Modified OEM Muffler 996TT
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Did you have to drop the exhaust? Hopefully not!
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Joined: Aug 2009
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From: northbrook,il
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just have to get a new hole saw looks like the one i've been using was worn out. the drill bit that was lost inside luckily stick to the magnet. i never stopped trying to get it out whenever i get a chance but got lucky.
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Joined: Jul 2003
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From: Texas
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i'm really in the market for a new exhaust and i've modified a few car in the past and never had this kind of mod. i was following this thread and got curious especially with the back up research on hp gain and sound inmprovement plus the fact that a lot of 6speeders have done it and recommending it. so i took a chance and did it. my skill is about 4/10 when it comes to diy but just messed up with this one.
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Joined: Jun 2009
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From: Westlake Village CA
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I just had this done.
RevolutionExotics in Agoura Hills California just did this for me. They were a bit **** about the proceedure and recorded everything, with photos, etc.
Woosh, can he use your dyno screen shots on his website? He asked me to ask you. Please let me know.
I will let you all know how it sounds when I pick it up today.
Cheers,
Richard
Woosh, can he use your dyno screen shots on his website? He asked me to ask you. Please let me know.
I will let you all know how it sounds when I pick it up today.
Cheers,
Richard
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From: Westlake Village CA
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I like it!: QUestion to the thread..
Just had 1" holes drilled and I like the increased 'bass' in the exhaust note. I feel the tubo spool-up is quicker and that it has more power and torque.
This may be in my head but the car seems to put an even wider grin on my face, I also broke down and washed it, so that also makes it faster.
From reading this thread, I believe my HP and Torque gains should be around 10 hp and 20 torque? Does that sound right?
I had FVD flash the computer before this change and the numbers they gave me were 490 hp and 550 torque, so does 500hp/570 torque sound plausible now? No other engine mods.
My question: I will be adding a KN airfilter and possibly a new diverter valve. Is it worth reflashing my computer after these two and the exhaust holes? Would that gain me anything?
Thanks, great forum, I have enjoyed reading all you guys have to say.
Richard
This may be in my head but the car seems to put an even wider grin on my face, I also broke down and washed it, so that also makes it faster.
From reading this thread, I believe my HP and Torque gains should be around 10 hp and 20 torque? Does that sound right?
I had FVD flash the computer before this change and the numbers they gave me were 490 hp and 550 torque, so does 500hp/570 torque sound plausible now? No other engine mods.
My question: I will be adding a KN airfilter and possibly a new diverter valve. Is it worth reflashing my computer after these two and the exhaust holes? Would that gain me anything?
Thanks, great forum, I have enjoyed reading all you guys have to say.
Richard
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Joined: Oct 2007
Posts: 204
From: South Carolina
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I had the diverters done about a week after the Flash and an update was not required. The upgraded DVs were definately required though.
Question- does water back up into these exhaust holes ?
(from rain and/or car wash jets)
Question- does water back up into these exhaust holes ?
(from rain and/or car wash jets)
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Joined: Jun 2009
Posts: 51
From: Saratoga Springs, NY
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Stock muffler drawing clarification
I didn't read through all 23 pages, so this may have been mentioned. The muffler drawing was very helpful, but it might lead you to believe that the two sides of the muffler are not connected. You cannot cut through that metal bellows to make the muffler into mufflers that are easier to handle. The middle ends are open, I suppose as a back pressure equalizer. If you cut it you will either have to cap both sides or buy a replacement on eBay. I will report on how well it runs with the two separate mufflers. I've seen aftermarket mufflers that are two pieces. Does anyone know how that works?
In hindsight, I really did want to see how this works. But, the connection through the two sides may be one of the reasons the factory muffler muffles without drone.
Does anyone have a stock muffler for sale? Cheap.
In hindsight, I really did want to see how this works. But, the connection through the two sides may be one of the reasons the factory muffler muffles without drone.
Does anyone have a stock muffler for sale? Cheap.
I dug around and around.
Here is the data for all to see (colors in top picture get flipped in bottom picture...oops):
Another way to see it:
1. One can really do this and not violate my state's law if the outer shell of the muffler is not violated. The orange is the drilled hole. It is INSIDE the muffler. This is a tiny mod compared to the RUF muffler, etc. BMWdemon's muffler is way more hacked than this one, for example. It has not blown his car up.... This should be "do-able"
2. Tom's mechanic is part lucky dog and part genius. Tom is brave.
3. The stock muffler, as Tom feels, likely is converted into a cat with a muffler bypass. Why it avoids resonance is just plain dumb luck. I suspect the shape and size of the muffler by Porsche is about 1/4 wavelenght of something....to cancel out the drone, that may be the "physics" of why they (EP and PSI, a copy of EP per some posts here) keep the Porsche joiner.
4. I hypothesize that the hole size simply alters the ratio of air going "bypast" the muffler and to the muffler. In theory, one could optimize this via a dyno .....Woosh is in a position to do this.
5. Woosh, please try to video tape with each hole size. Then, perhaps, people can pick their noice level.....sounds silly, but imagine if you could do a 100 dollar or less mod and select your noise level....baseline noise on your video camera with stock exhaust will be key for people to judge.
6. This picture expains my hypothesis. In fact, this then drives the question of the cat....changing that would give, perhaps, maximal performance....200 cell cats may be the sweet spot in terms of cost....anyone know?...or just leaving stock alone. Stock is durable.
7. This answers the hot air and rust idea/issue....no holes outside happen, neither is an issue.
8. If this works, I promised Tom a beer. One for his mechanic too.
Woosh, I await your data. Will be offline for a bit, but will be back. I suspect the turbos spool faster, etc. Tom, I defer to you to post the video, but the cat is out of the bag.
Tom, I think you figured out something pretty big...
Sound
power
spool up faster
no drone
CHEAP
Makes sense to me pending the dyno data....
JCB
Here is the data for all to see (colors in top picture get flipped in bottom picture...oops):
Another way to see it:
1. One can really do this and not violate my state's law if the outer shell of the muffler is not violated. The orange is the drilled hole. It is INSIDE the muffler. This is a tiny mod compared to the RUF muffler, etc. BMWdemon's muffler is way more hacked than this one, for example. It has not blown his car up.... This should be "do-able"
2. Tom's mechanic is part lucky dog and part genius. Tom is brave.
3. The stock muffler, as Tom feels, likely is converted into a cat with a muffler bypass. Why it avoids resonance is just plain dumb luck. I suspect the shape and size of the muffler by Porsche is about 1/4 wavelenght of something....to cancel out the drone, that may be the "physics" of why they (EP and PSI, a copy of EP per some posts here) keep the Porsche joiner.
4. I hypothesize that the hole size simply alters the ratio of air going "bypast" the muffler and to the muffler. In theory, one could optimize this via a dyno .....Woosh is in a position to do this.
5. Woosh, please try to video tape with each hole size. Then, perhaps, people can pick their noice level.....sounds silly, but imagine if you could do a 100 dollar or less mod and select your noise level....baseline noise on your video camera with stock exhaust will be key for people to judge.
6. This picture expains my hypothesis. In fact, this then drives the question of the cat....changing that would give, perhaps, maximal performance....200 cell cats may be the sweet spot in terms of cost....anyone know?...or just leaving stock alone. Stock is durable.
7. This answers the hot air and rust idea/issue....no holes outside happen, neither is an issue.
8. If this works, I promised Tom a beer. One for his mechanic too.
Woosh, I await your data. Will be offline for a bit, but will be back. I suspect the turbos spool faster, etc. Tom, I defer to you to post the video, but the cat is out of the bag.
Tom, I think you figured out something pretty big...
Sound
power
spool up faster
no drone
CHEAP
Makes sense to me pending the dyno data....
JCB
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Joined: Jun 2009
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From: Saratoga Springs, NY
Rep Power: 20
New Muffler
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Joined: Jun 2009
Posts: 51
From: Saratoga Springs, NY
Rep Power: 20
Want to Buy
I would like to buy to replace my cut-in-half muffler. I will pay today.
Thanks,
Mike
Thanks,
Mike
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From: Saratoga Springs, NY
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Silvershark - I want to buy it
I can't PM until post count is 15 so I will keep posting this message until I get to 15 then will PM you.
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Joined: Mar 2010
Posts: 112
From: USA
Rep Power: 21
YES---it works!!!
I did this mod 2 weeks ago---what a huge difference!
I have an '01 tip and felt like it took way too many rpms for the turbos to kick in--- I changed plugs, coils (this helped) --new filters-- new maf etc. I was somewhat underwhelmed at performance, it did not match my expectations.
After this mod I can both see and feel the turbos spool much faster in the lower rpms and I am able to maintain more boost for longer. I never saw above 6,7 bar, now I consistently see 8 and 9 bar. I have boost leaving the neighborhood at 2.5k ...before I had to be at WOT above 4k rpms for any kind of rush. It feels almost like HP has been unleashed, like something was plugged up.
My wife does not like the sound--I did not at first either, but now that I know what is coming when I punch it--I love it! I have a GT3 in my neighborhood and it sounds similar--a lot of burble. The first week I dropped 2 tanks of gas just driving around feeling the turbo whoosh. I stare at the boost gauge in anticipation. Great mod! Took 30 mins and a $50 Irwin Unibit (1.25").
I have an '01 tip and felt like it took way too many rpms for the turbos to kick in--- I changed plugs, coils (this helped) --new filters-- new maf etc. I was somewhat underwhelmed at performance, it did not match my expectations.
After this mod I can both see and feel the turbos spool much faster in the lower rpms and I am able to maintain more boost for longer. I never saw above 6,7 bar, now I consistently see 8 and 9 bar. I have boost leaving the neighborhood at 2.5k ...before I had to be at WOT above 4k rpms for any kind of rush. It feels almost like HP has been unleashed, like something was plugged up.
My wife does not like the sound--I did not at first either, but now that I know what is coming when I punch it--I love it! I have a GT3 in my neighborhood and it sounds similar--a lot of burble. The first week I dropped 2 tanks of gas just driving around feeling the turbo whoosh. I stare at the boost gauge in anticipation. Great mod! Took 30 mins and a $50 Irwin Unibit (1.25").
Last edited by LO_996tt; Jun 6, 2010 at 08:47 AM.