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How much performance gain do you get with a x pipe compared to two straight pipes? I am asking because I am looking to install a drive shaft loop and I am not sure I will be able to fit the loop and the x. The loop has to be within a foot of the trans and If I slide the x back to fit the loop I feel I may hit the drive shaft with the x.
 

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How much performance gain do you get with a x pipe compared to two straight pipes? .
Per David Vizard in his book "Max Performance SBC" he writes: In about 60 percent of the cases I've tried, the engine responded by delivering up to about 12-HP more with 5 to 8 being about the norm. In the remaining 40 percent the power was virtually unchanged." He also states in 100% of the cars there is a noise reduction....Jack
 

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Can you fit an "H" pipe instead? It should retain much of the current gains of your X, but should take up less space.

IMO, straight or H sounds better anyway. X-pipe seems to really mellow out the tone (nice on a modern car, not my favorite for an old car).

I think that gains from crossover pipes in general are less or mostly negated when header collector design and length is optimized.
 

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IMO, straight or H sounds better anyway. X-pipe seems to really mellow out the tone (nice on a modern car, not my favorite for an old car)..
I agree, at least to my ear. The H sounds deeper and the X combo seems to move the sound level up a few octaves giving it a higher pitch especially noticeable as RPM climbs...Jack
 

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It does move the sound up a few oct as rpm climbs. Nascar has been using them for years.
I think it was sterling marlin who was the first one in the kodak car.
OK then, that confirms why I like the H pipe better. I sort of like the L-88 deep rumble sound that the Super 44's give but they are harder on the ears at higher RPM. Nothing I can't live with for the short duration. Jack
 

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I dont like to cross post but I will.. There was some talk about H and X cross pipes in the first gen section.

Here is what I posted...


I have heard some straight through pipes and some of them do have a raspy somewhat "cackling" sound on throttle lift and a more sharp sound ON the throttle VS some exhausts I have heard with a crossover. The crossover systems sounded more mellow (no rasp, almost like backfiring) and a deeper tone.

As far as performance goes Im not sure because I haven't dyno-ed my car. But I originally made my exhaust with an H crossover. It sounded great and the engine seemed to perform just fine.



Then I needed to raise the car off the floor for some floor pan mods and decided to make an X pipe crossover just to see. I love to weld when I can and need ALL the practice I can get, you saw my H pipe right LOL

I bought some 45 degree mandrel bends and hacked them up to make the X crossover. I didnt do it like some you see where the center of the X is not a true X. Those are narrowed X'es with the center of the X narrow. Mine is a true X where one side of the main exhaust pipe has a full diameter going through the X and into the opposite side pipe. I had to add some material to the 45s to get a "full flow through" type design.



The making of the exhaust thread.
http://www.stevesnovasite.com/forums/showthread.php?t=171104

So the exhaust gases have a full 3" path on its same side (through the 45 and around to continue on the same side) or through the center of the X to the opposite side.

I dont think it matters, any of the X centers will prolly be the same. I just wanted to splain what I did. Why did I do it like that? Im thinking a full flowing X center (3" all the way through the cross over) lends to the objective of having an X crossover. I looked through some other X centers and the path for the gases was necked down considerably (two 45s welded together). I dont think that is a bottle neck for exhaust gases, thats not the reason for having the crossover anyway IMO.

I think its a pulse deal with the way the gases travel. The sharp report or sound you get with systems without ANY crossover might have something to do with the way the exhaust pulses hit a pressure wave right in front of the mufflers. When you add a crossover it gives the pulses another path before the muffs and breaks up the pulses. I dont F-in know!! LOL

After I put the X crossover in I did notice an improvement. It might have been my imagination but it sure felt like the throttle response was faster. Its like if I blipped the pedal the engine liked to rise in RPMs faster.

The sound? Not much diff.

More confusion? Solly!!! But I would recommend a crossover. H or X? If space doesnt limit you then I would suggest the X. But sometimes we have to use what will fit. The H pipe was easier to fit. The X pipe did take some major checking so I could still remove my transmission pan without removing the exhaust. I wanted to make it user friendly and there really isn't much free space under my 62. JR
 
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