Laguna Seca - passing sound check

[financialguy]

Does anyone have a solution to pass sound at Laguna Seca with their 350 or 350R?

I am looking for a bolt on kit for the exhaust or any other creative solution.

Thanks...

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[Sammy]

Does anyone have a solution to pass sound at Laguna Seca with their 350 or 350R?

I am looking for a bolt on kit for the exhaust or any other creative solution.

Thanks...

I would imagine there is a way to keep the exhaust valves closed at full throttle. I remember a thread that kept them default open. Shouldn't be too hard to send 12v. to the flaps.

 

[xt6wagon]

grab 6th going by the sound check station, or set exhaust in normal mode and back off going by.

I don't know what it would do to the quality, but from my experience if you add a couple (one per pipe) drilled core glass packs (straight through mufflers) of a different length than the current resonators, it should cut the volume by a large margin. So each pipe from the header will have a Cat, into the X pipe, into a resonator, into the muffler. So add a new one in there behind each resonator.

 

[1mic]

Ive seen a turbo NSX and a s197 5.0 have custom exhaust piping that sticks out the back of the car and exits to the left. It looks stupid but it gets the job done. Although I think these cars are louder so Not sure if it will work.

Has someone tried running an H-pipe setup? The H-pipes have a classic muscle car rumble and not a higher pitched raspy sound that x-pipes have. Would be better for drone too.

 

[nastang87xx]

Has someone tried running an H-pipe setup? The H-pipes have a classic muscle car rumble and not a higher pitched raspy sound that x-pipes have. Would be better for drone too.

H pipes generally make things worse because they cause more turbulence, long story short, resulting in HIGHER sound pressure levels. Also, mid pipe designs don't kill drone. Like, at all. X or H. It's the muffler system's job to kill the 133hz frequency that causes drone in V8's.

 

[SchultzLT1]

GT350's don't drone.

 

[Trackaholic]

I measured 98 dB at Laguna in sport mode. I was told that simply angling the exhaust and minimizing track-out was good for about 4 dB. So that still leaves a couple to go.

I ended up just putting the exhaust in quiet mode and staying off the throttle so the valves would not open.

The double exhaust pipe setup makes it tough to mount external pipes, so what I would prefer is a hack to keep the valves closed. Haven't looked into it much, so in the meantime I will be sticking with Sonoma and Thunderhill.

-T

 

[xt6wagon]

I measured 98 dB at Laguna in sport mode. I was told that simply angling the exhaust and minimizing track-out was good for about 4 dB. So that still leaves a couple to go.

I ended up just putting the exhaust in quiet mode and staying off the throttle so the valves would not open.

The double exhaust pipe setup makes it tough to mount external pipes, so what I would prefer is a hack to keep the valves closed. Haven't looked into it much, so in the meantime I will be sticking with Sonoma and Thunderhill.

-T

If you do the angled pipe, you only need to do it on the valved outlet side. The other side is the quiet side already.

edit: you mean the cosmetic tips not being part of the exhaust.

Also need the open exhaust at high rpm for thermal issues.

 

[financialguy]

If you do the angled pipe, you only need to do it on the valved outlet side. The other side is the quiet side already.

edit: you mean the cosmetic tips not being part of the exhaust.

Also need the open exhaust at high rpm for thermal issues.

Very helpful thanks!

 

[1mic]

H pipes generally make things worse because they cause more turbulence, long story short, resulting in HIGHER sound pressure levels. Also, mid pipe designs don't kill drone. Like, at all. X or H. It's the muffler system's job to kill the 133hz frequency that causes drone in V8's.

Good info, I always thought by sound alone that X pipes were louder and raspier, while H pipe had a deep rumble. I didnt say the mid pipe kills drone. :shrug:

 

[nastang87xx]

I didnt say the mid pipe kills drone. :shrug:

No but they won't help with drone either, regardless of the mid pipe. The mid pipe itself really isn't going to change the frequency pitches despite the idea that X pipes are "raspier" or "higher pitched" or whatever wive's tale is still believed nowadays. Drone is a function, or shall we say dysfunction, of frequencies which are derived from firing order, the number of cylinders, the total length of the primary exhaust system pipes, and the bank angles of the engine. Basically what that means that just because of the inherent length of modern exhaust systems, changing pipe length that tiny bit by going to an H or X pipe will just move the drone frequency up or down a hz or two. Gotta cancel it out or push the frequency straight out of the exhaust tips.

 

[nastang87xx]

I measured 98 dB at Laguna in sport mode. I was told that simply angling the exhaust and minimizing track-out was good for about 4 dB. So that still leaves a couple to go.

I ended up just putting the exhaust in quiet mode and staying off the throttle so the valves would not open.

The double exhaust pipe setup makes it tough to mount external pipes, so what I would prefer is a hack to keep the valves closed. Haven't looked into it much, so in the meantime I will be sticking with Sonoma and Thunderhill.

-T

I take it you got in trouble then, right?

 

[Trackaholic]

I take it you got in trouble then, right?

Not exactly. I asked for a sound check so they knew I wasn't sure what the volume would be, but when I failed I still was forced to sit out for the session. I didn't realize that was going to happen. I was talking to the track steward, saying that I could easily adjust the sound and could I try again in that same session, but he said I needed to wait until the second session before I could get another sound check.

So, I didn't cause any black marks for myself or the club, but they did force me to sit out for a session.

edit: you mean the cosmetic tips not being part of the exhaust.

Also need the open exhaust at high rpm for thermal issues.

yes, I had a tough time getting something to work around the cosmetic tips.

As far as thermals go, I'm not ready to agree that they would be a problem. I'd need to see some test data or get an explanation on what exactly is overheating. At some point I may try to figure out how to manually shut the valves, but I'm honestly a bit too lazy (I mean, busy) to make the effort. LOL.

-T

 

[xt6wagon]

yes, I had a tough time getting something to work around the cosmetic tips.

As far as thermals go, I'm not ready to agree that they would be a problem. I'd need to see some test data or get an explanation on what exactly is overheating. At some point I may try to figure out how to manually shut the valves, but I'm honestly a bit too lazy (I mean, busy) to make the effort. LOL.

-T

Can you pull the cosmetic tips?

Also the thermal issue is straight from Ford. That was the explanation as why normal mode opens up at 1/2 throttle or periods of longer low throttle acceleration.

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