Author Topic: Bigger exhaust size and addition of X pipe HP gain  (Read 744 times)

Offline 7Dcuda

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Bigger exhaust size and addition of X pipe HP gain
« on: January 21, 2018 - 04:42:59 pm »
I've got a 70 Cuda with a 440 4 speed which is a typical street build (headers, cam, intake, elec. ignition, dual exhaust).  Im guessing about 450 HP.  Right now the exhaust system is a dual exhaust with 40 Series Flowmaster Mufflers with no X pipe and is 2 1/4" diameter

I'm about to install the TTI Exhaust system that includes an X pipe and is 2 1/2" in diameter.  I'm staying with the Flowmaster Mufflers.

I assume I'll see a small HP gain with the addition of the X pipe and the bigger 2 1/2" tubing.  Anybody know about how much of a gain to expect?
« Last Edit: January 21, 2018 - 05:42:11 pm by 7Dcuda »




Online 1 Wild R/T

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Re: Bigger exhaust size and addition of X pipe HP gain
« Reply #1 on: January 21, 2018 - 04:47:57 pm »
Zilch..  You current biggest restriction is the flowmasters... They sound cool but they don't flow that well...
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Online 70chall440

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Re: Bigger exhaust size and addition of X pipe HP gain
« Reply #2 on: January 22, 2018 - 10:29:04 pm »
it depends on who does the marketing but many "experts" say that an appropriate X pipe will yield between 10 - 20 HP (some say even more); that said you most likely won't realize/feel it directly. You would see it on a dyno for sure but there are a lot of variables.
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Offline GoodysGotaCuda

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Re: Bigger exhaust size and addition of X pipe HP gain
« Reply #3 on: January 23, 2018 - 07:30:13 am »
May shift the power band a little, youll see some improvement.


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Offline 7Dcuda

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Re: Bigger exhaust size and addition of X pipe HP gain
« Reply #4 on: January 23, 2018 - 09:33:28 am »
Well I'm hoping that between the addition of the X pipe and going from a 2 1/4" to 2 1/2" ill pick up a few xtra HP.

I know it was mentioned that Flowmaster mufflers don't flow that well but I happen to be one of those that like the sound of them.

I've been considering the Pypes brand Street Pro mufflers.  Anybody have any info/experience on those.....as far as sound and flow?

Offline Aussie Challenger

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Re: Bigger exhaust size and addition of X pipe HP gain
« Reply #5 on: February 24, 2018 - 03:34:05 pm »
If your current system is 2 1/4" the flow masters are that size also so going to 2 1/2" will offer you very little as the mufflers are the restriction, remember it has to be a total package not just adding a larger size.   :2cents:
Dave

Offline Topcat

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Re: Bigger exhaust size and addition of X pipe HP gain
« Reply #6 on: February 25, 2018 - 05:19:26 pm »
Chuck the Flowmasters and take off the resonators if you still have those.

Get the Magnaflow straight thru flow mufflers.
Little or no restriction.

This is a 2.5" front to back exhaust system on my car.

Mellow rumble until you get it on it.
But load as hell once you stomp it.

Mike, Fremont, CA.


Offline todd383

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Re: Bigger exhaust size and addition of X pipe HP gain
« Reply #7 on: April 05, 2018 - 09:23:34 pm »
Well, according to my car, stroked 383/496, a little under 600 hp, I tried both x and h pipe, xpipe had 3 more hp over h, tq was the same! The flow Masters will kill your power, straight thru mufflers are your best choice for performance, like magnaflow or dynomax welded, we tested flowmaster 40 and hp dropped over 20 hp!