Klubbs, I found the thread that had the Magnaflow X pipe in it.

 

Did some reading on H and X pipes. According to the Mustang guys and Hot Rod magazine, they concluded that the H pipe is slightly better for low end (deeper sound) and the X pipe performs better in the high rpm (more exotic sound *probably higher pitched).

So since this Borla exhaust isn't crossed over at all (which IMHO is the worst case), I might try to get a simple H pipe installed. Low end torque is what I'm trying to achieve here and the H might be the way. Question is where? Before the huge Borla 2in/2out muffler? Not sure if that's ideal as it would be right at the bends where it goes into the Borla resonator/muffler. BUT this is where I see H pipes installed.



Or I could get it installed right after the 2 in / 2 out borla but I don't know if that's an ideal location (although it would be the easier of the two locations to install)

 

Jeff,

I'd do it after premuffler and not at the y-pipe convergence. I'm not an expert on pulse tuning, but I'd think you'd want the "H" in an area where the pipes finally straighten out.

 

I don't know if that's ideal though. All the H pipes I've seen are pretty close to the merge. After hearing Hydrazine's comment about H pipes, I'm tending towards the Magnaflow X again. If I could find a Nismo Y for cheap, I would be more willing to experiment by hacking the Y merge off and adding a H up closer to the engine somewhere.

 

I do agree, the best scenario is just to get rid of the premuffler, install x-pipe or H-pipe, then maybe a small premuffler after that. While I was at it, I'd put in some flex sections.

And how in the hell do you have 15K+ posts?

 

Magnaflow has a resonated true X pipe in a 2.25" diameter. It would solve two problems at once. (torque and hopefully some noise suppression or at least move the resonance up or down).

 

Just ordered the Magnaflow 14385 resonated X pipe just now. Since people have been able to use the unit "as-is" to slip fit the connection to the Borla system, I'll have a shop just hack the front Y side and weld it to the Magnaflow and slip fit it to the rest of the Borla (I hope) Performance peddler had it for $99 shipped. That's way cheaper than anywhere else. You have to put an offer in (pop up) and wait for the email reply. the order using the discount code they give you. Normally it's $121 or more.



Material: 100% Stainless Steel - Mirror Finish
Body Shape: 4in.x9in. Oval
Inlet/Outlet Size: 2.25in./2.25in.
Body Length: 14in.
Overall Length: 20in.
Core Size: Dual 2.5in.
Position: Dual/Dual


Features and Benefits: Straight-Through Wide-Open Performance, Reversible, Tru-X Perforated Core, Lifetime Warranty, Dyno Tested And Proven To Make Power, Performance Gains In Horsepower And Torque, Great Sound - Has A Smooth Deep Tone, All Welded, Built To Last.

 

Just got it done today. Guy agreed that the X pipe was the way to go. Just cut off the Borla 2 in 2 out premuffler (which I confirmed is not an x pipe in any way) and had the X put in. Slip fit on the outlet side was retained.

Hard to tell about the performance as it's wet/rainy out and performance always seem to soften when humidity is high. But on the Z forums, everyone that has replaced modified their duals that had a H pipe (borla) or had nothing but dual pipe, reports noticable differences in low end torque. I hope that is the case with me. The torque does seem to pick up lower in the rpm range by about 200 rpm. But I haven't got on it yet.

Sound. The tone is different. It's very coupe-like now. From all the reading, this X did exactly what it said it would do. Make the tone higher pitched. I really like it.

Drone. The system seems quieter as a whole which is good. Drone seems to be reduced by a noticable amount. BUT I wasn't expecting it to be as I'm pretty sure most of the drone is from the muffler. I might end up having the muffler replaced by another resonated X or a non X magnaflow.

 

Love to see/hear some video if you can swing it. Not that I'm planning to go this way, just curious about the sound.

 

Yeah, I'll see if I can figure it out. I'm trying to get this review done before I throw on my coupe 19s again. So I had a chance to drive it on my work commute:

The Borla (especially with the auto) was always boomy. And right at the shift/cruise rpm. Ask Dave B about that! Although decreasing this boominess/drone was one of my ultimate goals, I wasn't expecting alot with this addition. But after driving it for a few days, I can tell the drone is noticably reduced. Maybe by a 1/3rd or 1/2 at the most. It's still there but not nearly as loud. Cruise rpm is alot quieter. I was hoping the resonated X would help with this and it did! But I considered a bonus and not an expectation.

Overall sound is alot more exotic vs again boomy. The vibrations that this thing has because it doesn't have flex pipes is also reduced (by 1/2). The sound is sorta like a coupe but louder and better. Again once you hit the high revs, it quiets out just like before. The exhaust is smoothed out too.

Performance. Again, the streets are wet and I'm on my blizzaks. Everytime I get on it from a roll and shift into 3rd, it just results in wheel spin. But the low end torque is improved and the high end hp seems to be better. The torque band seems to have moved maybe a few hundred rpm lower. For us autos, any improvement in this area is good. Not as dramatic as when I added the crawford plenum, but it's definately there. The Z guys that have done this to their Borla or HKS etc... dual setups have raved about the performance (mainly torque) improvement.

I'm going to try to take pics when I get around to putting my coupe 19s back on.

Update: Pics:

 

Great job, Jeff. Makes you wonder why Borla didn't do this in the first place. Did you add flex sections too?

 

Great idea and research. I have a sedan borla as well and have been exploring simmilar ideas but never pulled the trigger. Well done. Id love to see/ hear the final product...mostly hear!

 

Dave. No. I didn't add any flex sections. The exhaust guy didn't recommend them either. Although I could add some later.

Tampasedan. I tried to alot of research on the Z forums before doing this. Alot of their duals don't have any type of x,h or otherwise. But the Z bora has a H. Even then, guys are putting some type of X in to replace it. Mostly to combat rasp from the addition of test/high flow cats. But many reported better torque too.

Today was drier and when I'm in 3rd or 4th, the low end torque is noticably better. I'm just now able to do some driving in manual mode to compare for sound and power.

I'll try to get some videos up. I'm a tech idiot though.lol

 

I tried to take a clip while driving (using my camera)but the exhaust doesn't get picked up at all. I wanted to show the sound level during normal driving with the windows up. I guess I'll just set on the ground and rev it up. Any specific requests?

 

This is a very interesting experiment, Jeff. Thanks for the writeup. I chased drone in several exhausts in my old 300ZX for 2 years before finally settling on an HKS Sport model with larger, non-straight through mufflers. I considered the rsonated x pipe setup you have done as well, but never ended up trying it. The larger HKS mufflers seemed to solve the drone problem and returned some lost low-end torque as well. It's mainly why I have left the G's exhaust alone - I couldn't stand the drone in the 1.5-3k RPM range.