DIY Exhaust Mod Question

[ChrismCagle]

Ok, I found out about a quick, easy mod to do on your exhaust that will leave it stock, but increase the volume so I did it and documented what I did with my digital camera, then made this site. (http://home.earthlink.net/~clonewolf/exhaust.htm)

What I want to know is if there is anyone out there with a good deal of performance modification and or auto maintenance experience who can let me know if there are any problems that might arise from running your 350Z with this modification to the exhaust? :confused: I obviously don't want to damage my car just to make it sound louder, but I'm not overly concerned with losing a few hp. If you have some valid problems with this setup, please let me know! Thanks!

-Chrismcagle

[jtree007]

I did that on my car for a month or so and no damage the exause must be opend enough to make it sound better but not to wide open as it will get annoying.

it might mess up and strech the rubber exaust hangers but thoes are replaceable....

[westpak]

Other than fumes I wouldn't think it would be a problem, and since that flange is by the muffler the fumes will close to where they come out the tips anyway.

[ZPRESENCE]

Do we have westpak's approval?

[westpak]

I wouldn't do it myself, I let my Fujitsubo do the talking.

[ZPRESENCE]

Do you think this could do anything for dyno numbers?

[ChrismCagle]

Today was my first full day of driving and I have a love/hate attitude toward this mod. I love the sound, but hate the volume (if that makes sense). ;-) I think that I am going to remove 1 or maybe even 2 of the washers to close the gap to 1/8 or maybe even 1/16th and see if it keeps the low growl but decreases the volume a bit. It just drones VERY bad on the highway at about 75mph. I showed a buddy of mine at work today who "races" on the weekend (Acura NSX) and he mentioned that he could think of 3 bad things off the top of his head that might be caused by performing this mod:

1. Decrease in backpressure which would cause a loss of hp
2. Moisture might get sucked into the space between pipes and damage the valves (extreme scenario)
3. Exhaust might enter the vehicle from under the car

Does anyone agree/disagree with this info?

-Chrismcagle

[ZPRESENCE]

..might as well leave well enough alone,JMO

[dotCPP]

Nice NSX!!

[ChrismCagle]

Well, after a lot of debating with myself I decided to undo this mod and go back to "stock" and just save up for a Borla. The sound was great, but the volume was a bit too loud and really irritating on the highway at speed. First I removed 2 washers on each side which closed the gap to 1/16th of an inch and then took it for a spin around the block to see how it sounded. I think that if I were to keep this mod, I would run it with a 1/16th in gap because it still had that low growl, but cut the volume WAY down to a nice level. I undid the mod mainly for the following 2 reasons:

1. I don't want to damage anything and since I don't know much about how engines/exhausts work, I didn't feel comfortable running it and not knowing what might happen.

2. I have to leave for work early in the morning and don't want to piss off the neighbors.

Ok, now here is the strange part of the whole thing. I have not dyno'd my car either stock or with this mod so I have no solid evidence to back up this claim, I am only stating what I "felt". When I performed the mod, I noticed nothing different when I was driving. Seemed normal to me. BUT after connecting the exhaust back together like it was originally and driving it to work this morning it feels stronger. It's a bit hard to describe, but it feels like it has more "punch" when I get on the gas. After driving this morning I am REALLY interested to see some dyno data on this mod. I would be willing to bet that there is a pretty good loss of hp if you do it (maybe 5-10 hp??) It's still a cool mod to do since it only takes about 5 minutes and I might do it occasionally when I am going to a show or something until I get a real exhaust system, but for everyday driving I'm not running it that way.

-Chrismcagle