[billapex]

Hi, all. This is my first post, as I bought a new 2020 ZL1 1LE last weekend. After about 20 years off the track, I want to get back into it with the ZL1. Arizona Motorsport Park is about 45 minutes from me, but they have a 96dB limit at 50' (tested as a full-throttle drive-by before the track day starts), which I've been told a stock ZL1 won't pass. Have any of you driven at AMP? Their website shows all sorts of cars/motorcycles that I know would never pass the limit, so I'm a bit perplexed. Thanks for any insight!

[Vtor_ZL1]

Get some slip on clamp on turn downs made.. it will knock noise level down significantly. Been way of life at many tracks, not sexy, but very functional. Minimal impact on power level. Beats sitting out.


Example:

https://www.uspmotorsports.com/AWE-T...-Down-Kit.html

[billapex]

Does anyone know if putting the (stock) exhaust in Stealth mode will keep the valves closed, even under WOT? If it doesn't, then I could put it in Stealth and then pull the valve fuse, thus keeping the valves closed for the sound test. Then I'd just put the fuse back in before the track event started.

[Scargoes]

If you pull the fuse, you lose power to the valves, and the valves default to open from spring pressure. I don't know if the valves stay closed at WOT when in Stealth mode. Best to go out and try it to confirm. But don't do it a lot, someone blew up their muffler and melted their rear fascia trying to pass sound in Stealth at a track.

[Woody6244]

Originally Posted by billapex

Does anyone know if putting the (stock) exhaust in Stealth mode will keep the valves closed, even under WOT? If it doesn't, then I could put it in Stealth and then pull the valve fuse, thus keeping the valves closed for the sound test. Then I'd just put the fuse back in before the track event started.

I believe that they monitor sound level during track events not just in the test before I know that they actively monitor sound levels at AMP autocross events.

[Rodan]

Couple things...

First, they do check sound throughout the day... you can't just 'fake it' for the sound check.

Second, keeping the car in 'stealth' mode generates too much heat on track and will likely destroy your bumper. This is not my photo, but this is worst case...



I cut off the outer tips on our ZL1 and added V bands so I could make turnouts to direct the sound away from the sound check location. It passes at Arizona Motorsports Park with our otherwise stock exhaust. After the track day, just swap the stock tips back on.




The other option is just lift past the sound check locations, but where's the fun in that?

[SCCAForums]

Just get turndowns made, there is no way to pass sound in a ZL1 without turn downs.

If you have an SS, then you can pass sound with out any turndowns.

Here's a pic of mine with turn downs as well:

Best regards,
Dave

[m3bs]

I suppose those F16s taking off across the street meet 96 dB......... I ran there shortly after the track was built.

[Rodan]

I've seen them shut down sound checks while the planes are taking off if the AF is playing on a weekend morning...

[SCCAForums]

Originally Posted by Rodan

I've seen them shut down sound checks while the planes are taking off if the AF is playing on a weekend morning...

Yeah, much more lenient on Jet days, but those are typically during the week, not on the weekends.

Best Regards,
Dave

[billapex]

Thanks for all the suggestions, guys. I passed sound just fine with the Laguna pipes I had fabricated. I can swivel the pipes depending on the side of the track where the sound booth is located (or which direction we're running).