Hi i am driving with the fuse 22 out (thrown away) i was looking at the factory workshop manual and when looking at the diagram of how the outward gasses flow it seems to me apart from the fact that they cross over from left to right and visa versa, the box adds no value with the fuse out?

would I be correct in thinking i could take it out completely and save a couple of Kilos on weight? if so will it be to loud and will it add or detract from performance? we will obviously make up stainless pipes to route the exhaust gases

 

You'd definitely save about 30-40 pounds (probably even more of you go with no box at all). Most aftermarket silencers advertise a 30lb savings or so.. the stock box is an absolute beast compared to the aftermarket ones. The noise would be pretty bad though -- I couldn't imagine the drone that you'd hear on the highway around 65mph.
Power-wise I think there's been a few dynos on here that have shown a 3-5hp increase going aftermarket.. so figure maybe a tad more with no box.. though I'm not sure how the torque curve will look with such a drop in back pressure.

 

Forget the drone it will be deafening at all rpm
I've driven one with hi flow header 200 cell cats and a quicksilver super sport back box and that was LOUD owner went back to stock box

 

but I am not removing the cats? and if the box is technically a straight through with the fuse out i am battling with the concept of how it attenuates the sound?

 

Capt. Greg... move to the 200 cll cats with the same rear box as mikey as that will give you the best of both worlds.

 

Doesn't the box itself have baffling material inside that reduces the sound? That reduction in noise would occur with or without Fuse 22 by virtue of just having the box.

 

I think macsamus is right...

 

pity I cannot upload the drawing from the factory workshop manual? it will make the issue a bit more clear, but yes i think macksamus is most likely correct

 

Capt Greg is actually right, but with the valve open the box still has a resonator effect even with no flow through the packing. Also there are enough changes in direction to give the required level of drone free noise

 

If you want loud on the cheap then sure, put in bypass pipes. But I was shocked how loud the hi flo cats were with a stock exhaust. I love it but I could not go louder. The drone on the highway would be too much for me I'm sure. And when you drop the pedal with the cats, the car just screams. I get non-stop compliments on the sound at enthusiast meets with cats alone. It's adds a little bit more metallic, race track grunt to the already gorgeous sound the car puts out.