nstymatt

I’m currrently running stock sides + GMG center bypass. Thinking of switching to some kind of side delete for weight loss and to change up the sound.

from what I understand about the stock center muffler, the top connection is baffled and the bottom connection is straight through. So when using a side delete that attaches to both inlets in the stock center, the top pipe is able to baffle some of the sound. But for a side delete that goes to only the bottom inlet, would this be equivalent to deleting both the sides and center mufflers? Since the baffled inlet of the center muffler is now not used. Unless the bottom piping of the center muffler is still muffled a little, perhaps by the housing of the muffler? Because if this is the same as side and center delete, then I might try to find a side bypass that will work with my GMG center for max weight savings.

misterwaterfall

Im running side deletes and a center delete, it's loud but not as bad as many make it out to be in my opinion. I get compliments every time I take it to the track or cars and coffee.
Some side deletes are single outlet, some I've seen are dual. If you want to run single outlet with a stock cenyer it will be roughly the same in noise level as your current bypass in my experience.

bweSteve

OP you've got a lot of questions crammed in there.

Maybe these pics will help you. I grabbed them from a RLer who posted them in another thread.

Oh, & unless you actually put an end cap on any of the inlet/outlets, you need to buy the bypass(s) that match up to your config.

Side Muffler Cutaway Path with valves closed:


Center Muffler Cutaway Path valves open:


Center Muffler Cutaway Path valves closed:


=Steve

SocalTouring

bweSteve

Hey SoCalTouring, can you help me understand this a little better? .. When you say "non-valves",... or "with valves" ,... is that to say that the valves are "on" or "off" in your examples?

... or are you stating that with certain "bypass" type pipes (RSS, SW, or other), you might get, or might not get drone?

... I guess I'm just used to folks stating whether they have side-deletes, or center-delete,... and whether or not they get drone might be dependent upon the type of bypass they bought.

so I'm just confused on the details of your matrix below (as it relates to the drone someone might get). Thanks.

As a point of reference,... Here are the three scenario's that I went through with my 997.2 3... (I did not like the 3k-4k opening/closing of the valves, and wanted a more consistent exhaust sound throughout the rev range)
1) Decided to unhook the vacuum solenoid & see how that sounded. Loved the consistent sound thru rev-range, but got a drone when just cruising around 60mph.
2) Decided to buy a center-delete (Sharkwerks) and LEAVE the vacuum solenoid unhooked. Love it. ZERO drone,... ever. Pretty much have it that way all the time (weekend twisty touring events)
3) On occasion (maybe twice a year) when my wife & I decide to take the car on a multi-day-weekend driving event (GT club & PCA), and we know we will have a long section of highway driving, I'll hook the vacuum solenoid back up, so we can talk or listen to music.

Side-deletes are a bit too aggressive for me. Do not need that much sound, and I had heard that leaving only the center muffler puts a lot of heat into it (although I've read from RLers, that really only the titanium centers crack in those circumstance).

SocalTouring

Sorry, Apple's auto correct got me and I overlooked it. Please see edit. Non-valved means there are no valves in the pipes. With valves means the pipes have valves that directs exhaust flow to the baffled chambers to deal with drone in the lower RPM range, particularly 2-3K RPM.

1) Single bypass: FVD or BBI
2) Dual pipe design: https://soulpp.com/product/porsche-9...-bypass-pipes/
3) Dual pipe with valves: https://soulpp.com/product/porsche-9...-bypass-pipes/
4) Bypass both / no muffler: Sharkwerks Race or JCR's Ti Race

JB911

There are a few valved side deletes in the market now-FVD, TPC, Fabspeed, AWE, Soul, Tubi and a few others. I've thought back and forth about getting them but for now will stick to my FVD center bypass with the excellent Carnwal remote, so I can control the valves:

http://www.carnewal.com/products/997...Manual-Control

I could use the oem center with valved sides, though there's quite a lot of talk about catastrophic cracking/exploding of the oem center with sides under extreme conditions.
I'd love to use valved sides with center bypass, but activating the valves with center bypass would probably do little difference, (but some) since then it's practically straight pipes. AWE's Switchpath is pretty much that, valved center deletes plus center delete.
In my case, straight exhaust with the valved sides is very tempting, but neighbors would go nuts at night. There are very loud Mustangs and Camaros with straight pies in the area though, I can hear them for miles. Very tempting to go that loud route

nstymatt

Thanks for the inputs everyone. I'm using GMG center bypass with side valves unplugged at the moment. There's a bit of drone at cruising speed, but the sound definitely makes up for it.

My main question was using single pipe side delete (FVD, BBI) + oem center. Since the bottom pipe of the OEM center is straight through, would this setup be the same as straight exhaust (ie. side bypass + center bypass)

matt33

Sound is of course subjective but here is my experience:

Stock sides + BBI center: absolutely incredible sound, but tips the scales at 105db
Stock sides + SW center: sounds very good, not BBI good, but a few db quieter which helps pass sound
TPC valved sides + stock center: removes all that dead weight but.. just didnt sound good enough for me

Matty

misterwaterfall

JB911

It does seem like the path would be straight pipe and it should sound pretty loud with that setup, so it is a good question

Modena 1

Question for the valve solenoid control guys.

Stock the car opens valves at 4K rpm
In non sport mode.

At ídle. Press sport. Valves open.

So what exactly are you controlling besides what the sport button doesn't already control? Additionally aren't you los ring power / back pressure at the expense of volume?

nstymatt

With sport mode on, the valves are open at idle but will close when the car starts moving. They then open again at around 3k rpm. By unplugging the connector, the valves are open always. No more annoying opening/closing around 3k rpm and sounds way better throughout the rev range. In regards to losing power with valves open all the time, I'm not sure. My butt dyno does feel like some power is lost but would like to see some dyno testing of valves open/closed to prove this. I think obsessed garage on the 991 gt3 forums did this and didn't see any power loss on the 991 platform.

nstymatt

Yeah it seems like everyone agrees that side and center delete is too much, but single pipe side delete and oem center is a pretty common setup. Wondering if there's really much difference between the two.

widers911

I've had the FVD single pipe delete with stock center before as well as straight pipes (SW track) from cat back. The single pipe side delete into a stock center is not nearly as loud as straight pipe. Not comparable at all in loudness.

my favorite setup was full cup car exhaust with cup headers, 100cell cats, side deletes (single pipe) into a stock center. It was louder than just the side delete, but quieter than straight pipe with minimal/no drone.