[gdgraph]

I recently installed the Borla S-Type axle-back w/NPP (11924) and the car sounds great. I wanted to get some better flow through the x-pipe and get rid of that hideous "crushed" section of the stock exhaust so I got the Borla x-pipe w/ mid-pipe set up (60610).

This system goes from a few inches behind the secondary cats and matches up with the Borla Axle-back systems while also maintaining the AFM valves. I'll post some videos if anyone is curious how this set-up will sound!

Sound Clips:

Start up, Revs, Drivebys, Inside, Outside

Outside by exhaust tips

[mosaic16]

Do they have a system that bolts up to the primaries and deletes the secondaries?

[gdgraph]

Yeah they do.

60609 deletes the secondary cats and maintains the AFM valves, and 60606 is the same thing as 60609 but doesn't have the AFM valves for those who have the manual. Both will match up to their axle-back systems (S-Type or Attack).

You can go to Borla.com and search those part numbers and the you can see pics and check out the install guides to make sure it's exactly what you are looking for. Here's the install manual that came with mine for the 60610 but it also includes the install guides for 60606 & 60609.

Originally Posted by mosaic16

Do they have a system that bolts up to the primaries and deletes the secondaries?

[mosaic16]

Great thank you for the help. Beautiful color you chose by the way.

[oldman]

I like the consistent 2 and 3/4 size.

[gdgraph]

No Problem!

Thanks! I always stuck with black for most of my cars but after seeing this car in person at the dealership it really grew on me and so far I've been loving it!

Originally Posted by mosaic16

Great thank you for the help. Beautiful color you chose by the way.

[Doyal_Mcneff]

Originally Posted by gdgraph

I recently installed the Borla S-Type axle-back w/NPP (11924) and the car sounds great. I wanted to get some better flow through the x-pipe and get rid of that hideous "crushed" section of the stock exhaust so I got the Borla x-pipe w/ mid-pipe set up (60610).

This system goes from a few inches behind the secondary cats and matches up with the Borla Axle-back systems while also maintaining the AFM valves. I'll post some videos if anyone is curious how this set-up will sound!

Better flow? These are 2.75 right? If so you've effectively purchased stock mid pipes with a Borla logo.

[oldman]

the stock system not only has the crush at the axle, it had two flex joints and rather abrupt transitions. So this is better than stock, but stock was actually pretty good at this point.

[Doyal_Mcneff]

Originally Posted by oldman

the stock system not only has the crush at the axle, it had two flex joints and rather abrupt transitions. So this is better than stock, but stock was actually pretty good at this point.

The flow is the same. Sorry. When you crush a 2.75 pipe it still has the same flow. You're just making one side wider and one side shorter. It equals out to be the exact same. The only thing prohibiting flow are both sets of cats.

[gdgraph]

Yes it's a 2.75" which is the same diameter as stock however the stock one is not truly 2.75" all the way through, it's very inconsistent in size and there are multiple crushed sections on the stock exhaust. Also the stock "x-pipe" is not a true high flow x-pipe design.

I did the mid-pipes more for the sound. When I installed the mid-pipes & x-pipe there was a considerable sound difference from when I just had the axle back (Borla S-Type), it's a much deeper and it's louder. Love the way it sounds now.

Originally Posted by Doyal_Mcneff

Better flow? These are 2.75 right? If so you've effectively purchased stock mid pipes with a Borla logo.

[gdgraph]

Here are some picks of the stock set up.

[gdgraph]

And some pics of the Borla 60610 (mid-pipes & x-pipe w/ AFM valves) hooked up to my Borla S-Type axle back 11924 (w/NPP)

[gdgraph]

And some sound clips so you can hear how it sounds:

[JaxChris]

Originally Posted by Doyal_Mcneff

The flow is the same. Sorry. When you crush a 2.75 pipe it still has the same flow. You're just making one side wider and one side shorter. It equals out to be the exact same. The only thing prohibiting flow are both sets of cats.

An oval and a circle with the same perimeter length do not have the same area. Therefore when a circular pipe is reshaped to an asymmetric form, it is no longer at its' optimum flow rate.

For visual reference, let's look at the perimeter of 12 feet using 1x1 blocks.



Notice that changing from 3x3 (pseudo circle) to 4x2 (pseudo oval) drops area from 9 sqft to 8 sqft. The area is the opening of the pipe. We haven't changed the outside circumference. In this example, you can imagine this was 3" diameter pipe. By flattening it you have dropped the flow rate by 11.2% (8/9 = 0.8888r).