It's been a good week so far. I took my winter tires off on Monday and put the summer Toyo T1R's back on. My handling is back, although I'm very happy with performance of the Bridgestone Winter Sport M3's. They got me through the snow and allowed some performance when things were dry.
On Tuesday, a new pair of Toyo T1Rs for the rear arrived, so I'm ready when the current pair reach the end of their lifespan (which won't be too long)
Today, I got my Dinan exhaust installed. It is just what I was hoping it would be. At idle and when I feather the acceleraor around 1k rpm, the sound is much deeper. The car now sounds flat bad azz coming into the driveway. However, with this exhaust, I can come and go in my neighborhood without any unwanted attention, unless I get on the throttle, then it comes alive but again not too loud. In my opinion, this is the exhaust for someone that wants the deeper sound without the increased noise levels. I'm sure headers and removing the resonators would be loud but this is the level I wanted. I did take some decibel readings of the stock exhaust using a meter I have. I took measurements at startup, idle, 2k rpm, and 4k rpm. I'll do the same with the Dinan and post the results.
Oo, I envy you. Here in Finland we still have a lot of snow, so I guess that earliest time to change tyres is end of month I really look forward to this and my planned mods, as I really hope for much improved handling (´00 with 115.000 km and absorbers never been changed)
__________________ 2000 E39 M5. Le Mans Blue/Black. Driveability: KW Variante 3 coilovers, AC Schnitzer Sway Bars, Weicher strut bar. Rogue Engineering SSK, TCD sway bar brackets. Powerflex bushings Sound: Inside: Infinity Subwoofer/JBL amplifier. Outside: Kellener SuperSound exhaust, SuperSprint X-pipe Looks: Facelift, G-Power front flippers, Black Kidneys, M-pedals, AngelIBrights 3.0, 19" Dotz Mugello wheels
It's been a good week so far. I took my winter tires off on Monday and put the summer Toyo T1R's back on. My handling is back, although I'm very happy with performance of the Bridgestone Winter Sport M3's. They got me through the snow and allowed some performance when things were dry.
On Tuesday, a new pair of Toyo T1Rs for the rear arrived, so I'm ready when the current pair reach the end of their lifespan (which won't be too long)
Today, I got my Dinan exhaust installed. It is just what I was hoping it would be. At idle and when I feather the acceleraor around 1k rpm, the sound is much deeper. The car now sounds flat bad azz coming into the driveway. However, with this exhaust, I can come and go in my neighborhood without any unwanted attention, unless I get on the throttle, then it comes alive but again not too loud. In my opinion, this is the exhaust for someone that wants the deeper sound without the increased noise levels. I'm sure headers and removing the resonators would be loud but this is the level I wanted. I did take some decibel readings of the stock exhaust using a meter I have. I took measurements at startup, idle, 2k rpm, and 4k rpm. I'll do the same with the Dinan and post the results.
2007 Z4 M Coupe, Titanium Silver with Imola Red, black and silver interior -for details: www.mymcoupe.com
2003 M5, Imola Red with black and silver interior
-Dinan S2 drivetrain
-Dinan stage 3 suspension with JRZ shocks
-StopTech brakes
-Rogue Engineering short shift kit and clutch stop
-275/35R18 Michellins f/r on 18x9.5 BBS RS-GTs
-Progressive window tint
-Euro dash and armrest conversions
-CDT/Total audio, NavTv w/ DVD
-Seat massagers
2002 540iT, Sapphire Black with black and red interior
-Dinan S2 drivetrain
-Dinan stage 3 suspension with Koni shocks
-StopTech brakes
-255/40R18 PS2s f/r on 18x8.5 BBS RG-Rs
-Progressive window tint
-Euro dash and armrest conversions
-Custom interior trim and seat massagers
-NavTv with DVD
Well, I got the Dinan readings today. Interesting results that back up what my ears were telling me.
First, here's the test setup.
I used a sound meter located about 1' -1.5' above the ground. I took measurements at 3' and 6' distances from the rear of the car. I set the meter on "A weighting", which filters out some of the high and low freqencies that are outside human hearing. "A weighted" figures are most often used.
The differences between Stock and Dinan exhausts are more pronounced than I thought based on just listening to them. The sound at idle is not only deeper, it is 13 db more than the stock exhaust at idle (10 db represents a 10 fold increase, see attached link). On cranking the car, the sound with the stock exhaust is only 6 db more than at idle. With the Dinan, it is 11 db more than the Dinan at idle and nearly 20 db more than the Stock exhaust at idle.
3' from the car at 4k rpm, the sound jumps a whopping 16 db and has a similar increase in sound level 6' from the car. This says that as the rpms increase the exhaust is able to re-create the same sound levels whether you're 3' away or 6' away, probably due to the higher exhaust velocities. Regardless, 99 db is pretty loud at 4k rpm given the stock exhaust only managed 82 db.
The one thing this little test did not address is the frequencies of the exhausts. My ear tells me the Dinan frequency is lower at idle than stock, but I would have loved to have a device for testing that as well. I didn't, so I just roll with what I have. And the best part, no resonance at any frequency. All day today the radio stayed off and the sunroof open.
earl, radio shack makes a decent one. Ive had one for awhile and used it for many different things.
Was like $25-30 IIRC.
I might have to test my car out at same distances. Curious to see if they are the same..
Also want to do this to roblvs2xlr8, Dinan mufflers with removed resonaters, sounded great!.
Wonder if we have anything at work that can show frequencies decently..
Anyone know the CA spec on exhaust? I think its 95dB (up from 92 few years ago), but I dont remember the distance or RPM...
Also Earl, regarding front plates, I thought CA required it to be on the front most part of the car? Was reading your mod post, saw you arent running front bracket, but didnt see where plate was being located..
earl, radio shack makes a decent one. Ive had one for awhile and used it for many different things.
Was like $25-30 IIRC.
I might have to test my car out at same distances. Curious to see if they are the same..
Also want to do this to roblvs2xlr8, Dinan mufflers with removed resonaters, sounded great!.
Wonder if we have anything at work that can show frequencies decently..
Anyone know the CA spec on exhaust? I think its 95dB (up from 92 few years ago), but I dont remember the distance or RPM...
Also Earl, regarding front plates, I thought CA required it to be on the front most part of the car? Was reading your mod post, saw you arent running front bracket, but didnt see where plate was being located..
-Thanks for the Db reference. I'll go pick one up, never know when it might come in handy.
As to the front plate, I'd have to look up the law again to be sure but I don't recall any parameters being stated other that maximum height and "visible from the front". I could be wrong. My front plate in in my passenger seatback pocket.
I did remember to take some readings at 70 mph. The road surface has a lot to do with the interior noise. The difference between the two exhausts when cruising in 6th gear is not discernible. Both were in the 74-78 db range. The Dinan tended to be more on the higher end. It's still relatively quiet at the lower cruising speed rpms. The readings are inconsistent, unlike when the car is sitting still so it's hard to say for certain. I can't tell any real difference at cruising speed. Accelerating however in any gear, there is a different sound, less of the engine I use to hear and more of the exhaust note.
I like the looks of the Dinan. The diameter is larger and the inside pipes are offset, with the inside ones about 1/2" longer. The design follows the shape of the bumper more and with the offset, each tip is exactly even with the contour of the bumper.
The sound meter I have has been discontinued but it is made by Extech. Here's the closest replacement I see. I initially bought mine to help locate speakers in my basement but have found all sorts of uses for it, albeit infrequently.
I really look forward to this and my planned mods, as I really hope for much improved handling (´00 with 115.000 km and absorbers never been changed)
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