IIs this a definitive statement? Assuming this is correct ... the following, taken from MINI2 exhaust shootout, 3K and 6K. I guess this means everyone with the following configs cant hear anymore if the have taken a 4 hour trip?

Milltek header/Milltek cat-back: 88/107
Magnaflow: 89/101
Milltek: 89/101
Milltek header/Borla Race: 88/105

If you got one of the above and cant hear no more ... shout out

 

It just means that permanent damage will occur, i.e. hearing loss. Of course this will occur to different degrees, but it doesn't mean that you will go deaf, just that you will lose some hearing.

 

OK, that sounds better (no pun intended) Kind of like working a jackhammer for a living.

 

Ya, essentially the same idea. hehe

 

I'm sorry I missed this post earlier but you are exactly right...........I had to look it up.... I had forgotten......it has been years.

Thanks

 

I finally saw the 2nd video. I love the exhaust system, it sounds so mean in the open position. Any idea when it will be out for sale and how much its gonna cost ??? (i´m expecting the $800 range and around christmas time) i´m trying to convince my dad that this would be a good christmas present lol... thanks spider for the great videos!

 

I actually just stopped by Webb's shop today for the first time, me being from UT. It was cool to see all the work that's going into this new exhaust. Wasn't able to talk to Randy directly, but to get to the point, I just was told today that Christmas would be best case scenario, but to count on mid to late January. Didn't ask about pricing, but I've heard on this thread that it would be high $800's. Can't wait!!

 

$799 and I order now . That's around $1000 Can. plus shipping and taxes.

 

Well, here's the thing about sound- intensity [volume] decreases at a rate approximating the square of the distance between you and the source. That sounds awkward, but basically the videos were taken with the camera behind the exhaust, a few feet away. This puts the camera in the line of the exhaust- where it's REALLY loud. But, sitting in your car, you're a) not directly in the line of the exhaust and b) a few feet away and separated from the tips by metal. The distance and the insulation make the once nearly 90 dB sound more accurately like mid-70s or so, as SpiderX is measuring. The volume at source is not equal to the volume in the driver's seat. This is why the volumes they recorded with the camera outside, behind the car were so loud. To answer your question, if the volumes were approaching 90 dB at the position of the driver, you would steadily lose your hearing- it would just be a question of time. This is why race car drivers wear ear plugs. Occupational hazards .

 

Just some info for you on this development. We are working many different aspects of the project, and it certainly isn't a simple matter.

As to the numbers, we have done testing in a controlled method here, same car, same day, same dyno, and the numbers are good. They also jive with the acceleration tests we've done and Bob has done.

Bob's power data:

WMS open v. closed: 10 hp delta
Milltek V. WMS system 10 lb/ft of torque

This data is inconclusive to say the least, as the method and testing facility set up are questionable.

What can't be fudged with is the acceleration data Bob has done - timed runs in the same gear. You can measure sped difference or RPM difference - it doesn't matter as long as you compare the same thing. The significant changes reflect the power changes we've seen - 2 seconds faster than the Milltek. Go out and time your car, that is huge.

Bob's sound measurement

Almost all of the big dB numbers are coming from low frequency - 32-500Hz. That was unweighted as well if I recall. Hearing damage is dependent not only on dB, but frequency as well, and the lower frequencies we are discussing are not nearly as damaging. I would say the system is in the high 70's on an A scale - I have an SPL, but I am waiting for the last prototype to get here to do some testing on the stock header car here.

Our continuing development

My goal is to make the system about the same as the Milltek with the valve closed. That may be unrealistic, as we are dealing with 3" instead of 2.5" diameter tubing. The larger the tubing, the more noise you need to deal with.

I am getting a system as tested by Bob here for eval on a car with a stock header and a Milltek header to determine whether the noise levels are loud or not. If they are, we go back to the drawing board and try for a release of mid-January. If they are good, we release by Christmas.

Cost is another stump right now. Do to the changes we've made, the cost has risen. We are trying now to keep the system with the valve in the $850-875 range. Remember that is using a rally quality cut-out, which is MY COST $212. I am trying to work out more pricing details, but I absolutely refuse to give on quality (we are using 1.5 mil wall instead of the cheaper 1.1 mil for the muffler and resonator, we are using a very high heat capable resonator, etc.). I will offer the system with and without the valve. If you order without a valve, you will get a block plate that can be removed for track days, or you can source your own valve.

I hope that ties up some of the loose ends. Everyone needs to take a step back and realize that hearing loss is determined by a number of factors, and if we applied a blanket statement without regard to distance, frequency, and ambient noise, we should all be deaf by now. There are several folks out there running numerous systems on numerous cars that are not in the "safe" range, yet they are still reporting no hearing losses.

I'll post our data with the stock header as soon as wqe receive the unit.

Hope that helps!

Randy

 

I was just trying to keep people safe, is all.

But it's really not smart to say that hearing loss isn't happening since people aren't reporting it. In fact, it's usually not so immediate that one would notice unless one is being tested on a regular basis. Gradual losses in hearing ability are normally not picked up on because people adapt to the abilities they have, so unless it's immediate and severe, it's likely not going to be reported. Tell these people to get tested, then I think you'd change your tune.

Have you measured the frequency data broadbanded? If so, I'm sure a number of people would like to see the graphs. Since a human ear has sensitivity down to 20 Hz, to say the frequency is between 32 and 500 Hz primarily does not place it outside of the realm of possibly damaging hearing. High frequencies are more damaging, but they are also much much more dependent on direction. Low frequencies have the advantage of reaching almost isotropic levels with respect to directivity, meaning they are homogeneous from all directions, meaning it's easier for low frequecies to reach your ear than high fequencies. So while they may be less damaging overall, they are more efficient in reaching your ear.

Primary speech frequencies are 500-4000 Hz, so that range is probably the one you should focus on, but hearing loss at lower frequencies, and continued exposure to the damaging source, will eventually impede hearing at higher frequencies as the biological components that allow you to hear break down over time.

As for taking a step back, I feel the onus is on you to prove that your system will not damage the consumers hearing, or at least provide adequate disclaimers to that effect. Since this subject has been wholey ignored, I felt that I needed to bring it to the attention of the people. What you do with it is your call, same with everyone who's read it.

 

I completely agree with Will that the manufacturer of a catback must meet certain criteria if it's being marketed to street use. In fact, it can be a serious liability not to. One of those concerns is that it meet reasonable/average maximum SPLs set all over the country for street exhausts [these are set outside the car, at a given distance]. It would suck to be pulled over unknowingly cause your exhaust is too loud .

It would also suck to lose your hearing- and this is potentially a liability issue, too. I think that a standard part of the exhaust design should be ensuring that the volume is not too high _in a stock MCS, at the driver's seat_. If this is only met with the valve closed, then it should be declared that the valve open should only be enjoyed with ear plugs [which are illegal on the street]. I highly recommend that you investigate the legal implications of these and other issues for your own protection, and for the benefit of the consumer.

Now's the time to get it right...

 

Well as long as it's quiet enough with the valve closed, it should be fine. Not many of us are going to be driving around every day with the valve open; plus it's probably not legal with the valve open. When at the track, you wear something to protect your ears. During those short spirited drives on the street with an open valve, a very loud exhaust shouldn't be too much of a problem.

 

But, there must absolutely be an "offroad only" descriptor included by the manufacturer. Does that sound familiar ? Look around at headers... The point is, it's a liability waiting to happen, and for unknowing people a sorta unwelcome fact, if in fact the tests show danger/the law is broken.

 

ive got the miltek catback and there is NO WAY possible i will get def from driviing for 4 hours+ in the car.. the exhaust is simply too quiet. The scream of the alta cai drowns it.

 

If we're going to break this thread down to a discussion of human hearing loss and exhaust noise...can we start a new thread? Unless someone is specifically discussing the WMS noise level on a production ready piece, it doesn't really apply to anyone but SpiderX, as he has the only unit like this at the moment. Obviously the valve open position is incredibly loud... use at your own risk.

"Let the buyer beware"... that's whose responsibility it is to decide if it's too loud. I don't see anyone campaining against APPLE for people suffering for hearing loss from listening to their IPOD at high levels. Mini didn't put a warning on my stereo to not turn it up too loud...

Thanks for the update Randy.

 

Yeah, you're going to have to be careful, because installing it, the old one may fall on your head...

I do have testing, and we are looking at all noise levels, not just exhaust - you are talking about ambient sounds as well as the note of the exhaust. I will get the range.

I was saying to take a step back based on blanket statements that are neither here or there. You can't base fact of hearing loss from simply taking an SPL reading and not applying appropriate filters. Hope that clears up my point.

I certainly wasn't saying we don't take our responsibility as a manufacturer seriously, in fact I'd say it is the opposite. I don't know any other aftermarket manufacturer doing the amount of testing we do - durability, performance, sound, beta, etc.

If you or anyone else has driven a car with the Milltek, you can certainly see my point. The Milltek is showing SPL readings of 88/100+, and the sound is just plain undamaging.

As far as having the hearing tested, I do - every six months. I have hearing loss in certain frequency ranges, no doubt due to racing, crewing, and flying airplanes (the 727 is one of the loudest around). It is a slow deterioration, and I understand your concern.

My point, again, was to say that you can't take one slice of the picture and make a blanket fear monger statement.

I will post all data once the production unit is ready to go. I don't see that as irresponsible in any way, shape or form. I definitely appreciate feedback though!

Stay tuned...

 

Will,

I also saw you are the one who has done some of your own exhausts, and they are VERY loud by your own admission.

Are you planning on selling those? Just curious as to the comments and their motivation.

If it seems to forward an assumption, I apologize in advance - I am just getting kinda tired of politics.

Thanks!
Randy

 

nuff said ,

worst comes to worst if it is too loud, buy something else

 

Let's get off this too loud thing...I think that Randy is aware and he is taking steps.......I have spoken to Randy more than anyone on this subject and from day one ...... outside of power .... SPL was his chief concern...... Having seen the exhaust on the car ,... there is plenty of room for alternatives that are being considered..... I have worked in the professional audio business at a very high level for over 25 years ..... I need my ears .... so I don't want to damage my hearing either......

Please understand, I am not saying it is not important but rest assured .... steps are being taken to deliver a safe, powerful exhaust system which has the potential to be the benchmark for a long time IMO.

I am going to do the comparative dynos this week

 

No, I was never planning on selling my exhausts. Just playing around because I can. I've made three so far, and the first two were very loud, about equivalent to what you have put together becuause they were essentially open pipes with some stuff in line to quiet it down some, but not that much. So I know how loud your exhaust is by experience. I also know that I left those on for a total of about 30 minutes each. I know the power you will get out of open pipes, and I know it's very addicting.

But the concern I had to my own and my passengers hearing outweighed the need for the power, so they came off and I continued to work on a better solution.

My concern has nothing to do with business or politics. I'm not a business man, I'm a government scientist. I'm only concerned with the wellbeing of my fellow motorist. And having more experience with your exhaust than almost anyone else here, because I've done it, makes me feel like I have to say something, even if no one listens.

 

the primary point of the WMS exhaust is that it is bipolar. Considering the above hearing concerns, and having driven with a droner (and ultimately getting rid of it), my suggestion is quiet the closed position for comfort at the expense of overquieting. ***** to the wall when open.

 

jlm bingo! i think i would buy this system even if it put out less hp/tq than the others in the closed position, but knowing that when the valve is open, it's on! I don't race my car, but some fun, spirited driving is what I enjoy. Now if my car sounds like a race car when I'm doing that, even better. I think this system is incredible and I am so glad I've waited on purchasing an exhaust/header combo.

Randy, will this system be as easy for the do-it-yourselfer to install as others? Congrats on such an incredible system.

 

I really hope you don't take my voicing a concern based on well known health impacts to be fear mongering. Nothing I mentioned was fear mongering, only scientific fact you can find in any text or internet source. Just be careful, that's all I'm saying. I'm not trying to sway anyone's decision either way. Ultimately, I don't care. Just be careful. I suppose that's all I have to say in the matter, since being concerned apparently gets one nowhere.

 

Then why did you make your posts?

[QUOTE=Samurai Will I'm not trying to sway anyone's decision either way. Ultimately, I don't care. Just be careful. [/QUOTE]