vettereddie

Does anyone have a Flowmaster Hushmaster II on their xB, and if so, is their a way to quiet it?

Before I get railed for not going with a Magnaflow, Borla, or import axleback, let me explain my design constraints. I have a wheelchair ramp installed that takes up the space where the muffler would normally go. I am left with stock space from the front of the vehicle to halfway from the edge of the rear door. The gas tank has been shifted forward of the ramp as well, leaving only a 17" x 5 1/2" space from the axle back. The exhaust system installed by the wheelchair lift company was not satisfactory. It was some garbage no-name aftermarket oval muffler mounted midbody on 1 3/4" piping. It hung so low that it ended up cracking the weld behind the muffler on speed bumps. I needed something that sat closer to the body.

It seems the best fit would be a low-profile canister muffler in the stock resonator location to at least make use of the stock heat shield and have a close fit to the body. The Hushpower was designed for low profile applications such as low riders and custom cars, so it seemed like a good fit.

I now have a Hushpower in the stock resonator location on 2 1/4" pipes. The shop, however, did not see a need for a resonator when they installed it and now it is way too loud, especially around 2000 RPM. I'm having them put the 12" long Hushpower resonator behind the axle, and am looking to have a custom tip with a 90mm Apexi ATS silencer on the back end. I just hope it will be enough. With the rear seat and trunk space removed, I have exactly zero sound dampening on the rear floor pan. Next step would be to remove the no slip floor and put in Dynomat underneath.

I went with 2 1/4" pipe because with a cold air intake, supercharger, and stainless headers I wanted it to breathe a bit. I have no complaints about performance with the new exhaust, it's just not fun, safe or convenient to have everyone in the vehicle wearing earplugs every time I go driving.

vettereddie

As a second question, anyone know where I can get a 2.25 inch inlet 90mm exhaust tip?

crabbyman

I am on the search for a similar sized silencer for my exhaust. Smallest I have seen is 3.5" universal or 2.5" special applications.

vettereddie

Well, picked up the Apexi super silencer at 90 mm (3.54"). Worst case I will fit it into a 4" tip with either a fabricated metal ring welded to it to make up the difference or a high temp gasket material wrapped around it, only needs to be ~1/4". Was also thinking about using a high-temp silicone, place the tip in the middle of a 4" no stick tube, pour in the silicone, let it cure then remove the tube. Should be a perfect fit then in a 4" tip. Resonator goes on tomorrow, I'll post if the silencer is actually needed.