How To Quiet Loud Side Pipes
 

Greetings,

I'm new to the Forum having purchased a 1966 Convertible yesterday. I looked for quite a while and found what I believe is the perfect car for me. However, the prior owner installed factory correct 21/2" side pipes which are EXTREMELY LOUD!. The workmanship, fit and finish is excellent, as is the appearance. I went to a few "muffler shops" in hope that they could provide a solution. No luck there, they simply stated "not enough room to install a resonator..." With that said, I have to believe that there may be a solution and I'm hoping that I will find it on this Forum.

Thanks in advance...

Dave

Welcome to the CF! Contact Allens Exhaust 574-722-7272. The make custom stainless steel side exhaust with specialized sound attenuation material. Others on here will chime in on additional info etc. :cheers: Dennis

Dave - As Dennis already said...Welcome to the Corvette Forum. On the subject of side pipes, read through this older thread I started a while back.
C2 What Aftermarket Vendor Made Factory Style Side Exhaust 'Without' Baffles? - CorvetteForum - Chevrolet Corvette Forum Discussion
My 65 NOM 396 Roadster had what looked to be brand new side pipes on it when I bought it, but as soon as the engine started, the sound out of them was
terrible, not good in any way, shape or fashion. Mine were identified as having been made by Sweet Thunder. There was no external markings to determine that
exactly, but check out the pics I took looking in from the chromed tip end. That's the give away that they weren't like the original GM pipes.
After all the research, I have found that a number of mfrs do make what they call their 'Quiet' or 'Original Sound' type pipes but
no one yet has said they sound just like the factory pipes, which might be the case all around so at least there are options.
Is your Vette a smallblock or Bigblock, tell us more about it.
Mike T - Prescott AZ

Side pipes and loud are ALWAYS mutually inclusive. No exceptions - just various degrees of loud.

If in mentioning 2-1/2" side pipes is a reference to the inner core of the chambered muffler - that is not factory correct. Factory sidepipes were 1-7/8" diameter core and were fairly loud, somewhat mellow until rusted out, but also very HP restrictive. Inner core chambered pipes of 2-1/4", 2-1/2" and 3" are all after market and are generally arranged in increasing order of very loud to crazy loud. Different forms of chambered perforations and various packings affect overall noise some. If you want quieter and good power you can install an undercar exhaust system with stock mufflers and turn down tips and connect it to the side pipes with motorized valves so you can run it quiet or loud, depending on your mood. A cross over pipe can be added between the side pipes up near the bell housing which will make the sound deeper and mellower, but not necessarily quieter.

Check out the options available here…. Sound bites also

http://www.classicchambered.com

Is your Vette a smallblock or Bigblock, tell us more about it.
Mike T - Prescott AZ

The car now has a ZZ4 350 with 400 HP. The owner included the number matching engine along with every single (in a crate) OE part that has replaced. Like many enthusiasts he was meticulous as it relates to documentation, receipts and overall details. Here is the Build Information the former owner displayed at car shows.
https://cimg1.ibsrv.net/gimg/www.cor...b9d5cb2abc.jpg

There is no such thing as quite sidepipes and no way to quite them down. To add to your misery if they are original GM pipes the 2 1/2” is the exhaust pipe size BEFORE it gets to the crimped section under the covers which turn into a 1 3/4” pipe size which is restricting your engines power.

I spoke with a person, who "knows Corvettes" about the excessive noise. He conditionally suggested "stuffing" the now hollow side pipes. Specifically, a combination/intervals of steel wool and wire mesh to hold in the contents. He is suggesting that this could very well decrease the decibel level. One one hand, it sounds plausible on the other hand it sounds waaaay too easy!?
https://cimg2.ibsrv.net/gimg/www.cor...691ffdfb4a.jpg

Hey! I know Nyle and Kathleen! I didn't realize they were even contemplating selling their car.

Congratulations on the purchase. I think you got a solid, dependable vehicle.

It will probably quite It down if you can keep the contents from blowing back out but the performance will likely be like trying to take a crap with your fingers stuck up your butt. :D

Welcome to the best Vette forum. I used to add factory side pipes to my Sting Rays back in the day, but years later got tired of the constant bedlam and started taking them off of C2s I bought. A 2800 mile drive from Michigan to Calif. in my current 67 ragtop with factory side pipes (now gone) reminded me of why I long ago got weary of them.

I'm always surprised by people that buy a midyear with side pipes then complain they are loud. Put under car exhaust on problem solved.

I can't imagine going that distance with these side pipes. I have a new Jaguar F Type that has active exhaust that I almost never use. When I'm driving the Corvette, of which I absolutely love it's almost embarrassing! I don't think there's a quick fix on this issue as such, I will probable have to purchase a new system. I can't see the car without the side pipes.

If you intend to keep the side pipes but aren't opposed to modifying the exhaust, consider adapting the products of Spiral Turbo Specialties (website link below).

My track car with side pipes has to meet sound limits which vary by track. Some tracks, Laguna Seca most notably, have limits that even bone stock factory exhaust sometimes doesn't meet. My car, with STS inserts (and maybe one or two tricks of my own) meets the sound limits at Laguna. To put a fine point on that: At one Laguna Seca race with severe noise limits in force, I pulled back into our paddock spot and my bride, who was sitting right there, did not hear me approach.

So, the point is that you can make side pipes much quieter.


spiral turbo specialties

Thanks for the tip, this sounds promising!

...... must be the "voice of experience" ....


https://cimg9.ibsrv.net/gimg/www.cor...b8afabf251.jpg

Black Tux - The engine in my NOM 65 396 Roadster 'was' a .060-over 454 with a fairly warm hydraulic flat tappet cam, 228/238 duration. When I first heard the seller back the Vette out of his garage, it wasn't the engine or cam that was making the obnoxious sounds, it was due to the pipes. Did you check out the older thread I started about side pipes, if you did you'd see the pics taken while looking in from the end, and notice the odd looking baffles or dimples, whatever they call them. I've made a lot of calls, emails, etc trying to find out who makes a decent set of pipes, which I'll be installing onto the 427 10.3 compression hyd roller cam engine I'm putting together now. Here's the pic of the (believed to be) Sweet Thunder pipes that were only my roadster for maybe 100 miles. They look new because they almost are but...the outside looks have nothing to do with the sound they produce.
Mike T - Prescott AZ
https://cimg6.ibsrv.net/gimg/www.cor...d8c9777a4b.jpg

Tux,
Great looking car brother and welcome to the forum. :thumbs:
If you're considering going back to the under body exhaust, maybe I can help.
I recently finished a full restoration on my '65 L-79 coupe, including a complete new 2 1/2" exhaust system with factory style mufflers. After putting approx. 200 miles on it I found a deal on a set of factory side pipes so decided to make the change and I'm happy with the results.
So now I have a complete, almost new exhaust system, including center hanger, rear hangers with frame brackets, correct tail pipe extensions, clamps, even the rear valence (which is currently Nassau Blue) with stainless steel bezels so, everything a guy would need to make the change over to an under car system. I'd be happy to make you a great deal on the whole package as it's only taking up space in my garage. I am in Palm Springs. Shipping could be a bear, but if you're here in southern California it's worth considering.
Cheers, Greg
:cheers:

https://cimg3.ibsrv.net/gimg/www.cor...06ab62a94a.jpg

if you click “corvette chambered mufflers” , the 2”core vettepacs are significantly quieter (less harsh) than even the stock 1 7/8” core pipes.

Losing the sidepipes to make mine quieter was not an option. I'm sure there are quieter pipes than mine (and yours), but for me the volume button is 5th gear. Keep that in the back of your mind because the 5-speed brings other benefits beside dB control..... unless you intend to do the judging gig. Welcome. Beautiful car. Enjoy