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YOUR RESEARCHAnyone used these bypass pipes?
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Check mechanism this weekend
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I can check the mechanism this weekend, but there is an inch or so of adjustment fore/aft.
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Now if you were to run open headers, then backpressure might be an issue for some exhaust valves.
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Suggestion
I'm going to be using fabspeed 100 cell cats that are 2.5" at the inlet and 3" at the outlet into 3" x-pipe with 3" vibrant race mufflers dumped out the back.
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I'm going to be using fabspeed 100 cell cats that are 2.5" at the inlet and 3" at the outlet into 3" x-pipe with 3" vibrant race mufflers dumped out the back.
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I'm sure Fister D are better, but if these will give some nice throaty sound, it seems like a good buy, seen a few vids on youtube for other makes, but none for similar porsche.
Has anyone tried them out or heard them?
http://www.ebay.com/itm/Porsche-911-...a41704&vxp=mtr
ive got the Fabspeed for my 99' cab, installing them soon. Most people here dont seem to like the sound they produce, i have seen youtube videos and heard them on another car, and i think they are heavenly! im just waiting for the warmer weather so i dont freeze my !@# off during the install.
The fabspeed ones cost me 500 shipped, the service there was great.
I've been running them ever since I bought my c2. Loss of tq and loss of 60-100lbs, hmmm, you decide. They do add a bit of drone so it will kill your musical ears a bit. It doesn't bother me bc I build cars to enjoy them and I like the top end and lighter curb weight. These cars don't even like to perform till the upper rpms anyways.....
I'm actually building my own exhaust now. I'm going to be using fabspeed 100 cell cats that are 2.5" at the inlet and 3" at the outlet into 3" x-pipe with 3" vibrant race mufflers dumped out the back. I hope to have them done by next weekend when I return from Miami, FL. I'll get a sound clip up once they are completed.
I had the Fabspeed ones on my car for a few weeks, but couldn't handle it anymore and swapped them out for Fabspeed mufflers. Too damn loud, I got headaches from the drone on the freeway.
They sounded awesome though!
Before i put my gemballa cans with gundo hack back on my car i drove it without mufflers for a day to get a feel of what it would be like with bypass pipes. It did sound awsome especially when you jump on the throttle. But like Capt. said it will get annoying on long trips and I did notice power loss without any backpressure. So i suggest before you pay almost $300 for two pieces of pipes take your mufflers off and drive it for a day and see if you like it.
Those sounds stupid, attentionwhore loud. I started the car last weekend with no mufflers; ridiculous.
Also
stop with this backpressure/torque bull****.
Taking muffers off will increase exhaust velocity and increase the output of the engine .
http://www.gomog.com/allmorgan/exhaustbackpressure.html
I bought the 996 & GT3 Maxflo Mufflers from Fabspeed for my 2004 996 C2 and can't tell any difference from factory mufflers. After spending $1800.00 with tips plus installation, I was very disappointed. Before I bought them, I checked out this video from Fabspeed:
Porsche 996 Carrera with Fabspeed Maxflo Muffler and Tips - YouTube
If anyone has installed these and it sounds like the video, please let me know.
I can check the mechanism this weekend, but there is an inch or so of adjustment fore/aft. Mine stick out about an inch past the bumper, and I've had no problem with drone.
Halik
Maybe you should read the link yourself before posting. From your link: Conclusion. Each engine will before function its best with a exhaust system balanced to its needs and characteristics with a goal of to producing the the highest exhaust gas speeds.
FROM MY PERSONAL EXPERIENCE i noticed loss of power without mufflers. If you have more air going in then yes you need to go bigger on the pipes to let it flow right but when you have the same amount of air going in and bigger pipe to come out its not gona perform right.
Removing mufflers, ie a device that is an obstruction to flow by design to decrease the pressure waves we perceive as sound = slow exhaust gas pulses down, will obviously not decrease exhaust velocity.
http://www.donspeedracing.com/Lightn.../technical.htm
What the author is trying to explain is that adding larger diameter pipes exhaust pipes can, because the same volume exiting from the head now expands to the larger diameter and slows down.
I made my own bypasses and they arent that bad. They are a fair bit louder, but with the exhaust exiting outside the body the resonating noise isn't terrible inside the vehicle and I do like the sound personally.
http://www.thumpertalk.com/topic/571...sure-the-myth/
http://www.dieselnet.com/tech/diesel_exh_pres.php
I can do this all day. Literally as soon as you say that not having backpressure robbed you of torque, you're advertising to the world you have no idea what you're talking about.
Even without cats, the muffler deletes will not reduce backpressure to harm the car or lose power. Now the car might lose some torque at a very low rpm, but unless you're towing at low speeds, it's not a useable part of the powerband. The tradeoff is more power in the useable range of the powerband. With proper tuning there will be even greater gains across the board and a more linear powerband.
Now if you were to run open headers, then backpressure might be an issue for some exhaust valves.
I've had the Fabspeed Maxflo mufflers on my '99 C2 for about a year now. And I noticed significant difference in the noise after installing them. Its exactly as in the video they posted.
The fact is, removing the mufflers will cause a decrease in torque and performance at the low-end, which you will notice. You will gain some power at the high-end though (meaning high RPM--WOT). If you are doing this for sound-because that is what you like to hear, go for it, or if you are building a race car with modified engine (intake, etc.) go for it... Otherwise...
Lacking power? ummm, no i disagree, maybe if you drive it like a prius!
Its a high end sports car, old or new, it was meant to be driven hard.
Something breaks or fails, replace it.
I accelerate hard in first , all the way to (min) 4000rpm, then into second and so on.... no loss of power for me, quite the opposite is true.
I purposely cut off prius drivers on the road. I drive this car like i stole it and this is my DD. My RPM is never below 3K at crusing and sees redline at least a few times throughout the day. But when you compare it to lets say an M3 which is roughly in the same sports line the M96 engines lacks a little bit of power in the low end up to about 3k rmp. But at the end of the day i would not trade my porsche for anything else.
I have an '02 C4S and added the Fabspeed Valvetronic mufflers and the air intake. I put on the air intake a day before having a shop put the mufflers on, and I could not believe the extra sound (good) from the intake alone. Kind of wish I'd put the mufflers on first so I know how they sound without the intake, but I like them both
These mufflers are the ones with the built-in PSE-type bypass pipe (like the Gundo hack idea), only it is a large diameter pipe with a vacuum-operated butterfly valve in it so you can open and close it at will, via a remote control switch that activates an electric valve that bypasses the vacuum to the butterfly valve.
At low RPM, I don't notice any difference with the bypass valves open or closed. But under acceleration, there is a very nice difference. Engine sounds good when closed, but howls nicely when you get on it with the valves open.
They are a bit pricey, but I like them. Be careful how you route the vacuum lines, my original ones got too hot and cracked, causing a vacuum leak and a CEL. Easy fix tho.
I think it's important for people to specify hp/tq increases or decreases in relation to rpm's or this discussion can go around and around and be useless IMO.
Thanks for being such a constructive asset to this board... (some of us have other/better things to do than prove ourselves to internet jabbers)
Or maybe you're being serious and you know that I can't post an image on here for some reason...
I can't upload an image file for some reason, but my dyno graph was posted at one point in the Racing Forum and can be viewed here:
https://rennlist.com/forums/8289270-post103.html
The top line is the dyno pull performed with mufflers pulled off. Power increase appears across the entire RPM range. Now that you have the graph, how do you guys prove that muffler bypasses lose power? I can't see it, especially as objectively you all seem to make it.
58lbs removed from the rear of the car is a nice bonus, too.
Fabspeed dyno chart of muffler delete:
https://www.fabspeed.com/dyno53.html
Fabspeed dyno chart of cat delete:
https://www.fabspeed.com/dyno56.html
Again, with tuning, more power would be gained throughout the powerband.
There are other benefits, such as weight reduction and lower heat generated. So you can remove some of the factory heat shields (lose more weight) or leave the factory heat shields and not worry about heat soaking the engine bay.
