Well, I just couldn't find what I wanted for a muffler, so I built my own. I wouldn't recommend this unless you have lots of time and enjoy metal fabrication. I don't think I saved a lot of money going this route, but it cost me about half of what a RB muffler would cost (plus lots of time). Why? because the RB muffler just wouldn't fit!
Here's the deal - I'm running a streetported 12A engine in my Opel GT, I tried using off-the-shelf magnaflow stainless mufflers, but they were just too loud.
A lot of aftermarket performance mufflers are just perforated tube with packing in a shell. After cutting open an RX7 junkyard muffler, I decided to use a combination of perforated tube and packing and some chambers.
This is made from 16 ga stainless, with SS wool packing and perforated tube (good ol' Evil-Bay). I made a case which I could slide the 'guts' in and out of, which allows me to re-pack or change the configuration.
I'm pretty happy with the results, it's quieter and has a better tone than the magnaflow, plus the outlets are where they ought to be for my car. I might put some polished tips on eventually...

Hope someone finds this information useful one day,

James

 

Wow that looks great on your car, I really like it. Any more pics of the car?

What makes up the rest of the exhaust. And what made you go with that design for the car with a rotary motor, do you think it making more power with that configuration?

Sorry I'm trying to pick your brain, that exhaust just has me very interested.

 

All you need to know is right here brother...
http://ausrotary.com/viewtopic.php?f=16&t=115214

 

I always thought those were really cool cars - nice to see it still around and looking good!
Scott

 

My dad had one of those Opel GT when I was a kid. If he knew that it would have been better to put a Rotary engine in it, he probably would have kept it. Always had transmission problems with it. I would love to see more of this one. Looks great so far!

 

More pictures of the opel please

 

That opel pretty sexy!

 

the 1.9 that came in those adam-opels was pretty frigging slow. most guys drop 60 degree buick motors in them. Nothing beats throwing that big lever buy the shifter to roll over those headlights lol.

The last 69 my friend had he had to buy lead additive for the fuel to Or upgrade the valve seats!

 

Awesome work. I always like to see people showing creativity and skill. Consider some Pacesetter polished tips. They fit the era of your car.

 

I'm not 100% clear on whether you are asking why a rotary, or why this exhaust configuration. I'll assume it's the latter.
Well, after examining a cut-up stock RX7 muffler (reverse-flow chambered) and finding out what I could about the RB powerpulse muffler, I made one with roughly the same overall volume in a different shape that would fit the car. The chamber volumes are roughly similar to stock, but I didn't want the reverse flow aspect, so I went with a combo of packed sections and chambers. This was all kind of an experiment, so if it sounded like crap I could pull out the guts and change it. I'm pretty happy with it, it is definitely not quiet, but is quieter than a flow-through, and has a deeper tone. I would like to flowbench test it to see what the CFM is, but I'm guessing it's pretty good (a lot better than stock, anyways). I'm sure I'm losing a bit of power as compared to a straight flow-through, but I'm willing to do that to keep my hearing and hopefully keep the cops uninterested.

Here's some more pics. There's also a forum for these cars, www.opelgt.com There have been a few rotary conversions, and a ton of other engine swaps. And yetterben, if you think the 1.9litre was bad, some of them came with a 1.1litre automatic

HTH,

James

 

how does it sound?

 

wow...that came out really nice...where did you get the packing from?

 

yeah i never saw the 1.1 i just rember getting the right dizzy cap was always a pain with the two diffrent dizzys. SAd thing is there worth more in parts than a whole lol i am sure you know that. I havent been to opelgt.com in ahwile. Sold most of the parts to opels unlimeted if he is still around! I actually still my buds locking gas cap around somewhere!

 

NICE...
I have always liked those little Opels since I was a teen....

L8R

 

How well do those flex joints hold up to rotary heat???

 

Great link, thanks. I haven't been on that site in a while that it was very helpful.

Your assumption was correct, I was speaking about the exhaust, it looks great. Thanks

 

We just gotta find the same type of **** here in the states...(i.e. perferated tubing, big *** rockwool....

Jaime

 

Concerning Opel GTs (the stock type):





More at:

http://www.nytimes.com/slideshow/200...PEL_index.html

 

Hi,

Thanks for the interest! Yes, there are some Opel parts that are worth quite a bit, and the gas cap is one (especially if it is in good shape and has the key). The front bumper is another. I always liked the opel GT, but thought it sat a little high, so mine is lowered (actually, all the suspension is different than stock, and adjustable for ride height).

We'll see how the flex joints hold up to the rotary heat, hopefully the pipe is far enough away, and I have a heatshield around the muffler. Haven't run it hard yet, still breaking in the engine.

As for the muffler guts, I couldn't find the stuff easily in Canada (OK, I didn't look too hard), so I ordered it out of the States as I live close to the border.

Stainless wool was from http://stores.ebay.com/SteelWool-biz
Perforated tube was from L.A. Choppers (?) http://cgi.ebay.com/PERFORATED-STAIN...QQcmdZViewItem
The stainless sheet used to be shelving in a bakery(?). That's the great thing about stainless, the scrap is just as good as new.

James

 

sweeeeeeeeeeeeeeeeeeeeeeeeet!

 

Where did you get that long perforated tube from?

I made a muffler for my dirt bike before, it was so hoopty, it consisded of two apple juice cans, JB weld, a piece of pipe with not enough holes drilled in it, and fibreglass insulation.

 

Evil-Bay, http://cgi.ebay.com/PERFORATED-STAIN...QQcmdZViewItem
they sell it by the foot.

James

 

Nice work, I like how you recycled the stainless from the bakery.
What grade steelwool did you use coarse/fine, I would think the coarse would last longer?

 

Hi,

I used coarse wool, that's what the steel wool guy said most people use in mufflers, plus it made the most sense to me.

cheers,

James