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Discussion Starter #1
Recently installed the Courtesy Exhaust on my 98 Sentra SE. At one small point just above the rear axle, the b-pipe actually contacts the body. I wrapped it with several layers of header wrap, and the clanking stopped. However, the b-pipe is now in constant contact with the body.

I know there will be droning at some rpms due to resonant frequncy of the exhaust and car body. Will adding Dynamat, or a similar material to the trunk/under seat area make much difference? Has anyone tried this? Any input is greatly appreciated.
 

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pwnd
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Well I know Eric(NoVTECSER) put Dynamat over his Stillen muffler when he had it on. It was in the trunk right over the muffler but i think that would just cut down on the heat more than anything. It may make a difference you may have to put it from the back seat all the way to the trunk tho. I dont really know if it will make a huge difference maybe someone with it knows more.

Why does it come into contact with your body? Cant move it a little to fix this? I really shouldnt come into contact i would think.
 

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The Dynomat in my trunk helped a little, but not much. I put 2 boxes on the corner right above the muffler. I also have the Courtesy b-pipe, and for a while I have noticed a thumping sound from the right rear. I took the shock off and turned the spring a little thinking that was the noise. I had the car on a lift one day, and I noticed that the pipe was making all the noise. I thought about using zip ties to make the rear rubber hanger smaller so it would drop it enough to keep it from hitting over every small bump. I'll post the results of this as soon as I ahve time to try it
 

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Not only shoud you cover above the mufler its self but try to cover the inside of the spair tire well. Doing that made a huge diffrence to me.


Mike exhaust is alot quieter now with the turbo Gosselin ;)
 

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ya, just throw it right over where the muffler is, not a huge diffrence, but what can you do?
 

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Discussion Starter #6
I want to put it on a real lift - not the one we "made" at a friend's. It IS touching the chassis in one SMALL spot right over the axle. This is where I've added the header wrap. It now contacts 100% of the time. I've considered bending the hangers to slightly lower the entire exhaust, but it would still contact during abrupt RPM changes. When I get the car up on a real lift, I will see if the body panel can be deformed, or if some sort of hight temp, thick damping material can be inserted between pipe and chassis.

Still open for suggestions, and I'll post my results when I have some.

Thanks guys.
 

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Track Whore
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If you want a quiet aftermarket exhaust system, then you must custom make one. There is no other choice. You need a glass pack to quiet down the exhaust. I custom made mine and it sound very quiet. Really good. Take a look at it in my web site. Plus, my b-pipe does not touch anything. I am glad I did not keep that Courtesy exhaust system.
________________________________
98 SE-R, http://www.geocities.com/n_dahi PR CAI, HS G3 Header, JWT S3 Cams,
Custom Exhaust, Timing @ 18, PS Shifter, STBs, Pro-Kits/AGXs/ST Bars,
AD22VF/Axxis Pads/SS Lines, UR 4-Pulleys, Volk TE-37/RE-71 205/50ZR15.
 

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Discussion Starter #8
Well, I *think* my primary problem is the b-pipe touching the chassis, not the amount of of overall noise. I will dynamat some of the trunk, and all the suggestions are helpful.

If I could always putt around or wind it out, then I would avoid or quickly spin through the car and exhaust's resonant frequency. But this cannot be, so I need to somehow insulate the b-pipe from the chassis. The header wrap stopped the "clanking" that may be NOVETCSER's culprit, but allows the b-pipe to transmit it's accoustic energy right to the chassis via vibration. So some dynamat in the trunk/spair tire well/under rear seat areas will help. I just need to find the best solution for the touching parts - may take it to a local shop for suggestions/ideas. I'll let you know what I learn/try.
 

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Chris, did you get the Courtesy b-pipe shortened like you need to on the 98-99's? Read thru these posts and I didn't see that you did that. Maybe you need to? I know brian did this
 

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Discussion Starter #11
Jacen, I did take it to a quality shop here in town. AS we looked at the pipe together, different methods were discussed. While evaluating, one of the guys removed the rubber connector from the b-pipe hanger. The pipe dropped about an inch(with all three muffler rubbers still connected). This allowed for an inch of clearance at the rubbing point with the body(including the header wrap). Muffler man left and quickly returned with a longer rubber hanger, which had holes center-to-center equal to the dropped b-pipe hanger. This rubber hanger also has metal shims molded in for added strength. The b-pipe now hangs clear of the chassis, safely above the rear axle, and can not jump up to hit the body(metal shims).

Amazing difference! I can actually hear the exhaust now - before it was more of a head-numbing vibration. I will still dynamat parts of the trunk/spair tire well/etc, as there is still some drone on the interstate - though not nearly as tiring as before.

And yes, Ben, I did shorten the b-pipe in our model shop 1" before installing.(I may not have made it clear in the Sentra SE post). And as a side note, the muffler men were quite impressed with the Courtesy exhaust.

Thanks all for the suggestions, and hope this can help others when purchasing the Courtesy Exhaust.
 

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The shop I brought mine to mounted it and then shortened it while it was on the car. I think that's the best way to do it. I have had zero problems with mine. In fact it fits better than the *custom* exhaust the same place had made for me.

Mike G.
98 Sentra SE w/BBDET+FrontMount Intercooler 8), Courtesy B-pipe,UR pulies,GABS,Eiback springs,ST bars,*FRONT* hehe and REAR STB 8),Pacesetter SS and 96 trans w/VLSD

P.S.
Yo BEN! If you want that HS header I'll get you the $$ for shipping sorry it's been so long.....I've been busy!

Anyone else want a PR CAI? It dosen't have the MAF adaptor plate but it has all silicone hoses and the bottom pipe has a hole for the 98+ ambient temp sensor.

Also I have stock 98 header and flex pipe in prestien condition,stock struts F/R,stock 28mm front sway bar,stock 98 trans and axles,stock 98 long block with bad head and full intake manifold.
 

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Discussion Starter #13
Well, I tried Dynamat's aerosol application(2 cans) for the right side and tire well of the trunk. Have approx. 1/16 to 1/8 of an inch application per instructions. I don't notice any appreciable difference. May try one more can, or a heavy sealant to add more dampening mass to the sheetmetal. I also placed a heavy blanket between the thin fiberboard cover and the spare tire and sheetmetal to prevent it from rattling against both. Some improvement.....

Mainly I want to reduce the droning on the interstate when the engine is under load - running through the gears dosen't bother me.

The search for automotive serendipity continues.......

Your PR CAI is for the standard K&N isn't it, Mike?
 
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