non-straight collector extensions?

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ChargerST
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non-straight collector extensions?

Post by ChargerST »

What would be the effect of having collector extensions that are not straight? Unfortunately I can't attach straight header extensions as I have to route the exhaust pipe around the torsion bar cross member. Plan is to aim for a 18" collector length and add large mufflers after that. I have 3.5" collectors (D452 headers) if it matters...

Not my car but for clarification (straight tube would run directly into the crossmember):

Image

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BradH
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Re: non-straight collector extensions?

Post by BradH »

Long story short: Don't worry about it.

I've run both Dr. Gas and tti x-pipes that require that sort of routing and they performed fine on my street/strip ride. The tti looks like this:
tti_E-body_X-pipe-AR_chamber_locations.png
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skinny z
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Re: non-straight collector extensions?

Post by skinny z »

Is this for an "open header" effect?
With the collectors provide the properly timed reverse pulse, and then mufflers there to both quiet it down and act as an open atmosphere?
Curved or otherwise shouldn't make any difference according to my inquiry about a similar thing and consulting with Larry Meaux and PipeMax.
Kevin
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Re: non-straight collector extensions?

Post by 1980RS »

A few weeks ago I ran an old 400 sbc I had sitting around for some heads testing again. Both times I ran with a 3" mandrel bent exhaust with two 3" electric cutouts and two not so good Flow master mufflers. Guess what? the car on both set of heads I tested went the same 12.26 ET with the cutouts open or closed, pretty efficient if you ask me. What I have found in the past that hurts performance is tiny pipes and crappy turbo mufflers. Had a 375hp 396 in my car in the late 80 with Hooker S/C headers, 2 1/4" pipes to the rear axle with cyclone turbo mufflers. Car ran 13.40 closed up and when I dropped the exhaust the next run was 12.09, now that's restrictive.
skinny z
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Re: non-straight collector extensions?

Post by skinny z »

Similar test but with a 400 HP SBC and a 2 x 2.5" into a single 3" full exhaust with the muffler behind the rear axle. That thing was fully choked as I figure that muffler might have flowed 300 CFM at best.
With a single 3" cutout at the bend after the axle and before the muffler the car picked up a tenth in the 1/8 and almost 2 MPH.

The plan here is to keep the crappy exhaust (at least for now) but do my racing with a PipeMax calculated open collector with the traditional cutouts.
Sort of like this.

4.jpg
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Kevin
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