[oldman]

Originally Posted by Shaunsmb

Bottom line its my car. I didn't like the crushed pipe on there so I changed it. I never said it gained hp from doing this because I don't know. I do know It changed the sound of the car. It doesn't pop while driving or revving like it did. To me I can hear the xpipe better. If it cost me 1 or 10 hp changing the pipes so be it. I'm happy with it.

amen,

[586mx]

As long as cross sectional area isn't reduced at its minimum there shouldn't be a loss in flow, essentially. When the crushed area is compared to non-crushed area, i'd bet its the same amount of square inches. It could though, change the sound wave pattern enough to make a difference.

[oldman]

Originally Posted by 586mx

As long as cross sectional area isn't reduced at its minimum there shouldn't be a loss in flow, essentially. When the crushed area is compared to non-crushed area, i'd bet its the same amount of square inches. It could though, change the sound wave pattern enough to make a difference.

already did back of envelope calculation using gas law, the front cat is the smallest at 2.25 in relation to volume.

[BradfordCamaro]

Isn't anyone worried that removing this Exhaust Velocity Enhancing feature from their vehicle will void their warranty?

When the gas gets compressed into the smaller velocity chamber it increases in mass and density therefore and where-by the molecules of oxygen get more volatile and make a deeper rumbling sound when entering and exiting the power chambers in the muffler.

No seriously - When the gases leave what some of you call the "crush zone" - it picks up velocity creating a negative pressure field which helps draw out the exhaust gases behind it. This allows the pipe to act as a larger pipe. The figures I have calculated show that after the velocity zone - as we will call it now - The mass of air moved is equivalent to a 5.72" pipe and could possible create as much as 2.3 HP

[oldman]

complete nonsense that making something smaller creates anything but less flow.

[jimmypop13]

Originally Posted by BradfordCamaro

Isn't anyone worried that removing this Exhaust Velocity Enhancing feature from their vehicle will void their warranty?

When the gas gets compressed into the smaller velocity chamber it increases in mass and density therefore and where-by the molecules of oxygen get more volatile and make a deeper rumbling sound when entering and exiting the power chambers in the muffler.

No seriously - When the gases leave what some of you call the "crush zone" - it picks up velocity creating a negative pressure field which helps draw out the exhaust gases behind it. This allows the pipe to act as a larger pipe. The figures I have calculated show that after the velocity zone - as we will call it now - The mass of air moved is equivalent to a 5.72" pipe and could possible create as much as 2.3 HP

April Fools!!

I hope

I'm betting this was done solely to change the sound wave to keep it from getting that raspy, metallic sound x-pipes so often have. It's not for clearance as there's more than enough room

[oldman]

a little story and some history. The 4th gen's optional SLP or SS 3" had a similar crush going over the rear axle. It was ONE 3" pipe, it was done for clearance PERIOD.

I had the 2 and 3/4 stock exhaust which I cut up. The first restrictor cone in the single muffler before the baffle was 2.5" ID. All LS1 flow went through it. All 320 actual HP of flow. Since then I tried not to get all bent out of shape mentally about flow restrictions so far back in the exhaust stream.

[Hyper16]

This is interesting. I'm changing to the GM performance mufflers next week. Long story................

[camaro1&6]

Just not worth it

[BradfordCamaro]

Originally Posted by jimmypop13

April Fools!!

I hope

Yes, Just added a little humour to lighten up the mood in this thread

[L99]

Originally Posted by cellsafemode

The crushed pipes exist for one of three reasons (or all of them).

Clearance
Tuning the sound
Tuning the backpressure

Regardless of what the reasoning was, it's not going to improve performance by removing it. Even with serious "restrictions", exhaust is still hot and low density and it wont make any measurable effect on performance.
This has been posted before but still good to watch.

Wish I could find but saw a similar test on stock ZL1 vs headers. No significant difference.