Under the hood

[tjrockcrawler]

What mods have you done/seen/read/heard about/ on TJs under the hood? Or should I even worry with them and just keep up with standard engine maintenance?

I want to have the best well rounded DD(for now).

[yotakrawler]

I had a tj ... i did a new air intake then went to a snorkel ... but i noticed a little better gas mileage with the intake!!!

[tjrockcrawler]

Thanks... I have been really thinking about an aftermarket intake.

[yotakrawler]

Yeah their really not that expensive either ... get ya a snorkel and an intake and tie them in together ... i made a decent power gain along with that combo

[HANO]

I purchased a K&N FIPK for the TJ 3 years ago. I did not notice any power difference, however when cleaning the filter I did notice a trail of "dust" on the bottom of the intake tube, all the way to the PCV valve. Be careful with getting a filter that flows to well, often you lose the proper filtering your engine requires. I would have stayed with my stock box if I had it to do over again.

J.R.

[tjrockcrawler]

:shock: Thanks HANO, I was looking at that very same product.

What do yall think about TB spacers? Makes sense to me in theory, but I don't know for sure.

[BillM]

SNAKEOIL

[Hadfield4WD]

I purchased a K&N FIPK for the TJ 3 years ago. I did not notice any power difference, however when cleaning the filter I did notice a trail of "dust" on the bottom of the intake tube, all the way to the PCV valve. Be careful with getting a filter that flows to well, often you lose the proper filtering your engine requires. I would have stayed with my stock box if I had it to do over again.

J.R.

My Audi had premature cylinder wall scoring, the shop attribited it to the K&N filter. Didn't filter to enough microns.

[dogbluedrummer]

Okay, I will be the lone dissenter and messenger of second-hand bad news.

Throttle body spacers, Banks headers, cold air intakes, high-flow cats, K&N filters, and the like just don't provide enough performance gains - EVEN COMBINED - to merit their cost.

The sad fact is you are driving a tractor with a back seat. The 4.0L engine is not designed for performance or efficiency. It is desigend for torque and longevitity.

Think of it this way. Have you ever known a Jeep to run out of power before it ran out of traction? Almost every obstacle failure is due to ground clearance or traction. I have never heard a Jeep owner say, "If I only had 10 more horsepower, I could have done ____."


Foghorn, if you have the bug to spend money, I have a few suggestions.
1. 33" tires
2. Aussie or Powertrax locker in the front
3. ARB or OX locker in the rear
4. Reagear to 4.56

Bring on the rebuttals......

[Hadfield4WD]

Okay, I will be the lone dissenter and messenger of second-hand bad news.

Throttle body spacers, Banks headers, cold air intakes, high-flow cats, K&N filters, and the like just don't provide enough performance gains - EVEN COMBINED - to merit their cost.

The sad fact is you are driving a tractor with a back seat. The 4.0L engine is not designed for performance or efficiency. It is desigend for torque and longevitity.

Think of it this way. Have you ever known a Jeep to run out of power before it ran out of traction? Almost every obstacle failure is due to ground clearance or traction. I have never heard a Jeep owner say, "If I only had 10 more horsepower, I could have done ____."


Foghorn, if you have the bug to spend money, I have a few suggestions.
1. 33" tires
2. Aussie or Powertrax locker in the front
3. ARB or OX locker in the rear
4. Reagear to 4.56

Bring on the rebuttals......

You are not the lone dissenter. You just add more info. And good info at that.

[tjrockcrawler]

The sad fact is you are driving a tractor with a back seat.

:lol: thanks Tony.

oh, and 33's will be on Friday. :wink:

[Bluegill]

SNAKEOIL

And you have tried one? Most folks that bash TBS have never tried one. Mine has the Poweraid spacer - no power gain, but I did get .8 more mpg and quicker throttle response from 2,000rpm. :grin: In 4 months of DD duty, the spacer paid for itself with the gas saved. IMO that ain't snake oil.

Ryan, the only way to see a major PERFORMANCE boost from the 4.0 is to install the crank & rods from a 258 (aka 4.2) in it - this will produce 50-70 more hp from the added cubic inches (it then becomes a 4.6 liter straight six :smokin: )

That said, you can get decent MPG gains just by installing a performance intake & cat-back exhaust. But be sure that whatever intake you get has a conical filter that you can fit a pre-screen slip cover on it for extra engine projection.

[tjrockcrawler]

Wow thats a novel idea, I bet its pretty costly.

[Marty G]

tuned port injected 350 :lol: :lol: that would wake her up

ide say go with the gear change first and then you probablee wont need any more power

[partsjockey]

One of the guys in our club went the Stroker route, spent a ton of money. It was quicker on the street, but as far as off road a properly geared 2.5 had no trouble doing everything the mega buck stroker was doing. Seems like his fuel mileage went down the tubes also.

Sounded mean, would roast 35's, but wasnt really worth imo

[Adurbin]

The "stroker" would be designed for top end power. If you are in a mud bog where you need to be bouncing off the rev limiter, then yes. At low-to idle speeds I.E. rockcrawling, its useless.

[Andy's01]

I have a TB spacer and I have noticed that mine has much better throttle response and low end pick up than other jeeps that I have driven. Dont know if the TB spacer has anything to do with it or not as it was on my jeep when I bought it.

[Jeep07]

regearing or replacing axles or going lower in the tcase and adding an SYE is your best upgrade not including lockers.. Leave the motor alone expect for installing a motor mount lift to help with rear driveline angle.

[Hadfield4WD]

Yeah but if you have a stroker you can tell everybody that. My next motor will most likely be a 4.0 with cam, head, ported intake and headers. Good and reliable. Don't have to worry about all the "tuning" issues of a stroker motor as well. You'll like the gears. I have 5.13's and I have plenty of accelration on the road. Holds hills fine.

[SurferSami]

I have seen geared samurais on 35s go anywhere they want without problems on stock motors, so a geared 6 cyl should have no problems. The closer you leave the engine to stock the less potential problems you will have in longevity.