There is a ton-o-threads on X pipes and H pipes so I am shy to bring it up again but I do have a question.

Is there valid reason to swap an H for and X on a 94 lt1. I read a post that I tend to agree with stating the H allows the straight flow where the X will bend. The H is sufficient to allow the pressure to release.

There are also convincing post that the X is better.
Has anyone had results that support the change.

I live in CA so LTs are out. Don't want to mess with the cat either. I ordered some dynamax super turbos. Hope to get a little better performance and wake the sound up a little.

Ideas?

 

FYI

Did some more homework on the web.

This article at http://www.magnaflow.com/05news/magazine/vette.asp

It shows that on a C5 the results between a H and X were about 2hp.
Results may be different for a C4 LT1. Either way it hardly seems worth the extra money for the 2hp gain for street use.


DYNO TEST RESULTS

(rear wheel horsepower, approximate 20 percent less than at flywheel with automatic transmission due to drivetrain frictional losses)
BASELINE W/MUFFLERS MUFFLERS & "X" PIPE
RPM HP TORQUE (lb-ft.) HP TORQUE HP TORQUE
3,900 206.5 278.1 220.8 297.4 222.1 299.1
4,000 219.9 288.8 226.2 298.1 227.7 299.7
4,100 225.1 288.3 233.2 298.7 234.6 300.6
4,200 231.7 289.8 239.8 299.8 241.2 301.6
4,300 235.8 288.0 244.3 298.4 246.1 301.1
4,400 242.3 289.2 249.5 298.1 250.9 300.7
4,500 246.5 287.7 255.6 297.8 257.6 300.6
4,600 246.9 286.4 260.5 297.4 263.0 300.3
4,700 248.3 282.1 265.6 296.9 267.6 299.9
4,800 249.9 279.2 270.9 296.4 274.1 299.0
4,900 251.6 266.6 276.0 295.8 278.2 298.2
5,000 258.4 274.5 278.4 292.5 283.6 298.0
5,100 264.2 272.1 277.7 290.9 285.7 294.2
5,200 269.3 272.0 288.0 287.1 290.6 293.6
5,300 271.4 268.9 289.7 286.0 290.7 288.1
5,400 273.5 266.0 290.1 281.2 291.6 283.6
5,500 274.9 262.6 291.6 278.5 293.9 280.7
5,600 275.6 258.4 292.6 274.4 294.0 275.7
5,700 277.8 256.0 293.4 270.3 294.4 271.3
5,900 279.8 249.1 292.8 260.7 295.1 262.7
6,000 278.6 243.9 290.9 254.6 293.4 256.9
MAX HP
279.8@5,900 rpm

MAX TORQUE (lb-ft.)
289.8@4,200 rpm
293.7@5,800 rpm
(+13.9 over base)

299.8@4,200 rpm
(+10.0 over base)
295.6 @5,800 rpm
(+15.8 over base)

301.6@4,200 rpm
(+11.8 over base)
SOUND LEVEL STOCK MEASUREMENTS, IN DECIBELS(db) STOCK MAGNAFLOW WIDE OPEN W/X PIPE
IDLE, NEUTRAL, INSIDE 83 dB 76 dB
IDLE, NEUTRAL, 50 FEET BEHIND 70 dB 74 dB
3,500 RPM, NEUTRAL, 50 FEET BEHIND 75 dB 75 dB
30 MPH, SECOND GEAR, INSIDE CAR 101 dB 90 dB
30 MPH, SECOND GEAR, DRIVE BY 80 dB 78 dB


How And Why "X"-Pipes Work
By Br

 

I've heard that an X pipe to eliminate a single main cat will improve performance. I guess what some do is run high flow bullet cats and a X pipe instead of the main cat to pass a smog. That eliminates the bottleneck going into the main cat. You end up with true duals and less resistance. Also, an X pipe should increase the scavenging effect and let the engine breath better.

I have heard that a X pipe will flow better than a H pipe. If you simply replace a H with an X you might see an extra 2 HP. That's not much of an improvement.

I understand why you're concerned about the California smog *****.

 

Would love to put on the Long Tubes and do what they other guys on the site do!.

Richard Newton in "101 Projects for your corvette" states that shorts are less effective than the stock manifolds on the LT1. I haven't seen much to counter that point.

My LT1 has a 2 cat dual system on it. SO it looks like the muffler swap is all she needs. Wife said happy early Father's day gift, there in the mail!