Exhaust decibel level

[EZ$]

I know this topic has probably been talked to death, but I've got a little time while I wait for a set of intake manifold gaskets to arrive tomorrow.

I was looking at the exhaust augers from Patriot and Dynatech. Now I know that everyone who has gone with their pipes swears by Boig, and I've seen the videos comparing the stock pipes on both the FIA and the 427, but I really can't do $600+ to go with their pipes even if I wanted to with the fact that I will need to have them ceramic coated also. Does anyone have any experience with the augers? I'm running shorty headers and J pipes. Could the augers be placed in the J pipes? Amount of performance decrease? I can deal with some if it fixes the sound problem a bit.

Anyhow, all opinions are welcome! I'm just kicking this around.

Oh, and one more option. Has anyone taken their FIA side pipes to a muffler shop, had them cut out the center section, and replace it with a more effective muffler unit? I'm assuming that this is basically what Boig is doing, but then I shouldn't assume.

Thanks Guys.

[Itchief]

Rick

I used the 3 1/2 inch Dyna Tech insert cones to help reduce the exhaust sound levels.

I’m considering adding a second set to help reduce the exhaust sound levels even more.

You can get them from Jets for $69 each

https://www.jegs.com/i/Dynatech/329/772-32510/10002/-1

[EZ$]

Itchief, Thanks, I was looking at those as well. I figured that if the augers weren't enough, and if they could be put in the J pipes, I could always add these, and put them in the tip of the side pipe. Did you find a measurable difference in the exhaust note with the cones?

[Itchief]

Rick

Yes they seemed to help I didn’t have a dB meter but I could tell the difference. I didn’t use anything to attach them, I just opened the tabs enough for a tight fit and used a broom handle to push them in place.

fifteen thousand miles later they are still in place, I think that I could install a second set and reduce the sound levels even more

Good luck

Rick

[NAZ]

I've used the augers and they will reduce the sound level a couple dB. I used these with a stack of discs made from perforated steel and they were still too loud. I've also used the perforated cones both single and double, they work better but don't get the sound level low enough. On my car the mufflers I've made attach directly to the header collectors so the exhaust is very short which makes it hard to reduce the sound without restricting the exhaust flow. My latest set of mufflers I made from SuperTrapp discs: https://supertrapp.com/shop-products/universal/auto-disc-only

I used the 5" OD x 3.5" ID with 18 discs and this is the best compromise I've found yet to balance low restriction & sound level. My next step was to incorporate the double cones with the SuperTrapp but it appears that won't be necessary. With the SuperTrapp discs you can tune the sound by adding or subtracting discs. They come with 12 discs but you can purchase just the discs in a set of 12 and add as many as you need or reduce the number of discs to reduce the sound level.

I should have added that my current engine is way louder than most any other "normal" build -- this engine flows maybe twice what the average engine a builder will use so if the SuperTrapp works on mine, it should work for most builds looking for a custom solution to their hard to package exhaust.

126578Double cone muffler 126579SuperTrapp muffler

[Joel Hauser]

I used the Patriot exhaust augers in my FF sidepipes. I think it sounds much much better with the auger's than it did without. I cut the ends of side pipes off so I could slide the augers into the sidepipes. I welded a coupling nut to the auger so I could then bolt it to the pipe. I also wrapped some fiber glass cloth around the auger. I reattached the ends using 3 or 4 inch stainless band clamps. I pointed the tips down a little. The modification is hardly noticable. I think the parts cost under $50. I'm sure there is some HP loss, but the car is still plenty fast for me. I don't think there is an off the shelf auger that will simply slide into the side pipe. I had to do a lot of grinding and filing to get it to fit. I'm using a 4.6L SOHC engine with headers. I am not using the J Pipes. Because they are bolted in I can remove them if I want.

[Maui coupe]

I used Car Chemistry inserts in my J pipes and they helped quiet it down to a reasonable level.126562

[EZ$]

Thanks guys. Lots of good options that won't break the bank. I'm going to look into all these, and see what way I want to go.

[chuckster]

I feel ya. When I first heard the FFR 289 pipes, I was stunned. Both the dB level, and the raspy bark were too much for me. The first summer I drove the car in gelcoat, with FFR cats. They knocked the dbs down some, but I wasn’t happy with the sound and I really don’t like the look of the cats. I did run a borescope up the pipes and the center section was your basic glaspak ie perforated inner pipe wrapped with f/g. But there was still a 2”straight through. As for the Boig treatment, I drove the car all last summer with the massaged pipes, and I couldn’t be happier. I thought about modding the pipes myself, but I’ve lost a lot of dexterity in the last couple of years.and I’d have just screwed it up. Add to that his shop is 40 minutes from my house, I had no shipping to pay.

[EZ$]

Chuckster, I would so love to go with their pipes, but just too much right now. I'm just wondering if a muffler shop would, or could do anything if I brought the pipes in to them. Like cutting out the center section, and installing an actual operating muffler! I may take some pictures of the side pipes with some measurements, and check with a couple shops in the area. It'll still be awhile before I'm on the road with this thing, so I have the time to look into some different options. From California, I hate to think what the shipping both ways would be on the side pipes. I actually saved the box they came in with all the shaped foam packing, so I've got that part covered. I've also lost dexterity, but that's not the issue. I just never had the skills to do it myself!
Thanks for the input.

[Norm B]

I used a set of Patriot augers I bought from Jegs. The turnout was carefully cut off the pipe by grinding the weld. A plug was welded into one end of the auger to prevent straight through flow. This plug was drilled and tapped to except 1/4 20 stainless steel machine screw. Holes were drilled through the pipe of the auger by the spiral closest to the plug to allow some exhaust through the centre. The forward two auger sections were trimmed to fit very tightly inside the glass pack while the third was trimmed to match the transition from muffler to turnout. A spacer was used to centre the auger assembly in the turnout and the turnout was welded back on the muffler with the opening turned down 30 degrees.

The results were well worth the effort. The metallic ringing bark was gone at idle and you can hardly hear the exhaust in cruise. Still loud enough when applying the go pedal.

Here are some pictures. The first is the modified auger and side pipe with the turnout cut off. The second shows the machine screw head just in front of the heat shield mounting clamp, and yes I have to fix the header tape. The third is inside the pipe showing the auger and spacer.

HTH

Norm

[Railroad]

Speedway sells stainless steel wool. It is sold to be wrapped around the spirals on the augers. Just FYI.

[Jim1855]

Anyone actually use a dB meter to test before & after? Placement of the meter is critical. A meter provides a basically unbiased measurement, ears generally do not as they are frequency sensitive. What the race tracks test is different than what you hear sitting in a car.

Not a FFR but I tested my first car after installing a set of performance sidepipes. Had the meter secured centered on the cowl just behind the seats, aimed at the windshield. Idle was about 95dB, full throttle at about 4,000rpm was about 123dB. This was with a pro quality meter. Also played with measuring frequency response using an audio system frequency analysis meter. All interesting but somewhat academic.

Ear plugs are a great addition to anyone's car & driving experience. They help at rock & roll concerts too.

Jim

[GoDadGo]

Earplugs!
You can buy them by the buckets.

[cnutting]

Anyone actually use a dB meter to test before & after? Placement of the meter is critical. A meter provides a basically unbiased measurement, ears generally do not as they are frequency sensitive. What the race tracks test is different than what you hear sitting in a car.

Not a FFR but I tested my first car after installing a set of performance sidepipes. Had the meter secured centered on the cowl just behind the seats, aimed at the windshield. Idle was about 95dB, full throttle at about 4,000rpm was about 123dB. This was with a pro quality meter. Also played with measuring frequency response using an audio system frequency analysis meter. All interesting but somewhat academic.

Ear plugs are a great addition to anyone's car & driving experience. They help at rock & roll concerts too.

Jim

Bob Boig and I tested the 289 pipes using a meter. At chin height in the drivers seat we saw a 10dB improvement in the prototype "quiet-er" pipes over stock. Idle with stock pipes was about 92dB.

[Norm B]

I have a video the neighbour shot last summer of my wife and I leaving for a drive. PM me an email and I can send it to you.

Norm

[EZ$]

Norm, Interesting idea to close off the center tube of the auger and limit the amount of exhaust movement by drilling holes. I'll PM you an email. I'd be interested in the sound!

Railroad, I'll have to look into that.

Jim & GoDad, I definitely plan to use earplugs. I'm in construction, and concrete saws, drills, etc. have caused a loss of most of my high frequency hearing. The sound coming from the side pipes would finish me off!

Chris, As I mentioned, the Boig Quieter Pipes would be my choice if I could afford them. So it's either win the lotto, and get them, or figure a less expensive way!

Thanks guys

[CraigS]

My post from years ago
https://www.ffcars.com/threads/inexpensive-exhaust-quiet.290641/
They are still there and working just the same. I did have to find a more permanent way to keep them from rattling. I drilled a 1/4 inch hole through the outer pipe into the center pipe in the spiral. Pulled the spiral out and welded a nut to it. Dimpled the outer hole inward. Slipped the spiral back in and ran a flat head machine screw from outside into the nut. Now about every 1-2 years I tighten the screw a 1/4 turn. Originally I put the machine screw in from the bottom so it wouldn't be seen. Now w/ the heat shields it wouldn't matter.

[Al_C]

Rick,

You asked about performance decrease due to augers and other stuff. I can't speak to that, but I can comment that shorty headers and J-pipes are more restrictive than 4-into-4s, so you'll get a hit there to some degree. But, it's all relative. As are sound levels. Thanks to a prior life as a musician, I already have a hearing loss, so the pipes aren't so bad for me. I fall into GoDad's camp and suggest ear plugs. Much cheaper. That said, you need to do what you believe is right. I'll be quiet now.

[EZ$]

Craig, thanks for the input. In reading your post, it sounds like you've had both the CC inserts in your J pipes, and the Patriot spirals in the side pipe back near the turn down. In your post you also mentioned that the 3 disc CC insert was too restrictive so you went with two. Which system performed better sound wise? Is there a reason that you went from the CC inserts to the spirals?

Al, I knew that the shorties with the J pipes would restrict the power somewhat, but doing an FIA car, with that style side pipe didn't leave any option. I'm just looking down the road when I actually start driving this thing. If I was to leave real early with the way it is now, I'd be concerned because I know some of my neighbors are armed!

[Norm B]

Rick the CC inserts from Jegs https://www.jegs.com/i/Car-Chemistry/176/2DI02R/10002/-1 look like they will slide directly into your FIA side pipes and be easily secured wit a couple of screws through the pipe into the disc flange. Much easier to secure than the Auger type for your application.

[EZ$]

Norm, I was looking at them and they have a lot more varieties in sizes, from 2" up to 4" I believe, and I think the 2.25 or 2.5" would slide right inside the J pipe without interfering with the O2 sensor, and those pipes would be a straight in shot, no cutting off the tip to get them in. In Craig's thread on the other site, he did mention that the three disc setup was too restrictive, so he went to a two disc. Just curious what the difference in sound level there is between the CC's and the spirals. They also make a SS packing material that can be put between the discs, and they have plugs for the through tube to either block it off completely, or partially. I gonna keep thinking about it. Every time I make a quick decision, it comes back to bite me on the as*!

[JETAV8R]

I just installed a pair of these today in my FF stainless side pipes. https://www.jegs.com/i/Car-Chemistry/176/2DI35L/10002/-1
I did cut 2" off of the inlet side, and tack welded the restrictor plug to the inlet side. Used a dead blow hammer and drove them in the outlet end of the side pipes. I did not install any of the packing. I then tack welded in place. They quietened my exhaust. It now has a deeper tone. Gone is the high pitch raspiness of my exhaust. VERY pleased with the result.

[GTBradley]

I just installed a pair of these today in my FF stainless side pipes. https://www.jegs.com/i/Car-Chemistry/176/2DI35L/10002/-1
I did cut 2" off of the inlet side, and tack welded the restrictor plug to the intake side. Used a dead blow hammer and drove them in the outlet end of the side pipes. I did not install any of the packing. I then tack welded in place. They quietened my exhaust. It now has a deeper tone. Gone is the high pitch raspiness of my exhaust. VERY pleased with the result.
That’s good news, you wouldn’t happen to have any pictures, would you?

[EZ$]

Ditto to what GTBradley said! I'd be interested to see pictures of exactly what you did.

[JETAV8R]

127468
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127469

[EZ$]

JETAV8R, thanks for the pictures. I'm glad to hear that they helped with the exhaust note. Something I'm going to look into.

[GTBradley]

So, the way I’m reading this is, you got them installed without cutting the side pipe. This is exactly what I’ve been looking for, at least I think. It all depends on what they sound like. I think what I’ll do is make this change on my FFR supplied side pipes and keep my GasN side pipes for show and the track.

[JETAV8R]

So, the way I’m reading this is, you got them installed without cutting the side pipe. This is exactly what I’ve been looking for, at least I think. It all depends on what they sound like. I think what I’ll do is make this change on my FFR supplied side pipes and keep my GasN side pipes for show and the track.

Exactly, no cutting of the side pipe at all. That's why I cut the 2 inches off of the insert first before installing, so it would make the turn in the radius of the turnout of the side pipe.

[chuckster]

The FFR video yesterday is worth watching/listening to. It gives a good idea of what the unaltered 289 pipes sound like. Especially for you, as the car is running Weber’s.

[FLPBFoot]

Exactly, no cutting of the side pipe at all. That's why I cut the 2 inches off of the insert first before installing, so it would make the turn in the radius of the turnout of the side pipe.

Great idea. When you say you tacked welded them in, was it with a MIG gun? A spot or two in a few locations around the diameter?

Steve

[JETAV8R]

Great idea. When you say you tacked welded them in, was it with a MIG gun? A spot or two in a few locations around the diameter?

Steve


Yes. I only did one spot weld. You can see it on the last picture. It's it a pretty snug fit as is. I actually put a little grease around the circumference of the disks before tapping them into place. They probably would have stayed put as is, but just added the tack for safety.

[GTBradley]

I ordered a pair, not cheap when you add it all up, but then again every improvement I’ve done in the last 6 months has been a hundred bucks.

I don’t have a welder, you think a rivet would be okay? Also, I have to think it would have a different note depending on how far in it is, did you try different locations?

[JETAV8R]

I ordered a pair, not cheap when you add it all up, but then again every improvement I’ve done in the last 6 months has been a hundred bucks.

I don’t have a welder, you think a rivet would be okay? Also, I have to think it would have a different note depending on how far in it is, did you try different locations?

I think a rivet would work just fine. I didn't try different positions.