HD2pct

Since some of us were hijacking the thread about the V6, I thought I would start a new one. As well as this has been discussed, I'd like to throw out my $.02 since I just installed these. This is one of the easiest mods you can do to the vehicle and get something truly different out of it. As others have said, there is no difference in cabin noise, but the sound is great. Nothing objectionable at all.

Performance-wise, there is something a little more there besides the placebo effect. All you have to do is hold in your hands the two heavy cats that used to be on the car. And certainly it FEELS and sounds like it's breating better, IMO. I think they claim an extra 10 hp. I wouldn't argue with that.

pokerjarvis

Agreed. I've read the many posts and threads regarding the Cat Bypass mods. I went with the Fabspeed pipes; approx $600. Their info claims an increase of 17 hp, perhaps. Seeminglly some increased performance and definitely improved sound w/o resonance. IMHO all Cayenne owners should absolutely do 2 mods: 1) clear side markers, and 2) cat bypass. Both are affordable and both offer immediate improvement.

HD2pct

Yep - you said a mouthful. Those are the two mods to do. It is a crime to not do clear side markers. But of course it's a major felony for Porsche to not make those markers flashing for turn signals, so that is even worse and another story altogether.

The FabSpeed web site needs a little work in the area of claims about horsepower, but I am sure they will get there. In one area they seem to indicate that you get 17hp from the cat bypass pipes, AND the rest of the Fabspeed exhaust system, AND the ECU upgrade.

Then somewhere else they indicate that you get 10 hp from the bypass pipes alone. Interesting.

Whatever - the bypass pipes make sense, and it isn't that expensive, so it's sort of a no-brainer.

Stone43

I semi-agree.

I had the bypass pipes installed because I simply like good deep exhaust noise.

At idle, definitely a small improvement.
Slow acceleration, nice improvement.
Hard acceleration, that is where I don't like it as much as it can sound "tinny" when you are hitting it hard. According to Fabspeed, this would be eliminated if I were to add their muffler, of which I have been tempted.

JRCTT

I must add 3 the Sylvania clear bulbs for the front turn signals - got to lose the fried eggs...

http://www.sylvania.com/ConsumerProd...RG-Results.htm

DSPTurtle

I just did the Fabspeed bypass pipes this evening. Started at 8pm finished at 11pm. Except for those two darn nuts on the backside of the cats it was pretty simple. I took lots of pics in case anyone is interested. I too thought they were a little pricey, but they came with everything needed and bolted right up with no rigging required. Nice job Fabspeed!!!
I also did the sidemarkers the second day I had the car. The thrid mod I would recommend is desnorkling the stock system or going to a aftermarket cold air intake. Between the intake and exhaust mods, the truck now seems to inhale and exhale with much greater ease. Butt dyno says the pipes made a difference... but we all know that the butt dyno can be more sensitive after spending three hours cursing and burning your arms on a hot transmission
Here's a pic of my bypass pipe install just because I can
Oh yeah... some kind of muffler mod is next... need more noise to wake up the neighbors!!!

Haha... just kidding. Had to post a pic of the parts too. Here is the install.

DSPTurtle

Oh yeah... I weighed both sets on the bathroom scale:
32lbs for the cats (set)
11lbs for the bypass pipes (set)
Seems like I lost 21 pounds without doing any exercise!!!
Sweet...

cayenne-kimo

DSP,

I sent you a PM.

stealthn

I'd like to see more pictures. It looks like the factory pipes are bigger (excluding the cats), so other than the cats, isn't this a restriction?

Has anyone ever done a dyno on these alone?

Cheers

User 4221

Give it a few mins.... Joey will chime in about how the new sound makes your truck feel faster or some ****e like that.

egr58

Agreed. I've had the cat backs on 08 CS for 2000 miles. Overall pleased - car sounds like a 327 corvette - would prefer a little deeper but it's OK. If I were to do the install again, I'd do what I did when I removed the second OEM Cat. After spraying the forward flange [pressed in studs] with penetrating oil and letting them sit for 15 minutes, I used a breaker bar and a short 1/2 (Drive) 12mm impact socket. TIGHTEN the studs until they snap off. Saves you 15 to 30 minutes per side. Especially effective on the hard to reach top stud that is easiest removed with multiple (I used four (4) six inch) extensions from the engine compartment. Use a wobble extension at the socket end (bottom). That annoying top stud is 'removed' with a satisfying snap in less than one-half turn of the breaker bar - takes 10 seconds. The OEM flange end of the Cat drops right out too - no cursing and less talking to one self using this method too.

Slow Guy

IIRC they aren't 13mm, I expected them to be but the weren't. They're something odd like 12mm. Also IIRC, even though I tried to remove the nuts from the bolts (actually studs) I think 2 or 3 of the studs broke off anyway, if I ever want to reinstall the pre-mufflers I'll have to replace the studs. Yes, that top inner nut is a bitch to get to esp. on the passenger side.

stealthn

Do you need to remove the tranny mount?

Do the pipes come with nuts & bolts?

Thanks

k722070

if you remove the transmission mount, which only takes a few minutes, installing the bypass pipes will be very easy.
the mesh flexible joint will then bend down and the top bolt is easy to reach.

stealthn

Anyone know the torque on the cross member bolts?

Cheers