Prodigy Performance

It's hard to diagnose whether you have "the right amount of power" over the internet, as it can depend on the terrain you drive on, and your personal expectations vs everyone else's personal expectations and assumptions about how you drive.

Since you say it's running great otherwise, and if it's not throwing any codes, then flow restriction of some sort in either the intake or exhaust does seem like a reasonable assumption to investigate.

I think it's safe to assume your new Banks Ram Air Intake and air filter are not clogged, unless it has been a long time since you installed it and the "sluggishness" has gradually gotten worse. If it's not recently brand new, it's worth checking the air filter.

With the amount of miles on that engine, are you due/overdue for some basic preventative maintenance like spark plugs/wires, PCV valve, etc?

As for the possibility of clogged cats, there's ways to test for that: Symptoms Clogged Catalytic Converter: Loss of Power

If your final conclusion ends up being that everything is "working as intended", and it's just not as much power as you want, then some bolt-on boost is always an option that's cheaper than an engine conversion We can help you with that:



~Jeff

silverbullet88

I get a terrible smell accelerating up hills above 3k... cats clogged?

VEGASROBBI

How about nearly 350 foot pounds of torque off idle to 6,000 rpm

Prodigy Performance

I'd wheel that

It's awesome that there are so many different aftermarket engine performance options available for the Wrangler. Probably more options than many sport/performance cars. All with their own balance of different pros/cons, price points, etc.

Superchargers of multiple types (centrifugal, twin screw, roots/hybrid), turbos, small V8s, big V8s, Hemi, LS, turbodiesel...

Wrangler owners looking for more power are lucky to have such a variety.

~Jeff

Trail Jeeps

As others have said, check for clogged cats, get someone who knows what's up to check over the engine, check intake, exhaust, ect. If the engine is just worn out, I would just run it until it dies. Save up for a swap if you want big ponies. I'm also wondering if you trans is healthy? Does it ever lock up or is it permanently in slush mode? Is downshifting on point? The 42RLE is barely enough transmission to move a JK around in stock form, so when they get long in the tooth they can start to slowly burn up.

With 32s and 4.56s it should have enough oomph to take care of you, just set your expectations low. The 3.8 just kinda sucks, add the 42RLE into the mix and you have one of the lamest drivetrain combos Jeep has every bothered to put in a Jeep, but in good health it'll still get you to where you want to go.

We have mixed opinions about forced induction here at the shop, I love it, some here don't (a lot has to do with our living at high altitude which is not conducive to these sorts of things). But either way, I would not throw forced induction on a 180K mile old 3.8. Make sure you're getting cold air with a good filter, maybe stick an exhaust on there then grab yourself a tuner that will allow you to wring a couple extra ponies out of it, then just drive it with the pedal to the floor. After that, there really isn't much else worthwhile out there, someone makes a cam, but I wouldn't bother. The 3.8 is just kind of a turd.

rob_engineer

For the OP, do you have any spark knock? I once had a Ford Explorer with power issues while trying to pass. It had spark knock whenever I tried to call for more power. My research told me it was likely a leak in the intake. I never fixed that. I learned that running 93 octane made the symptoms go away. If I messed up and but in 87 or 89 the problem would almost instantly return until I filled back up with 93.

VEGASROBBI

Pre-igniton can be caused by carbon build up in the combustion chamber or more likely a plugged or malfunctioning EGR valve. The EGR valve(also known in the old days as the anti-knock valve) recirculates inert exhaust gas into the volatile combustion chamber to reduce chamber temperature(<2500*) to prevent the formation of NOx and reduce pre-igniton. Performing a carbon clean on the chambers and EGR passages can be beneficial. I'm glad the Gen IV and V LS's do not run EGR valve's for the most part, in the 80's and 90's you could make a living cleaning out EGR passages that were plugged and the engine were knocking.

Prodigy Performance

BTW - I just noticed that this is an invalid comparison to our chart. Your numbers and chart are measured at the crank. Our dyno chart is measured at the wheels on a chassis dyno.


The stock 3.8 produces 202 hp at the crank.
Our dyno recorded 135 hp at the wheels in stock form.
Drivetrain inertial/friction losses = ~33%


Apply the same drivetrain losses to your chart, and it brings an estimated reading at the wheels down to about 234 ft-lbs off idle to 6000 rpm, and a peak of 308 ft-lbs and 281 hp at the wheels. Use those numbers when comparing to our dyno results for the 3.8 turbo. Dyno charts for all forced induction systems are based on chassis dyno (at the wheel) numbers, each with their own % drivetrain loss depending on type of dyno, test procedure, etc.


The 6.2 L86 is still very impressive, nice torque throughout the RPM range, substantial advantage at lower RPM, etc., but not quite as huge of a difference in power as it first seems (unless you are only comparing the L86 dyno chart to a manufacturer's chart for the 3.8 measured at the crank, then the difference you see is correct).


Of course, that's just an estimate assuming same drivetrain losses. Only a direct comparison on the same dyno would be a 100% valid comparison.


A good example of why one needs to be careful when comparing power/torque numbers from different sources.


I'll stop hijacking this thread now


~Jeff

VEGASROBBI

Well after 300 swaps I'm impressed with the L86. The Butt-O-Meter says I can roast 40's off the line at will and pull hard to redline. We have had several builds in house with turbo chargers and many more with superchargers that were removed.

I do not feel we can make an accurate comparison since the drivablilty is so different, I drive 400 HP+ SC and TC engines but they are completely different than driving a V8, and of coarse the cost is completely different.

We're seeing 17-18 mpg with the L86 in a heavy JK with 4 cylinder mode active. The L86(and L83) are halfway to a diesel, Direct Injection, Continous VVT, over 11:1 compression all on regular gas. The 8 speed transmission helps a lot, with a 4.6 low and .6 high you have a lot of gear diversity.

I really like these Gen V engines, I'm excited after 8 years of building LS JK's, they are the future in engine swap technology IMO. Performance, economy, emissions compliance, longevity(200,000 miles+)..... Here's a couple vids, these JK's are geared tall, 4:10's with 37's and 4:88's with 40's, on regular gas

https://www.youtube.com/watch?v=eP1dRucxrJU&t=7s https://www.youtube.com/watch?v=UtjJGzxTI9o&t=13s https://www.youtube.com/watch?v=h7EW6sBABzk&t=35s https://www.youtube.com/watch?v=WI-4kYxX2h0&t=703s