Nice day for a bike ride, 86 degrees and sunny, so my friend and his friend with the meter did make it over.
So I got some readings of the 7 and the AMX as well since they were here.
I don't know much about the types of db meters, they brought a Reed, how good or how pricey I don't know.
I don't have any insurance on the car yet, not until the end of the month, so no drive by readings.
My exhaust is homemade headers thick pipe for the headers 13ga, all under the hood including reducers.
From under the reducers it is about a 100 degree bend for 14 inches to the front of the muffler case.
Then a 21 inch muffler and 37.5 inch side pipe from the back of the muffler case that end in a 90 degree bend with a slight turn down.
In the driveway with the meter just above the console it registered 68db on startup with a fast idle of 2000 rpm.
After I kicked it down to 850 idle it read 64db.
Still at idle we took a readings at:
12 feet=55db
25 feet=50db
50 feet=44db
We held the meter 12 inches from the drivers tailpipe at idle and it was 78db.
From the passenger side we got 81db, my only guess for the slightly different reading is the headers are not symmetrical.
I can't prove it so I don't know, just a guess as everything else is the same.
I brought the revs up to 3500 and took a reading at the tailpipe 12 inches out and the reading went up to 85db.
Then while I held it at 3500 another reading was done at 25 feet, the reading dropped to 72db.
And since they were here I fired up the AMX and at 800 rpm the reading from inside the car was 73db.
12 feet from the back it was 60db.
25 feet back it was 54db
Both rear pipes were 80 db at idle from 1 foot out.
I never took any readings at higher rpms.
On impulse I started up my Passat and at idle it showed 44db just standing about 4 feet behind the car .
So that is what I got this afternoon, not sure how much it proved other than my hearing must be a bit wonky as I thought it would all be a lot louder.
On the other hand I have no problem carrying a conversation with the wife at 50 miles an hour.
Anyway it was fun, let me tinker and get the cars ready for summer.
Who knows maybe I can get the guys over again some time in the summer and do some blast down the highway readings.
All in all I have been happy with the exhaust as it is, it does have a kind chorkle sound at lower revs, I suspect a cross over might cure that to some extent.
I have been to lazy to look at it though.
Also it does highlight the lumpy cam at certain rpms and that isn't bad at all.
So a decent day, in fact a rare day as there didn't seem to be a single person home in the neighborhood, so very quiet, kind of unusual.
Al