I am putting together a 3.5" exhaust system for my new turbo and need something to keep the sound in check. Borla and Magnaflow both make universal mufflers in that size. I have searched and found many posts about using them in place of a cat, but there are only a few vague references to using them as a primary muffler. Based on appear I imagine they sound similar to the apexi GT spec, which is way too raspy/loud for my taste.

Does anybody have personal experience using either of these two units as a primary muffler? Are there any other mufflers I should consider?

 

Anything 3.5" wide is going to be loud. As far as Borla and Magnoflow they're probably if not as loud as the apexi GT spec, louder. What you could do to quite it down is to run two big mufflers, one after you dp and another at the end, this usually makes a noticable difference. Good luck man.

Alex

 

With my single turbo, downpipe, midpipe and RB exhaust, noise was a problem. With the RX7Store resonated midpipe, I can now drive stealthily around town. It has certainly quieted the beast!

 

There's a trick to getting mufflers to work better in terms of exhaust noise supression without sacraficing performance.

Make sure the muffler has a straight-through perforated pipe in the center.
Try go get the perforated pipe that has (round) holes in it with a smooth surface.
Try to stay away from the pipe with has "vents" in it, which effectively reduces the I.D.

We typically try to get the oval mufflers which the inlet and outlet are at extreme ends.
Due to the offset, this muffles the exhaust noise the most.
Center in / offset out also works pretty well if you need the smaller offset due to mounting.

If you have a totally straight-though center muffler, you can offset the angles entering and exiting the muffler.
This gives you almost the same effect at the above.

Racing Beat and GReddy has been using these tricks on their exhaust systems for years.
And this is how they offer "straight through" mufflers with the best performance but without the nasty increased exhaust note.

We've used Borla ProXS and Walker Dynomax UltraFLO brand mufflers with good success.
I know Borla offers 3.5" mufflers.


-Ted

 

Great info, thanks!

 

I used a 3.5" Ultraflo and it was reasonably quiet.... Straight thru design you can put your arm thru! If you need it even quieter you should think about installing inline an extra muffler or two. I'm serious!

-Mark