Custom sidepipes - Phase I

[RedBarchetta]

I was going to create a "Phase II" thread, but I thought I'd keep everything together and in one place for anyone's future reference. If you haven't taken a peek at page 1 of this thread, you are better served to start there.

This update will cover the fabrication work on the pipes. Here is how everything looked after I pulled the stock (and ceramic coated) Superformance side pipes from #747:



As you can see, the Stainless Specialties custom mufflers were built to exacting specifications, with exception to my requirement to add one (1) inch of length to the case. As was discussed prior in this thread, this was done so that the fabricator had enough material to work with to maintain the exact length of the entire assembly from the collector to the tip of the tail pipe.

Here is an "after" shot of the side pipes once Alex Mikkelson of American Roadster (Placentia, CA) did his magic. I laid a factory muffler beside them for reference:



Alex is a pro, having done all the chassis work on the recently restored BankAmericar front-engine top fuel dragster. He also did all the chassis work on the Hot Rod eBay rail dragster (both cars were heavily featured in the magazine). Alex's attention to detail was incredible, as he built a temporary jig out of scrap tubing and spot welded it right to his work bench! This allowed him to match all of the correct angles, lengths and attachment points (especially for the side bracket, which had to be dead spot on). Alex got $250 for his efforts and I was more than pleased with the work. Word to the wise: Muffler shops can't handle this type of work. If you are not an advanced welder, then farm out the work to someone that knows what they are doing.

I did a quick reassemble to ensure everything was true and both sides bolted up with hardly much effort (driver side was too easy and the passenger side was maybe 1/16" off...a little coaxing got the side bracket to match up). Unfortunately, I did all this in the wee hours of the morning and couldn't fire it up.. So I tore it back down and that same day sent the pipes out to Embee Coatings in Santa Ana for a fresh ceramic coating (just as before). Embee gets $300 plus tax for their efforts.

I will get the pipes back in roughly two weeks time, in which I will then report on the sound and performance. "Eric" has another thread going on right now in which he has performed a near-identical modification to a similarly configured (stroked Windsor) Superformance. He's reporting over 20HP and 18FtLbs improvement with just minor jet tweaking (to compensate for the lean condition that the better breathing will cause). "Karl" is another CC member that did this exact same mod on a 514CI Superformance. He says they sound "crisp", certainly louder than stock, and the seat-of-the-pants performance increase is a seat wetter! Woohoo!

Stay tuned for the final chapter on this whole odyssey, which has cost me about $950 once you add in some new gaskets and all new grade 8 fasteners for the flanges. Some may say that this is a lot to spend for arguably a 20HP increase. Consider two factors. (1) The factory headers are not Hooker Super Comp quality, so those will eventually go next, and (2) I was after a much more aggressive sound versus achieving the power increase (which was obviously going to occur).

-Dean (now going through the tool box looking for some ear plugs )

[Lowell W]

Dean,

Thanks for a very interesting thread. Eric and I have discussed a similar modification to my mufflers but at this point I'm still willing to sacrifice some HP to have a (relatively) quiet car, since I spend a lot of time in it and already go "Huh?" way too much. I'm hoping to see some cars with the muffler mods at the London show in June.

Great idea to have them make the mufflers an inch longer to give the welding shop some wiggle room. I'm wondering whether making the OD larger (1/2"? 3/4"? 1"?) would help reduce the sound level or whether there's some possible balance among OD, core diameter and length which would give back some of the performance, not increase the sound level by too much and not look strange. Anybody?

One quick suggestion. You said:

... the passenger side was maybe 1/16" off...a little coaxing got the side bracket to match up).

On SPF's, the rubber-cushioned brackets which secure the mounting brackets on the sidepipes are none too sturdy. Mine separated during the first year. When I replaced the brackets, I found a little misalignment so I either enlarged the mounting holes or drilled new ones (can't remember now) so there would be no tension on the brackets at rest.

Thanks again for starting a great thread and sharing your info.

Lowell

[RedBarchetta]

Lowell, thanks for the kind words and suggestions. Yes, my rubber-cushioned mounting brackets are already separating (one worse than the other). I called my local dealer and they stock them for $20 ea, so I plan to pick up a pair and use one of the old ones for an emergency spare. Like you, I will probably elongate one or more of those mounting holes to relieve the tension on the passenger side.

Just as a heads-up, the additional 1" of case length actually proved to be about 1/2-3/4" more than I actually needed. Alex (the fabricator) did such a clean job cutting the old mufflers out that I'm actually going to re-sell them. But if anyone is unsure, the 1" is plenty and it didn't change the look of the pipes at all.

Sunny and 75+ here today....and no pipes. Waaahh!!!!!

[misfit41]

I wanna share a sidepipe idea I have had for opnions.
I had thought of using a straight 3 inch tube slid inside an empty muffler blank with the air space between the 2 filled with heat resistant material of some sort,I have some of the ceramic cloth left over,then using racing baffles inserted inside the full lenght inner pipe for sound deadening,the goal is to make a stock looking side pipe that may not burn skin upton contact while having an adjustable noise level via slidein racing baffles.
will this work ? thanks,Tim

[bmcmillan]

TK

I think the heat will still travel along the outside from the collector anyway.

Brian

[bmcmillan]

Tk

By the way, you might want to start your own thread with this topic. This is kinda Red Barchetta's thread and we don't want to be accused of hijacking it.

Brian

[ezplans]

Dean, what's the latest?

Bill

[RedBarchetta]

Bill and all,

Still waiting on the ceramic coaters!!!

They've had the pipes for 3 weeks now. Originally committed to 2, then stretched it another 1. Called them today and the pipes should be ready on Monday (April 18). They told me they completed the first coat and the second coat was today. Then off to the polishing dept on Saturday.

Keeping my fingers crossed! I don't think I can add another coat of wax to the car. In the meantime, I've stocked up on jets and carb bowl gaskets in anticipation of a lean condition after the install. Will take the car down to a local shop that has a A/F probe and we'll dial-in the mixture, accordingly.

As promised, I'll have pics and a full write-up when installed.

-Dean

[ezplans]

Dean - Keep on them, nothing better than free horsepower and good sounds.

Bill

[JAM1775]

C'mon Dean....You don't have to wait . Fire that big boy up as it is right now and see if you can knock the blackbirds from the trees !!!!

[RedBarchetta]

* * * F I N A L - U P D A T E * * *

Well, for the faithful that have been following this thread for the past few months, I now have the final results in (well, sort of!). Here's a quick pic of the driver's side installed, with the passenger side still in the wraps from the ceramic coater:



First of all, these pipes came off a whole lot easier than they went on! Of course, doing this as a one man job required some dexterity and ingenuity (blocks of wood to prop up the other end), but it all went together as nuts and bolts should. You will also notice that the new stainless mufflers have two ridges going around the pipe (each about three inches from the ends). These are where the inner core is welded to the outer shell. It's part of the design that went into these things, creating a chamber fore and aft to prevent too much expansion and splitting. It's not as "clean" as the factory SPF pipe that had no ridges from end to end, but keep reading and you'll then know why it's not a big deal to me.

OH MY GOSH!!!! THE SOUND!!!!! I think the best way to describe it is "all business." Night and day versus the factory SPF mufflers. If you are running a small block like me, you want this set-up. It will make your car sound considerably closer to a BB. Much more crisp sounding at idle and a great gurgle off idle. Get past 2,500 rpm and they really start to sing! If you want quiet, this is not the route for you. But let me tell you, they are not excessively loud. Louder than stock SPF 2" cores? Definitely yes. As loud as straight pipes? Definitely not even close to straight pipes. Just a gutsy "I can hear you from two blocks away, race car-like roar." Like I said, they will know you are "all business" as you approach.

I put about 10 miles on them, then re-tightened all of the bolts. I will need to jet-up a few notches, as it's undoubtedly running a tad leaner now. I also plan to take the pipes (on the car) back to Alex Mikkelson at American Roadster and he's going to add some stainless steel gussets to the side brackets. I should have had him do this when he did the the fabricating, but I neglected to do it and I'm already experiencing a slight crack in the passenger side (it happened during the re-install, not after I fired it up). We are going to use 3/4" stainless steel strap and he's going to mount it in such a way that the only people to notice will be the ones with their noses to the ground. Oh yes, he can definitely do this with the pipes on the car, so I don't have to yank everything apart.

Last comment. I don't want to lay blame on anyone else that has handled these things, but they did come back from the coaters with a couple tiny dents (smaller than a dime) on the passenger side pipe. They are noticable and I'll just have to live with them. I did not have the coater sign any kind of waiver prior to dropping them off, so I can't prove that their people put them there (although I'm 99% sure they did). When you consider the multiple steps they put piece of metal through just to ceramic coat them, it's no surprise when you see stuff like that.

In closing, this has been a very long project and has cost me close to $1,000 end to end. One with welding skills or access to friends that have the right equipment can cut into that cost significantly. For only having driven 10 miles, I'm a very happy camper with my re-born sidepipes.

[excelguru]

Can you show some pics of the insides of your old muffler sections, for comparison? Your new ones appear identical to the ones Unique uses and, yes, they are quite loud. A fellow SPF owner in Atlanta (who collects toys) once commented on how loud mine was.

[RedBarchetta]

Keith, if you do a search on this web site under "SPF sidepipes" you will find a thread in which a guy cut one in half. Take a perforated tube 2" in diameter and surrounded by steel wool and you can picture it. Superformance clearly took the conservative route when they spec'd their mufflers, but unfortunately they are too restrictive.

-Dean

[RedBarchetta]

Keith, as a courtesy to you and others that are curious, I took a quick pic of the stock Superformance muffler. I've also gone ahead and reposted a previous pic on page 1 of this thread so that you can see the difference.

Factory Superformance muffler - 2" perforated I.D. with steel wool as a packing material:


Stainless Specialties custome muffler - 3" perforated I.D. with ceramic matting as a packing material:


A better view with a baseball rolling down the center.


Hope this helps!

-Dean

[excelguru]

Got your mail. Thanks. Yeah, that should make quite a difference in sound, indeed! Ya gotta love that sound!

[bremillard]

Red,

I just finished modding my stock Shell Valley mufflers. I cut the muffler apart and used a Car Chemistry baffle and vortex cone in each one. I had to richen carb 6 jet sizes to compensate for more efficient flow. I did not dyno test before so I cannot tell you how much h.p. the mod was worth but throttle response is much crisper. My total cost was about $500.00 including the cost to recoat. -Bob

[Edley Rondinone]

Dean---How do you like your new sidepipes by now? Any chance of me coming down this weekend and checking the sound out?

I have to replace my sidepipes, as one of them has a broken baffle.....!

[trularin]

Red, those pipes look very nice.

Did the ceramic coater send them that shinny, or did you have to polish them?

I had mine ceramic coated, but I wanted the duller "Silver" finish. Now, I am not so sure.

[Tongue Pirate]

Wow! Those look awsome!

[RedBarchetta]

Hi. Let me answer a few of these inquiries.

trularin, the pipes came back from the coater pretty shiny. If you rub them a little with Mothers Billet (or other fine polish) they come out even shinier.

Edley, I'll send you a private message with my cell phone. My kid has a ball game Saturday morning, but I should be around the house early/mid afternoon.

All, the pipes sound CRISP and they growl! They are measurably louder than the stock offering, but I am very, very happy with this mod! I think I've said it here before, but I honestly feel that the car now sounds like a Cobra should. So many people think I'm running a BB since the change....

BTW, I do wear ear plugs, even around town. Not going to chance losing my hearing (not to say that rock concerts and weekends at the drag strip 20-25 years ago haven't already done damage, but why chance it?).

-Dean