2010 at 08:10 AM..
xdgt03 is offline   Reply With Quote
Unread 05-06-2010, 10:34 AM   #37
sloan74
Registered User
2013 JK Wrangler 
 
Join Date: Apr 2010
Location: Charlotte NC
Posts: 606
Gotcha Stan. I will throw up a request for a DIY maybe come end of summer on re-gearing. Sounds like there will be quite a few steps and some research on my part.
sloan74 is offline   Reply With Quote
Unread 05-06-2010, 10:59 AM   #38
samsonitesamson
Registered User
1995 ZJ 
 
Join Date: Mar 2008
Location: Bellingham, Washington
Posts: 1,213
Ever watch extreme 4x4? I think every other episode is a DIY guide to R&P installs.
__________________
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
Unread 05-06-2010, 11:48 AM   #39
SDGBASSE
Registered User
1990 YJ Wrangler 
 
Join Date: Jul 2009
Location: Mtl, Qc
Posts: 650
Here's a link to some dyno results of a 4.0L TB, and how sure are you guys about that 14.7:1, because I've been taught that on newer vehicles the factory ECU program leans the ratio a bit to lower the fuel consumption?
__________________
[QUOTE=ZeroGravity;10681914]I didn't click the link because it says "power probe" in the url.[/QUOTE]
SDGBASSE is offline   Reply With Quote
Unread 05-06-2010, 01:46 PM   #40
xdgt03
Registered User
1994 YJ Wrangler 
 
Join Date: Feb 2008
Location: a2, mi
Posts: 160
14.7 to 1 is considered the stoichiometric air/fuel mixture. Anything more than that is considered lean and any thing less is considered rich. Lean can be very dangerous because it causes the engine to run hotter. Way hotter. Hotter such that internal parts can warp and melt. Gas is not just used for the "bang" but also for cooling the combustion chamber. Oxygenated fuels can lower the a/f ratio to somewhere around 14.1 to 1 but as you see it is only very marginal. On more modern engines with special alloys and coatings I can see that the ratio could be leaned out a tad.
__________________
1994 Wrangler YJ
/l ,[____],
l---L--''lllllll''-
()_) ()_)--o-)_)
2.5L
31x10.5x15 BFG MT
xdgt03 is offline   Reply With Quote
Unread 05-06-2010, 01:58 PM   #41
xdgt03
Registered User
1994 YJ Wrangler 
 
Join Date: Feb 2008
Location: a2, mi
Posts: 160
Quote:
Here's a link to some dyno results of a 4.0L TB,...
His baseline was 125.3hp Typically, chassis or axle dyno's produce readouts in BHP not HP. Now I don't know if this engine was on an engine stand, compensated for driveline loss and rated at bhp (displayed as HP), or if he did other mods which raised his bhp number but the 90's YJ's came with 130 engine HP. Some clarity on this would help.

If he had done other mods and the readout was in bhp I can see that the 4.0l tb swap could help since it is compounding the benefit of the other mods. 7bhp seems like a lot but not out of the question.
__________________
1994 Wrangler YJ
/l ,[____],
l---L--''lllllll''-
()_) ()_)--o-)_)
2.5L
31x10.5x15 BFG MT
xdgt03 is offline   Reply With Quote
Reply
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.