Tibo

iTrader: (15)

Moving onto the next project of making a re-packable muffler. I had heard from a friend that it's common for racing bikes to use a muller that can be repacked, he even showed me some of the packing he had. I started doing internet searches and it seemed like something relatively easy to build.
I bought all the materials and am only waiting on the 5" stainless tube to arrive. In retrospect this is something that I would have been better off had I purchased the exact muffler I wanted from Magnaflow and used it till it lost it's sound deadening quality and then cut it open to repack it and then welded on a seam that could be riveted onto the body.

I purchased a sheet of 20 gauge stainless with 1/4" perforations making 58% of the sheet open. Magnaflow and borla from the pictures I've seen look like they use a more closed off sheet. I wrapped it around a piece of 3" OD tubing for the middle and on the end I used the exact 3" stainless pipe I would use for the exhaust. I also cut a strip of stainless that was 3/4" wide and the same length as the tube I was making, 24". I made sure to leave some overlap of the ends and put the stainless strip under the overlapping ends. I next used simple radiator clamps to clamp the entire assembly together which took about a dozen clamps. You can see in the pictures I got everything to overlap and line up near perfect.




I had originally tried to use some thin TIG rod for stainless but it was requiring too much heat and I was melting the honeycomb so no dice. So I had to make a second assembly and this time I used TIG brazing rod for stainless and was able to TIG it up. I only broke through the honeycomb on one or two spots but it turned out pretty good with noticeable distortion.



This week the 5" tubing will arrive and I can hopefully weld up the whole thing.

Tibo

iTrader: (15)

The 5" tube came in this week. It was 30" long and I had the ends expanded to fit over a 5" tube so that I could cut off the expanded portion and use it as the sides of the end cap. I made the whole thing from scratch. I looked into what Magnaflow uses in their mufflers and it seems to be a layer of stainless steel wool and then a thick layer of fiberglass. So I bought a roll of stainless steel and a 24"x24" square of ceramic fiberglass. This stuff won't catch on fire and is supposed to with stand temperatures up to 2000° F. I'd like to have an officer come out with a sound decibel meter and take one reading with my old glass pack muffler and another with this new muffler. I've seen YouTube videos where they posted mufflers with decibel ratings and it would be neat to compare. Anyway, the muffler body is 24" long and the end cap is held on by three rivets but honestly it is a bear to get off without the rivets. The whole assembly is tight. I used a V-band clamp on the entrance of the muffler.

robguitargod1

iTrader: (4)

Looks awesome! I gotta hear them, and let me know how the v-bands seal? I've NEVER been able to prevent warping during welding and I've tried everything.

I tried these and they're very good:

https://www.ebay.com/itm/MARMAN-FLAN...~1uL:rk:2:pf:0

Tibo

iTrader: (15)

I'm looking forward to hearing them too and as long as they don't scream "look at me! " everytime I step on the gas (like this current blown out glasspack does) I'll be happy.

For distortion in welding I took some advice of using heatsinks for as much as possible. I went down the metal recycling yard and they sell scrap aluminum for $1/lb. And Steel for $0.30/lb. I got a bunch of flat and circle and angle and it's helped on thinner stuff. I have some saved YouTube videos on distortion I'll edit this post later and add them in.

I went with the V bands because you recommended them. They are much easier to remove than a guillotine clamp. I'd be surprised if the V bands have a noticeable leak, their isn't near the pressure that turbos see.

the muffler is sufficiently long enough that I'll have to mount it in the stock location to avoid the import tuner look of having a muffler sticking out right under the bumper.

Tibo

iTrader: (15)

FWIW to the guys that follow this build thread, I was nominated for COTM and voting is going on : https://www.thirdgen.org/forums/auto...tm-voting.html

Tibo

iTrader: (15)

Took a break from wrenching to take some early morning pictures from atop the dam. Mainly took them for the COTM voting page (https://www.thirdgen.org/forums/auto...tm-voting.html), but good pictures none-the-less. Ill get to welding up the new exhaust next week.

MeenZ28

The outside pics look great! That side shot.... OMG... perfection. One question... you planning on any kind of grill or just leaving it open like it is?

Tibo

iTrader: (15)

I'm okay with leaving it open, as is. I have one of the bar grills from my previous Camaro if I want to use it. What do you think?

Billgluckman

MeenZ28

I think it looks fine open the way it is... i just think if you do that you need to paint the support black... that white bar with the white of the mounting taps from the bumper make it a little strange.

FART_NUGGETS

I agree about adding a grille or something down there. We know better, but it kinda looks 'unfinished'.

FART_NUGGETS

But yeah also leaving it open and blacking out those tabs and the lower rad support would work also.

Tibo

iTrader: (15)

I might try that first, painting black the tabs and the lower bumper bar. You've never noticed them because there's usually the license plate plastic there.

IROCZman15

iTrader: (25)

yes, put a grill insert in for sure it will look finished


those headlights lights make it look very tired. a sleepy camaro

Tibo

iTrader: (15)

Put the car back on jack stands and started work on the exhaust. I'm just remaking the whole thing from scratch from the headers back. I bought 5' of 2.5" stainless tube and 8' of 3.0" stainless tube. Doing the entire length with pie cuts-- no pre-made bends or taking sections to the exhaust shop for bending. So 2.5" from each header into a Y just behind the transmission cross member and then a single 3" to the axle, over it and connecting to the repackable muffler I made. To make the bends I cut opposing 7° angles on a piece of tubing that is 1/2" wide at it's shortest point. Each angled section has to mate up with another section that is within 7° of the other section. If a pipe's cut is more than 7° different then it will not mate up well and you will have an underhang on one side and an overhang on another side. So a 90° cut will mat up with a 83°, 90° or 97° cut. Even though it seems small you can make some really tight turns with 7° cuts, much tighter than a bending machine can allow.



Here is the progress after a few hours, most of the time is in cutting the angles and finding the best mock up position.




Worked on it for another 90 mins the next day and I'm now ready to make the Y-pipe portion which will be the hardest part...




So next week I will start on the Y pipe and assuming it doesn't take too long then the over axle section.

91ls1t56

It looks much better than I thought it would. I am curious why would you do it in this fashion ? When I did my exhaust I used the mandrel bends and they worked out very well.

Tibo

iTrader: (15)

Thanks. It's actually kinda fun making the exhaust with pie cuts. Very tedious but you can get it to do exactly what you want it to do and it just looks like a smooth snake.

Perhaps the biggest was cost. The tubing cost me between $75-100 and the welding supplies are minimal. I also enjoy projects and this is time consuming. The next reason was because with the pre-bent sections I think I'd be somewhat limited in how tight I could get everything to tuck up. The car is pretty low so any additional clearance I can gain, even 1/2" is a help. Also once one of the bends is cut, if it's wrong you are down a bend.

Can you share any pictures of the subframe connectors you made?

91ls1t56

Your pie cuts have a 90° side and an angled side? That makes them 1/2 pie cuts. True pie cut would be angels on both sides equal distance from 90° center line. If you were to divide a mandrel bend into equal peices it would be a true pie cut and not be a waste after one cut. You would be able to make tighter bends with less welds.

Tibo

iTrader: (15)

I allow my pie cuts to become whatever they want. I encourage them to experiment and try different angles, whatever works for them works for me.
If a particular curve works better with mating a 87° or 83° to a 90° I will but most of the curves are 7° on both sides. The picture I posted is a 7° cut on both sides, you can see the tubing has been turned if you look to the left side.

No way can you make a tighter bend with a mandrel than a pie cut. If that's what you're saying.

91ls1t56

Maybe rotating them makes them look like 90° on one side. Sure you could run a pure tight stove pipe 90° and that would flow terribly.

Billgluckman

Tibo

iTrader: (15)

I bought an AHP AlphaTIG 200x a year ago and am TIG'ing it together with 0.045" TIG rod (309L maybe). I think I'm using a 1/16" electrode. I've got Argon as a shielding gas but for the backside I'm trying out Solar Flux instead of backing it with more argon. Some of the welding channels have had made videos of solar flux on the backside of stainless and shown adequate results. Some of the other well known welders have even admitted to not even using anything to protect the weld on the backside when welding up stainless exhaust. Their thought was that while the weld could eventually fail the part probably won't see enough use to reach that point. Jodi on WeldingTipsandTricks had a good round table discussion on this.

Tibo

iTrader: (15)

There are one or two that are 7° cut on one side and a straight on the other but I just looked for them and I can't even pick them out of the lineup. One was on the driver's side just behind the transmission crossmember and the other was passenger side almost where I stopped.

Billgluckman

Tibo

iTrader: (15)

I do a quick spot weld in three places on the outside of the tube and then I brush the inside with the Solar Flux. Then I'll go back and weld all around. Using a MIG would be much faster but I think I would have more issues using a MIG. Like blow through. With TIG I have loads of control.

Billgluckman

Tibo

iTrader: (15)

https://www.harborfreight.com/butt-w...-pc-60545.html

I've used these guys when doing MIG welds on exhaust tubing and sheet metal. They worked great as long as my travel speed was fast enough, otherwise I would just burn through. But on sheet metal especially, once the weld was ground down you couldn't even tell there was a weld there.

Tibo

iTrader: (15)

Got some welding done last night. Slow going since I can only weld about an inch before I have to roll the tube or move to the next section below. Most of the welds are good, a little hot but OK. Some of them get that Champagne color but I'm a ways from a pretty rainbow weld you see on YouTube.

Tibo

iTrader: (15)

I was able to make the Y portion of the exhaust this past week and it was easier than I thought it would be. I decided to have the passenger side portion straight and the driver's side portion angle into it. I eyeballed (conservatively) about where and how I needed the driver's side tube cut and cut it in the bandsaw. I checked the fitment and just slowly took more out with a cutoff disk and then rounded it out with a carbide bit. Fits up pretty good. The tubes from the headers are 2.5" and the merge pipe is 3.0". I just crushed the 3.0" pipe down to 2.5" in the X dimension and it fits pretty well. I'll tack it up and weld it in place this coming week and then move on to the rear portion of the exhaust.

Tibo

iTrader: (15)

I also decided to modify the headers to also accept a real V band flange so I cut off an inch and welded on the new end. I'm slowly getting better with stainless steel, I've heard for regular guys it helps to use one of the clear monster sized cups so I'll buy one this week and give it a whirl.

antman89iroc

Holy geez that's a lot of pie cuts. Sure a few pre-bent pieces wouldn't make sense? It looks like you're doing a great job and I have done this enough to appreciate the work performed so far. I mean, your in this far and it will work but you could save yourself a lot of welding and internal turbulence if you selectively used SOME bends. They're not evil

Tibo

iTrader: (15)

You're right on all of that, no argument here. I wanted to stay away from pre-bent mandrel sections because it saves a ton of money and I really don't think I could tuck it under and around the transmission as well. Pre-bent sections or angles for over the rear axle would work out great but I already have enough 3.0" tubing and I don't need to drive the car and the next car show I'm doing isn't until February.

I'll try to post a picture of the inside of the butt-welded section, the Solar Flux really seems to be doing a good job.

antman89iroc

Tibo

iTrader: (15)

Here is the Y portion of the Y pipe. It took less time than I thought it would to make.



The inside took me some time because I forgot to remove the overlapping section before I welded it in place but it turned out fine IMO.



Everything from the Y pipe up welded together.

Tibo

iTrader: (15)

Proceeded to work on the middle portion which obviously goes much faster. I'm still trying to find a spot (or if I even need one) to put an exhaust hangar for this middle section. The 16 gauge tubing is pretty light so I don't think it's putting much stress on the headers.



Welds are looking better. I'm not burning out all the stainless qualities of the metal and I'm shrinking my heat-effected zones. I found that a pulsed lay-wire technique works pretty well some of these joints.



With that rear V-band welded on the center section is complete

Tibo

iTrader: (15)

The rear portion I'm still working on but it isn't too bad. My thought is to bring mount the muffler in the stock orientation, sideways to the car and then have a short length of tubing that directs the exhaust down and back in the direction of the driver's side rear corner. I'd like to hide the exhaust tubing from sight. So in the picture where the pipe is stopping I will make a 90° turn and weld another V-band clamp to that where the muffler will attach. I will use the stock rear hangar locations (I'll be making my own though) and I'll be mounting the heat shields.

antman89iroc

Looks pretty good T. I didn't use a hanger in front of the rear axle. If you are going to have a hanger for the tail pipe(s) then you probably don't need it. I see you have a disconnect in front of the rear axle too. Good idea, I wish I had put one there. Mostly so I could drop the mid pipes for open headers at the track. I put my disconnect at the "Y" so it's just at the trans rear. I can drop the mid pipes but the rest is still there.

Tibo

iTrader: (15)

Have you noticed any excessive swing in the exhaust or stress on the headers or anything?

That was one of my must do items, the ability to quickly and easily disconnect the exhaust in sections. Although I might end up having to add in another V band if the over axle length is too long and curved to be able to curve in. I should have it done this coming week so I'll know soon.

antman89iroc

No issues, rattling or noise.
Don't remember having a hanger in front of the rear axle from the factory. The car was 16 years old when I bought it but was 99% stock.
My car has shorty headers so the collectors aren't in the same position as a long tube header. Not sure if that matters but everything hangs well and doesn't come loose. I used typical 3 bolt flanges which are subject to working loose if the exhaust moves around a lot.

Tibo

iTrader: (15)

Looks like I have the over-axle section solidified. Just have to finish welding a few seams on it. Kinda pretty isn't it?




Some pictures of it on the car, albeit with poor lighting and no hangars yet.

Tibo

iTrader: (15)

Here are the hangars I made. They are stainless rod of 3/8" welded to a 1/8" plate of regular carbon steel with some 309L filler rod. I just heated the rod up to orange hot and bent it in a vice with pliers. I was pleasantly surprised to see how much better I am at welding carbon steel after all of the stainless welding I've been doing.




This week I'll be welding the last few seams on the rear tube, forming a turn down and welding the stainless rod to the tubing and hanging it up. Really excited to start this up and fingers crossed it doesn't sound like a fart can muffler. I still have projects to do on this car but the holidays slow down any projects to a crawl...

antman89iroc

Looks very good. Did you end up with enough clearance over the rear axle? Looks like it hangs down pretty close to the tube there.

Tibo

iTrader: (15)

In person it looks like there is enough clearance everywhere. I guess I won't know for sure until I go driving around over some bumps and dips. The front springs are 950# and the rears are 200# so I won't have as much movement as a stock Z28.

antman89iroc

I hear you, it's difficult to tell just from pics. BTW you are doing a ton of quality work. No one will ever truly appreciate how much goes into it unless they've done it themselves.

You mentioned spring rates, do you happen to know what the "stock" F/R rates are for a Z? I was looking into fronts and couldn't ever really find out the stock spring rate. Haven't tried calling a manufacturer yet so I'm curious at this point.

Tibo

iTrader: (15)

I appreciate that. The downside to all this work is that it makes me very sensitive and protective of this car. Protective in that I'm skittish to drive the car in town because of the bad/illegal/drunk drivers that could total or seriously harm the car. Sensitive in that I get upset if the car doesn't do well in a contest, hence why after November I won't do another COTM.

I'd have to look, I thought it was 600# for the strongest OE front springs. The Eibachs I heard were barely above them at like 630-650#. The rears are 130-160#

antman89iroc

I hear you and understand. Some people are very content to put a car cover on and park it in the garage. Trailer it to shows with every nut and bolt polished. Nothing wrong with that. Me on the other hand want to actually enjoy driving my car. And with driving comes the risks. I somewhat drive like I am riding a motorcycle, very defensively. And I don't do street racing or donuts like I used to do. I found it is better to be safe but relax about driving and really enjoy the experience.
My car isn't a show car so I don't know exactly what you mean by the COTM contest but I do regularly drag race. One thing I have learned is there is always someone faster. Car shows can be personal opinion driven so I wouldn't take it too seriously. Again, enjoy the ride. If it's not for you then do something else. Because you want to not because you feel someone else wasn't fair, that attitude leads to a lifetime of disappointments.

QwkTrip

iTrader: (22)

Tibo, my exhaust is similar concept to yours. The exhaust midsection gets extremely rigid once the over axle portion gets tightened up on the muffler. You probably won't need a middle hanger. Although, my exhaust hangers are more rigid and bolt to the frame so maybe that's the secret (Stainless Works hangers, https://stainlessworks.net/products/...ps-and-hangers)

Tibo

iTrader: (15)

Got the muffler mounted in place and started it up, sounds great! Much quieter than before and still has a deep sound to it, absent is that higher pitched cackle that you hear out of some glasspacks that I was afraid I might get. I'm hoping to find someone with a Magnaflow at a car show that I compare sound to. Very happy with this project!

Tibo

iTrader: (15)

Yes, once it was secured in the stock hangar locations on both sides it became pretty sturdy. So you're right, no middle hangar needed.

Tibo

iTrader: (15)

Took the car out for a drive and it really sounds fantastic, so much fun to drive. Before while driving I would shift at 3K RPM and it would be so obnoxious but now I can accelerate up to 4K RPM and not worry at all about a loud exhaust ticket or dirty looks from the retirees in my subdivision. Unfortunately I am leaning towards the Pilot bearing needing replaced. I used a needle bearing when I installed the last time so as I understand I shouldn't wait to replace it. Supposedly the needle bearings can chew up the input shaft and a new input shaft is $100 plus the cost and time of rebuilding the transmission. The noise only occurs when I am pressing down on the clutch pedal and the noise sounds very similar to what an impact wrench or loud cricket would sound like. It began after about 20 minutes of driving and the car still drove fine and shifted without any noticeable difference. If I barely press the clutch there is no noise but the noise increases in volume the further you press the clutch pedal. The clutch was almost new when I put it in last summer and it's only been driven 100 miles. My thoughts were the throw-out bearing or Pilot bushing with me favoring the Pilot bushing but I'll be replacing both anyway. I'll also use a Pilot bushing this time instead of the bearing.