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The system would be total ineffective if there was not an opening bewtween the two pipes. Just think of it as an extream "H" pipe without those nasty 90 degree turns for the exhaust pulse to fight with.
 

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Mike Goble said:
The ones you get from Dr. Gas have a brace welded between the halves.

So you're saying that I implied that you would think that because the Dr. Gas units units are braced that they don't have a fistula? How would they work? Osmosis? Tympanic coupling?
That's my point, a lot of X pipes look like they don't have a fistula, so I thouht a lot of them were just pipes bent and welded by noob exhaust people that thouht they could make X pipes. I didn't mean to offend or anythin, it's just you said there was a brace between the halves. So it sounded like even if there was a hole, they welded a piece of metal between and that filled it up. :eek:

Matt
 

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I've heard of people painting or writing on the pipes with a crayon and seeing where it burns off at. Personally I think that sounds like the stupidest thing that I've ever heard. Put it where it's easiest and worry about somthing more important like '' am I out of beer?'' Kidding... cause I dunno. I'm not sure if you will ever get a strait answer or if it even matters. Amber Bock me.
 

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It depends on the operating range of the motor. I have a program by Larry Meaux of Meaux Racing Heads that figures things like that out.
 

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I've heard in different places that they perform best directly after the headers, but I've also heard after the mufflers. I bought a universal x-pipe kit for my 76 from Summit. The kit came with the x-pipe and 4 short radius 45 degree elbows which are about 3-4 foot long. I had to cut about 4 inches off 2 elbows coming off the collector for proper alignment, connected the x-pipe and the other 2 extensions to the mufflers. I used Dual Flowmaster Delta 40 mufflers and tried my setup with the mufflers before the x-pipe and again with the x-pipe directly behind the headers and mufflers behind it. I personally had better results with the x-pipe directly after the headers.

As I've been told in plain terms, the principle is to evenly distribute your exhaust to the mufflers to prevent unequal exhaust pressure. My setup put the x-pipe approximately 2-1/2 ft. behind the collector. I can get an accurate measurement tomorrow if it'll help.
 

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Thanks for the reponses!!

I am going parts shopping tonight, (if the BOSS lets me, :D ) and see who has the better deal of the week, SUMMIT or JEGS. I guess from this post is that everyone is going with an "X" pipe vice the standard "H" pipe, correct?

MIKE, didn't you mention in another post about the differences between the H and X pipe?? For the price as it stands now, the H pipe is arround $30.00 and the X is $80.00. Is that $50.00 difference going to make that much of a deal on my exhaust??

Dan
 

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Just swaped from a 2-1/4" H-pipe to a 2-1/2" X-pipe.

The H-pipe design left the collectors with about 5" of 2" pipe on each side, transitioned to 2-1/4", and the pipes came to within 5" of each other about 9" behind the u-joint. The H joined and the pipes continued along each side of the tunnel to the mufflers and out the rear bumper.

The X-pipe is the universal Summit kit. New 3" x 2-1/2" collectors were installed. The X is positioned where the H was the the routing is very similar.

Sound at the tailpipes is identical. I notice slightly more resonance inside the car with the X design.

Most significant is about 1-1/2" Hg manifold vacuum loss at part throttle in-town cruising with the X-pipe. I'll attempt to get some of that back in the next week or so tuning the carb with my LM-1.
 

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From the H to the X, you will notice a significant drop in your exhaust tone. I do have a video clip of my 66 but I am not able to post it yet. But, in the beginning, it had a dual 2 1/2 set-up with no H and super turbo mufflers. The second run has the X installed and "Cherry bomb" mufflers and there is a much deeper sound. I would definitely say "do it!", if you have the room.

Dan
 

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As Paul said, there's a whole section on it in the archives. The X pipe generally makes the exhaust note noticeably higher especially at higher rpm ranges. Some people refer to it as "it makes it sound like an Indy car", not quite but if you hear one, you will understand their comment. There are also some performance gains with the X pipe. I didn't have sufficient room, so did the next best thing...an H pipe.
 

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Ok,
My turn... :)

I need to meet a db requirement at our local track (PIR) and which one will generally have lower db's at the top end?????
 

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Ok,
My turn... :)

I need to meet a db requirement at our local track (PIR) and which one will generally have lower db's at the top end?????
Speaking of PIR, I was surprised that my 2.5" x-pipe system just barely meets their post-10pm noise limits at WOT. I think this is more due to my muffler choice than the exhaust system though x/h pipe detail though.
 

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Will It Help

I was considering taking to 3 1/2 45 deg bends cutting them open and tiging them together as an X pipe ,but was wondering if i would see a benifit of running an X pipe as opposed to running without one ? It would be hard to tuck the tubing ub there and the more bends will make it harder. I will be turning the motor to aprx 8500, its a 412 sbc with a decent size tune up in the plate ,, with 2 in primary to 3.5 collectors, should hopefully run high 8's
 
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