Not too loud exhaust setup (approvable by Norwegian gov)?
#1
Not too loud exhaust setup (approvable by Norwegian gov)?
I want a new exhaust setup, but building cars in Norway is not easy. Keeping things legal is a real pain, and this is where you guys come in...
When it comes to a car's exhaust system, it should be legal to modify this as long as the car's rated noise level is not exceeded, and the CO levels and such do not increase. Each car has a noise rating (dBA at a certain engine RPM, 3000rpm for the Blazer I believe).
So, I need to find a good sounding exhaust setup that is not louder than stock (or not by much anyway). Changing the cat is probably illegal (not 100% certain about that), so I guess I'm looking for a muffler.
I really like the sound of the Flowmaster 50 series. That throaty V8 sound is awesome (even at high RPM), and it seems not to be too loud. Since it is also deeper sounding than stock, I was sort of hoping that the dBA level will not increase too much. Can anyone tell me how much louder it is?
The car is a '94 Blazer S-10 with a 4.3 V6 (TBI), rated at 165hp (5sp manual tranny).
When it comes to a car's exhaust system, it should be legal to modify this as long as the car's rated noise level is not exceeded, and the CO levels and such do not increase. Each car has a noise rating (dBA at a certain engine RPM, 3000rpm for the Blazer I believe).
So, I need to find a good sounding exhaust setup that is not louder than stock (or not by much anyway). Changing the cat is probably illegal (not 100% certain about that), so I guess I'm looking for a muffler.
I really like the sound of the Flowmaster 50 series. That throaty V8 sound is awesome (even at high RPM), and it seems not to be too loud. Since it is also deeper sounding than stock, I was sort of hoping that the dBA level will not increase too much. Can anyone tell me how much louder it is?
The car is a '94 Blazer S-10 with a 4.3 V6 (TBI), rated at 165hp (5sp manual tranny).
Last edited by Oystein; 05-21-2011 at 09:14 AM.
#2
Flowmaster 50s are legal in all US states (some of which have a specified acceptable exhaust noise level). I just took a sound pressure level meter to mine and measured beside the exhaust tip. With an ambient noise level of 75dB on the 'C' scale with a 'slow' response time, mine reads 107dB at 1,000rpm. Without knowing what the Norwegian acceptable level is or at what distance they measure it, I would guess you would be okay.
#3
Thanks!
I don't know how far away this is measured, I might ask the local traffic center about the details. I believe the Blazer is rated at 82dB(A)/3000rpm, but I don't remember exactly. If it's not overly loud compared to the stock exhaust I'm probably okay.
I don't know how far away this is measured, I might ask the local traffic center about the details. I believe the Blazer is rated at 82dB(A)/3000rpm, but I don't remember exactly. If it's not overly loud compared to the stock exhaust I'm probably okay.
#4
Turbo mufflers flow better than stock and are barely if at all louder than stock when cruising and at idle, you can really only tell if you don't know what it sounds like stock, you can tell it's there when you hit the throttle over halfway.
#5
Okay, I contacted the traffic center, and it turns out there are quite specific rules to how this is supposed to be measured. I quote:
The full document can be downloaded at http://eur-lex.europa.eu/LexUriServ/...68:0115:en:PDF It's an EU-thing.
So basically, one should measure 0.5m (20 inches) from the exhaust tip, with the microphone pointed towards it. If anyone can do this with a flowmaster (or even the stock exhaust) at 3000rpm (or higher), that would be extremely helpful (thank you rriddle3 for already having helped).
3.2.2. Acoustic measurements
A precision sound level meter as defined in paragraph 1.1 of this Annex must be used for the measurements.
3.2.3. Test site — local conditions (Figure 2)
3.2.3.1. Measurements should be made on a stationary vehicle in an area which corresponds to that for
measurements of vehicles in motion and therefore corresponds to the provisions given in Annex 8 to
this Regulation.
3.2.3.2. During the test nobody shall be in the measurement area, except the observer and the driver whose presence
must have no influence on the meter reading.
3.2.4. Disturbance noise and wind interference
Readings on the measuring instruments produced by ambient noise and wind must be at least 10 dB(A)
below the sound level to be measured. A suitable windscreen may be fitted to the microphone provided that
account is taken of its effect on the sensitivity of the microphone.
3.2.5. Measuring method
3.2.5.1. N a t u r e a n d n u m b e r o f m e a s u r e m e n t s
The maximum sound level expressed in A-weighted decibels (dB(A)) must be measured during the operating
period referred to in paragraph 3.2.5.3.2.1.
At least three measurements must be taken at each measuring point.
3.2.5.2. P o s i t i o n i n g a n d p r e p a r a t i o n o f t h e v e h i c l e
The vehicle shall be located in the centre part of the test area with the gear level in neutral position and the
clutch engaged. If the design of the vehicle does not allow this, the vehicle shall be tested in conformity with
the manufacturer’s prescriptions for stationary engine testing. Before each series of measurements, the engine
must be brought to its normal operating condition, as specified by the manufacturer.
If the vehicle is fitted with fan(s) having an automatic actuating mechanism, this system shall not be
interfered with during the sound level measurements.
3.2.5.3. M e a s u r i n g o f n o i s e i n p r o x i m i t y t o t h e e x h a u s t ( s e e A p p e n d i x , F i g u r e 2 )
3.2.5.3.1. Positions of the microphone
3.2.5.3.1.1. The height of the microphone above the ground should be equal to that of the outlet pipe of the exhaust
gases, but in any event shall be limited to a minimum value of 0,2 m.
3.2.5.3.1.2. The microphone must be pointed towards the orifice of the gas flow and located at a distance of 0,5 m from
the latter.
3.2.5.3.1.3. Its axis of maximum sensitivity must be parallel to the ground and must make an angle of 45° ± 10° with
the vertical plane containing the direction of the gas flow. The instructions of the manufacturer of the sound
level meter with regard to this axis must be respected. In relation to this plane, the microphone shall be
placed in such a way as to obtain the maximum distance from the longitudinal median plane of the vehicle;
in case of doubt, the position which gives the maximum distance from the contour of the vehicle shall be
selected.
3.2.5.3.1.4. In the case of an exhaust provided with two or more outlets spaced less than 0,3 m apart and which are
connected to the same silencer, only one measurement is made; the microphone position is related to the
outlet nearest to one extreme edge of the vehicle or, when such outlet does not exist, to the outlet which is
the highest above the ground.
3.2.5.3.1.5. For vehicles with a vertical exhaust (e.g. commercial vehicles) the microphone should be placed at the height
of the exhaust outlet. Its axis should be vertical and oriented upwards. It should be placed at a distance of
0,5 m from the side of the vehicle nearest to the exhaust.
3.2.5.3.1.6. For vehicles having an exhaust provided with outlets spaced more than 0,3 m apart, one measurement is
made for each outlet as if it were the only one, and the highest level is noted.
3.2.5.3.2. Operating conditions of the engine
3.2.5.3.2.1. The engine is operated at a constant speed having the following value: 3/4 S for both controlled ignition
engines and for diesel engines.
3.2.5.3.2.2. When constant engine speed is reached, the throttle shall be returned swiftly to the idle position. The sound
level shall be measured during a period of operation consisting of a brief maintenance of constant engine
speed and throughout the entire deceleration period, the maximum sound level meter reading being taken as
the test value.
3.2.6. Results
3.2.6.1. Readings, rounded off to the nearest decibel, shall be taken from the measuring instrument.
Only those values obtained from three consecutive measurements which do not differ by more than 2 dB(A)
respectively will be taken into consideration.
3.2.6.2. The highest of these three values shall constitute the test result.
A precision sound level meter as defined in paragraph 1.1 of this Annex must be used for the measurements.
3.2.3. Test site — local conditions (Figure 2)
3.2.3.1. Measurements should be made on a stationary vehicle in an area which corresponds to that for
measurements of vehicles in motion and therefore corresponds to the provisions given in Annex 8 to
this Regulation.
3.2.3.2. During the test nobody shall be in the measurement area, except the observer and the driver whose presence
must have no influence on the meter reading.
3.2.4. Disturbance noise and wind interference
Readings on the measuring instruments produced by ambient noise and wind must be at least 10 dB(A)
below the sound level to be measured. A suitable windscreen may be fitted to the microphone provided that
account is taken of its effect on the sensitivity of the microphone.
3.2.5. Measuring method
3.2.5.1. N a t u r e a n d n u m b e r o f m e a s u r e m e n t s
The maximum sound level expressed in A-weighted decibels (dB(A)) must be measured during the operating
period referred to in paragraph 3.2.5.3.2.1.
At least three measurements must be taken at each measuring point.
3.2.5.2. P o s i t i o n i n g a n d p r e p a r a t i o n o f t h e v e h i c l e
The vehicle shall be located in the centre part of the test area with the gear level in neutral position and the
clutch engaged. If the design of the vehicle does not allow this, the vehicle shall be tested in conformity with
the manufacturer’s prescriptions for stationary engine testing. Before each series of measurements, the engine
must be brought to its normal operating condition, as specified by the manufacturer.
If the vehicle is fitted with fan(s) having an automatic actuating mechanism, this system shall not be
interfered with during the sound level measurements.
3.2.5.3. M e a s u r i n g o f n o i s e i n p r o x i m i t y t o t h e e x h a u s t ( s e e A p p e n d i x , F i g u r e 2 )
3.2.5.3.1. Positions of the microphone
3.2.5.3.1.1. The height of the microphone above the ground should be equal to that of the outlet pipe of the exhaust
gases, but in any event shall be limited to a minimum value of 0,2 m.
3.2.5.3.1.2. The microphone must be pointed towards the orifice of the gas flow and located at a distance of 0,5 m from
the latter.
3.2.5.3.1.3. Its axis of maximum sensitivity must be parallel to the ground and must make an angle of 45° ± 10° with
the vertical plane containing the direction of the gas flow. The instructions of the manufacturer of the sound
level meter with regard to this axis must be respected. In relation to this plane, the microphone shall be
placed in such a way as to obtain the maximum distance from the longitudinal median plane of the vehicle;
in case of doubt, the position which gives the maximum distance from the contour of the vehicle shall be
selected.
3.2.5.3.1.4. In the case of an exhaust provided with two or more outlets spaced less than 0,3 m apart and which are
connected to the same silencer, only one measurement is made; the microphone position is related to the
outlet nearest to one extreme edge of the vehicle or, when such outlet does not exist, to the outlet which is
the highest above the ground.
3.2.5.3.1.5. For vehicles with a vertical exhaust (e.g. commercial vehicles) the microphone should be placed at the height
of the exhaust outlet. Its axis should be vertical and oriented upwards. It should be placed at a distance of
0,5 m from the side of the vehicle nearest to the exhaust.
3.2.5.3.1.6. For vehicles having an exhaust provided with outlets spaced more than 0,3 m apart, one measurement is
made for each outlet as if it were the only one, and the highest level is noted.
3.2.5.3.2. Operating conditions of the engine
3.2.5.3.2.1. The engine is operated at a constant speed having the following value: 3/4 S for both controlled ignition
engines and for diesel engines.
3.2.5.3.2.2. When constant engine speed is reached, the throttle shall be returned swiftly to the idle position. The sound
level shall be measured during a period of operation consisting of a brief maintenance of constant engine
speed and throughout the entire deceleration period, the maximum sound level meter reading being taken as
the test value.
3.2.6. Results
3.2.6.1. Readings, rounded off to the nearest decibel, shall be taken from the measuring instrument.
Only those values obtained from three consecutive measurements which do not differ by more than 2 dB(A)
respectively will be taken into consideration.
3.2.6.2. The highest of these three values shall constitute the test result.
So basically, one should measure 0.5m (20 inches) from the exhaust tip, with the microphone pointed towards it. If anyone can do this with a flowmaster (or even the stock exhaust) at 3000rpm (or higher), that would be extremely helpful (thank you rriddle3 for already having helped).
#6
I put a 40 series on mine. Don't really care if its legal though. I'm probably going to put a magnaflow aftercat system on if it doesn't pass pkk.
#8
Almost, an American who married a norwegian and moved here ten years ago. Where are you from anyway. I live about a half hour outside of Stavanger.
#9
I'm from Sogn myself, far out in the countryside somewhere
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