im confused, a friend of mine wants to install an x pipe on my L and he says it replaced the mufflers,but from some of the pics ive seen the x pipe is installed already and the mufflers were still on,which way is the correct way and how loud will it be!!. thanks

 

Maybe checking how much of this applies to a L is in order, but the generic over view.

An X pipe is used when doing 2 SI/SO mufflers on duals.

I thought the pictures of the stock L xhst system that I had seen were to have shown a DI/DO muffler, which contains more of an H pipe then X pipe configuration.

Yes you can use a X pipe with or without mufflers, but how loud you want it to be is up to you. Maybe checking with cyntaxx to see how he likes his straight system ( if he still has it installed ) whould be a good place to start.

I know the Bassani " cat-back" for the L has a X pipe included in the kit, why this would be if the factory already included a true X pipe before the DI/Do muffler is beyond me.

If you crawl under your truck and look, the system might have a DI/DO muffler as factory, and the upgrade to the X pipe and mayeb the mufflers is an aid in xhst gas flow, which in turn helps perf ( on an L, I have only read what is in the HD and L forums on this, don't know first had on S/C I've got a N/A 5.4 with the Bassani L system as a true dual install ).

Good luck

Steve

 

Steve, maybe you can help me with this since there are so many conflicting views. I have an '02 S-crew 5.4 with true duals and no mufflers. Would the Magnaflow muffler with the built in X pipe give me back my low end? Is this what you did, or did you do 2 SI/SI mufflers? Do you like the sound? Loud? Looking to quiet it down and get some TQ back without spending a bundle.
Thanks.

 

Currently I stil have the cat back system off the L on. This is the Bassani, with the X pipe, and the 2 SI/SO 5x8 mufflers.

I have the parts here, just need to find the time to install the Magnaflow X pipe, and the DI/DO muffler to remove some of the noise level that I am getting from the Bassani system ( NASCAR Truck series ready at over 3k RPM ).

If the current system you have has no X pipe, and no mufflers, you could do better by at least adding the X pipe as close to the front as you can. The other problem is how was the pipe bent ? bad bends in the system has take as much of a toll on the TQ as a bad muffler. This might be the cause of the loss of TQ that you are seeing ??

BTW : did you actually get a dyno to show the loss of TQ, or is it missing backpressure ?

 

Steve, thanks for the reply. No Dyno test here(live up in the mountains in CO) but after driving some other 5.4s and SOP testing, it seems to want to wind over 3000 rpms before it really punches. This gets too loud as well, especially up our hills at 10,000+ feet. I may have given you the wrong impression on the exhaust too. The cats are still there, but then the system goes to 2 separate 2.5 inch pipes all the way to exit at an angle behind each rear wheel with 12inch chrome 3inch diameter tips. The system is not connected anywhere along the route. True Duals ? Is the DI/DO you got the Magnaflow with the built in X? Many posts here say that an X won't do much if it is not far enough forward in the system, but then a regular DI/DO would still help, and create some scavenging effect compared to my present non-connected system. Thanks for the help.
Want to get this right the first time.

Dan

 

DAn,

Well the 3,00 RPM level is the "meat" of the HP range, so what you might be feeling is either a loss of TQ, or a loss of backpressure. I know I had a great SOP delta from the stock Y pipe & Gibson ST to the Bassani system, but I have lowered by 60' and 1/8' times, so I have not bad so far.

I actually have a MagnaFlow X pipe that is going right at the 90* bend from the driver's side pipe, up close to he front.
The DI/DO muffler has somewhat of a H pipe in it, but I did not want to use only that, so Mike hooked me up with the X pipe in front of the muffler.

So your system is 2 singles, you would want to, at least, stuff in an X pipe up towards the engine, as close to the 90* bend as you can, and then either straights, or mufflers inline, going back to the dumps that you have now. The H pipe in the muffler is only for pressure equalization, nothing to do with scavenger effect.

Hope I got them all this time, if not let us know.

Steve

 

FYI the bends look really nice on the system, no real crimping or anything. I think I just have a loss of backpressure. Will a DI/DO help this considering the present lack of any muffler? The pipes are routed together most of the way back, so this should work well with most DI/DOs like the magnaflow or Flo-Pro. Are you getting rid of the Bassani because it's just too loud? The larger DI/DO should help this right? Larger muffler size = noise suppression in general right. Let me know how it goes.

Dan

 

Performance wise I love the Bassani over the Gibson. I will now be able to comment on the MagnaFlow system.

I am getting rid of it due to noise level only, other then that, it is a great system.

I need to find time to swap it out, else I'll be paying to do it.

For your system, a lack of crimps in the bends is not the only indicator, the other item is how many bends and how tight they are,

If they rise too high going over the rear axel, then this can be a cause of the TQ loss ( i.e. jacking up the flow ).

The sound level of the MagnaFlow that I got should be just above the sound level of a stock L. I might miss the sound ever now and then, but in the long run I think I will be better off with something quiter, so I can talk on the phone while driving