increase tj power

idrthrbfishing

New member
1047431

After reading the posts on increasing the power out of a yj by removing some plastic in the intake, I decided to take a look under the hood of my 97 tj 2.5l. And guess what I found a some removable restrition in the tj also. I dont know what it does for the hp rating but I can tell you BIG change in acceration and my milage went from 14-18 to 24 on my first tank, I even tried to refill at another gas station because I didn't believe it was full. Now to find this plastic remove the intake above the throttle two 5/16 on valve cover and the lower clamp on the rubber hose, below much simpler. Look for little button on the intake side and press while pull on the plastic insert, then reassemble and take it for a drive. took me 5 min to find and remove. what a change good luck.
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[addsig]
 

1047440

Why not just get a K&N intake system????????? And throttle body spacer...... and 4.0 throttle body?????????????????????????[addsig]
 
1047508

i have a thing with spending tons of money for only a few HP... 4.0 tb, spacer, 100 bucks... K&N system... another hundred bucks... HP gain? i dunno, 5 or 10 HP? not worth it in my book... i'd get tires/wheels/quick disco's first...



i support the free/cheap HP gain techniques... i'll be modding my stock airbox soon...[addsig]
 
1047515

Hey, thanks!



I just went outside (it's a balmy 48 in Baltimore) and pulled that sucker out. Put the jeep back together

and drove it around. Definitely more responsive. Will keep an eye on the gas milage and see how it looks.



btw - the "insert" is about a foot long and ~2.5" around. I though it would be a little thing. Took me a few extra

minutes to figure that out. Ended up just shaving the button down with a knife and using a screwdriver to

push the insert out from the output side (closest to the throttle body). Gotta love freebees.



Will consider the 4.0 throttle body and spacer when I have the cash flow. As is, my K&N needs cleaned.



jcooper.



Anyone know how this affects emmissions? (yeah, I know, little late for that) [addsig]
 

1047518

You can make a fake K&N intake kit out of a 4.0 tube. Just cut the end off where it has the flex section and add on the K&N filter. Cost about $20 bucks at a junkyard and then the price of the filter. The 4.0 TB can be had for 80-100 from a junkyard as well. TBS run about $69.95.[addsig]
 
1047522

I never thought about my emmissions as I belive you can get thruogh in new jersey with a K&N. But I'm keeping my parts just in case.[addsig]
 
1047524

I'll admit, I'm at a loss as to why it may affect emissions, but I also kept the part just in case.



The only thing I can think of is California doesn't like the K&N for whatever reason, so opening up the

flow even more may cause other state emissions tests to fail.



Does anyone in California know why they don't like K&N? is it because it's a mod, or because of a

legitimate (although picky) reason? If the K&N actually affects the emissions test, then there maybe a

problem with this mod in other states. If the K&N fails the CA test based on the sole fact that the

inspector sees it there, then this mod may not affect things.



jcooper. [addsig]
 

1047626

HowTo get member status at jeepz.com: Answer your own questions.
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Just got to talking to a friend about the mod (he's a ford guy.... poor soul) and he mentioned it might

affect the volume of exhaust recirculated (reduce it). Which makes sense, if there is more fresh air on demand,

there will be less need to pull in exhaust. This is assuming the recirculated exhaust isn't forced. I'd guess

it isn't, but I haven't looked yet. Maybe tomorrow.



jcooper[addsig]
 
1047642

the basic idea behind K&N and other bolt on HP increasing mods (intake, exhaust, headers, TB's, etc...) is that the more air you let through the engine, the more power it produces. increasing airflow will allow the engine to pack more air/fuel into the combustion chamber, allowing for a more powerful combustion, hence more power. follow that?



emissions will not be affected with any of these bolt on mods, unless you tamper with sensors or the PCV system. many cars have sensors built into the airbox that tell the engine the air volume and temperature of the air coming in. the PCV system recirculates cruddy air back into the airbox from the valve cover. then the cruddy air (not sure what's in it... vapor oil most likely, mudderchuck'll know) is sent back through the engine and burnt up. emissions are helped in this matter by not releasing the cruddy air into the atmosphere (which is another free HP mod, btw... just unhook the PCV tube and let it vent; i did it to my civic)



each state makes its own inspection/emissions laws, so you have to call up an inspection shop and ask some questions. try to get your terminology down so you don't call them and say "is it legal to unhook that doohickey on top of the black thing?" kuz all you're gonna hear is some laughter and a click. for example, in PA it is ILLEGAL to unhok the PCV vent tube, but i did it anyway. i brought my civic in for inspection and it got passed. the laws are written, but many of the techs aren't that anal about them. bringing your rig to a 'sticker stop' or some other in-and-out inspection shop is a surefire way to get an IDIOT to put stickers on your car. mine passed recently with 4 blown bulbs and non-working reverse lights. the rear brake pads are virtually gone; so thats the bad part... you have to look at the car yourself too!



ok, i'm done rambling, hope that clears some things up

-nate[addsig]
 
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