Flexible exhaust insert

[cobrajj]

FFR4FUN, Are the round phillips heads shown securing the insert tube to the SS flex tubing, sheet metal screws or bolts going completely thru the insert and nutted on the other side? Jim

[FFR4FUN]

Hey Jim, the fasteners are 8-32 or 10-32 phillips hd screws with a nut on the other side. I used nyloc nuts but the nylon melted (but still held), I'd use either blue loctite or double nut. I've been running the inserts for the past several days and I really like them, no rattles at this point, nice mellow rumble.

[dajomaco]

Larry, Jim, Very interested in this ...Jim keep us posted on your progress ..Pics Thx Darc

[PUDDY]

Great idea!

[cobrajj]

I've been slowly working on quieting my sidepipes using FFR4FUN's auger insert design. Have the first one completed and the other one will be easier now that I have a pattern to duplicate. Once installed, I'll report on the results. Jim

[FFR4FUN]

Jim, great pics . . . keep 'em comin' . . . really hope your inserts work as well as mine have been. Larry

[cobrajj]

Larry, Thanks for your idea and photos. They've been a big help. Jim

[cobrajj]

Finished my flexible exhaust auger mod for the FFR sidepipes. Followed FFR4FUN and it worked out great. Started up in the garage without earplugs, noticable reduced noise level and no more annoying high pitched bark. Only drove around the block, but I expect it to also be much less irritating on the freeway. Jim

[FFR4FUN]

Hey Jim, so glad that all is going well with the exhaust inserts. If you can, please shoot a couple of pics of the whole side pipe, maybe a couple of angles. The inserts do indeed cut down on the noise level on the freeway. However, the road noise is still pretty tough. My next design effort will be a wind screen that sits behind the seats and maybe attaches to the roll bars. I had a BMW 3 series rag top with a windschutz (German spelling) and it made a real difference in lowering high speed road noise.

[dajomaco]

Hi Jim, Did you have any issues with the first 2 augers going into the smaller part of the side pipe....did they slide in OK or did you kinda have to screw them in ? Thx Darc

[cobrajj]

I cut off 5/16" off of the first two augers, then grinding and trial fitting them, until they would screw into the louvered tube. Used a extra long needle nose pliers to turn the eyebolt, until it stopped, lined up and drilled to allow a 5/16" bolt to be inserted in from the back of the sidepipe(about 45 degree angle). Can't be seen unless you're under the car. Jim

[cobrajj]

FFR4FUN, Here's some photos of the sidepipes you requested. Jim

[dajomaco]

Heres is my inserts...I JB welded in between the pipe and the ss flex hose ...will install in the next couple of days ......I measured the sound level at 101 dbs, we have a city bylaw here now that 96 is the limit ...I hope this works ........Darc

cobra augers.jpg

[Silverstreak02]

Originally Posted by FFR4FUN

Hey Jim, so glad that all is going well with the exhaust inserts. If you can, please shoot a couple of pics of the whole side pipe, maybe a couple of angles. The inserts do indeed cut down on the noise level on the freeway. However, the road noise is still pretty tough. My next design effort will be a wind screen that sits behind the seats and maybe attaches to the roll bars. I had a BMW 3 series rag top with a windschutz (German spelling) and it made a real difference in lowering high speed road noise.

I'm interested is what you come up with for the windscreen. The noise from the pipes don't bother me as much as the wind at 70mph. If you need help posting pictures of that just let me know.

Jeff

[MikeKelly]

Originally Posted by dajomaco

I JB welded in between the pipe and the ss flex hose

I'm pretty sure the JB weld isn't going to last long in the sidepipes. What were you trying to accomplish there?

It looks like you've got the inserts bolted to the flex pipe so you should be Ok.

We're only using 2 per side (with no flex) and we're under 95db @ 6K rpm in second measured from 50'.

You should easily stay under 96.

[emac]

I saved and read a bunch of old posts on this topic. I read about some folks having success installing the car chemistry silencers into the J pipes, I also read that some noticed significant HP reduction.

I am wondering if the augers would do better in the J pipes? They seem less restrictive. I assume the folks installing the augers in the side pipes dont have j pipes or need something that is easily removed for track day. Any thoughts on putting augers in j pipes?

ernest

[dajomaco]

Mike, I was just trying to eliminate any possible rattles by putting in the jb weld ...if it doesn't hold i know that the scews are double nutted and should hold from the vibration .........I will install the next couple of days and let you know what the new sound level is ...I sure hope your right ............Darc

[FFR4FUN]

Jim, thanks for the additional pics, everything looks great. I like the sizzle protectors.
Jeff, I appreciate the interest in the windscreen, it'll be a couple of weeks before I can try some of my ideas. Starting to install new carpeting in the next few days, I'll keep in touch.
Darc, the inserts look good. I'm not sure about the JB weld, let us know how/if it works. I thought about using Hi-temp RTV to fill the space between flex tube OD and insert tube ID.

[dajomaco]

FFR4FUN, Thx on the inserts.....I will let you know how the JB weld works out .......The high temp silicone i think would have been a better idea, i guess wait n see....... should be inserting them on Wed of this week .......will post after that .......Darc Thx again to this thread for all the help ...much appreciated ....Darc

[FFR4FUN]

Hi Ernest, my FFR has j-pipes, several reasons for the flex inserts, they actually reduce noise, cost effective, easy to make and install on already installed side pipes, easily removed for race day . . . I'm really not convinced about any significant power loss on my set up . . . need hard data from a dyno. If you try the inserts in the j-pipes let us know how it works. Larry

[MikeKelly]

Originally Posted by dajomaco

Mike, I was just trying to eliminate any possible rattles by putting in the jb weld

It can't hurt - worst case it burns away.

[dajomaco]

Well....I just finished my inserts and what a difference, Like Jim commented before...the bark is gone and in its place is a deeper throatier sound coming out of the pipes.....the 347 sounds awesome......off for some sound testing this afternoon ........Darc

[dajomaco]

Here is a quick video shot this morning with the auger inserts in ......Darc

Cobra sound - YouTube

Cobra sound - YouTube

[FFR4FUN]

Hey Darc, Really nice ride with a great sound . . . thanks for sharing . . . have a Great 4th!! Larry

[cobracruz]

The Italian,

Can you give details/pics of the turnbuckle?

Originally Posted by The Italian

I did a similar mod but i used a small turnbuckle to hold it in.
pushing on both ends of the pipe
That way I did not have to drill holes in the pipes

[Joe.S]

Originally Posted by dajomaco

Here is a quick video shot this morning with the auger inserts in ......Darc
Cobra sound - YouTube

That sounds really nice. nice lower tone from the pipes.

[SeanHM]

One word:Brilliant. Thanks for sharing and for adding to the to-do list.
Darc- I'm not usually much for red, but your car is gorgeous. Very clean and simple, like they should be.

[dajomaco]

Originally Posted by SeanHM

One word:Brilliant. Thanks for sharing and for adding to the to-do list.
Darc- I'm not usually much for red, but your car is gorgeous. Very clean and simple, like they should be.

Hey Sean, Thankyou on the car ....The car has since been painted blue as this video was shot while the car was still in jel coat ...Darc

[SeanHM]

Originally Posted by dajomaco

Hey Sean, Thankyou on the car ....The car has since been painted blue as this video was shot while the car was still in jel coat ...Darc

Oh that's funny. You know I watched the video like 3 times looking for the seams because it it seemed like it might have been. I was on my phone though. Guess I'm weird because I kinda prefer a not so deep gloss on these cars and that it what it looked like. I think it let's the shape speak for itself without the clutter of too much reflection. That said, I'm probably doing blue too . And flexible inserts...

[Cheapsnake]

FFR4FUN, you still here? You mentioned last year you'd be experimenting with a back windscreen. Just wondering if you fabbed one up and how it worked. And thanks for the flexible insert design, my winter project.

Tom