1st revision of 2015 rules released

[MCoach]

Woah, woah, woah, guys. Not trying to start a war here, just throwing out a number from when I went looking for information and thought, "huh, that was short and concise".
Calm down, Bemo. :P

As an update on the noise testing and protest on our end, it turns out that in the US, all cars are tested using a 20" distance from the tailpipe and must be quieter than 95dBA. However, they have much larger, lower revving engines and are able to sound loud while still passing because they push a lot of their frequency lower, well away from the dBA ideal test range...much like the single cylinders for FSAE...just a lot less blatant about it.

We have tested at least 5 road vehicles which fail either the FSAE idle or test speed at this point....one of them happens to be our tow vehicle. But, they would still pass road requirements due to the difference in weighting. At this time, if anyone else would like to test on their own STOCK vehicles and either submit video proof of the vehicle test procedure and results and collaborate to submit a more comprehensive document, or give suggestions for easily obtainable vehicles which may fail which we could find at a dealership or friends to test, PM me.

Again, we're looking for completely stock (no cat-back, no headers, STOCK) road cars which may fail the new sound test. Either link me the video, or if not hosted on the internet, I can redirect you to my email to send the file. Another alternative is to upload the video to some place like Youtube and then point to that. Introduce yourselves, Name your vehicle and test speed, run your test, show the meter and the test rpm. This is the start of the official "My Road Car is Louder Than My Racecar" program and we're reaching out to help everyone who disagrees with the new rule set.

For reference, Idle is usually loader at fast idle from a cold start and test speed can be derived using the same calculation from mean piston speed in the FSAE rule book.
The vehlcles we've failed so far:
2013 Fiat 500 Abarth
2003 Nissan Sentra SE-R Spec v
2013 Ford F-250 Diesel
2014 Mustang Boss 302
2015 Charger w/Hellcat

[mech5496]

[offtopic]I am pretty sure everyone expected that Hellcat to fail...at least I would be dissapointed if it wouldn't! [/offtopic]

[NickFavazzo]

Objections to including standard road bikes in this? since we do use similar engines?

[MCoach]

Nick,

If you have them on hand, bring them out!
I'd actually be interested in what the stock application of these engines put out with reference to noise emissions.

[NickFavazzo]

I work at a yamaha dealership so I'll get my hands on a meter an measure what all we have. Measuring as per FSAE rules correct?

[apalrd]

I work at a yamaha dealership so I'll get my hands on a meter an measure what all we have. Measuring as per FSAE rules correct?

Yes.

0.5m (19.5") from the tailpipe, 45deg angle to the stream, parallel to the ground

Measure all idles (including warmup/fast idle) and noise test speed (~915m/min mean piston speed).

[bob.paasch]

Yes.

0.5m (19.5") from the tailpipe, 45deg angle to the stream, parallel to the ground

Measure all idles (including warmup/fast idle) and noise test speed (~915m/min mean piston speed).

No video, I'll try to get that next time. But numbers for a stock Honda TRX450. Less than 50 hours, so the muffler should still be good.

Fast idle on start-up: 101.2 dbC (93 dbA)
Slow idle (warmed up): 98.0 dbC
FSAE test speed: 111 dbC

So no pass for a stock Honda 450 quad.

[Kevin Hayward]

Out of curiosity is anyone aware if any noise measurements were taken at comp (or elsewhere) in order to determine if the new sound limits were reasonable?

Is it likely that this has come from a standard somewhere?

Kev

[Mbirt]

No video, I'll try to get that next time. But numbers for a stock Honda TRX450. Less than 50 hours, so the muffler should still be good.

Fast idle on start-up: 101.2 dbC (93 dbA)
Slow idle (warmed up): 98.0 dbC
FSAE test speed: 111 dbC

So no pass for a stock Honda 450 quad.

Wow! There you have it people. This is something you should be more up in arms about. Thanks for performing the test, Bob.

For a measurement as quiet as idle, dBC is not the proper scale to use--dBA makes more sense at this SPL. I discussed the FSAE dBA-dBC switch with the representative from HEAD Acoustics at Clean Snowmobile 2014 and he gave excellent input. Kaley should get the rules committee in touch with the representative from HEAD because this is yet another area where the rules committee needs to increase its depth with some external advisement.

Kevin,

The noise test at FSAE Lincoln 2013 was recording dBC measurements, but it appears to me that the data was not effectively analyzed or even looked at in the creation of this rule change. Our car, one of the quieter singles on track, tested at 109 dBA because I didn't change the cal or play with tailpipe placement. The dBC measurement was 117. Louder singles were passing sound and pushing 120 dBC. This led me to believe that 115 dBC might be the reasonable round number they settle on to keep loud singles in check.

Concerning standards using dBC, even the hearing protection industry uses dBA because, while dBC might be how we perceive loud sounds, dBA more closely fits the hearing damage limit of the human ear. http://www.howardleight.com/images/p...tedMeasure.pdf

[Bemo]

Who said, the change from dBA to dBC is made due to the risk of hearing damage? Quieter cars make it easier to communicate at the track while cars are running. If you ever worked for a whole day in the Autocross queue and had to talk to team members all the time while engines are heated up everywhere you will know what I'm talking about. If you want to have an improvement according to this the singles are the ones you have to make more quite not the fours. To make it not this hard to meat the number it would have been propably reasonable to increase the number somewhere in the range of 115 dBC. But in general I think the switch to the dBC scale makes sense.

When I was an active team member the points for fuel were increased from 50 to 100 what basically meant, that we would immediately lose 50 points compared to a team like Delft who were our big opponents back then. We would have been happy to trade that for a lower sound level which only adresses our concept. But people love to complain...