Flex coupler?

[FastWoman]

Hi all,

So I ordered and received the MSA premium exhaust, and I already know I need to put a resonator in the middle. I'll get a local welder to modify one of the pipes with the resonator, so that it will all still bolt up.

But since I'm doing the modifications, I'm wondering whether it's also a good idea to include a flex coupling to isolate the bulk of the exhaust system from engine movement and vibrations. I've seen these couplers on transverse-mounted systems, but don't know if they're also useful/helpful/beneficial for rear-wheel-drive cars. Any thoughts?

I'm looking at this coupler... or better, maybe this one in SS.

Also I'm looking at this muffler as a mid-pipe resonator. Any thoughts?

I'm guessing I would insert the flex coupler between the down pipe and the resonator, with the rest of the exhaust attached behind the resonator?

Edited August 19, 2010 by FastWoman

[Mikez73]

I don't think it's necessary but it isn't going to hurt.

http://cgi.ebay.com/ebaymotors/2-5-x-8-Exhaust-Flex-Pipe-Tube-Stainless-Steel-_W0QQcmdZViewItemQQitemZ200507908762QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

[FastWoman]

Thanks, Mike.

The flex coupler seems to be constructed of a metal bellows. Would that mean it would bend but not twist?

If it only bends, I suppose it would need to be inserted somewhere perpendicular to the axis of the drivetrain, so that it would bend when the engine rocks. There's no way to insert it that way on the MSA downpipe.

Or does it twist too?

[Mikez73]

Under enough force it would probably have some twist. I think that a flex coupler pretty much just dampens vibration. I had planned to use one when I was building the 3" exhaust on my 300zx. My intent was to eliminate stress cracking in the exhaust piping. My 300zx friends (that I trust) told me it was unnecessary. I believe they were correct.

[pbarcher]

I have the MSA system on my 73, and originally thought that it needed a resonator because of an annoying resonance at about 2,000 rpm in fourth gear. I may still do that, but with the windows down I now rarely notice it. The exhaust really isn't that loud but the resonance can be annoying. I spent about 100 hours over the winter installing Dynamat on every interior surface, and that has quieted the car substantially.

I'm not sure that the flex coupling is needed, but if you're going to have the resonator installed, the incremental cost is worth it.

[Z train]

Hi all,

So I ordered and received the MSA premium exhaust, and I already know I need to put a resonator in the middle. ?

Why do you NEED a resonator?

[Mikez73]

Maybe she doesn't want it to sound like my car

I don't think this site has youtube embed code capability

Edited August 19, 2010 by Mikez73

[Z train]

Linky no worky

[FastWoman]

Ztrain, I understand from multiple sources that the MSA exhaust has a rather annoying drone at cruising. I don't have much in the way of sound deadening materials in my car. And yes, I want to kill the raspier notes (e.g. as in Mike's exhaust). I'd never miss the small performance difference, and it's a great investment in happy neighbors. My Mustang had a very aggressive exhaust, and it wasn't really my cup of tea.

I apparently put up a link to the wrong page for the muffler (corrected now). Do you think this muffler (a Magnaflow 4" dia x 14" long glass-pack) would be well suited as the "resonator?" It's rather compact and shouldn't have a rust problem.

Edited August 19, 2010 by FastWoman

[Mikez73]

Sorry but no matter. I don't think this site has youtube embed code enabled or I'd just post the vid. I don't want to jack the OP's thread anyway.

My point was just that she may have a different idea of what constitutes an acceptable dB level than you or I have. My car isn't illegally or obnoxiously loud but it will get your attention .

BTW I don't have a resonator and there is no drone at any rpm.

[Mikez73]

I don't know how well that will diminish any drone or rasp problems but it will probably do as well as any other round muffler although 20" is not my idea of compact with an s30 exhaust. At any rate there's no point in spending more than you need to:

http://www.google.com/products?hl=en&q=MagnaFlow+10416&um=1&ie=UTF-8&ei=valsTKnfMIKB8gas4ZigCw&sa=X&oi=product_result_group&ct=title&resnum=1&ved=0CC4QrQQwAA

I'm not sure about having noise concerns in a performance exhaust though...maybe a 3 chamber muffler would be best

I just snapped that you said that you have a down pipe. Do you have an L28et in your 280?

[Z train]

Ztrain, I understand from multiple sources that the MSA exhaust has a rather annoying drone at cruising. I don't have much in the way of sound deadening materials in my car. And yes, I want to kill the raspier notes (e.g. as in Mike's exhaust). I'd never miss the small performance difference, and it's a great investment in happy neighbors. My Mustang had a very aggressive exhaust, and it wasn't really my cup of tea.

I apparently put up a link to the wrong page for the muffler (corrected now). Do you think this muffler (a Magnaflow 4" dia x 14" long glass-pack) would be well suited as the "resonator?" It's rather compact and shouldn't have a rust problem.

O.K.-what is the pipe diameter on the system you are getting?Plenty of "stand alone" mufflers that will keep things "neighbor friendly".I just finished a LZ-23 stroker for the wife and the Walker Super Turbo sounds good with a quiet idle and only gets a tad bit loud when you put your foot in it.