I have the EMS midpipes (1 cat per) and the stock Toyota muffler.
My truck is very quiet.
I noticed no change in the sound of the exhaust between the factory midpipes and the EMS midpipes, except for elimination of the rattling heat shields on the rusty old factory cats. I have also not had any check engine lights since changing the midpipes. I am using the same O2 sensors as before. The engine is more responsive off the line and revs a bit more freely with the EMS powered midpipes compared to stock.
I bet the noise and 'drone' are products of that bigass Magnaflow straight through muffler that is included with the EMS kit- it looks like it was made for a Camaro.
The factory muffler is designed to minimize drone and keep the exhaust quiet; the Magnaflow muffler is not.
It is not a coincidence that most of the horsepower gains from the EMS cat-back kit are probably the result of getting rid of the original equipment muffler, which does a very good job of keeping the exhaust quiet.
An engine with a clear path from the exhaust valves to the outside will be noisy but will make more power; an engine with a good muffler will be quiet, but will make less power. It's a tradeoff, and the sweetspot depends on your application.
If you are gonna enter a truck pull contest, the Magnaflow would be prefereable.
If you are gonna drive around in a nice neighborhood at night, the Toyota OEM muffler is probably better.
My truck is very quiet.
I noticed no change in the sound of the exhaust between the factory midpipes and the EMS midpipes, except for elimination of the rattling heat shields on the rusty old factory cats. I have also not had any check engine lights since changing the midpipes. I am using the same O2 sensors as before. The engine is more responsive off the line and revs a bit more freely with the EMS powered midpipes compared to stock.
I bet the noise and 'drone' are products of that bigass Magnaflow straight through muffler that is included with the EMS kit- it looks like it was made for a Camaro.
The factory muffler is designed to minimize drone and keep the exhaust quiet; the Magnaflow muffler is not.
It is not a coincidence that most of the horsepower gains from the EMS cat-back kit are probably the result of getting rid of the original equipment muffler, which does a very good job of keeping the exhaust quiet.
An engine with a clear path from the exhaust valves to the outside will be noisy but will make more power; an engine with a good muffler will be quiet, but will make less power. It's a tradeoff, and the sweetspot depends on your application.
If you are gonna enter a truck pull contest, the Magnaflow would be prefereable.
If you are gonna drive around in a nice neighborhood at night, the Toyota OEM muffler is probably better.