I took some time last weekend to make a modification to my flopro muffler. The flopro is great for keeping down interior noise. But my supercharged high-flow setup needs more flow. I tried a big magnaflow, but it just killed the interior noise level. So I decided to move back to the flopro after a little reconfiguration. I love the quiet. I can actually hear the supercharger whine again.

The default setup of the flopro has most of the gasses traveling through internal vent slits in the pipes. I cut a hole in the end of my flopro and added a cutout. That allows me the ability to open up a 3" dump directly in line with the inlet pipes. I have a 3" electric opener that I haven't installed yet.


Sketch of my flopro muffler:



Pic of my added cutout:



Installed on my truck:



http://www.flopro.com/FP2500oval.htm

 

Oh yeah, I also recently added a pair of 3" high flow metallic substrate catalytic converters. The internals are made of super thin stainless steel fins, not the common ceramic bricks. They hold up to the higher temps of forced induction better. Flow on them is very good. I haven't had cats installed for nearly 2 years. I didn't notice any loss in power after installing them, but they removed the raspy sound I had.

I did relocate the cats from the front header pipes to a location further back after an X pipe. That allows equal flow between both cats.

 

That is nice work. I hope that it works well for you and that the new cats don't slow you down any.

Nice pics.

 

so the magnaflow was too loud?

great idea on that muffler cutout!

 

I'll test it out with the electric cutout soon. Yeah, interior noise level with magnaflow is way higher than with the flopro. Cats helped tame the magnaflow a little, but not to the level I wanted. I was running a 4" 90* bend tailpipe and sending exhaust out before the rear tire. I think a full over axle tailpipe would have helped some, but not enough. Original cats would have cut sound down, but would have dropped flow level.

 

Excellent idea with the cutout,I gather you didnt open up the flopro and cut some of the baffle out,the cats sound like a nice piece ,a link?My flopro is raspy without the cats, now days just leave them on,you should be happy with the overall tone/sound and lack of drone.

BTW,i sent you an email 6/20

 

what does it sound like with the mods? did the exterior levels come up? it looks like it would flow like crazy.

 

damn now that is sweet

 

Sound is just about right now. Its got planty of sound outside, in fact, its louder outside that I would have thought. Inside, I can talk on the phone and listen to the radio again.

These cats flow well enough that I won't need to take them off. It even passed inspection last week. Guy asks if I have cats, then looks under the truck, and says "yeah, they're over here".

Sorry about the email Gonz, I took the family to Sea World last week. I'll look and reply.

 

great idea, nice work Id be interested to see what the inside of that muffler looks like