Just had the exhaust replaced on my 535; went with a custom setup of a manga flow x-pipe and two single mufflers out into two y-tips for quad exhaust.

It looks awesome, but is a little two loud, and it feels like I've lost a bit of low end grunt. With the stock exhaust, even slightly stepping on it would give you that ass shoved in the seat feeling.

The exhaust is a bit too loud for what I want, and the shop said they could add a couple of extra mufflers to tone it down. The drone is just too high for me. I spend most of my days driving between clients offices and on the phone in the car.

Would adding the second set of small mufflers increase backpressure and thus regain some of that low end torque?

Or did we just choose the wrong setup for my engine?

 

What size piping did they use? Mandrel bends or crush bends? Is it downpipes back with dual pipes all the way to the x-pipe, or did they just cut and weld after the stock downpipe/midpipe flange? What brand and model of mufflers were used?
Did you do a before and after dyno to confirm your suspicions?

All these variables could affect the performance loss you might be suspecting. Personally if you lost performance, then adding another muffler isn't going to help things. Engines needing "backpressure" is largely a myth. You have a twin turbo, less backpressure is better.

 

From a lot of the stuff I've read in the past 24 hours, I think the piping might be too wide. I read something about the larger pipes causing overscaviging of the air/fuel mixture.

They're mandrel bent and were installed after the stock down pipes. Basically cut right before the stock resonator.

The mufflers are mangaflow. I dont have the specs in front of me though, but I think the pipes are three inches.

 

Oh and thank you for replying. This is one area of cars that I have a little trouble understanding. Mechanical, I'm good. Physics... Not so much.

 

I have a similar setup, I have a single in dual out magnaflow however. I ordered the wrong exhaust at the time and had it installed. So the front resonators go from a Y pipe to single in then dual out, I think this is even worse from a power loss perspective. I definatley felt a loss in power, and its WAY too loud at low RPMS. The drone kills me, however highway speed is OK. I've been wanting to ditch this exhaust for a while, and I finally bought a RD sport quad this week. I'm hoping it will address my power loss and drone.

 

Leftcoastbias - I PM'd you.

 

Weird... I don't have the message?

 

Please share your experience once you get the new one installed.

 

I ordered a Magnaflow muffler yesterday from Summit Racing. So now just waiting on the dual diffuser before all of this comes together.

 

I had the same issue with a loss of torque and droning due to an exhaust change. The solution to that was ccinserts, it's a silencer that gets welded in the pipes and as a result the throttle felt just like oem again. As for the drone it was reduced significantly by I would say a good 60-70%.

Here's a review from another forum
CC Insert for reducing exhaust drone....wow it works! - Page 2 - AcuraZine Community

The website for the cc inserts
Exhaust - CC Inserts - Car Chemistry, Inc.

I purchased mine from the same company on eBay to save on tax not sure if the price has changed. It has been 2 years since I had them installed. I originally purchased the 3 disk, however, it was a bit too quiet so I had them cut off a disk. Well hope that helps feel free to pm me if you have further questions.