JEEP 392 STOCK manifold size / upgrade cat. Has anyone performed that?

[jeepedmax]

Hello!

Looking to replace the stock cats with some High flow cats.

Had a few questions if any members have knowledge on:

1 . Confirming, that 2.5" slip will fit stock manifold?
2. What is the best to get access to cats, looks a bit tricky?
3. Is there 2 or 4 cats?

Has anyone here upgraded stock cats wonder how it went.

Don't currently want to add headers atm.

Thanks!

 

[Tank2112]

Unless you are highly modifying your engine....cam, lifters, roller rockers, pistons, so you can supercharge your 392.... you will not gain much if any by enlarging from factory cats.

I also doubt any hp gain when switching exhaust systems. I had a Magnaflow cat-back exhaust system installed, they claim by increasing to 3" pipe you gain 10-15 hp.
After removing and seeing how open the factory resonator is...I doubt much, if any, hp gains are realized.
Love the deeper tone of Magnaflow though. And no drone.
My favorite mods so far.

 

[KuntryRube]

Hello!

Looking to replace the stock cats with some High flow cats.

Had a few questions if any members have knowledge on:

1 . Confirming, that 2.5" slip will fit stock manifold?
2. What is the best to get access to cats, looks a bit tricky?
3. Is there 2 or 4 cats?

Has anyone here upgraded stock cats wonder how it went.

Don't currently want to add headers atm.

Thanks!

Hey, hope this helps you out. I came from the modified car scene. I was deep in there as you could go for many years, legal and otherwise. I'll try to skip the jargon and keep it simple and easy.

If you're looking to net some power, then I hate to say it, but you're wasting your time AND money. Our closest cousin - the 392 Scat Pack, with all the parts that it could bolt on would barely net them 50whp (wheel horse power) with a tune. I'll give you points so you're not flooded with information.

1. They're heavy like us. Except you're even heavier!
2. You, swapping out for HFCs instead of doing a cat delete.
3. Only doing catalytic converter...

Here's to put it in perspective in easy to read words:
392 scat, stock = ~400 wheel horse power (whp for short)
392 scat, full bigger exhaust with no catalytic converters. Cold air intake + a tune = ~420whp
392 scat, all the above + e85 = ~450whp
392 scat still loses to many cares because it's so fat. All that work and money netted it 50whp. A Hellcat with similar work will net ~150+. Why? Because it has a supercharger.

To answer your question, we have 4. Most modern cars have 4. Two upstream and two downstream, pre-cat and post-cat respectively. Work from below, hard and tricky but can be done. Do with it what you will. Your car your money.

 

[RJP]

Hey, hope this helps you out. I came from the modified car scene. I was deep in there as you could go for many years, legal and otherwise. I'll try to skip the jargon and keep it simple and easy.

If you're looking to net some power, then I hate to say it, but you're wasting your time AND money. Our closest cousin - the 392 Scat Pack, with all the parts that it could bolt on would barely net them 50whp (wheel horse power) with a tune. I'll give you points so you're not flooded with information.

1. They're heavy like us. Except you're even heavier!
2. You, swapping out for HFCs instead of doing a cat delete.
3. Only doing catalytic converter...

Here's to put it in perspective in easy to read words:
392 scat, stock = ~400 wheel horse power (whp for short)
392 scat, full bigger exhaust with no catalytic converters. Cold air intake + a tune = ~420whp
392 scat, all the above + e85 = ~450whp
392 scat still loses to many cares because it's so fat. All that work and money netted it 50whp. A Hellcat with similar work will net ~150+. Why? Because it has a supercharger.

To answer your question, we have 4. Most modern cars have 4. Two upstream and two downstream, pre-cat and post-cat respectively. Work from below, hard and tricky but can be done. Do with it what you will. Your car your money.

Excellent explanation. Thank you.

Surprised the Facebook Fan Bois aren't attacking you for not posting technical reports, charts, and graphs all of which they can't understand nor will bother to research.

 

[Jeepstin392]

For about $14k in parts, labor and a tune, you can do the 426 stroker kit. I seem to recall 100-120hp gain at the crank. Can’t recall the Tq gains.