I packed one of my cannon style mufflers 500 mm long and 178 mm diam. last week with a high temp rockwool ( 800 deg. C )and did a db test compared to a glass packed identical muffler and it was 4 db quieter , a good result. Quieter and more capable of handling rotary high temps. These are available at the moment $250 + freight.

what do they look like, polished etc, tip??? and whats there flow like??

They are cannon style mufflers up to 178 mm diam. soon maybe up to 203 mm and as long as required usually 500 mm.Bore size as required .They have spun coned ends. Mild steel construction and externally tigged. They are painted in high temp. charcoal grey paint. The perforated tube has an expansion joint so the expansion that occurs with high temp. generated by rotary engines wont distort and destroy it. I dont know of any other rotary muffler that has this feature. The mufflers are straight through so the flow rate is as high as is possible , no baffles or restrictions of any kind. I wrap the perforated tube with a layer of s.s. wool and then fill with either high quality glass or rockwool as requested. The tip is mild steel diam. as requested or you can fit your own. I have pics I can send. I will soon have a basic website. I am trying to keep the overheads low so I can sell them at a reasonable price. They have performed well in the quietness area with good sound quality. I continually try to improve them.

good quality mufflers with excelent note and reduces noise of rotarys.

best sounding muffler ive heard on one yet

pm sent waiting for pics

I just finished installing one of Kev's mufflers.

I first contacted him a couple of weeks ago and told him what i wanted and he made it to my specs within a week.

I was surprised as shit when i got a call less that week later to tell me it was ready to be picked up. He even sourced an awesome collector for me as well.

The workmanship on the muffler is outstanding and i couldnt be happier with the finished product or Kevs service. Its a fair bit quieter that the Rotaflo i had on it previously, flows much better and was much cheaper than replacing it with a new Rotaflo unit.

I couldn't reccomend them more.

Heres a little pic and ill do my best to get a vid of how it sounds in the next few days.

When I first decided to make rotary mufflers I designed the housings with 45 deg spun, coned ends. The reason was to make the housings as strong as possible. I then found that many prefered flat ends like rotaflow which I thought was a bit sad because good functional design was being over ruled by asthetics. I suppose the best thing to do is to offer both options. I will organise spun, flat ends. The jury is still out which is the best packer for street driven rotaries. I rely on feedback to decide. I have a totally open mind to design hopefully the best mufflers all decisions being determined by r&d.

i have one of kevs mufflrs on my bp rx7 and love it

I did a test on one of my resonators yesterday which had a portion of the housing removed to increase road clearance and the packer removed. Before replacing packer and bottom I belted an lp flame up the perf tube to similate hot exhaust and being fitted with an expansion joint I observed the perf grow 3 mm . resonator being 400 mm long. Without the expansion joint the perf tube would quickly fatige and crack. The longer the muffler the bigger the problem becomes. Every time I get the opportunity to check my mufflers for this problem i do it. Since I started using the expansion joint I havn,t seen it occur. I still can,t work out how thher muffler makers survive without it being fitted. Maybe they don,t.

Are you solely making mufflers with round casings? I'm struggling to track down a decent oval body muffler to suit my application.

Delt with Kev last week at length. Very knowledgable bloke who takes his exhaust seriously. Supplied me with what I needed ASAP and at a very good price.
Clear, concise and a very good trader.

thanx mate

I have made the occasional oval muffler. Originally I would have them rolled up at a local metal shop. Recently I tried a new method. I split a 7" diam. pipe lengthways so the pipe is now in two sections and then weld in 2 sections top and bottom anf presto an ovalised muffler. I then discovered an advantage in this process. The housing was in a stressed state because the pipe opened up when split and had to be forced back into shape when the insert was welded in. This means that the housing will not vibrate , like a speaker, and is a better housing. a better muffler. Also the muffler can be made to fit the space available as big as possible.

Practicing putting pics on forum. My muffler and resonator on rx4. I now also have flat end caps on mufflers.

not bad lookn mufflers....

Nice. Is that an exhaust valve between the resonator and muffler?

How do these mufflers size up on gen 1 rx7's? Decent ground clearence?

-Dave.

Also keen on information and price to suit 1st Gen RX7 3"

The muffler is 500 mm long and 178 mm diam. Either coned or flat ends available depending on choice. I made my muffler longer and smaller diam. than major competitor to gain road clearance. Note expansion joint in perforated tube. This helps to stop tube from self destruction when expanding when very hot. The usual combo is muffler as described with resonator 400 mm long and 127 mm diam. This fits generation 1 , 2 rx7,s. Gen 3 can go a bit longer. At the moment muffler $250 and resonator $150. Material costs have risen so next year prices will be $300 and $170. These mufflers have a deep sound and quieter than most. That valve is a Hyperflow AES stage 3 kit. I can make mufflers to custom specs up to 4" bore.

Hi everyone,
I have one of Kevin's Butterflies and 3 of his mufflers fitted on my RX-4.
The picture above, is my car when it was at Marshall Street Mufflers, where the system was fitted.
The sound is amazing, and I hoped to have it quiet, no loss of power, and with a deep note..........guess what? I got!!
I cannot recommend this guy highly enough, give him a try, you have nothing to loose!
Will post some pics and vids soon.


(Does anyone know how to post pics up from the computer or do we still need to use Imageshack, Photobucket, etc)

I contacted Kev about getting a muffler and resonators made for my R100. As I'm trying to achieve an original look with my resto, I required the physical dimensions of these to closely match those of the original items. Kev certainly came through with the goods. Prompt service, quality workmanship and a darn good price to boot.



- Clint

A pic of cannon style muffler , 500mm long, 178 mm diam. with flat ends which some prefer to coned ends. This muffler has inox wrapped around perforated tube and then packed with high temp. rockwool (peaks at 800 deg C).