Mandrel bends.. How many?

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Old Oct 24, 2009 | 03:46 PM
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Mandrel bends.. How many?

Hey, just a short question

I know straight through pipping = bad... so you need mandrel bends... with the design i want.. i'll need 4 bends.. will this harm the cars performance? 2.25in piping all the way... with a dual outlet muffler (Im willing to sacrifice performance for the muffler, for the aesthetic value )
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Old Oct 24, 2009 | 07:09 PM
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Originally Posted by Shadoh
I know straight through pipping = bad... so you need mandrel bends...
What do you mean by that? Crush bent piping is bad. Mandrel bends are better since they create a lot less turbulence. You also want an exhaust with the least amount of bends as possible and then pair that to the appropriate diameter of piping.

Four bends sounds about right unless you're building an exhaust with a severe slant at the muffler, or routing the exhaust under the gas tank and LCA.
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Old Oct 24, 2009 | 09:51 PM
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I read somewhere that exhaust needed to pulse, and straight through pipping created issues with the pulsation of the exhaust. Im wanting to release underneath my License plate.
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Old Oct 24, 2009 | 11:07 PM
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The exhaust will naturally pulse since each cylinder is firing in sequence. One of the most important things to take into consideration is the diameter of piping that's used. There's an ideal diameter for low end performance and also one for high end performance.

Have you ever been to the drag strip and seen someone use an open exhaust? They just remove the catalytic converter and catback exhaust and run an open header, which gives you more top end performance. Also, the guys that are into circuit racing often have an exhaust that dumps right before the gas tank. Only reason they do this is because of noise regulations which require you to run some sort of resonator. Both of these exhaust are basically straight except for the bends in the header.

Smaller piping helps with exhaust scavenging in the low end of the power band. That's the ability of the exhaust to help suck the gases out of the cylinder that aren't pushed out by the piston on the exhaust stroke. Larger piping helps do this in the top end of the band because the gases are hotter and moving faster. Since we need to have a proper exhaust system on a street car, you want something that flows freely enough to make top end gains, but not too much that you lose a lot of low end torque. To do this, you would want something like an electronic exhaust cut-out so you have the best of both worlds.

Last edited by Blazin Si; Oct 24, 2009 at 11:10 PM.
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Old Oct 24, 2009 | 11:48 PM
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Enjoy your lack of torque and power.

btw what muffler are you putting on?

function>form.
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Old Oct 25, 2009 | 12:26 AM
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Originally Posted by Blazin Si
Have you ever been to the drag strip and seen someone use an open exhaust? They just remove the catalytic converter and catback exhaust and run an open header, which gives you more top end performance. Also, the guys that are into circuit racing often have an exhaust that dumps right before the gas tank. Only reason they do this is because of noise regulations which require you to run some sort of resonator. Both of these exhaust are basically straight except for the bends in the header.
.
So straight pipping doesn't actually harm the performance by any means? I was told go with 2.25in pipping throughout from this forum, so i won't argue that size


@gnate Will me going from 1 pipe into a dual outlet muffler cause that much decrease?

Haven't picked one but heres the type i saw.

2.25"single 2.25"dual 5x8 18" 24" 17lb 12251 $118.99
Magnaflow


----
My concern is low end power and torque, its a daily driver within city limit, i rarely see any top end usage.

I know function > form but this car is my daily driving car, and i dont mind losing a little bit of function for form when it isn't a car i plan to race, aside from friendly hey lets mess around after work.

Granted if doing this will kill my performance by tooo much do let me know
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Old Oct 25, 2009 | 12:46 AM
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Well I'm just saying from personal experience with 2.25" custom piping from my header back, there was nothing but power loss, especially low end. When I finally got around to putting my stock (ultra quiet and restrictive) muffler on, the power I gained back was noticeable. If anything, i'd only recommend you add the muffler and don't waste the money on piping unless it is essential.
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Old Oct 25, 2009 | 10:57 PM
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so new exhaust pipping is a total waste hmm? Damn But atleast this will be cheaper than whole new pipping. Thanks Gnate.
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