Quiet exhaust

[ariesdude]

Hi, I have a 94 1.6L DOHC and i recently had to change my muffler and the middle pipe (the one with the small muffler) - the original middle pipe had a oval shaped small muffler but the new middle pipe has a very small round muffler - almost looks like a bump in the pipe. After the replacement my engine has become a little louder than before (back when the original muffler was ok). i checked for leaks in the pipe and joints- and there's none. Is there anything i can do to make it quieter again - i dont like the sound of the exhaust right now because it makes me think that the engine is running rough. By the way - the replacement came off a 92 GS i think. Thanks.

[Ricksmx3]

Add a glasspack as a resonator http://store.summitracing.com/default.a ... wordSearch that is the one i put on mine and it made it alot quieter. You my need to get a smaller one (DIA) or even a shorter one but they are real cheap and work great.

[ariesdude]

Hey thanks for the tip. I will try to get one.

[Juans_93_MX3]

The small oval "muffler" was not a muffler. Its a Catylistic Converter and without it, your car gets louder and wont pass emissions

[Teal_93]

I used the same one as well. Works great!!!!

[ariesdude]

The small oval "muffler" was not a muffler. Its a Catylistic Converter and without it, your car gets louder and wont pass emissions

No it's not the catalytic converter - the cat sits almost below the (4 cyl) engine. This one is after the cat and i just learned that it is called a resonator or according to the manual (F1-127)- a "pre-silencer".

[Teal_93]

If it is welded or clamped on the pipe it is a resonator. The cat is bolted in with 2 bolts on each end.

[Cpl_Bryant]

Does that glasspack stuff cause any losses in power? My friend's Evo has gotten him 3 tickets for loud exhaust (along with whatever they pulled him over for) and I told him to throw the silencer on his muffler, but he said he would lose a boatload of HP. Damn 4-doors.

[Ricksmx3]

Not as far as i know. Still the same air flow just with thicker walls to silence the sound.

[Yoda]

Does that glasspack stuff cause any losses in power? My friend's Evo has gotten him 3 tickets for loud exhaust (along with whatever they pulled him over for) and I told him to throw the silencer on his muffler, but he said he would lose a boatload of HP. Damn 4-doors.

Yes a glass pack muffler will create a flow restriction. They are free flowing as long as the air (exhaust gases) flow is cool but when hot gases flow through them they start to create restriction to the air flow. The problem with glasspack muffler is the packing material itself. The packing material is there to adsorb the sound wave but at the same time it adsorbs heat. This retained heat creates a boundary layer of super heated gases that does not flow at the same rate as the exhaust gases entering the muffler. Turbocharged cars really bad for this either a glasspack muffler has to be grossly over sized to the point of having minimal affect on sound damping or in a lot of cases I have seen the car suddenly cough and them you see part of the packing material get blown out the muffler in a blue flame. A better solution would be to use a chambers resonator for two reasons. First is the chambers allow the hot gases to expand, in the process losing thermal and sonic energy as it goes through each chamber. The second benefit is that as the gases cool it condenses allowing more room for exhaust gases to flow out than what entered the muffler. The biggest benefit to this is that it creates a low pressure zone after the inlet of the muffler which in turn draw more exhaust gases from the engine that what could have normally flowed out than if it was a pipe of a continuous diameter and on with a turbo helps to spool up the turbine. In several type of motorsport racing including NASCAR and several classes of NHRA drag racing were mufflers are now required they found that HP has actually gone up and not down with a chambered muffler over a glasspack or even straight pipe. I make my own chambered resonator but the most common commercially made choice for performance chambered mufflers and resonators is Flowmaster but Moroso and Car Chemistry make a chambered mufflers and resonators that work well under most sport compacts.

[Ricksmx3]

Does that glasspack stuff cause any losses in power? My friend's Evo has gotten him 3 tickets for loud exhaust (along with whatever they pulled him over for) and I told him to throw the silencer on his muffler, but he said he would lose a boatload of HP. Damn 4-doors.

Yes a glass pack muffler will create a flow restriction. They are free flowing as long as the air (exhaust gases) flow is cool but when hot gases flow through them they start to create restriction to the air flow. The problem with glasspack muffler is the packing material itself. The packing material is there to adsorb the sound wave but at the same time it adsorbs heat. This retained heat creates a boundary layer of super heated gases that does not flow at the same rate as the exhaust gases entering the muffler. Turbocharged cars really bad for this either a glasspack muffler has to be grossly over sized to the point of having minimal affect on sound damping or in a lot of cases I have seen the car suddenly cough and them you see part of the packing material get blown out the muffler in a blue flame. A better solution would be to use a chambers resonator for two reasons. First is the chambers allow the hot gases to expand, in the process losing thermal and sonic energy as it goes through each chamber. The second benefit is that as the gases cool it condenses allowing more room for exhaust gases to flow out than what entered the muffler. The biggest benefit to this is that it creates a low pressure zone after the inlet of the muffler which in turn draw more exhaust gases from the engine that what could have normally flowed out than if it was a pipe of a continuous diameter and on with a turbo helps to spool up the turbine. In several type of motorsport racing including NASCAR and several classes of NHRA drag racing were mufflers are now required they found that HP has actually gone up and not down with a chambered muffler over a glasspack or even straight pipe. I make my own chambered resonator but the most common commercially made choice for performance chambered mufflers and resonators is Flowmaster but Moroso and Car Chemistry make a chambered mufflers and resonators that work well under most sport compacts.

Ok then i guess it does. Even tho it is probly to the smallest percent.

[Yoda]

[quote="Ricksmx3
Ok then i guess it does. Even tho it is probly to the smallest percent.[/quote]

Yeah the percentage is pretty small. Looking over the dyno data I estimate the losses due to the heat retention of the packing in a glasspack muffler is about -3 to 4% reduction in flow once the engine is a WOT for a given pipe size. With the chambered resonator I seen a small % increase in flow maybe only 3 to 7% increase in flow. The only problem with the increase flow of created by the chambers resonator is that the negative pluse wave going down the exhaust also affects the intake side too were more air is drawn into than before when can cause a power robbing lean out affect. I had this problem with the exhast for my (8V) 1.6 SOHC. I mean my power increase by 3.1whp over using a glasspack muffler after switching to a chambered muffler. After a fuel and cam timing correction was made, on the dyno a 6.8whp gain was achieved over a straight through glasspack muffler.