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Old 12-14-2015, 12:28 PM
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CGT000
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Default 911 Turbo Exhaust

I just purchased a 1988 Turbo Slant Nose which comes with a fake dual tip exhaust (it has the factory exhaust system with a fake extra outlet) so I am planning to replace it with a after market exhaust that would hopefully do away with the cat. converter. I have seen B&B, Fabspeed (the most expensive), GHL and RarlyL8 all have exhausts for this model. Can anyone recommend one that adds to the performance and is pretty loud?
Old 12-14-2015, 12:29 PM
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I have a B&B and its just about perfect.....
Old 12-14-2015, 02:57 PM
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I'm confused. I have never heard of a fake exhaust outlet. Is it really a closed outlet? Is it just a extra side-by-side tip on the same muffler side that is not connected to the actual exhaust system?

Is it (remotely) possible that you are talking about the wastegate side of the exhaust system that only allows exhaust passage when we are WOT and the wastegate open? If so, that is certainly not a fake portion of the system.

Also, regarding the other portion of your goal (to eliminate your Cat),... Catalyst Converter -vs- Resonator:
First, I'll just assume you are taking advantage of the 25 yr or older State Emission Testing Waiver, thus you have no legal negative impact to removing the Cat. Mine has been gone for 15 yrs, and I use a full GHL Exhaust system. It has a catalyst shaped resonator on the wastegate side that has fooled MD State Emissions for over a decade (although now my '91 is exempt from testing).

I'd also acknowledge that your goal appears to be more sound. Probably much more sound. My GHL exhaust, on the muffler side (yes I have a GHL muffler too) is not as loud as I would like. But the rest of the GHL exhaust is excellent. I like the wastegate side of GHL which has a resonator (that looks like a Cat), and provides a very nice bump in sound when I go WOT and open the wastegate spring. My son used to LOVE that sound when we would travel underneath a highway overpass ("Dad! Turbo Tunnel!!!"). But of course you could put any loud muffler in conjunction with the full GHL system...

Sounds like you already know about the main choices out there. But for ease, here are a few that I had bookmarked... I didn't have FabSpeed & B&B, but both are also excellent in fit & finish!
I think Rennlist Supporter Pelican Parts has a partnership with GHL:
http://www.pelicanparts.com/techarti...m_upgrades.htm

Plus, this RL Thread where a lot of water pumper guys replied with their impressions of the GHL...
https://rennlist.com/forums/996-foru...parts-inc.html

Many guys do seem to love the Rarely8.
http://www.rarelyl8.com/930-headers.html

Here are a couple other links to RL discusions that may help you too.. (I did a wastegate side tip gut of the perforated tube within the exhaust tip, that you may want to read on...)

https://rennlist.com/forums/964-turb...affle-gut.html

https://rennlist.com/forums/911-turb...o-headers.html

Let us know what pros & cons you come up with during your research, and which system you go with.
Even better, Do a BEFORE-CHANGE audio recording (GoPro video even better), and then do a AFTER modification recording too, for comparison!!

=Steve

Last edited by bweSteve; 12-14-2015 at 06:13 PM.
Old 12-14-2015, 03:20 PM
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or you could just load this on your phone & play through your 911 stereo... (stole this from another thread)...

http://butifnot.tripod.com/racecar.html


Last edited by bweSteve; 12-14-2015 at 06:12 PM.
Old 12-14-2015, 04:32 PM
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Originally Posted by bweSteve
I'm confused. I have never heard of a fake exhaust outlet. Is it really a closed outlet? Is it just a extra side-by-side tip on the same (RH) muffler side of the car that is not connected to the actual exhaust system?

Is it (remotely) possible that you are talking about the wastegate (LH) side of the exhaust system that only allows exhaust passage when we are WOT and the wastegate open? If so, that is certainly not a fake portion of the system.

Also, regarding the other portion of your goal (to eliminate your Cat),... Catalyst Converter -vs- Resonator:
First, I'll just assume you are taking advantage of the 25 yr or older State Emission Testing Waiver, thus you have no legal negative impact to removing the Cat. Mine has been gone for 15 yrs, and I use a full GHL Exhaust system. It has a catalyst shaped resonator on the wastegate side that has fooled MD State Emissions for over a decade (although now my '91 is exempt from testing).

I'd also acknowledge that your goal appears to be more sound. Probably much more sound. My GHL exhaust, on the muffler side (yes I have a GHL muffler too) is not as loud as I would like. But the rest of the GHL exhaust is excellent. I like the wastegate side of GHL which has a resonator (that looks like a Cat), and provides a very nice bump in sound when I go WOT and open the wastegate spring. My son used to LOVE that sound when we would travel underneath a highway overpass ("Dad! Turbo Tunnel!!!"). But of course you could put any loud muffler in conjunction with the full GHL system...

Sounds like you already know about the main choices out there. But for ease, here are a few that I had bookmarked... I didn't have FabSpeed & B&B, but both are also excellent in fit & finish!
I think Rennlist Supporter Pelican Parts has a partnership with GHL:
http://www.pelicanparts.com/techarti...m_upgrades.htm

Plus, this RL Thread where a lot of water pumper guys replied with their impressions of the GHL...
https://rennlist.com/forums/996-foru...parts-inc.html

Many guys do seem to love the Rarely8.
http://www.rarelyl8.com/930-headers.html

Here are a couple other links to RL discusions that may help you too.. (I did a LH wastegate side tip gut of the perforated tube within the exhaust tip, that you may want to read on...)

https://rennlist.com/forums/964-turb...affle-gut.html

https://rennlist.com/forums/911-turb...o-headers.html

Let us know what pros & cons you come up with during your research, and which system you go with.
Even better, Do a BEFORE-CHANGE audio recording (GoPro video even better), and then do a AFTER modification recording too, for comparison!!

=Steve
Steve,

I have to tell you that this is one of the most informative responses I have ever received and I wanted to thank you for taking the time to write the post. The car is at the mechanic shop. I am supposed to inspect it Friday or Saturday. I will have a better idea if the 2nd outlet (right side) is fake or if it has a purpose. But one thing for sure, I would like to do away with the cat. converter. I will make a recording of the exhaust note as well.
Old 12-14-2015, 05:42 PM
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Ya know what CGT,... I forgot to take into account the differences between my 964T & an '88 930 too.

Don't those have only 2 tips on the LH Drivers side, but both are active muffler exhausts. And then the wastegate dump pipe is on the same side, but tucked under?

If so, you can disregard my left & right hand side comments. But still, I don't think there were ever any exhaust tips that did NOT have exhaust gases exiting (ie fake).

Maybe yours is a aftermarket system, and they added something to the RH side, which is a fake tailpipe tip. If so, yea I agree with you,... replace that with something functional.

Last edited by bweSteve; 12-14-2015 at 06:16 PM.
Old 12-15-2015, 08:10 AM
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Originally Posted by bweSteve
Ya know what CGT,... I forgot to take into account the differences between my 964T & an '88 930 too.

Don't those have only 2 tips on the LH Drivers side, but both are active muffler exhausts. And then the wastegate dump pipe is on the same side, but tucked under?

If so, you can disregard my left & right hand side comments. But still, I don't think there were ever any exhaust tips that did NOT have exhaust gases exiting (ie fake).

Maybe yours is a aftermarket system, and they added something to the RH side, which is a fake tailpipe tip. If so, yea I agree with you,... replace that with something functional.
I believe the wastegate dump pipe is also on the left hand side. I want to change the exhaust system mainly to do away with the car's cat converter, which I am being told is a 3.2L cat converter attached to the turbo! Sadly someone had just put whatever parts they had available on this car. My mechanic insisted on Fabspeed exhaust mainly because of better fitment so I called them and John B. spent a lot of time explaining all their exhaust systems to me and sold me a "Porsche 911 Turbo 930 Supercup Race Exhaust System with Dual Outlets". I will post a review on the new exhaust.
Old 12-15-2015, 02:37 PM
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Originally Posted by CGT000
I believe the wastegate dump pipe is also on the left hand side. I want to change the exhaust system mainly to do away with the car's cat converter, which I am being told is a 3.2L cat converter attached to the turbo! Sadly someone had just put whatever parts they had available on this car. My mechanic insisted on Fabspeed exhaust mainly because of better fitment so I called them and John B. spent a lot of time explaining all their exhaust systems to me and sold me a "Porsche 911 Turbo 930 Supercup Race Exhaust System with Dual Outlets". I will post a review on the new exhaust.
Great choice! When you get the exhaust installed be sure to get on the bypass and decelerate next to the divider
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Old 12-15-2015, 04:01 PM
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Depending on what you go with, just wanted to add a note that we will be having a 10% off Billy Boat Exhaust sale on the 17th. You can keep an eye out for it HERE. It's a one day sale only.
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Old 12-19-2015, 12:54 PM
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I don't have experience with with all the different brands mentioned above but I do have experience with dual outlet BB mufflers.

When I bought my car it had the original exhaust system on it but the seller had given me a BB dual outlet muffler with the larger tail pipes. I wasn't sure if I wanted to use it on my car, my mechanic/friend recommended that I go ahead and put it on and when I raised my concerns about noise he suggested that I drive his personal 930 which has the BB headers (with heat) along with BB dual outlet exhaust on it, however, what I didn't realize was that his tail pipes on his exhaust has the smaller diameter tail pipes that BB offers. I test drove his car and was satisfied that I could live with it and asked him to go ahead and install my BB muffler.

Well, if you want a loud system, the larger diameter tail pipes will definitely give you that! It is noticeably louder than the smaller outlet dual muffler system they offer, sounds bit like a muscle car. Accompanying the noise was the benefit of noticeable increase in performance, however, the noise level was beyond what I was willing to live with.

Last time I dropped off my car for a tuneup I told my mechanic about the conversation I had with an engineer at BB about my noise concerns. He had suggested that I could block off the right side outlet, so I experimented by stuffing a large towel in the right side tail pipe. Sure enough, the noise level dropped dramatically! My mechanic has connections at a HVAC contractor, he took the tail pipe off my car and took it to them and had a technician fabricate a spring loaded flap that could be opened and closed with a lever on the back side of the tail pipe. Wow! What a difference it made, now I have best of both worlds.

Last edited by Matsuzaka; 12-19-2015 at 01:22 PM.



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