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Old 01-04-2010, 04:48 PM   #1
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Default Flex section in down pipe

Well I have been meaning to put new springs on my car to address the low ride height, to little to late! A speed bump pulverized the flex section on my down pipe.

Im about to send the car to the muffler shop to have the flex section removed for a solid pipe.


So the question is how important is this flex section? FM doesnt do it so I assume its not necessary..
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Old 01-04-2010, 04:51 PM   #2
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Old 01-04-2010, 05:05 PM   #3
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I think I'm doing the exact opposite of what that thread says to do... Hard mounted to the transmission and a flex pipe, oh well.

Last edited by JayL; 01-04-2010 at 06:11 PM.
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Old 01-04-2010, 05:12 PM   #4
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Why? Do you have a reason for adding this?
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Old 01-04-2010, 05:25 PM   #5
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Wouldn't you assume that the people that build these DP's would rather save the money and labor and just mount them solid if they could get away with it? They are there for a reason.
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Old 01-04-2010, 05:49 PM   #6
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I've never installed a downpipe minus the flex, but it sure does aid in ease of installation and also gives you a little more wiggle room making fabrication a little easier.
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Old 01-04-2010, 06:12 PM   #7
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Not saying anything against manufactures but they all have reason for all that they do.. from my observation BEGIs manufacturing Specs seem to be alot looser then FMs. I assumed that they used the Flex section for that reason.

But of course I have never read of a cracked BEGI manifold like I have of FMs and I read that not having one can put extra stress on the manifold so Hmmmmm????????

I really am just looking to hear from people that ran with and with out one to see what are the benefits.
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Old 01-04-2010, 06:13 PM   #8
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I see these running 30 to 60 dollars so I may just replace it as it seems cheaper than I expected.
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Old 01-04-2010, 06:13 PM   #9
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You might be able to get away with it if you either

A) Just dump the exhuast after the hard mount.

or

B) Leave the mounting pretty loose down stream so that the whole exhuast can move OK when the engine shifts around. Even then you are likely asking for trouble.
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Old 01-04-2010, 06:27 PM   #10
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The price seems OK to go ahead and replace it so thats what im going to do.

Thanks
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Old 01-06-2010, 07:05 PM   #11
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I've tried both ways... 1st the stock Greddy downpipe mated to stock Mazda downpipe, then an upgraded 2.5" replacement downpipe.

Neither of the above had flex sections and I ran the car that way for well over 2yrs with no problems.

Just got another downpipe recently and this one DOES have a flex section in it.
I don't know why but I feel better knowing the exhaust has the flex-pipe in it now.
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Old 01-07-2010, 06:09 AM   #12
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Flex sections are a very good idea.
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Old 03-23-2010, 08:37 PM   #13
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Quote:
Originally Posted by Savington View Post
Flex sections are a very good idea.
Agree. I had a flex section installed in my former FM2 system. You can visualize the flex when you rev the motor with car on jackstands.
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Old 03-23-2010, 08:52 PM   #14
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I am not quite sure how to phrase this w/o sounding like the ah that I tend to be.

Maybe this:
Is the system better with a flex joint?
Are vibrations likely to be less?
Is it easier to line up the fit?
If your intentions were to build the best parts, would you put a flex joint in the dnpipe?

Corky
Often accused of being "inflexible"
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Old 03-23-2010, 09:08 PM   #15
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Quote:
Originally Posted by Corky Bell View Post
I am not quite sure how to phrase this w/o sounding like the ah that I tend to be.

Maybe this:
Is the system better with a flex joint?
Are vibrations likely to be less?
Is it easier to line up the fit?
If your intentions were to build the best parts, would you put a flex joint in the dnpipe?

Corky
Often accused of being "inflexible"
Flex pipes take stress off the manifold. My latest exhaust all vbands no flex. My manifold is made out of sch40 stainless to boot.
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Old 03-24-2010, 02:54 AM   #16
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i bought a "turbo" flex pipe for my miata. previously i used normal flex pipes on my dsm's and turbo honda's. the turbo version has a flexible steel sleeve inside that's smooth when straight, but opens up when it flexes. think of your dad's or grandpa's watch band. the kind that would pinch your skin. yeah, like that. supposedly they are quieter and last longer than standard flex.
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Old 04-05-2010, 05:24 PM   #17
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you can buy this stuff all over eBay for cheap
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