On the recommendation of Messrs. Linser, Curtis and Sharpes, I am seriously considering the installation of the bypass pipe which replaces the primary muffler. Does anyone know if there is a difference between the various items available or are they all basically the same? It seems to be a straightforward piece of hardware, but does any fabricator produce better-fitting, higher-quality parts? Any sound differences (I heard there's some French version which is more subtle)? The item offered at Type 911 costs less than $200 USD vs. $350 for local suppliers. Any US resident have experience buying from Type 911 and care to comment?

Like Mr. Sharpes, I regard this modification as an "enthusiast" upgrade. The extra grunts would be nice, but I don't expect dramatic hp gains. Just a little more sound and perhaps slightly better pick up.

 

Joey-
I went with a Dansk last year. You save about 14-16lbs. I felt that the mid-range torque was improved (butt dyno) but when I actually performed a before and after dyno, there was about 3HP gain.

 

FVD, or Schatz Motorsport, sells them for $266, and when I bought mine I asked an east coast vendor and they beat that price. Between that and drilling the airbox, the additional sound under full tilt boogie conditions is very nice. Maybe a few hp, too.

 

Shop around. I bought mine for USD 180 (can't tell you the name though, promise) but I wouldn/t pay more than 200. You just have to take a phone session if you want a low price.

 

Bought my Dansk about a year ago...well made and a good fit. I think I paid about $300. I've switched back and forth between the muffler and the bypass pipe 2 or 3 times just for kicks. I honestly believe I feel a slightly stronger pull at high RPM's with no loss of low end torque. It's probably psychololgical though. I have an MAF and felt like the exhaust should be less restrictive to match the intake.

The sound is only slightly louder than with the muffler. Won't set off any car alarms.

It's a good and simple mod but don't expect huge performance gains.

 

Joey!

Just picked my Cargraphic catalogue and looked for the price of the so called "Racingrohrbogen" also known under the name bypasspipe: Cargraphic which is quite expensive is selling the pipe for 174.-Euros (part N°CARP64ETER), at FVD-Brombacher you can have it for 150.-Euros (part N°170 111 045) and it's exactly the same pipe. Just for your Info I held the piece in my hand and IMHO it's no even worth the price they all are asking for, the materials costs including the production costs of this piece must be between 5-7 Euros. Anyway since it's for a Porsche it's expensive. BTW the mod of the bypasspipe is the same for a 965, on the 3.3 litres you have back fire on the 3.6 litres there is no backfire since the fuel injection system is almost the same as the one of the 964. So if any turbo owner is interested in having great sound for not that much cash he can follow the same path!

Joey You won't be disapointed since the sound is great! Enjoy

Bets regards to all of you THOMAS

 

I remember reading a while back that the secondary muffler is about the same weight as the primary muffler. The secondary bypass pipes however, weight a lot less than the parimary. So wouldn't it be more advantages to replace the secondary muffler instead?
I too am thinking about replacing either the primary or secondary. Just can't decide.

Mike

 

The "Racingrohrbogen" is not the bypass for the primary muffler, the"Racingrohrbogen" bypasses the secondary muffler. It is a small round u-formed steal piece which sells for much less than the bypass for the first muffler. Don't get confused here. The bypass for the first muffler, often called cup bypass ("Cup Rohr") is a long piece, mostly made of stainless steal, often chrome.
Thomas, BTW, I am interested in a secondary bypass for 10 dollars, I would pay you 50 dollars without a blink, let me know how you intend to do the transaction

 

Thanks a bunch, guys! I heard from a fellow Rennlister who offered me a secondhand Ruf pipe at a very good price. We spoke this morning and I will hopefully have the part installed by week's end.

Can't wait!

 

[quote]Originally posted by christian:
Thomas, BTW, I am interested in a secondary bypass for 10 dollars, I would pay you 50 dollars without a blink, let me know how you intend to do the transaction [/QB]<hr></blockquote>


Christian I think You misunderstood me? Sadly for you and me and all other who wish to have a bypasspipe (not a cup-pipe) I cannot get this piece for 10 or even 50$ quid! All I was saying is that the price of this item is somewhat exagerate regarding the tremendous (ironic!) complexity of the thing .Speaking for the bypasspipe, the piece is not even a proper piece of tube but two pressed stainless steel shells which are welded together, at least the one I saw.

Hope everything is clear now, and again sorry that I can't get this stuff for less than the 150 Euros asking price!

All the best THOMAS

 

I received my pipe on Thursday (thanks David K) and had it installed Friday. Everything went smoothly and the car displayed a great new sound. When I fired it up, I noticed a deeper rumble (not louder) and as the revs climbed between 2000-4000 rpms, the new growl was a noteworthy addition to the already pleasant flat six symphony. Above 4000, it's hardly noticeable since I previously drilled the airbox which provides that purposeful roar at "full tilt boogie" which Bill G mentioned above.

With windows up, the mod is hardly noticeable except for a slightly firmer shove back into the seat when I bring down the hammer. Overall, a very nice straightforward upgrade. Thanks all for the advice!

 

Is it possible to put in a primary muffler bypass (cup) pipe and then the u pipe to bypass the second muffler? Would you want to do both or is some backpressure required?

Anyone every tried this out?

 

Word on the street is that results in lower performance. Haven't tried myself but that's what I've read.

 

Michael W:

Replacing the primary muffler provides a weight reduction that is laterally equal across the back of the car. Replacing the secondary muffler would reduce weight by about the same amount, but the weight reduction would be concentrated on the rear right corner of the car. This would throw off the corner balance of your suspension and may be noticeable in spririted driving. I vote for the "balanced" weight reduction.

Just my 2 cents...

 

I had previously done the Techart Cup primary muffler bypass pipe. I subsequently put the original primary muffler back in (sold the Techart cup pipe) and put a Gemballa secondary muffler bypass U tube.

Felt no overall seat of the pants improvement in either case- BUT the U tube combined with the original primary muffler has provided the most amazing sound, when compared with the Techart and secondary muffler (which was a somewhat subdued and restrained sound by comparison). There is no resonance at acceleration, but the car genuinely screams under load- fantastic!!!!! This is the only modification that has stayed on my car!!!

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