jangell
07-27-2015, 09:41 AM
About four years ago I replaced my failing stock stock exhaust with a DPI SPEC I exhaust. While it's a great free-flowing unit, it's too loud for my taste -- in fact, even the stock exhaust is too loud for me. I'm completely willing to trade power for quietness here.
I'd like to come up with a way to make the car REALLY quiet, like no louder than most consumer cars on the road that you barely even hear most of the time. The 2.8L engine was used in a Volvo that I imagine wasn't very loud, after all, and the 3.0L Monaco/Premier engine I'm installing now was also used in a sedan, so in principle it must be possible.
However, those cars had their engines in the front. With the DMC's rear engine design, I expect that the extremely limited space available to manipulate the exhaust gases makes getting down to that level likely impossible to achieve. But I'm certainly willing to give it a try.
I know relatively little about exhausts beyond what my Googling has provided. I understand that reducing noise will likely reduce power, but I'm OK with that if I don't bother my neighbors every time I drive down the street, and don't have to wear hearing protection when I'm working on the engine, and can actually have a conversation without yelling at freeway speeds (road noise notwithstanding). I'm fine with installing a reverse flow muffler if that will significantly dampen the noise, even with the loss of power that will cause. I also understand that different cats can affect noise (I think), as can installing different mufflers and adding resonators.
My first idea was to install silencers into the tailpipe of the SPEC I exhaust, until I realized that silencers are too long (8+ inches) to fit. I'm not really wild about packing fiberglass into the tailpipes either. I'd like a more engineered solution.
The best I've come up with so far (with my limited knowledge, as an off-the-cuff idea without proper research into feasibility) is two separate mufflers and resonators. The driver's side exhaust would cross behind the engine, from the DPI headers through the cat and resonator and into the muffler, and then out the passenger side tail pipe. The passenger side would do the inverse. The problem with my cunning plan is again space -- while this gives me a bit more distance for each pipe to control the exhaust gases, I don't know if I can get a resonator and a muffler combination that will actually fit in the few feet available from one side of the engine to the opposite tailpipe, or at least not anything big enough to control the noise adequately.
Googling usually finds people trying to make their car louder, so I've found it tough to find information about how to proceed. I was wondering if anyone more knowledgable had any thoughts about how to build a very quiet exhaust in the constrained space provided by the DeLorean.
Thanks!
-- Joe
I'd like to come up with a way to make the car REALLY quiet, like no louder than most consumer cars on the road that you barely even hear most of the time. The 2.8L engine was used in a Volvo that I imagine wasn't very loud, after all, and the 3.0L Monaco/Premier engine I'm installing now was also used in a sedan, so in principle it must be possible.
However, those cars had their engines in the front. With the DMC's rear engine design, I expect that the extremely limited space available to manipulate the exhaust gases makes getting down to that level likely impossible to achieve. But I'm certainly willing to give it a try.
I know relatively little about exhausts beyond what my Googling has provided. I understand that reducing noise will likely reduce power, but I'm OK with that if I don't bother my neighbors every time I drive down the street, and don't have to wear hearing protection when I'm working on the engine, and can actually have a conversation without yelling at freeway speeds (road noise notwithstanding). I'm fine with installing a reverse flow muffler if that will significantly dampen the noise, even with the loss of power that will cause. I also understand that different cats can affect noise (I think), as can installing different mufflers and adding resonators.
My first idea was to install silencers into the tailpipe of the SPEC I exhaust, until I realized that silencers are too long (8+ inches) to fit. I'm not really wild about packing fiberglass into the tailpipes either. I'd like a more engineered solution.
The best I've come up with so far (with my limited knowledge, as an off-the-cuff idea without proper research into feasibility) is two separate mufflers and resonators. The driver's side exhaust would cross behind the engine, from the DPI headers through the cat and resonator and into the muffler, and then out the passenger side tail pipe. The passenger side would do the inverse. The problem with my cunning plan is again space -- while this gives me a bit more distance for each pipe to control the exhaust gases, I don't know if I can get a resonator and a muffler combination that will actually fit in the few feet available from one side of the engine to the opposite tailpipe, or at least not anything big enough to control the noise adequately.
Googling usually finds people trying to make their car louder, so I've found it tough to find information about how to proceed. I was wondering if anyone more knowledgable had any thoughts about how to build a very quiet exhaust in the constrained space provided by the DeLorean.
Thanks!
-- Joe