yetchh Posted January 30, 2014 Share Posted January 30, 2014 dads zephyr has two cobys in it. one halfway through and one behind diff with about 500mm of pipe afterwards. sizing about 2 or 2 1/4 inch piping. has a little bit of noise when cold or idling but once u get driving you can barely hear it I was always been told never to use resonators as they rob performance (not that its for that) I have used them before and they do work, I just wonder if there's another option Might be out of place but don't forget your headers. They make a huge difference. Work out what style you want ( 4-2-1 or 4-1) and how long the primaries and secondaries need to be for your target rpm. I am building one for max power at 7,000rpm but will loose hp down low. I maybe wrong but i think they are more important then pipe diameter and muffler choice. cheers, got headers, its not for full on performance so the volume is the biggest concern at this point Quote Link to comment Share on other sites More sharing options...
bobdylan Posted January 30, 2014 Share Posted January 30, 2014 When choosing a muffler I found the trd racing part and got as much information on it as possible and went to a muffler shop and went thru their catalogs to find as close as possible one to it. We got a pretty near perfect match. The guys on here know a million times more then me, they will see you right Quote Link to comment Share on other sites More sharing options...
Truenotch Posted January 30, 2014 Author Share Posted January 30, 2014 Markku, what have you ended up with muffler wise? (And what are your headers? - and are they doing header voodoo at the collector?) I've ended up with this and it's fucking LOUD: Here's what it sounds like: And in the background of this vid: I need to tone it down or at least kill some of the rasp… I was about to come in here and share a couple of ideas, so thanks for liking my post xssteve - it saved a lot of time looking for the thread . The problem is I have a very limited amount of space to add a resonator, so have been thinking about making something to suit… Thinking a small glasspack resonator towards the end of the pipe. Question: is there any reason not to make a 90° muffler? I'm thinking about buying a 5" mandrel bend, drilling the 3" bend and fitting the 5" stuff around it before cramming it full of glass fibre. Here's an artist's impression: Bad idea? Quote Link to comment Share on other sites More sharing options...
Styles Posted January 30, 2014 Share Posted January 30, 2014 About the only problem I could think of would be faster break-down of the packing, on the outer radius of the curve...... Quote Link to comment Share on other sites More sharing options...
kpr Posted January 30, 2014 Share Posted January 30, 2014 should be all good. but as above, i wouldn't drill any holes in the outside of the bend Quote Link to comment Share on other sites More sharing options...
Truenotch Posted January 30, 2014 Author Share Posted January 30, 2014 Aiit, will do more planning and see how it goes. More volume = more cancellation of yucky rasp? What size drill bit do you use? Quote Link to comment Share on other sites More sharing options...
kpr Posted January 30, 2014 Share Posted January 30, 2014 yeh even though your lacking some holes, the volume will still help. most of the ones ive done, have drilled holes about 4-6mm. more smaller holes maybe more effective? long as its letting the sound through, i wouldn't think it would matter too much. from what ive found. using glass pack's, generally when you drop the whole system on the ground and it makes a "thud" rather than a "ting," you're heading in the right direction 1 Quote Link to comment Share on other sites More sharing options...
kpr Posted January 30, 2014 Share Posted January 30, 2014 you could also do something like this if you're out of room. doesn't go all the way around the pipe. but still takes some noise/rasp out Quote Link to comment Share on other sites More sharing options...
Truenotch Posted January 30, 2014 Author Share Posted January 30, 2014 Cool, I'll do some measuring and come up with a plan. My biggest problem is the proximity of the pipe to the tunnel - the straight part between the muffler and the bend is fairly well tucked against it. So I only have room at the end near the bend, and there's only ~ 200mm of straight before the chassis rail gets in the way, so I dreamt up this idea to try and gain more volume and length. What's the best stuff to pack it with? I might go to Coby and buy the stuff to make my own muffler . Quote Link to comment Share on other sites More sharing options...
kpr Posted January 30, 2014 Share Posted January 30, 2014 I use normal fiberglass chop strand. This is after going to a muffler shop and ordering some muffler packing, then getting handed what looked to be a bag of fiberglass, they brought from a boat shop down the road. but 5 times the price. It does burn out after awhile. but lasts good enough for what i need. tear it up and pack it in fairly tight. sure to be alot better products out there! but chop strand is easy to get and cheap. dont use pink bats out of your parents ceiling! i tried that once. doesnt last too long! the other half of the muffler with chop strand was still good 1 Quote Link to comment Share on other sites More sharing options...
stillway Posted January 30, 2014 Share Posted January 30, 2014 I prefer stainless packed, fibreglass doesnt live long at all in an exhaust for a rotary though, maybe overkill/cost for your situation Quote Link to comment Share on other sites More sharing options...
sr1600 Posted January 30, 2014 Share Posted January 30, 2014 5 inch mandrel bend sounds like black magic to me haha Might be cheaper to have a couple of bits folded up to make a square box section then you can have whatever depth you want... Less noise transfer aroumd the bend maybe Quote Link to comment Share on other sites More sharing options...
xsspeed Posted January 30, 2014 Share Posted January 30, 2014 Ah yep was wondering if you had progressed from there. i didnt read all but why did you go side exit? no space or juat because racecar? 1 Quote Link to comment Share on other sites More sharing options...
Truenotch Posted January 30, 2014 Author Share Posted January 30, 2014 Cool. I've still got a bit of chop strand, so will see if there's enough to make a muffler. 5" mandrel bend would be a bit of black magic - I'd have to split it down the middle and re-weld it around the 3" tube, which is probably still quicker than folding something up. ** Edit - I did it because racecar. Less weight and more airflow out the back/just because I've never had a side pipe before. At this rate I'll likely keep modifying it until I have a full length 3" system again (like it did when I bought it ). Quote Link to comment Share on other sites More sharing options...
stillway Posted January 30, 2014 Share Posted January 30, 2014 I did it because racecar. can I put that on a tshirt? Quote Link to comment Share on other sites More sharing options...
Truenotch Posted January 30, 2014 Author Share Posted January 30, 2014 Yeah, definitely. Quote Link to comment Share on other sites More sharing options...
stillway Posted January 30, 2014 Share Posted January 30, 2014 that font is gross. Anyway back on topic, keen to see what you come up with/outcome! Quote Link to comment Share on other sites More sharing options...
xsspeed Posted January 30, 2014 Share Posted January 30, 2014 5" mandrel bend would be a bit of black magic - I'd have to split it down the middle and re-weld it around the 3" tube, which is probably still quicker than folding something up. ** Edit - I did it because racecar. Less weight and more airflow out the back/just because I've never had a side pipe before. At this rate I'll likely keep modifying it until I have a full length 3" system again (like it did when I bought it ). Just slide the 5" round with a bit of lube/spit (like manu getting his container up the drive) because racecar is valid. at leadt you have the option to run it out the back if the need arises. how much clearance under the lowest point? Quote Link to comment Share on other sites More sharing options...
Truenotch Posted January 30, 2014 Author Share Posted January 30, 2014 I have quite a lot of clearance. My car might be 100mm from the sills at the lowest point. Exhaust sits slightly below, but the worst part of the muffler is only 70mm or so from the ground. I'm all for experimenting with things and making stuff to throw away later. Quote Link to comment Share on other sites More sharing options...
xsspeed Posted January 30, 2014 Share Posted January 30, 2014 Reduce reuse recycle Quote Link to comment Share on other sites More sharing options...
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