This may have been discussed in other threads but does the JBA Evol Cat-Back replace the resonators? I have a KC 4X2 and while I was underneath it today I noticed the piping around the resonators looks real restrictive. If the JBA Cat-Back doesn't replace the resonators with straight pipe or something then I don't see much performance gain since the restriction at the resonators seems extreme.

This may have been discussed in other threads but does the JBA Evol Cat-Back replace the resonators? I have a KC 4X2 and while I was underneath it today I noticed the piping around the resonators looks real restrictive. If the JBA Cat-Back doesn't replace the resonators with straight pipe or something then I don't see much performance gain since the restriction at the resonators seems extreme.

Here's what little I know. The JBA Evol kit that is up for raffle is a cat-back for a 4x4 and a reso-back for a 4x2. In other words, it will not replace your resos. Back in the early day, JBA only made one exhaust for the Titan and it was modeled off a 4x2, so it was a cat-back that replaced everything from the cats back including the pipes with the O2 sensors and resos. This created a problem on the 4x4's since they have 4 cats and no resos. A couple months ago, they re-did their exhaust kit so that it is 4x4 friendly and is a cat-back for them and is a reso-back for the 4x2. I have no idea if they still offer a true cat-back for use 4x2 guys.

This may have been discussed in other threads but does the JBA Evol Cat-Back replace the resonators? I have a KC 4X2 and while I was underneath it today I noticed the piping around the resonators looks real restrictive. If the JBA Cat-Back doesn't replace the resonators with straight pipe or something then I don't see much performance gain since the restriction at the resonators seems extreme.

Here's what little I know. The JBA Evol kit that is up for raffle is a cat-back for a 4x4 and a reso-back for a 4x2. In other words, it will not replace your resos. Back in the early day, JBA only made one exhaust for the Titan and it was modeled off a 4x2, so it was a cat-back that replaced everything from the cats back including the pipes with the O2 sensors and resos. This created a problem on the 4x4's since they have 4 cats and no resos. A couple months ago, they re-did their exhaust kit so that it is 4x4 friendly and is a cat-back for them and is a reso-back for the 4x2. I have no idea if they still offer a true cat-back for use 4x2 guys.

Well that sucks! I wonder why they didn't just make a Cat-Back for the 4X4's and leave well enough alone on the 4X2's. I'm sure you've looked under your truck and the piping going in and out of the resonators is tiny. So if the JBA is only resonators back on the 4X2, it will do little in my opinion in the way of performance since bigger pipe after a huge restriction is useless. Oh well . . .

This may have been discussed in other threads but does the JBA Evol Cat-Back replace the resonators? I have a KC 4X2 and while I was underneath it today I noticed the piping around the resonators looks real restrictive. If the JBA Cat-Back doesn't replace the resonators with straight pipe or something then I don't see much performance gain since the restriction at the resonators seems extreme.

Here's what little I know. The JBA Evol kit that is up for raffle is a cat-back for a 4x4 and a reso-back for a 4x2. In other words, it will not replace your resos. Back in the early day, JBA only made one exhaust for the Titan and it was modeled off a 4x2, so it was a cat-back that replaced everything from the cats back including the pipes with the O2 sensors and resos. This created a problem on the 4x4's since they have 4 cats and no resos. A couple months ago, they re-did their exhaust kit so that it is 4x4 friendly and is a cat-back for them and is a reso-back for the 4x2. I have no idea if they still offer a true cat-back for use 4x2 guys.

Well that sucks! I wonder why they didn't just make a Cat-Back for the 4X4's and leave well enough alone on the 4X2's. I'm sure you've looked under your truck and the piping going in and out of the resonators is tiny. So if the JBA is only resonators back on the 4X2, it will do little in my opinion in the way of performance since bigger pipe after a huge restriction is useless. Oh well . . .
There have been a few guys that have removed those resonator pipes and taken them to an exhaust shop and had a pipe made up to replace it. That would be the way to go if your concerned about the restriction. You should be able to get that done pretty cheap.

There have been a few guys that have removed those resonator pipes and taken them to an exhaust shop and had a pipe made up to replace it. That would be the way to go if your concerned about the restriction. You should be able to get that done pretty cheap.

That's what I was going to suggest. I've got the 4X4, so I have no reso's. Let us know what you do, okay?

Since I do have a 4X2 would it make that much of a difference to have them replaced? Whatcha thinking that might cost..... I've never been under mine yet so I don't even know what it looks like yet.

Looks like I ordered mine just in time. (Yes this is a totally meaningless post).

Your gonna give bill a big head with your signature!! :lol:

Your gonna give bill a big head with your signature!! :lol:

Yea since he came up with the phrase, I promoted him to Sr. Servant - that's right...bow down to me! :lol:

LOL I still crack up everytime I see that avatar of yours.
m4ck

Since I do have a 4X2 would it make that much of a difference to have them replaced? Whatcha thinking that might cost..... I've never been under mine yet so I don't even know what it looks like yet.

The pipe to fore and aft the resos is about 2" I think. The inlet and outlet for the reso are about 1.5" for about .5".

If you check out the head's posts about his exhaust performance upgrades (not sure if he posted the info here or just on TT), he got the biggest performance boost when he replaced the OEM resos with some Moroso resos and bigger pipes (2.5" I believe).

That does make a big difference replacing the resonators. I did it on my last truck and kept the pipes when I traded it in for the truck I have now. Mine are 2.5" straight pipes and you sure can FEEL the difference all through the RPM band. It's a great mod to do whether you have resonators or cats.

hhhmmm...living in the great state of California I wonder if you are even permitted to remove them. Probably would have to ask a shop that's up on all our quirky smog laws here.

hhhmmm...living in the great state of California I wonder if you are even permitted to remove them. Probably would have to ask a shop that's up on all our quirky smog laws here.

I think you can, I did it on my former F-150 4X4. As long as you still have cats on it. I took it to Ledezma Muffler Shop in Chula Vista, California last year..... :)

Not sure, but I don't think removing the cats is "50 state smog legal".

Also, might affect your warranty. Scarab on TT tried to ask his service manager about this, but never got a straight answer. He got one of the early model JBA kits on his 4x4 and didn't realize until after that he had 4 cats and no resos.

Looks like I ordered mine just in time. (Yes this is a totally meaningless post).

You scored and got the original system that replaces the resonators right? You lucky dog. :) Your post wasn't totally meaningless unless you think gloating is meaningless. :) :) :) :)

hhhmmm...living in the great state of California I wonder if you are even permitted to remove them. Probably would have to ask a shop that's up on all our quirky smog laws here.

Removing the resonators should be no problem for us Californian's it's the cats you better not touch.

I would just have to beleive that if you did some beating of these people that you could probably find an old system. hhhmmmm....thinking here....I'll send them a message and see if I can get a response...first I have to find an e-mail address.

Looks like I ordered mine just in time. (Yes this is a totally meaningless post).

You scored and got the original system that replaces the resonators right? You lucky dog. :) Your post wasn't totally meaningless unless you think gloating is meaningless. :) :) :) :)

Just looked, gloating isn't in my dictionary :wink:

Ok, after hearing a bunch of conflicting information I made a call to JBA today to try and get the real scoop and here is what the tech told me. The current kit being produced (Post 12/04) is for the 4X2 only. It DOES replace the resonators but won't work on a 4X4 because of the extra 2 cats. They will have a 4X4 specific kit coming out soon but it is currently still in development. He said all kits manufactured before 12/04 will work on both 4X2 and 4X4 but will only be truly "Cat-Back" on a 4X4 and "Reso-Back" on a 4X2.

Anyone heard anything different from JBA directly?

Ok, after hearing a bunch of conflicting information I made a call to JBA today to try and get the real scoop and here is what the tech told me. The current kit being produced (Post 12/04) is for the 4X2 only. It DOES replace the resonators but won't work on a 4X4 because of the extra 2 cats. They will have a 4X4 specific kit coming out soon but it is currently still in development. He said all kits manufactured before 12/04 will work on both 4X2 and 4X4 but will only be truly "Cat-Back" on a 4X4 and "Reso-Back" on a 4X2.

Anyone heard anything different from JBA directly?

Yes, I have....just the opposite. Post 12/04 kits would fit either 4x4 or 4x2. This is the system that was raffled. I can take a picture of the date of manufacture tag if you like.

I haven't talked to them directly, but I know that in Oct 2004, their kit only came one way and it was cat-back for a 4x2. (there was a lot od discussion about this on TT) I'm not sure why the person you talked to gave you the info exactly backwards.

Ok, after hearing a bunch of conflicting information I made a call to JBA today to try and get the real scoop and here is what the tech told me. The current kit being produced (Post 12/04) is for the 4X2 only. It DOES replace the resonators but won't work on a 4X4 because of the extra 2 cats. They will have a 4X4 specific kit coming out soon but it is currently still in development. He said all kits manufactured before 12/04 will work on both 4X2 and 4X4 but will only be truly "Cat-Back" on a 4X4 and "Reso-Back" on a 4X2.

Anyone heard anything different from JBA directly?

Yes, I have....just the opposite. Post 12/04 kits would fit either 4x4 or 4x2. This is the system that was raffled. I can take a picture of the date of manufacture tag if you like.

This is bizarre because I ran through it with him twice because it sound backwards to me too. I also called an online vendor who advertises the JBA with a picture of the two resos included and he said that YES the kit I would purchase would have the new resos and be a full Cat-Back for a 4X2. What the heck?

JBA doesn't have their stuff straight apparently. I went to their website and on this page http://www.jbaheaders.com/04titannew.asp they show a pic of a cat back for a 4x2 that replaces the stock resos with JBA resos. In the description of the system, they do not mention JBA resos. In the pics of the evol system that was raffled, there are no resos. If you piece the raffle system together, you will see it does not contain pipes to replace the stock reso pipes.

I looked at a couple other sites and they don't mention the difference in a 4x4 and 4x2 JBA exhaust. They all show only the 4x2 cat-back kit that replaces the resos (or the back cats on a 4x4). So if you go by this, then they need to put info on their exhaust listings that the system will NOT work on a 4x4.

To me, I own a 4X2, that's good news! I guess when I order my exhaust I'll have to really drill the person I am getting it from. Make sure it replaces the stock resos on a 4X2. Not sure if I'll order it online or go to a exhaust shop. Guess it depends on price. So that more then likely means online and placing it on myself! So after April if your in California and you see a new JBA exhaust system lying in the freeway don't run it over....it's mine and it fell off because I will be doing it myself!

Interesting/potentially scary discusson going on here. Yesterday I ordered the JBA kit from AJ-USA (they had a really good special going on). I called them because their site did not differentiate between 4x2 and 4x4 and it pictured the 4x2 system with resos. I was told by the sales manager that the kit they are selling is the model that fits both 4x2 and 4x4 and I will not have to remove my cats. I sure hope he's right. I'll let you all know the verdict when it's in my hands Monday.

It sounds like your guy may be right. As I understand it the new system is a duel system for the 4X4 and 4X2. The problem as I understand it is that it works great for the 4X4, but no longer replaces the resos on a 4X2. It's a cat-back for the 4X4 and a reso-back for the 4X2.

But with some prying I'm sure you can get a cat-back for the 4X2 but you better ask alot of questions as I will be doing....

The more I think about this the more I confuse myself!! :coffee:

Interesting/potentially scary discusson going on here. Yesterday I ordered the JBA kit from AJ-USA (they had a really good special going on). I called them because their site did not differentiate between 4x2 and 4x4 and it pictured the 4x2 system with resos. I was told by the sales manager that the kit they are selling is the model that fits both 4x2 and 4x4 and I will not have to remove my cats. I sure hope he's right. I'll let you all know the verdict when it's in my hands Monday.

You should be fine QuadRacer. I just called JBA again and the first guy I talked to was wrong. I spoke with THE Titan guy over there and he said prior to 12/04 the kit was truly a Cat-Back for the 4X2's (contained new Resos) but required 4X4 owners to remove the rear 2 cats. They redesigned the kit in 12/04 and now it is Reso-Back on 4X2's and Cats-Back on 4X4's. No new system for 4X4's is in the works and the current system is the final one. I wish I could remember the knucklehead I talked to first who gave me the bogus information. I also talked to AJ USA (Quadracer) and they have no backstock of the older kits so the one you get should be the cat/reso back new system. The guy at AJ USA is going to call over to JBA for me to see if he can get me a pre-12/04 kit with the resos. I will let you all know.

One other thing . . . The guy at JBA mentioned that he was under the impression that the '05 4X2's had 4 cats as well which is why they decided not to make 4X2 and 4X4 specific kits for '04 Titans??? Anyone with a 2005 4X2??? Check and see if you have 4 cats.

Nope.....we have two cats...

Nope.....we have two cats...

Take the resonators off and have a set of straight pipes made. You won't be sorry, that I can assure you of......Oh yeah, don't do this if you have the stock exhaust system on it. I tried it with my 4x4 after I bought it and it sounded REALLY weird. Didn't notice much gain either, probably due to the restriction at the Y-pipe.

Nope.....we have two cats...

Take the resonators off and have a set of straight pipes made. You won't be sorry, that I can assure you of......Oh yeah, don't do this if you have the stock exhaust system on it. I tried it with my 4x4 after I bought it and it sounded REALLY weird. Didn't notice much gain either, probably due to the restriction at the Y-pipe.

I think that is exactly what I will do. I think I will have a totally custom exhast fabbed up. I love the sound of a Flowmaster 70 Series so I think that will be what I do and dump the resonators at the same time.

Hey Jet, so the 4X4's have resonators too or did you remove the rear cats???

Hey Jet, so the 4X4's have resonators too or did you remove the rear cats???

Ummmmmmm, well I guess I'm already guilty of removing the front cats when I originally put the headers on so yes, my 4x4 had rear cats. Notice I said had.... :devil:

The resonators that come on the 4x2's seem to be much more restrictive in my opinion. At least the ones with cats don't neck down to 1.5" before it goes into the cats like the resonators do.

Hey Jet, so the 4X4's have resonators too or did you remove the rear cats???

Ummmmmmm, well I guess I'm already guilty of removing the front cats when I originally put the headers on so yes, my 4x4 had rear cats. Notice I said had.... :devil:

The resonators that come on the 4x2's seem to be much more restrictive in my opinion. At least the ones with cats don't neck down to 1.5" before it goes into the cats like the resonators do.

My thoughts exactly! I mean, why would I buy a 2" garden hose if my spicket only had a 1" mouth? It's crazy! These cat-back systems are a waste of money in my opinion on the 4X2 unless you lose the stock resos. You might gain a little upgrading the Y-Pipe but not worth the money IMHO. The exhaust can only flow as well as it's worst restriction. To the drawing board >>>>>>>>>>>

Here's a simple response from JBA:

Ron,
Sorry to disappoint you, but the system we offer is res back because the 4x4 model had cats in lieu of resonators and they had to remain intact to stay 50 state smog legal. Thank you for your interest in our Titan system.


:redfaced:

Here's a simple response from JBA:

Ron,
Sorry to disappoint you, but the system we offer is res back because the 4x4 model had cats in lieu of resonators and they had to remain intact to stay 50 state smog legal. Thank you for your interest in our Titan system.

:redfaced:

ummm... The problem with their first system was that it lacked flanges behind the resos like the stock system. If they would just put flanges there, they could have 1 kit that would work for both 4x4 and 4x2. They could even charge an extra few bucks more for the 4x2 system if you want their reso pipes.

Here's a simple response from JBA:

Ron,
Sorry to disappoint you, but the system we offer is res back because the 4x4 model had cats in lieu of resonators and they had to remain intact to stay 50 state smog legal. Thank you for your interest in our Titan system.

:redfaced:

ummm... The problem with their first system was that it lacked flanges behind the resos like the stock system. If they would just put flanges there, they could have 1 kit that would work for both 4x4 and 4x2. They could even charge an extra few bucks more for the 4x2 system if you want their reso pipes.

I thought that too but who knows?

Ugh!!!! So after all the checking (e-mailing and calling before ordering), my JBA system shows up at my door. All excited I open up the box, reach inside and what's the first thing I feel...you guessed it, a resonator! That's right, the kit I received is the old 4x2 system with the replacement resonators! I knew I had a bad feeling about it. I guess it's time to call the company and complain. I will wait however, in case there's a 4x2 owner here that would want to work out some kind of a deal (swap the new 4x4 friendly kit for this one, or just the pipes in front of the muffler?) Oh well, I'm off to have a beer.

Ugh!!!! So after all the checking (e-mailing and calling before ordering), my JBA system shows up at my door. All excited I open up the box, reach inside and what's the first thing I feel...you guessed it, a resonator! That's right, the kit I received is the old 4x2 system with the replacement resonators! I knew I had a bad feeling about it. I guess it's time to call the company and complain. I will wait however, in case there's a 4x2 owner here that would want to work out some kind of a deal (swap the new 4x4 friendly kit for this one, or just the pipes in front of the muffler?) Oh well, I'm off to have a beer.

woah, hold off on complaining about it. I'm sure there will be someone MORE then willing to take it off your hands here....or better yet, install it on your truck. It will make a big difference.

JetTech...the devil inside me does say to install it, but I'm more concerned with what the dealer would say? If I had to take my truck in for some work, I'd probably have to reinstall the stock exhaust so they're not inclined to void my warranty or something.

JetTech...the devil inside me does say to install it, but I'm more concerned with what the dealer would say? If I had to take my truck in for some work, I'd probably have to reinstall the stock exhaust so they're not inclined to void my warranty or something.

Oh heck no man, the dealer wouldn't even know the difference. Do you realize the people they have working for them?? I challenge anyone to ask any Nissan mechanic which trucks have resonators and which have cats. I can almost gaurantee not one could answer that correctly. I shouldn't be encouraging you so much but if I was you I would feel lucky you got the one with resonators........EQUALS====MO POWER!!!!

Ugh!!!! So after all the checking (e-mailing and calling before ordering), my JBA system shows up at my door. All excited I open up the box, reach inside and what's the first thing I feel...you guessed it, a resonator! That's right, the kit I received is the old 4x2 system with the replacement resonators! I knew I had a bad feeling about it. I guess it's time to call the company and complain. I will wait however, in case there's a 4x2 owner here that would want to work out some kind of a deal (swap the new 4x4 friendly kit for this one, or just the pipes in front of the muffler?) Oh well, I'm off to have a beer.

QuadRacer! Old Buddy Old Pal. I will buy the Resonators off of you! Without the resos you should still have the Cat-Back System for your 4X4. Let me know what you want for them and shipping. SERIOUSLY!

QuadRacer! Old Buddy Old Pal. I will buy the Resonators off of you! Without the resos you should still have the Cat-Back System for your 4X4. Let me know what you want for them and shipping. SERIOUSLY!

This is the problem with their old system. They don't have flanges at the stock locations to just be able to use the 4x2 system on a 4x4. You will need to buy the whole system from him for it to do either of you any good.

hhhmmmm....how much did you pay for it.

I have the JBA Evol Cat Back on my Titan crew cab. The Resonators on the new system are a straight through design. The exhaust sounds good at lower rpm's & when you kick it over, the problem I have is the system doesn't sound good when you stomp on it. Because of the design of the baffels in the Muff. On my crew SE I have the Evol ystem and a Volant cold intake.This truck desperatly needs a computer mod for the upgrades to work.

HavockWK is correct...to get rid of the resonators on this system is to get rid of everything in front of the muffler. I got a good deal on the system as it was on sale though 2/28 at AJ-USA, however I couldn't really sell it for what I paid because I couldn't replace it for that (if that makes any sense). So, at this point, I'm just confused as to what to do (use it as is, send it back, sell/trade with someone, etc.).

JetTech, you've heard this system with the resonators...how's it sound (outside and inside the cab if you know)? Does it correspond to belcher's comment?

HavockWK is correct...to get rid of the resonators on this system is to get rid of everything in front of the muffler. I got a good deal on the system as it was on sale though 2/28 at AJ-USA, however I couldn't really sell it for what I paid because I couldn't replace it for that (if that makes any sense). So, at this point, I'm just confused as to what to do (use it as is, send it back, sell/trade with someone, etc.).

JetTech, you've heard this system with the resonators...how's it sound (outside and inside the cab if you know)? Does it correspond to belcher's comment?

I've heard the system you have now and it sounds awesome. The one to ask is slurppie because it was his truck that I heard while it was on the dyno. He could give you more insight as to how it sounds on the highway and around town. I was impressed with the way it sounded at 6K rpm on the dyno.... :amazing:

Good point...I'll go back and look at Slurpie's prior posts. JetTech, based on your experience, if I ditched my 2 rear cats and used this system with resonators, would it throw any weird codes (aside from possibly one during initial adjustment to the system) that would make the truck not pass emissions testing (only computer based, no exhaust sniffer)? I think I'm leaning towards using it as is.

Initially slurppies truck had 2 codes flash up, left and right bank lean shift. He found that he had a small exhaust leak, fixed that and cleared the codes. I don't think they've returned since so it should be fine. PM slurppie and get the latest from him..

As Dale mentioned I believe both codes were due to the leak at the flange before the rear O2 sensors. At first I had a small leak on bank 2 and shortly after received a lean shift code. After fixing the leak the code cleared itself. About a month later I had a small leak on the drivers side at the flange and once again received a lean shift code. I had the leak fixed and cleared the code and have not received one since.