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My stock 958 CTT is everything i hoped it would be, except for the sound/exhaust note.
The turbo really quiets down the exhaust which some may be satisfied with.
As for me, this calls for a mod.
Due to this, and reading so many positive reviews for CTT/CTTS with bypass pipes, i picked up a set.
I was determined to install myself since the directions appeared to be straightforward.
I also appreciate the satisfaction of doing my own work (e.g. detailing, oil changes, etc).
As i mentioned in another thread a week or two ago, i bought a near new set of bypass pipes but was unable to complete the install. Lesson learned: the 958 CTT pipes are larger than the GTS or S pipes.
The Fabspeed pipes are not cross compatible across the 958 models.
While that mess cost me quite a bit of time and frustration, the installation with the correct pipes took about 2.5 hours start to finish.
Overall, i love the bypass pipes.
They add just the right level of growl at startup and while accelerating, but not much louder while cruising or add any significant drone.
Below are a few pictures i took along the way.
I also took a few videos and i will eventually add as time allows.
If you have any questions along the way, feel free to post or message me.
New Fabspeed Cat Bypass pipes - high quality and craftsmanship
Tools necessary to install cat bypass pipes. Fwiw, the half moon ratchet does not aid in install or removal of cat pipes on 958s. In previous Cayennes the ratchet could fit on the flange nuts. Based on my experience, the half-moon ratchet would not actually fit on the flange nut. Only a socket would fit.
Additional tools needed for Cat Bypass installation. The long ratchet extension and two universal joint sockets helped to access the hard to reach flange nuts.
I drive up on blocks, set the air suspension to the highest level, then hold the air suspension button forward for 8-10 seconds to disable the air suspension. That will prevent the vehicle from attempting to compensate/self level due to jacking it up. Next, I add two 6 ton jack stands and place the jack for added margin.
Last edited by BlazinPond; Oct 8, 2014 at 07:40 PM.
left stock secondary cat pipe, need to unscrew 3 flange nuts which are pretty staightforward
A closer view of left stock cat and the back side of the flange screw/nut. The right stock secondary cat pipe is DIFFICULT! Two flange nuts are easy to access; however, the third (on top) is a pain due to limited room to access.
Add a bottle jack to support transfer case and remove the cross beam. This allows more room to remove the stock secondary cats and install new Bypass Pipes.
Needed to remove a nut and disconnect a wire plug to allow access to remove the cross beam.
Remove two bolts at the center and two at either end of the cross beam.
New left Bypass Pipe installed - pretty easy on this side! You can see the flange bolts but the flange nuts are on the back side from this view.
Right bypass pipe installed - difficult removing the old pipe and installing the new pipe due to the top flange nut
new bypass pipe installed and clamp tightened. Start the pic and check/feel for leaks at the joint. You may need to readjust at some point during the install to get a nice straight and flush fit at the clamp
Last edited by BlazinPond; Oct 8, 2014 at 07:48 PM.
Thanks Rak and Harlequin! Appreciate the nice comments.
I've seen a lot better "how to DIY" step by step instructions on the forum, but what can i say, i did what i could to take a few photos along the way.
Jim (Warehouser) your a saint!
I am indebted to you for your significant assistance in getting me CTT specific pipes from Fabspeed.
If there is anything i can do for you, i will. Coming to MN anytime soon?
The bypass pipes 'feel' like they increase the performance and make the CTT quicker/smoother.
I really want to believe its more than just in my head.
Secondly I can confirm just slightly MORE gas consumption with bypass pipes installed....
but that is very likely attributed to driving a touch harder since it feels more like a sports car and makes me want to hear the rumble now.
I'm working on two more videos.....less boring videos at that.
One from outside the vehicle stepping on the gas a few times, and the second video with a few drive-bys.
On a 1hr road trip into Minneapolis, my highest average has been 23 mpg.
Below, is a photo of my first road trip after Fabspeed pipe install.
To me, this is proof in my mind that MPG has improved post Fabspeed.
LOL!
While 2.5 hours was factual, i had experience the first time around with the incorrect pipes.
That install took around 10+ hours...only to find that it wasn't gonna seal at the clamp (GTS pipes)
I can laugh about it now....it wasn't so funny at the time
Yes on another thread my MPG increased very similar to yours,,,on the highway,,,,less in the city,,,,,,goosing it through all gears to listen to the new rumble
Yes on another thread my MPG increased very similar to yours,,,on the highway,,,,less in the city,,,,,,goosing it through all gears to listen to the new rumble
Indeed!
Improving 1mpg on the highway is certainly an added bonus, beyond the better sound and smoother performance.
Just installed the cat bypass and thanks to the tips here it went pretty smoothly.
Ran into an issue installing the mufflers since I was under the impression the fabspeed simply bolts on but looks like I need to cut the OEM piping which I'm not too comfortable doing... Anyone done a muffler swap? Any tips?
958 CTT Fabspeed Cat Bypass pipe install - success!
