Rectangular Side Exhaust Tips (pics)

[95PGTTech]

For rear suspension reasons, I need to move to a side exhaust on my 1994GT. I previously had a Borla/SVO setup on the 98 Cobra but there is no chance of it working straight out of the attic due to the subframe connectors and the diameter of the tips/ground clearance. The 94 has no side skirts, pic for reference (not the car, but has similar rear ride height).

I am not a particular fan of the New Edge style Roush side exit (rectangular) but I have little other option. The entire exhaust is 2.5". Tips online range from $50 each to $130 each and I'm not really excited about any of them. I was going to go right over to the garage today and start playing it by ear like I normally do but I'm glad I took the day to draw it all out and come up with a prototype, changed it 3x already.

2.5 round to 2x2 square transition, 2x7 opening. The three slats are merely aesthetic, I thought the open rectangle was pretty boring. The two blue dots are where 3/8" holes will be drilled into the tabs for mounting. Studs are welded onto the underside of the car, allowing nut/washer assemblies to mount and adjust to a small extent fitment of the tip. Pictures are of the driver side tip, will sit immediately before the tire flush with the edge of the rear wheel well.

The immediate concern is solid mounting the tip so it doesn't move around (ask anyone with the Borla setup destroying their side skirts) versus it needing to move for engine movement. The muffler is in the OEM location and is a same side inlet/outlet similar to the Borla and Spintech side exhaust setups. There is a flex pipe between the H pipe and the muffler as well as on the pipe leading out of the muffler to the tip, so I am hoping that will allow plenty of exhaust movement in relation to body and cut down on nasty vibrations solid mounted exhausts can cause. HOPING...

If you would like to copy/modify for your own and can decipher my chicken scratch, here is the notes sheet I built/modified off of.

Comments/questions/concerns? Things I could change to spice it up a little (seems a little blah to me still, but I can't make a rolled edge like I'd like). Any input is appreciated, going to go pick up some more 1/8" plate and C-25 before class tomorrow and get started.

 

[Mustang Matt]

These go under my subframes.

Also, this guy went through his subframes. (This is what I'd do if I were doing it again.)

new mm rear susp install, nascar style side exhaust...cutting holes in subframes... - Ford Mustang Forums : Corral.net Mustang Forum

Or if you want to go all out: Ford Mustang Forums : Corral.net Mustang Forum - View Single Post - Through the body side exhaust?

 

[encasedmetal]

look just like boom tubes from DR. GAS

 

[95PGTTech]

Thanks for the input Matt, sorry I was not more clear in my wording. I meant to imply that because of the modifications that would be required to the Borla exhaust to get it to fit around current other things, it was not worth the effort to get it out of the attic and hack it up, rather build from scratch.

I have a minimum ground clearance specification I need to pass and I'd like to keep my rear suspension as-is, so I have already determined that my subframes (I have through-floor subframes) would need to be notched and the area where my tips terminate the pinch weld would need to be eliminated. These modifications I have already made - the pinch weld is pathetically weak from the factory so I just cut it out and stitch-welded the two plates at the floorpan level. My through-floor SFC is 2x3 bar stock so I was not too afraid of notching it 1" but I ran a second section directly next to it and welded them together similar to how you would reinforce a ceiling joist in a house.

I appreciate that Corral link a lot. For anyone who cannot picture what I am talking about routing wise, nearly exactly like this. I also have the MM T/A, PHB like he does but a H pipe (and much wider). Flex sections exactly where he has them, but an additional set where he has the clamps (outboard of SFC) on the pipes going from the mufflers to the tips.

The pics of the final install make me a lot more optimistic how it will turn out visually, very nice. I have no problem hole-sawing my quarterpanel to run it that way as the entire car needs paint, badly, but in my research I have been seeing way too many unresolved issues both with sealing the hole through the floor and through the quarter as well as in-cabin heat build up. While I do track the car, I still drive it on the street some and I've been trying to keep it away from my typical function over form racecar build.

 

[95PGTTech]

look just like boom tubes from DR. GAS

I had originally earmarked some Cup-takeoff boom tubes on eBay for $200 shipped, but all reports are that they are insanely loud. Like shake the car, shake the block, wake the neighborhood loud. I had LT/no cats/straight through for awhile and just couldn't take it. Can't hear problems with car, can't hear instructor (if applicable), can't even hear headset in helmet. Some tracks I go to have noise restrictions.

Car is currently shorty headers, custom H, and been mixing and matching mufflers. Not many choices when you need same side entry/exit, may have to build my own of those too.

 

[03 DSG Snake]

Yes.

 

[NVRL8TE]

Please post details on every step.

I want this!

 

[na svt]

Please post details on every step.

I want this!

No you don't.

 

[NVRL8TE]

Really?

How come?

Too loud?

 

[na svt]

Really? How come? Too loud?

Would ruin the look.

 

[NVRL8TE]

Oh okay.

 

[95PGTTech]

Please post details on every step.

I want this!

As requested.

I started on the 2.5" round to 2" x 2" transition as I thought that would prove to be the most difficult and time intensive part. As always, proper surface prep is a huge key. I got back to clean metal far enough (or so I thought) to make the relieving cuts.

The four cuts by my math needed to be 1.93 inches apart. I started with 1" deep cuts and later cut them deeper. For now, I'm leaving a long section of exhaust pipe because I don't know how far I am going to need to cut these and how far past that it will need to make the transition smooth. Another way to think about these cuts is every 90 degrees.

After the cuts are made, use vicegrips, bench vice, prybar, hammer, and most importantly...oxyacetalene torch to flatten out the cuts from C shaped to flat. Tacked into place.

And more or less finish welded. I left a bit at the end still loose for final fitment to the rest of the tip.

Started marking out my pieces. I picked up some leftover 16 gauge scrap from my supplier. I eyeballed it roughly the same thickness as the exhaust pipe I intended to use. Pretty thick without being too heavy, holds its shape well, I can use good heat and fast movement without punching through it.

Once all my pieces were cut, trimmed, and labeled, I matched them up to my prototype for final checks.

I worked through a plan in my head of what order I wanted to assemble. This may differ for you if you are a southpaw. Because of all the 90 degree angles, these magnets are cheap and really helpful.

The "slats" or whatever you want to call them are a thinner 22 gauge. I felt no need to go with the thick stuff on the inside decorative pieces.


All tacked together

Some of my welds are finally starting to get there, I need to upgrade this machine. I think I'm finally at the point where it is becoming the limiting factor, not my inability.

All finished. I was originally going to weld all the seams, but since the plate fitment turned out so sharp and I was able to weld it so solidly from the inside, I think I'm going to leave it as-is until I finish the other. I'm not worried about leaks in the last 4.5" of the exhaust and I think it gives it a sharp look.

A keen eye will notice that I didn't cut the different "C" section that I had drawn out with mounts built in, on advice of my wife. I later built them separately. I will attach them to the tips once I decide what orientation (triangle forward or backward) and what side of the car each tip will go on. I'm using 3/8" hardware so I drilled 1" wide 16 gauge to 9/16" in my press.

The sides are 1" x 1" on the long sides.

This gives some idea of how they will mount. One on the front side of the car, one on the back. Imagine the bolt as a stud welded to the chassis. There is a washer and nut on the underside as well if you cannot see, sorry trying to hold with right hand and take picture with left. Adjustment is like a tie rod end - loosen the top nut, adjust the bottom nut up or down, tighten with top nut to lock in place. I am hoping that the flex pipes and length of tubing will allow for some "final fitment" to be done by these adjustable hangers at the rocker panel.

Also, I cut up one of the Borla mufflers I was talking about earlier (2.25"). I have been researching a lot of DIY mufflers online being that same side entry/exit mufflers range from $150 to $250...EACH. But all the tech has been on straight through mufflers that seem more like resonators to me. So I decided to take this Borla apart to see how they make such a quiet muffler. Surprisingly simple and very similar to the DIY designs. I think later I will try and tackle my own mufflers.

 

[NVRL8TE]

Wow. How cool.

Nice work.

Respect.

 

[95PGTTech]

Wow. How cool.

Nice work.

Respect.

Thank you. I just realize I forgot to post pictures of the muffler dissection. Pretty simple setup, perforated tube wrapped in steel wool type material then fiberglass insulation. This makes me quite a bit more optimistic about making my own mufflers and having them not come out as just glasspacks.

The only issue I am running into is no one makes bent perforated tubing. I guess I could make that 180 bend internally and then drill holes in it myself but I'd be there forever. I'm down to two options:

1. Run the first pipe inlet (left) in straight, terminate it a few inches from the back wall of the muffler. Do the same with the right side (outlet). Eventually, sound waves will find their way bouncing around the muffler to find the outlet. Possibly do some kind of baffle on the back wall to bounce it toward the outlet. Many mufflers with opposite side exit/inlet that are offset are done this way (no complete connected perforated tube like the dissection). What effect this will have on flow or sound is beyond me.

2. I could easily make that bend with perforated sheet by making a square instead of round tube (think how I did the 2x2 out of 2.5"). Again, what effect this would have on sound or flow is beyond me.

We'll see, I have a bunch of other stuff I need to get sorted out with the car before I get to that point. Sorry, as quick as I was to fabricate the first tip after thread start date, the next update of the thread won't be for another couple weeks. I need to get the rest of the crap in before I worry about routing the rest of the catback from the H pipe to the tips.

 

[SublimeRT]

Cool thread. Nice work. Gives me some ideas. I pm'd you on the corral a while back about your cobra project. Nice to see you're still at it.

Sent from my SGH-T769 using Tapatalk 2

 

[95PGTTech]

Cool thread. Nice work. Gives me some ideas. I pm'd you on the corral a while back about your cobra project. Nice to see you're still at it.

Sent from my SGH-T769 using Tapatalk 2

Just sits these days. Money, an injury to my wife's shifter arm that is still unresolved, and needing decisions on powerplant and drivetrain. It came down to either sell it or let it sit, and we've had it so long I couldn't bear to sell it. I have a two car garage so I just finished up the SFCs and periodically wash it.

The 94 is my DD that we took off the road for winter (and her being out of work and unable to drive, to save money).

 

[95PGTTech]

Finished up the other one yesterday. Will be awhile before I get them on the car. Pretty happy with the turnout considering the cost.

If anyone is interested in the original prototype/mockup piece and my notes (pictured) $15 covers my gas to USPS and a flat rate priority box. I'll hold onto them for a week in case anyone else feels they want to use the plans or modify them to their liking.

Mufflers are the next project.

 

[Nickynick]

youre a baaad dude. nice work man!