Sidepipes

[Gilach1]

I just inherited my brothers Cobra and recently got the car running. It has a built 351 Windsor. My question is around the sidepipes. Its pretty loud when running, and I'm wondering how often do sidepipes need to be replaced...how long do they last? I believe the current sidepipes have been on in since 2002. Mileage is 13K.

[Tommy]

Sidepipes are loud, but some are louder than others. Yours likely has the equivalent of a glass pack and those do get louder over time. Does it appear that you can access the inside to replace what's inside?

As an aside, I built the sidepipes and mufflers for my Cheetah. There was only enough length for 19" of muffler materal. I tried nine different DIY inserts and was able to reduce the idle sound level eight feet from the car from 82 db down to 73 db. Anything quieter than that required a much more restrictive exhaust flow. .... If you want to get an objective measurement of your sound level you can download a free sound meter app for your phone. Check the levels in an open space without reflected sounds.

[kitcarbp]

I have heard good experiences from others shopping with this company for side pipes in all sizes and sound levels. They should be able to help you

Classic Chambered Exhaust Inc. - Home Page

[Bill Kesner]

Time to re-coat my Side Pipes! Any recommendations, as the last posts on coating side pipes are a little old?

[cycleguy55]

Originally Posted by Gilach1

I just inherited my brothers Cobra and recently got the car running. It has a built 351 Windsor. My question is around the sidepipes. Its pretty loud when running, and I'm wondering how often do sidepipes need to be replaced...how long do they last? I believe the current sidepipes have been on in since 2002. Mileage is 13K.

What make car / replica are these sidepipes on?

[Gilach1]

Thanks for the feedback guys. I think it is a midstates model, im not really sure, but I will take and post some pictures. I tried to post video, but I don't think it got approval, I will try again and take some dB readings as well.

[cycleguy55]

Originally Posted by Gilach1

Thanks for the feedback guys. I think it is a midstates model, im not really sure, but I will take and post some pictures. I tried to post video, but I don't think it got approval, I will try again and take some dB readings as well.

Midstates was purchased by Shell Valley, so that could be a place to start.

There was also a good thread on replacing sidepipe mufflers. It was for CR II sidepipes, so the mufflers would almost certainly be longer, but it's a good read. Keep in mind that, generally speaking, longer mufflers are quieter, as are those with smaller ID and those installed with the open side of louvers facing forward, all else being equal. Glass pack mufflers will lose their packing over time and get louder.

Question about rattle in CR sidepipe

[Gilach1]

I'm still waiting for the moderator to approve the pictures and video. I guess these boards aren't super active. Anyway, i did download and use a db reader and it came back with an average reading of 83 Db at 8 feet away at idle. I'm not sure if this reading is correct because when i moved my phone closer it really didn't change the reading, even putting the phone right up to the muffler during a test. I will check out the thread on CRII pipes Brian. Thanks again for the input guys.

[spdbrake]

Originally Posted by Gilach1

I'm still waiting for the moderator to approve the pictures and video. I guess these boards aren't super active. Anyway, i did download and use a db reader and it came back with an average reading of 83 Db at 8 feet away at idle. I'm not sure if this reading is correct because when i moved my phone closer it really didn't change the reading, even putting the phone right up to the muffler during a test. I will check out the thread on CRII pipes Brian. Thanks again for the input guys.

You are not going to get a moderator response to that question. If I remember correctly, 6 posts is the min requirement to be able to upload photos and or link videos.

[Gilach1]

Ok, thanks for the info. I will draw pictures with my words until the appointed time :-)

[Tommy]

If your db reading (and mine) is accurate, then I agree that your sidepipes are too loud for my tastes. Dropping 10 db was a noticeable improvement to my ears.

[Gilach1]

Agreed. I think these are fibreglass packed mufflers, and they are close to 20 years old. The slimeline flowmasters might do the trick.

[Gilach1]

figured out i needed to reduce the picture size in order to post.

[cycleguy55]

Originally Posted by Gilach1

figured out i needed to reduce the picture size in order to post.

That looks like a pretty short muffler. You should be able to go longer but, of course, you'll need to figure out how to support the longer muffler and sidepipe. Regardless, it's probably worth considering if you're looking to quiet it down a bit.

I don't believe the Flowmaster Slimline mufflers are available any longer. I was looking at using them a couple of years ago, but now they don't seem to be listed.

BTW, I don't know the recommended angle, but I believe the common wisdom on the turndowns is to install them pointing slightly down, but not enough to enable the sound to bounce off the road surface. Perhaps 15° off vertical? I'm sure others can weigh in on this.

[Gilach1]

The area that appears to be the muffler section is about 20 inches in length, pipe in total is a little more than 40 inches overall. i will have to look for another alternative to the Slimeline, or maybe DIY the existing exhaust.

[cycleguy55]

If you decide to DIY, there are a number of glass pack mufflers available without stubs. Jones and AP both make these but I'm sure there are others. Like this:


Summit Racing has a pretty good filtering system that allows you to pick inlet and outlet diameter, body length, etc.

Here's a link to one model: https://www.summitracing.com/parts/jex-a4524b

[Gilach1]

That's great Brian. Thanks again for your suggestions.