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DIY: Fabspeed Bypass Pipes (56K get FIOS)

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Pull downward on each of the aluminum arms and they should slide off of the studs. The skidplate is now free to come off the studs as well. Set it (and all its hardware) aside.

You should remove the two sway bar brackets to ease removal of the cats. It requires a 15mm socket. Let it hang.



Now you can see the exhaust system clearly. Let's start at the back and move forward. Loosen the 13mm nuts on each cat's coupling and slide it toward the cat or U-pipe, either is fine. Do this for both sides. It's not necessary to fully remove each nut. You may need to jam a prybar into the coupling to unstick it.


Now fully remove the support piece connecting the muffler to the cats. Thirteen milimeters here.


Now remove the 2 nuts and 1 bolt connecting the cat pipe to each header. They're 13mm.

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Now that all of the hardware is removed, ease the cat rearward until the studs clear the edge of the header flange. On non-PSE cars this is easy. PSE-equipped cars with the external muffler valves may need to bend the cat support bars on either side upward. It was a real pain on my car.

Save this stuff for reuse on the bypass pipes.


Now that the cats are out, preassemble your LEFT bypass pipe. Temporarily install the old coupling on the muffler's U-pipe. Slide on the new single-bolt coupling all the way to the bypass pipe flange (otherwise it falls off during installation). Lift the main bypass pipe into position and temporarily install it with one new bolt, loosely (make sure your gasket is in there). Now slide on the sub-pipe and bring back the single-bolt clamp to meet it. Now slide the coupling from the U-pipe onto the other end of the sub-pipe. Don't tighten anything yet!

Now the whole assembly should be hanging from the car. Inspect it for clearance and proper fitment (this important -- you'll find out why in a bit). If all looks well, install the other two bolts and nuts. Remember, one nut is welded to the header flange. Once the header is bolted up and tight, adjust your clamps if needed and tighten the bolts. Get them tight so they don't leak. For clarity, in the below pic, the sub-pipe is shown with the coupling (left) and the single-bolt clamp (right).



I had a clearance issue with the left side pipe hitting the transmission support. Since the exhaust and transmission are both carried as a unit by the engine and transmission mounts, I left it. No vibrations noted.


Done on the left side!

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The installation of the right side bypass pipe is identical. I ran into a problem though: Mine didn't fit! it appears the right side cat pipe on my car is shorter than the left.


See the excess? I had to chop about 1" off of the end of the right side sub-pipe to make it fit properly. Pretty stupid thing to have to do, IMO.


No configuration i could come up with would make the pipes fit properly without cutting. I even tried adusting the U-pipe out as far as possible from the muffler, but it didn't help.

OK, cutting completed, finish the right side. I had to reuse the old top bolt from the factory cats at the flange because of very little clearance between the flange and the engine. No big deal.



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The next step is optional, but *highly* recommended if you want to keep your CV boots intact. The factory exhaust runs under the inner CV boots and includes a pathetic heat shield. The Fabspeed pipes have no heat shield and are actually much closer to the boots. I wrapped mine with header wrap and some fiberglass tape I stole from work. It does a fantastic job keeping heat where it belongs.


Carefully inspect all clearances and all bolts for tightness.

Reinstall the sway bar supports to 17 lb.-ft.


Reinstall the skid plate and torque all nuts and bolts to 48 lb.-ft.


Test drive time! It's gonna stink, because your dirty hands put grime all over the nice clean pipes. Give it time, it will go away. It should be louder and you should have a little more power.

OK, my opinions:

Fabrication/materials: A. Nice welds, top-notch factory hardware with good locknuts.

Fitment: D The right side pipe was too long, the left side pipe touches the trans mount bracket, and neither pipe was bent exactly right to make the U-pipe couplings match perfectly. For my money, I expect better.

Sound: A++ Oh. My. God. It's fantastic!!!! It sounds exactly like I expected my PSE to sound right out of the box. I suspect a stock muffler would sound like mine does with the PSE turned off. With the PSE turned on, there's a definite bark to the exhaust note. With four cats and a PSE, there was almost no difference in the PSE on/off sound.

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I'll bet you thought I was done, didn't you? I've got video of the before and after.

Before: 2000 Boxster S, stock intake (desnorked), stock headers, stock cats (4), 2003+ PSE in Sport mode.


After: Same, except for Fabspeed Bypass Pipes. First in Stock mode (PSE off), then in Sport mode.


Also, the second I found out the right pipe was too long, I tried calling Fabspeed. Apparently they're not open at noon on a Saturday. You may want to replace your exhaust gaskets when doing this task, but mine were fine and no replacements existed in Anchorage, AK.

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  • 4 weeks later...
Very nice write-up. Sounds great!

Glad I saw this - I saw your other post about needing to 'mod your PSE' and was going to suggest that bypass pipes were needed.

I have a 99 and it comes standard with the equivalent of bypass pipes - only 1 cat per side hence, the original sports exhaust sounds good. I've just bought a 2003-5 PSE to replace my GHL (before my neighbors revolt).

The PSE sounded good - the GHL sounds awesome and would be fine for a track car but it's a little over-the-top for a daily driver. Check under my user name for links to the GHL on 2.5 video.

Thanks to you Rodger,A4EP and Loren, the installation should be a breeze - I'll post a video after I'm done.

Edited by LemmyCaution
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  • 4 months later...
  • 6 months later...

I cannot see the pictures or videos either....

Have they been reposted anywhere else?

I am very interessed in the bypass pipes....

The local tracks here have a 91 and 93 DB limit.... would these bypasses put me over the edge? (i have the stock exhaust)


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  • 1 year later...

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