Header Drone?
Thread Starter
Intermediate
Joined: May 2011
Posts: 35
Likes: 1
From: Panama City Florida
Header Drone?
Hi I have a 1986 corvette and I purchased an OBX header-back exhaust a while back and really like it, (look, sound, and price). At the moment it's not loud in the car which a big plus but I wouldn't mind it being a little louder outside of the car. So I've been thinking about getting headers. I know headers will make the car louder but will the drone be terrible? Was leaning toward OBX for my header purchase as well. Thanks
Instructor
Joined: Nov 2012
Posts: 120
Likes: 6
From: Phoenix AZ
Hi I have a 1986 corvette and I purchased an OBX header-back exhaust a while back and really like it, (look, sound, and price). At the moment it's not loud in the car which a big plus but I wouldn't mind it being a little louder outside of the car. So I've been thinking about getting headers. I know headers will make the car louder but will the drone be terrible? Was leaning toward OBX for my header purchase as well. Thanks
Le Mans Master
Joined: Oct 2004
Posts: 6,314
Likes: 508
From: South-central Missouri
"Drone" is result of resonance, related to length of the pipes. You will benefit from tuning (and suffer if you don't) once you've added headers: changes the flow dynamics significantly - for the good IF a tune goes along with it.
Just sayin!
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Headers on your existing system should mot make any real difference in interior sound or increase resonance. You may hear a different tone at the tailpipes.
I just installed Hedman headers on my '87 and I already had true duals with DynoMax race mufflers and an X-pipe. The exhaust tone is a little deeper at idle but there was no increase in overall loudness. Even at WOT, I can't tell the difference. At a recent track day, the car with this system was recorded at 95dB at 5200 RPM in 3rd gear jut before hitting 4th.
I just installed Hedman headers on my '87 and I already had true duals with DynoMax race mufflers and an X-pipe. The exhaust tone is a little deeper at idle but there was no increase in overall loudness. Even at WOT, I can't tell the difference. At a recent track day, the car with this system was recorded at 95dB at 5200 RPM in 3rd gear jut before hitting 4th.
Team Owner
Joined: Sep 2001
Posts: 62,160
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
The resonance has much more to do with the catback than anything else. I had Power Effects and Flows before the Header install on two C4s. The PE sounded better with stock manifolds but adding headers woke up the engine, and the sound along with it. My Power Effects would drone badly at 2000rpm with the pipes open, while my Flows have nearly none.
So it may not resonate now, but it could resonate worse with the headers on. You may end up wanting to change the catback again. If its not loud now I'd doubt it though.
So it may not resonate now, but it could resonate worse with the headers on. You may end up wanting to change the catback again. If its not loud now I'd doubt it though.
Team Owner
Joined: Aug 2005
Posts: 34,988
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From: Riverside County Southern California
Co-winner 2020 C4 of the Year - Modified
2018 Corvette of Year Finalist
2017 C4 of Year
2016 C7 of Year Finalist
St. Jude Donor '09 thru '20
I installed the OBX cat-back on Betty Boop, and I LOVE IT.
It has a rumble around 40-50 MPH, but on the freeway the Vette cruises quiet.
It has a rumble around 40-50 MPH, but on the freeway the Vette cruises quiet.
