Horsepower!!!???

[tjric]

Keep in mind I am not a mechanically inclined person, I have just started to work on my own jeep, & pretend I know nothing about engines.....

I have a 2002 tj X that I have recently switched from a daily driver to a wekeend toy. I am not ready to go nutz with it yet but I am curiouse about simple, EASY, bolt on style upgrades that can be done to the 4.0L engine to increase horsepower. I read all the magazines and know about the performance chip and cold air intake BUT what do you all have to say about those? What other ideas has everyone come up with? I love creativity when it increases horsepower!!!! One day I will yank the 4.0 and drop in a nasty small block, re-gear it, put in new axles, and the whole 9 yards but I am not ready for that yet...I still want this vehicle dependable because my 3 year old son loves it and I want to keep him safe.

I look forward to you all have to say...

 

[phall92139]

This is a subject that has been highly debated among owners of Jeeps with the venerable 4.0 for as long as it's been around. Obviously there are dozens and dozens of aftermarket products out there all claiming substantial performance increases but at what cost? The $$ per H.P. figures are generally pretty high and of those additional ponies, how much is really usable? Even those manufactures that provide "dyno run sheets" can be misleading due to all the possible variables involved in obtaining the claimed data.

I hate to refer you outside of the "family" here but a very good discussion on this subject can be found at Rubicon Owners Forum - View topic - Horsepower increase questions..

If nothing else, it may give you a reason to pause and think before rushing out and plunking down a lot of cash for bolt-ons that may or may not give you the satisfaction you were hoping for.

-Phil

 

[DeadHammer]

Well here my two sense. When it comes to increasing HP I stick to the basics, trying to let the engine breath easier reduce internal friction better fuel delivery & a strong spark. The most bang for the buck so far has been the Intake (AEM).

 

[Utah_jeepster]

Well there isn't a lot you can do to the 4.0. beyond chipping it, intake and exhaust equation part of it. By all of the articles read even replacing the head/cam combination doesn't get you more that 153lbs of torque and very little in increased HP. Stroking to a 4.6 gives the ECM problems, even after increasing the injectors to 10-15lbs/hr injectors. The pre-ECM type of chip add ons that can stabilize the incoming CPS to CSPS and MAS readings helps a little but it doesn't produce any more than 173 lbs of torque. The main problem is the integrated tech of the ECM and its proprietary code, that doesn't lend it self well to reprogramming.

The ECM and 4.0 adapts well to things like turbos and super chargers, but there is a finite line for HP vrs cost. If your looking for raw HP then changing the motor to a V8 is best for cost to HP ratio. But if your looking for raw torque than go to an after market air cleaner and open your exhaust. The ECM will not give you any problems there. Super charging will help with the throttle response time, then again some say the cost is not worth it and go to a V8 swap.

 

[SteelHeadz]

I'm all in on Utah_Jeepster's comments and advise. I think , if you want the HP, just do the conversion with the V8. There's no sense in wasting your time and money on something you might not be happy with after a minor mod here and there then later on just replace it anyway with a V8. Converting the TJ from an I6 to a V8 does not make it unsafe nor unreliable.. If you get a little too happy with the gas pedal then you might start breaking stuff and make it unsafe. Its how you drive it will be contingent on its dependability and safety of the occupants not just on a Jeep but on any Vehicles out there.

 

[Bounty__Hunter]

There are many small inexpensive mods that will free up HP and increase mileage, most center around improving air flow into and out of the engine.Consider adding a conical high-flow filter to the end of your stock airtube. It can be done cheaply or you can pony up for a 'cold-air' kit. Then there's the 62mm throttle body and spacer. Not only do they increase airflow and power, but throttle response is greatly increased as there is no taper beneath the throttle plate.For exhaust, the Banks 'Monster' cat-back is a great kit.Replacing the mechanical engine fan with an electric is a good mod, just google 'jeep taurus fan swap' for tons of info.I also sell 62mm throttle bodies and spacers for a fraction of what retailers sell them for. PM for more info if interested.

 

[tjric]

great input everyone & thank you for the info...It sounds like my original assumptions still hold true and that is to put up with the 4.0L for a while until I am ready to do the V8 swap. I just wanted to make sure that I was not missing something obviouse.