MUST Have Jeep Wrangler/Cherokee 4.0 Upgrades?

In this video we talk about your options for upgrades for your Jeep Wrangler TJ, YJ, Cherokee XJ, or your Jeep Grand Cherokee ZJ, WJ, WG, Jeep Comanche and probably others I am missing 4.0 Engine. I show you the Intake and exhaust, and header i have on my Jeep and then we install a 62mm throttle body from eBay and a performance ignition set from CRT performance. Is it really worth spending $200-$500 or more on engine upgrades.

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[merylpelosi]

To quote Stevie Wonder from over 50 years ago: " When you believe in things that you don't understand, then you suffer". A bigger throttle body will only make more noise. MAP will not be affected, partial throttle response will suffer. Bigger plug wires won't increase ignition secondary voltage or current. Your big-assed cat and turbo muffler get choked down by the stock sized exhaust pipe that now runs precariously close to the rear driveshaft. Your air filter now gets to suck in heated under hood air and is restricted by the primary filter, thus negating the bigger throttle body to begin with. Other than that, great job!

[seniorxj]

As far as motor upgrades on my 98XJ; Banks Header, Hi-flow cat, Flowmaster 44, true cold air intake, 62mm throttle body w/1" spacer, 703 four hole injectors, MSD Blaster coil pack, MSD ignition wires, cap & rotor w/iridium plugs, Mechman HO alternator w/two XS batteries with all 1/0 wiring. Also, all sensors are new & are Mopar and I have an on board OBDII that streams live data to my phone!!

Now I didn't do all this for power, I did it to let her breathe and be more efficient especially with 170k on the OD. 😉

[rayzielonka]

I got my injectors from Ksuspension. Noticeable difference. Ran smoother, more pickup. Eadier starting. The best benefit was gas mileage. I used to get 170 miles from a tank. With the new injectors, I got 250 miles from a tank of gas.!

[chriswhitehouse]

The greater plug wire diameter really only buys you more silicone for greater ability to resistance to loosing slight spark energy if routed near grounding items. I used to manufacture and test ignition systems back in the day. 8-)

[denniscosban]

One of the greatest motors ever made.
The only flaw. The fuel injectors are right next to the exhaust manifold. The fuel gets hot. After a while you go through catalytic converters, or mufflers. My suggestion. Buy fuel injector boots. They go around the fuel injectors. Solved my problem. ✌️

[scottbutts]

One other thing: if you change to an electric fan you can gain almost 30hp at the top end. This has been tested and proven. The only drawback as far as I'm concerned is that the mechanical fan moves more air, and sometimes that's what you need when you're moving slow out on the trail

[robertl]

In my experience, matching your axle gear ratio to the tires being run will is pretty much the best thing you can do for power.

All of the throttle body mods, plugs, wires, programmers might get you a little. But it won’t even compare to having proper gearing.

Unless you spend thousands and many hours swapping in a 4.6L Stroker or adding a supercharger.

[maxdicus]

Recommend replacing intake manifold with a post '97 intake. The updated intake allows more airflow to the ports, and will take advantage of your new throttlebody.

[ashtonmariefranklin]

Tune the EFI for even better results.
Not jeep related but. I put a 75mm ported TB on my chevy s10 4.3 factory was 75mm necked down to 70mm with a restriction plate on the butterfly. After opening up the factory TB. It has instant throttle response and noticeable difference. But then took hp tuners and tuned it for the extra intake flow and got even more noticeable performance increases. Im sure if you tuned the pcm you'll definitely have a bigger performance gain then from just doing bolt on mods.

[rhyelince]

I put a 62mm tb and a spacer on my 2.5... Lost low end torque, gained high end power, but I have a sweet intake whistle now

[leefhead]

Great video. Next time you want to “machine” or “lathe” a fitting down, chuck it up in a drill and run it against some sand paper or a bench grinder. Keep on keepin on brother

[motownXJdad]

there is a 4 part interview with Rick Mudge on youtube on the AMXJ channel i highly recommend every 4.0 owner take a listen. Rick Mudge was the engineer in charge of AMC- Jeep & Chrysler cylinder head, intake amd exhaust development from 1976-2001, hes the godfather of the 4.0 and knows more about them than anyone i suspect.

[litz]

I put the 4-hole Mustang injectors in my 97 XJ something like 22 years ago. Still in there. Honestly not sure they really made any difference, but I always figured better misting can't hurt things.

[barbe-rousse]

One way or the others, you need to change the spark plug sometimes. From what I heard the in-line 6 should be change every 50 000 km. So it's just regular maintenance.

[TimmayFilms]

One more setup you may want to try. a Holly Capacitive ignition system with tri-fire sparkplugs. Both create a tri-leg spark to ignite all fuel, and the capacitor (energy storing) ignition also creates, generates high/fast enough firepower to keep the juice flowing. I used a blaster coil and 10mm sparkplug wires, a Holly performance distributer cap and rotor; and Jeep oem style injectors with a four hole design.

[trakkerp]

I already had the 62mm throttlebody on my 4.0 when I got the Jeep, decided to do some other mods too. Cause its an 01 WJ I have electronics so ended up with Ksuspensions Viper coil mod and love it, also did a 12 hole injector swap. Injectors were el cheapo used so I'm expected a CEL soon but my mileage and power difference is noticeable over stock. Cold air intake, KSuspension 12 hole injectors and battery wire kit are next followed by skid plates.

As for your throttlebody missing the sensor nipple the ones from the stock TB come out easily with a torch and, at least on the ones I worked on, can be pressed into the new with a bit of sealer on.

[learner]

So I’m running the 12 hole injectors from K Suspension and I’m super happy with them. When I swapped the new injectors in I also swapped in a billet fuel rail as well.

[thousandoaksauto]

good info, fix the exhaust leak, then recheck your performance!

[xSKOOBSx]

I read a long time ago that some good power can be gained by swapping a TJ air intake manifold into a YJ. they basically redesigned it for better flow to make up for the power loss due to emissions regulation changes.

[TimmayFilms]

My 97 TJ 4.0 is the last model year with the single, primary coil setup. According to a couple of racecar builders I confer with regularly, my dreary throttle response, especially at the lower end was more about the explosion trigger and completeness, than the air and fuel content, which i had already addressed, similar to this video. They suggested that in order to prevent a "slow/low" firing condition, the ignition system needed a "middleman" to develop and maintain enough voltage for a sufficient amount of spark, firing consistently within the prescribed/preset timing intervals. I needed something between potential and execution that could/would manage the process. The primary reason that the (single) "coil over (spark) plug" is now the industry-standard is precisely for control and bottleneck elimination. The ECM can precisely control the voltage discharge level and timing consistency at each cylinder. This was less important in "the olden days" before the emergence of automobile standard and attachable, electrical gadgets and devices. Every time a device is turned on or off, there is a corresponding surge or drop in the direct-current loop. The residual effect is absorbed or lost within the succession of other devices powered at that time. There are only two ways to resolve the condition, "coil-over-plug" so the ECM can regulate it, or if that's not possible, then installing a regulator, one-step past the ECM, would be the next best thing. With that "regulator" you also get the additional benefit of an RPM "limiter" (in case you snap something within the drivetrain during high acceleration) The CDI prevents major damage to the engine from the ensuing spike in RPM's, while the uncontrollable bottleneck is also avoided, thereby eliminating the loss of performance from primary voltage-lag (slow) and/or a lowered, constant throughput (low). I used the Holly (MSD) Street-fire CDI. This essentially replaces the primary function of the ignition coil, while providing as much voltage as needed, when needed by the sparkplugs, to ignite the fuel, while also protecting the engine, (offroad) if say you bottom out and snap a u-joint during an up-hill climb.. Additionally, in order to fully and more effectively utilize the 3-legged spark, produced by the Street-fire CDI, I installed the E3 Tri-Fire sparkplugs (E3.58), which are made to split the spark into three legs. Then, in order to insure against any other bottlenecks, I installed the following: Taylor 36271, 409 Spiro-Pro Spiral Core 10.4mm Spark Plug Wire, a high-0performance Accel 120330 Distributor Cap, and a "Borg Warner D228" Rotor (better build). I also replaced the coil with an "MSD Blaster 8228". All other engine mods described in this video, are already installed and modified for optimum performance. The difference in performance is truly "night and day". One other thing I want to mention concerning "mods": I recently installed a "Spal 30102049 16" Curved Blade Performance Fan", but I am planning on switching back to mechanical. It's just way too, dang loud and the pitch is irritating and as obnoxious as heck. The Jeep is completely customized and that one aspect repels any would-be observer, coming within about a 20 ft radius.) I'll just keep a spare fan-clutch onboard; 'Cuz in the Jeep world. as we all know: "Two is one and one is none!"