EXCESSIVE ENGINE NOISE
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EXCESSIVE ENGINE NOISE
I just had a high-end audio system installed in my car and want to be able to appreciate it without having to crank it. She’s a fairly stock ‘81 that isn’t super loud, but a few recent add-ons have definitely pumped up the dBs.
The HD Chevrolet fan & fan clutch I put in adds an underhood growl that grows with RPM. I thought it might be the fan, but someone suggested that the clutch might be a factor. Which part causes the growl? I didn’t save the original units. Fans are in the $50 range, while fan clutches are more than double that. I’m going to have to swap back to the higher flowing system in summer anyway.
The Mid-America true(ly lame) duals installed also upped the volume towards the front end of the system, even though I’m still using stock-type mufflers. What is it about this system that makes it louder than stock (two pipes, “aluminized steel,” light gauge, other)? Any suggestions on how to temper the noise? BTW, I have zero problem with extremely healthy WOT sounds.
The HD Chevrolet fan & fan clutch I put in adds an underhood growl that grows with RPM. I thought it might be the fan, but someone suggested that the clutch might be a factor. Which part causes the growl? I didn’t save the original units. Fans are in the $50 range, while fan clutches are more than double that. I’m going to have to swap back to the higher flowing system in summer anyway.
The Mid-America true(ly lame) duals installed also upped the volume towards the front end of the system, even though I’m still using stock-type mufflers. What is it about this system that makes it louder than stock (two pipes, “aluminized steel,” light gauge, other)? Any suggestions on how to temper the noise? BTW, I have zero problem with extremely healthy WOT sounds.
Melting Slicks
Joined: Mar 2001
Posts: 3,365
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From: Lake Villa IL
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St. Jude Contributor
Re: EXCESSIVE ENGINE NOISE (Runner81)
How about trying some dynomat? It's supposed to work wonders, when applied to the doors, floor, and probably in your case, the firewall. Maybe some new weather seals and hood mat as well?
I think you could go crazy chasing the engine sounds, when simply blocking some of it would be a surer bet.
Just a suggestion... :cheers:
I think you could go crazy chasing the engine sounds, when simply blocking some of it would be a surer bet.
Just a suggestion... :cheers:
Burning Brakes
Joined: Oct 2001
Posts: 1,185
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From: New Wilmington PA
Re: EXCESSIVE ENGINE NOISE (Runner81)
I've never heard a fan clutch growl before. Not saying it doesn't happen I just haven't seen it.
Are you sure the sound you are hearing wasn't just masked by the other fan setup? My thoughts would be on the water pump (bearings) or the timing chain. Either one will growl when going bad.
Every once and a while the topic of an exhaust crossover comes up here. They are sometimes refered to as an H pipe or an X pipe. The purpose of these is to balance the pressure in both pipes. Switching to true duals got rid of that balancing effect. Adding a crossover will quiet things down without removing that WOT music. :D
Hope this helps.
BTW... What did you go with for the audio setup?
Are you sure the sound you are hearing wasn't just masked by the other fan setup? My thoughts would be on the water pump (bearings) or the timing chain. Either one will growl when going bad.
Every once and a while the topic of an exhaust crossover comes up here. They are sometimes refered to as an H pipe or an X pipe. The purpose of these is to balance the pressure in both pipes. Switching to true duals got rid of that balancing effect. Adding a crossover will quiet things down without removing that WOT music. :D
Hope this helps.
BTW... What did you go with for the audio setup?
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Re: EXCESSIVE ENGINE NOISE (Runner81)
Re the insulation thing, late C-3s have great sound deadening compared to earlier models. The noise has only been objectionable since putting in the above stuff – particularly the cooling items.
Re the HD fan clutch, it’s clearly not the growler (howler?), but it is causing the fan to spin faster (closer to 1:1) which may be causing more noise.
The water pump is brand new – not sure about the timing cover. Bottom line is, when I open the hood at idle, the air blowing out the engine side of the fan is like a hurricane. That's defintely where the howl is coming from.
My C-3 part replacement sources list a single fan – 18.5”, 7-blade – as the same fan for both the standard and heavy duty cooling system. This is what I have. Only problem is that I distinctly remember the original fan – the quieter one - being a 5 staggered-blade unit. The 7-blader is equally spaced. Anyone know the story with the fans?
Re the HD fan clutch, it’s clearly not the growler (howler?), but it is causing the fan to spin faster (closer to 1:1) which may be causing more noise.
The water pump is brand new – not sure about the timing cover. Bottom line is, when I open the hood at idle, the air blowing out the engine side of the fan is like a hurricane. That's defintely where the howl is coming from.
My C-3 part replacement sources list a single fan – 18.5”, 7-blade – as the same fan for both the standard and heavy duty cooling system. This is what I have. Only problem is that I distinctly remember the original fan – the quieter one - being a 5 staggered-blade unit. The 7-blader is equally spaced. Anyone know the story with the fans?
