Exhaust Volume

[treynor]

Another in my occasional series on Viper performance data
All interior measurements taken in dbA with the pickup mic by my right ear, pointing toward the passenger seat.

Idle:
'01 RT/10, stock, roof on: 62 dbA
'98 GTS, stock: 62 dbA
'01 RT/10, belanger headers, belanger exhaust, high-flow cats: 72 dbA
'97 GTS, Corsa 3" exhaust, high-flow cats: 68 dbA

2000 RPM:
'98 GTS, stock: 68 dbA
'97 GTS, Corsa 3" exhaust, high-flow cats: 72 dbA
'01 RT/10, belanger headers, belanger exhaust, high-flow cats: 78 dbA

2500 RPM:
'98 GTS, stock: 70 dbA
'97 GTS, Corsa 3" exhaust, high-flow cats: 71 dbA

 

[Ron]

<FONT face="Comic Sans MS">Thanks Ben..... Looks like the Corsa / Cat combo adds idle and low RPM volume only.... interesting observation</FONT f>

 

[MES]

Yes, very informative post. Do you have any more measurements? WOT would be interesting. Also what's the maximum recommended noise level before you start to damage your hearing? I thought continuous noise above 80db was considered bad, or maybe it was 85db.

 

[Ulysses]

Yes, anything continuous above 85 db will damage your hearing based on statistical numbers. This is akin to sitting in traffic with your windows down. Just imagine what happens to musicians in loud rock bands or the driver of a car with the mac diggidy ding **** doggy sound system.

If your ears are a'ringing, your damaging your hearing!!!

 

[Venom Lover]

Interesting. I guess I won't be wasting the $$ for hi-flow cats to go with my Corsas for my '01, unless you happen to have data at WOT that shows there's a difference.

 

[Ulysses]

Mike,

I wouldn't worry about getting those hi flow cats unless you have an existing condition. Note that this is continuous exposure at 85 db. anything at 90 db, you should limit your exposure to less than 8 hours. Of course, I'm not a doctor so don't go on my words alone.

 

[Gerald]

You, Ben, have too much time on your hands..


hehe

Gerald

 

[Skip White]

No problem with hearing damage at that level. The freqency leval is to low at that db level. It is mid range to upper freq. that can do some damage. Of coure lower mid on down if loud enough can be a problem to, but the Viper carries off most mid range out the back end. What remains in the car is mostly lower mids..........Just my opinion...

 

[treynor]

Mike,
I have some subjective experience with high-flows -- on my belanger+belanger setup, going from stock cats to high-flows the car was louder at mid- to full throttle, but not much different at idle or cruise. It also picked up 7 RWHP and 10 RWTQ, so I'd recommend them for that reason alone.

I don't have any WOT sound data -- who has time to stare at a DB meter while WOT in a 420+ RWHP Viper?? I do have the following additional data

Stock RT, 70 mph cruise, 5th gear: 79 dbA
Belanger+Belanger RT, same conditions: 83 dbA

Outside sound level, 3-4 feet behind car:
Corsa + high-flows @ idle: 80 dbA
Belanger + Belanger @ idle: 82 dbA
Corsa + high-flows @ 2000 RPM: 90 dbA


Oh, and Gerald -- this may seem excessive, but it's much faster than buying a Corsa system, installing it, then having it removed again after my wife informs me her car is now too loud

 

[Venom Lover]

Ulysses,
Actually, what I was saying was that unless the hi-flow cats make the car louder, I'm not interested. I'm not worried about going deaf, though maybe I should be.

Ben,
Interesting additional data, but I wonder how much of a difference the headers make. At this point, I'm not considering putting headers on the '01, since I'm (probably) selling it next year to get my '03, and time is too short to have it in the shop again and again fixing O2 sensors due to the check engine light syndrome.

 

[CitySnake]

Gentlemen:

For whatever it's worth, I'll be installing (I'll, as in Chuck Tator) Roe's oval HF cats on my '01 RT/10 next Tuesday (snow permitting). The balance of the exhaust system will remain stock (except any adaptors). Sean's told me I should get a about a 5db increase in volume and a 10 to 15 jump in HP. Atypical of most, I am NOT interested in much more volume. I don't mind the HP increase however

.

I'll be happy to post my subjective opinion of the results next week. May be helpful as a "baseline" for others to consider.

Scott

 

[Mark Young]

I can add a rough WOT decibal measure:

my 99 ACR + hi flos + 3" Corsa at WOT on dyno : 114 dbA

This was taken approximately 15 feet at a 90 degree angle from the rear of the car. It was on a dyno in a big garage bay so its obviously a bit higher than it would read if you were out in the open.

The hi flo cats DO make it louder. I've compared mine with a GTS with just the 3" Corsa and the hi flo cats make it sound even better (read that louder and clearer). Cooler side sills, more hp (with headers), and louder exhaust note - how can you go wrong?

My $.02

 

[TorQ Junkie]

With belanger headers and exhaust, I use earplugs to drive any long distance. Luckily the car is quietest at 74 mph. WOT is loud and sounds great but the sound you get when letting off from WOT is painful at times. Hearing loss is cumulative. Within a certain threshold, the ear cells can recover if given enough time. Above a threshold, damage is permanent. Reportedly, a single shot from a 357 magnum revolver can cause permanent loss and or ringing.
I have high flow cats and Borla XR-1's ready to install in the side sills. I'm hoping the high flows will make up for any potential loss from the Borlas. I got this idea from Treynor when he had the CDI headers and put the Borlas in. Less ear damage and cooler side sills is the goal.

 

[varanus]

I just wrote a long post on this and it dissapeared. So to surmise:
I think my car was the 97 GTS got the readings on at Ted may's shop.
I was very hesitant about having a loud car. I drive a very quiet luxery car now as noise bothers me. But the heat from the cats in the sills was killing me so I got the much cooler hi flow cats and a corsa so the cats wouldn't be bottlenecked. Now the sills are very cool and my feet aren't toast anymore.
As far as noise I really like it. The exhaust is much quieter inside the car. If you're right behind it it's kind of loud. So it doesn't bother me. The car sounds really agressive now. A while back i was talking to this guy who loved the car and refused to leave the parking lot (while his family waited) until I started up the car and drove off. He couldn't wait to hear it. I had a stock exhaust at the time. As I drove off i could see him in my rearview mirror. He looked very disheartened. it was if the car was all looks with the promise of power, but the exhaust said "passenger car!" I guess his bubble was burst. That made the decision to go with a different exhaust final for me. Now the car sounds like it looks...no false promises! I drive with the windows down a lot just to hear it. Kids hear it from a distance, turn around and point. Bottom line is i love it..No regrets with the louder exhaust. BTW I got a killer deal on the Corsa 3 " exhaust and Random Tech Hi flow cats from Jon B at parts rack. Ted May did a great job on the install and set it up so when I add headers it will be an easy add.

 

[genXgts]

hey Varanus
quick Q:
Did you get a chance to dyno your current setup or track it?
Just wondering as your mods are a nice level to have one up on a stocker without cracking into the motor!
Assuming a nice sticky track and driving the car like you stole it, think 11.5 is in the mix with traction????
Thanks for any input,
good luck with the headers,
Ryan

 

[Nadine UK GTS]

Custom stainless 3" exhaust + headers, straight through, No cats at 3' from the tail pipes, WOT: 123 DB (Ouch!)

I've had a drive by at the road side WOT of 109DB!

 

[varanus]

hey genxgts, if you look at the post on this thread by Venom Lover he says

"'97 GTS Blue (Borla headers and 3" cat-backs, hi-flow cats, smooth tubes, K&Ns, 3.55 gear, 456 rwhp, 490 rwft-lbs, 11.5 sec at 123 mph)"

So I guess 11.5 is a possiblilty depending on the track and driver.

I was going to Dyno before the exhaust & cats, but due to circumstances did not. I probably will dyno next month when i get headers. After these mods I might do a vec by Sean Roe. I guess that will be it for a while as I don't want to pony up the $$ to start getting into the moter internally i.e head .
work.
I just read an email from the so cal group who did a piggy back computer an had it calibrated on a dyno
"Just got back from the Dyno Shop and with very good results. I had the piggy
back computer installed that Paul (owner of Dyno Shop) discussed with us
during the club's Dyno Day.
My car has tubes and filters, Hennessey 3 inch cat back and high flow cats.
Also have aluminum flywheel and 3:55 gears.
Before computer: 410 RWHP and 445 torque,
After computer: 436 RWHP and 470 torque.
Got to love these cars!
Dale
2000 GTS Red/Silver"
It cost him about $1200 bucks because of the extensive dyno time to calibrate, but 35 hp for 1200 bucks seems pretty good considering $4-5K in head work seems to get you up to 50 or 60 hp. The dollar value seems pretty good so i'll be looking into that.

 

[MES]

Inspired my treynor, I bought a sound meter today at Radio Shack. I like quiet cars with a bit of rumble. I would still like to quiet mine down some more. High flow cats seem to work well, maybe I will add some. What kind of high flow cats were those?

Here are some readings taken in 2nd gear from inside the car
Idle 74 db
2000 80 db
2500 79 db
3000 76 db
3500 77 db
WOT 93 db
coast down while in gear 84 db max around 2500
Lightly accelerating through the gears averaged 80-84db
Idle outside the car with the meter sitting on the rear deck 84db
Idle outside the car about 5 feet behind the tail pipes 88db

For reference I checked it against the stereo (speakers and amp are not stock) while listing to a Marilyn Manson CD

level 9 79db (normal listing level)
level 15 92db
level 25 106db
level 30 110db
level 35 113db ouch!

 

[Makara]

I was a bit curious how loud my car was. I thought that it might be a bit illegal but I wanted to see by how much. In California, it is my understanding that a car must stay below 95 db. A-weighted, measured 2 feet from the exhaust pipe while the car slowly revs from 2,000 to 5,000 while out of gear. I measured 120 db using these test parameters. Driving down the street in 1st gear at 1,500 RPM I measured 95 db. from the drivers seat. Does this sound high to anyone? I have a 94 with belanger exhaust and random tech 3" high flow cats. It sounds great, just really loud.

 

[MES]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
RPM I measured 95 db. from the drivers seat
<HR></BLOCKQUOTE>

So your saying inside the car it was 95db with the windows up? That is quite loud. Having the sidepipe car don't leave as many options as us rear exhaust guys. The Belanger exhaust with a straight through 4" Dynomax race muffler does very little for sound suppression, if that's what you have.

 

[Makara]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by MES:

So your saying inside the car it was 95db with the windows up? That is quite loud. Having the sidepipe car don't leave as many options as us rear exhaust guys. The Belanger exhaust with a straight through 4" Dynomax race muffler does very little for sound suppression, if that's what you have.
<HR></BLOCKQUOTE>

Windows? I have a 94 so my windows are a joke. So no, the windows were off and the hard top was on. Fine by me being in southern california. Windows are for wusses anyway. I have the 3" belanger from Jon B. so if that is the one with the 4" Dynomax then that is what I have. On fridays people gather at Bob's Big Boy and show off their cars. Every once in a while I take the viper and check out the hot rods. The last time I went, as I was walking back to my car to leave, I overheard someone saying that they would never buy a viper because the exhaust sounded weak. I fired up my car and watched the group of people who were talking about how "weak" viper exhaust sounded turn and drop their jaws.

 

[Tomcat]

Makara, I have the same cat back that you do from JonB and it is very loud. I just purchased a sound meter to test the db level. It is likely in line with yours. I ordered ear plugs for my (with wife) drive from Hotlanta to Daytona for the Rolex. I need to do something to lower the volume to a level where ear plugs are not needed. I live on Quiet Hill Lane, but not any more!