Paul L

And we shall see how they turn out.

My Borlas are now in Arizona and I hope the Forum Member who purchased them is pleased those units. No doubt he will report when they are installed. My concern was with the straight-through pipe design and the possibilty that they might be a little bit much for my tastes. Others will enjoy the exhaust tone immensely, I am sure. So I sold rather than install.

I did a lot of searching to find a muffler that is a little above stock in terms of noise but reasonably efficient with flow specs. My search led me to a company called SpinTech. Apparently they are very well known in the race-car community but not much so for street applications. So I searched their patent as I am fascinated with radical product design of any kind. And here is what the innards of those mufflers look like. Very different. Promising low noise levels in the Sportsman Street XL series with high-flow performance. I ordered a pair of their 3334XL units.



This is their web site.
http://www.spintechmufflers.com/spin...ntechindex.asp

If you go to the US Patent Office web site and plug in patent #5824972 you can get a good read on the design concepts. Really interesting!
http://www.uspto.gov/

I will let you know how noisy they are!


[Modified by paul79, 6:08 PM 2/16/2003]


[Modified by paul79, 6:12 PM 2/16/2003]


[Modified by paul79, 6:13 PM 2/16/2003]


[Modified by paul79, 7:01 PM 2/16/2003]

Alwyn678

Cool I hope you like them :cheers:

ram82fire

Could you please tell us what they cost ?

Geo :rolleyes:

Paul L

They were $90.00US each.

Ken73

Interesting design.. there's also Ravin mufflers that have an interesting design also.

I think I've pretty much decided to go with the Warlock mufflers with the built-in bypass for racing. It's a typical s-flow muffler with the cap on, and uncapped it's literally a straight pipe. I wanted something I can uncap at the track but keep quiet during normal commutes (since my '82 is my daily driver.) Not to mention, I think Momma and I are going to take the '82 up to Bowling Green in May.. she'd probably want to strangle me if I put something loud on!

OHSIXX

They look smaller than the Borlas. Sorta boxy looking. They even look loud. It will be interesting to hear your opinion once they are installed.


[Modified by OHSIXX, 7:10 PM 2/16/2003]

joe73vette

A friend had them on his BBC Impala. For 10 minutes. They were so LOUD! This engine has had 2 chamber flowmasters, Edelbrocks, Dynomaxs and flowtechs. The spin techs were the loudest. He was setting off car alarms on both sides of the street just cruising at 10-15 mph. He has a Dr gas x pipe in it also. But you never know until you try them on your car. Joe

Paul L

They are boxy looking. But larger than the Borlas. The Borlas are 4x9 1/2x14. The SpinTech XLs are 4x9 1/2x16 to accommodate a sixth set (beyond the pic) of those cylinders to reduce noise.


[Modified by paul79, 7:24 PM 2/16/2003]

Paul L

Joe,
See my post above and check the SpinTech web site re the XL series. Your friend may have had the race series. But I will find out ;) .

gdh

I hope that they work for you Paul, I am very pleased with my Ultraflows, not too noisy but great flow rate. I love the sound of sidepipes as long as they are not on my car, just too loud and as for some of the flowmasters - the resonance got to me as well.
That being said, I am looking at an electric cut off switch for the occasional 1/4 or if my maturity goes south while at a stoplight beside a Civic with a hyperactive fart pipe. :rolleyes:

joe73vette

You are probably right, I didn't know there were different types. Joe

Paul L

Joe,
It's a real gamble on mufflers. You just do not know until you turn the key. And give them a try at various RPMs. These ones looked intriguing and my research said they are fairly mild in terms of noise. But a cut above stock which is what I was looking for. If you look at the web site they claim 95db compliance performance for race track applications with no reduction in flow through. Perhaps it is hype but if true, a new and novel design to cut back on noise and maintain performance is pretty impressive. Where I start to entertain doubts is the claim that noise entering the muffler is converted into heat by those cylinders. Those words appear on the web site and in the patent document. I am not a physicist but noise into heat? In any case, I will give them a try. I love experiments :) .

Paul L

Ken,
Yes the Ravin mufflers have a unique design also. A flattened restrictor plate design. I was tempted but had to make a choice. The SpinTech design won out for purely subjective reasons. There are many fine products out there but I can only afford one at a time ;) .

Desertdawg

The borla's are mounted, not much louder than stock at idle. and at WOT there is a little more rumble, but nothing near flowmaster noise.

I haven't driven my 82 much yet with them on, but I didn't notice any resonance inside at any RPM.

I will try to give a better account of the borla's at a later date...Let me get out and try them out first.

Thanks again Paul, I am very happy with them... :cheers:

Mystery Machine

Interesting looking design. Good luck, hopefully you'll be happy with them. :thumbs:

xrated

I am very interested in the spintechs also. They look like they may produce a unique tone.

blue72

I'm no physicist, either, but my understanding of noise absorbtion is that noise, as a form of energy, cannot be destroyed but rather converted into another form of energy. Strictly speaking, any muffler that quiets the sound is converting that energy into heat, unless it's using some sort of inverse phase cancellation techniques. In the case of phase cancellation, the sound wave is still present, but cancelled out by the presence of an opposing wave 180 degrees out of phase (You've heard this happen if you've ever wired up your stereo speakers backwards - one speaker is pushing while the other is pulling). From past casual inspection of some muffler designs, it looks as if many are using resonant chambers of varying sizes to quiet the exhaust through phase cancellation. Each chamber acts upon a certain peak frequency, basically bouncing the soundwave back upon itself so that it cancels itself out (this is called a "standing wave" in acoustic-speak). The exhaust resonances that we have all experienced are actually attributed in part to standing waves within the entire exhaust system that are reinfocing each other instead of cancelling out.
The picture you posted of the SpinTech muffler looks as if the spirals may be designed to actually absorb sound by resonating at key frequencies. The energy that the sound waves expel trying to make the muffler resonate doesn't make it out the pipes, but is converted to heat from the structural friction of the metal.
If any physicists out there find this to be inaccurate (or just plain BS), I apologize. I'm trying to apply some knowledge I've gained while planning a basement music studio where acoustics (primarily absorbtion and standing waves) play a major factor.

-Jason

Paul L

Just replied to your e-mail. I am very pleased that they arrived safely and your initial impressions are positive!

Paul L

Jason,
I really appreciate that reply! A nice translation of the bafflegab in the patent document. I believe that "phase cancellation" are the key words: the standing noise waves are reflected by the cylindrical inserts back against other. That results in the noise being muted while at the same time not restricting flow. It is a fascinating design. And unique or it would have not been granted a patent in 1998. Thanks again.

OHSIXX

I love my Borlas.
:steering:


[Modified by OHSIXX, 5:56 PM 2/17/2003]