Interesting solution to dB limits at race tracks

https://www.facebook.com/photo.php?fbid=10212200258269867&set=pcb.1316664195067054&type=3&theater

I think chknfarmer is on here.

Do you have a non-facebook version?

That's me.

I ordered some silicone plugs from McMaster-Carr to plug the valved tail pipes, thereby ensuring they're always closed. Basically, just shove it in there and pry it around the circumference to ensure they're good and tight. Test run on the road worked alright, one did pop out after about 60 miles, but the tether caught it just fine. The cool part is that they're easy to tether since each fascia tip has two holes to let condensation out. I need to come up with a better tethering string/wire material. Saftey wire is kinda overkill. I'll keep playing with it. I have some time until I can get back to AMP (which has a 96db limit) to actually test it on track.

$22 each
https://www.mcmaster.com/#5117T29

Thanks for the photo Matt. Looks great!

nice work, Matt. I'm very curious to see how these hold up...'cause if the do, I'm in. Being effectively locked out of driving at LS is killing me.

My nephew is a patent attorney (who is also a mechanical engineer), you might want to look into protecting your idea if it works. I realize its a small market, but the intellectual property could carry over to other applications if its not already protected.

Nicely done.

BTW, the real reason the holes in the tail pipe are is there to let out small rocks that were accumulating there during prototype testing. Saw an interview with the Ford engineer responsible for the project and he mentioned this.

mattlqx said:

That's me.

I ordered some silicone plugs from McMaster-Carr to plug the valved tail pipes, thereby ensuring they're always closed. Basically, just shove it in there and pry it around the circumference to ensure they're good and tight. Test run on the road worked alright, one did pop out after about 60 miles, but the tether caught it just fine. The cool part is that they're easy to tether since each fascia tip has two holes to let condensation out. I need to come up with a better tethering string/wire material. Saftey wire is kinda overkill. I'll keep playing with it. I have some time until I can get back to AMP (which has a 96db limit) to actually test it on track.

$22 each
https://www.mcmaster.com/#5117T29

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Great idea!

looks like a winter plug for a pool line.

mattlqx said:

That's me.

I ordered some silicone plugs from McMaster-Carr to plug the valved tail pipes, thereby ensuring they're always closed. Basically, just shove it in there and pry it around the circumference to ensure they're good and tight. Test run on the road worked alright, one did pop out after about 60 miles, but the tether caught it just fine. The cool part is that they're easy to tether since each fascia tip has two holes to let condensation out. I need to come up with a better tethering string/wire material. Saftey wire is kinda overkill. I'll keep playing with it. I have some time until I can get back to AMP (which has a 96db limit) to actually test it on track.

$22 each
https://www.mcmaster.com/#5117T29

Click to expand...

Nice let us know how it holds up on track with the 500 degree rating. I have yet to run AMP as I don't have a car that will pass sound.

Peter

Matt that is really cool! I always wondered what a workaround could be to run at Laguna Seca. I think Laguna tends to set the limit at 92db? I know I saw before at one point what the normal mode high db is, but I can't for the life of me remember. Does anybody recall? I can't wait to see how this works out for you on the track. Nice work.

CSL said:

Matt that is really cool! I always wondered what a workaround could be to run at Laguna Seca. I think Laguna tends to set the limit at 92db? I know I saw before at one point what the normal mode high db is, but I can't for the life of me remember. Does anybody recall? I can't wait to see how this works out for you on the track. Nice work.

Click to expand...

Thanks. Laguna was usually 92db while I was living there a few years ago. I know there have been 90, 89 and 88 days also.

Do you think having the valve open but the pipe closed will effect power?

Wait, hold on... the GT350 will exceed dB limits at tracks with the STOCK exhaust, even in the quiet mode (if so equipped with that adjustment)? I can do AMP (BARELY) with my Solo Mach XV and I never knew the stock GT350 would be louder than that.

Like... how do the Miatas that are always present sounding like a swarm of bees get on these tracks? Half of them are incredibly loud after they've been made a race car.

mattlqx said:

Thanks. Laguna was usually 92db while I was living there a few years ago. I know there have been 90, 89 and 88 days also.

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I raced there in November. On Thursday and Friday it was either 89 or 90. On Saturday and Sunday they raised it to 92. I didn't know if that was pretty much their limit.....guess so. I think I saw somewhere that with the valves closed the 350 was still about 96?