Black flagged at brands for noise - duratec

[sjl1]

After doing a few track days at brands last year in 360r spec i upgraded car to 420r spec (210bhp) earlier this year. This week i did the brands gp track day which was great until i got black flagged for noise on last session, probably because i started using 2nd round druids. Perhaps i shouldn't be surprised since i have seen other standard 420r’s have the same problem at Brands

Would appreciate any advice on how to prevent this happening again since easing off isn't something i am keen on (static noise test was 96db)

 

many thanks

simon

 

 

[AdamQ]

This might or might not help:

https://www.lotus7.club/forum/techtalk/acoustafil-good-stuff

FWIW ...

Adam

[ScottR400D]

You could always fit the rear exit silencer, I’ve seen some 420s with that. 

What induction do you have, and I assume an S3?

The reason I ask is that I understand a 220 S3, with the bonnet cut out, is very noisy whereas I’ve never had a problem at Snetterton or Silverstone with SV with the air intake under the bonnet and a standard exhaust. 

[sjl1]

Scott

its just a plenum and standard side entry air filter so not much induction noise which is the crazy thing

i have seen a few 420’s with the rear race exhaust and may have to consider it

just realised i have a decat pipe fitted, wondering if i should revert to the cat as a noise reducing tactic, seems the obvious next step :-(

[marvingbiggsicloud.com]

Mmmmm thats really weird , i thought i was going to get pulled as they said my static noise was 99! so i was very close but i never did ( obviously not trying hard enough!!)

[Guy Lowe]

I got black flagged that day as well (200bhp Zetec). Never had a problem before (static 93db) but changed from twin K&N's to a Pipercross on my Jenvey's over the winter. According to the marshal who removed the noise test sticker there are 3 metering points, one on the R/H/S of the hill going up to Druids, one on the outside of the exit at Clearways and one "out the back somewhere".  I would suggest with a Duratec it was exhaust noise climbing up to Druids. 

[Rob D.]

Simon,

Also got black flagged in the  middle and penultimate session despite having had a 20 quid faux silencing device fitted to my pipe in the pits.  I think I was holding the gears a little to long and also believe that the packing was sub-standard in my well used Raceco exhuast. I'm repacking it this week and will then see how noisy it is. 

Also couple of other observations - Pre track day I tested my exhaust using a calibrated noise meter at 75% of throttle and at 500 mm distance form the exhaust (92dBA). At Brands - they seemed to place the probe in the exhaust - which is a massive difference.  

Still - a great day out before the noise issues and my dry sump cracking. 

Cheers 

Rob. 

[CycleSi]

Hi Rob,

I assume you got back ok? As you know, I also got black flagged for noise in the first session of the day so had to (annoyingly) short shift the rest of the day too. I have just received some new Acousta-Fil from Textile Technologies which I'll repack over the next week or so.

I enjoyed chatting over lunch - many thanks. See you on track again soon hopefully.

Simon

[sjl1]

Rob, Guy, Simon

sounds like we have all hd similar experiences, i also agree its likely using 2nd round Druids did the damage. Will try adding the cat pipe back in for next time.

 

[Mark w]

My car tested at 96 or 97 ( cannot remember ! )  in the test but i didnt have any issues all day .

Ive noticed at Brands before that people tend to get black flagged towards the end of the day , it happened last year on the club day .

Either people push harder then or theres a variable in the metering .

[ScottR400D]

Wonder if this has anything to do with it?

”Temperature gradients in the atmosphere also impact sound propagation over long distances (Figure 3). On a typical sunny afternoon, air is warmest near the ground with temperature decreasing with altitude. This causes sound waves to refract upward, away from the ground and results in lower noise levels at the listener’s position. In the evening, this temperature gradient will reverse, resulting in cooler temperatures near the ground. This condition, often referred to as a temperature inversion, will cause sound to bend downward toward the ground and results in louder noise levels at the listener position. Like wind gradients, temperature gradients can influence sound propagation over long distances.”

[r300chris]

Just seen this, I’ve had issues over previous brands trackdays, and was black flagged for noise, R500 Duratech, running race air box and fully repacked Raceco, with decat.

i ended up fitting McMillan extra exhaust to the Raceco, had to have it extended by about 50mm, and using internal track air box.  Went to brands and recently snetterton, no issues on track, although static still appears noisy I.e. 99 to 100db.

Exhaust cost £240 last year.

regards Chris