Straightpiping The Secondary Cats...What Should I Expect?

no o2 sensors to deal with if straightpiping the secondary cats. it should be a little louder at idle but not excessive. other than that, chop away and slap those pipes on....

Cool. That's all I wanted to hear :thumbup:

Going to have that taken care of within a few days.

Yup yup, I think you'll like it. i don't know how much back pressure the 350 needs, but I'd guess it is minimal, compared to the E55.

You consider cutting out your resonator, too and do a real straight pipe?

I want to do both to mine. I've done the resonator, but been scared of the secondarys, since I don't wanna loose bottom end.

jangy said:

Yup yup, I think you'll like it. i don't know how much back pressure the 350 needs, but I'd guess it is minimal, compared to the E55.

You consider cutting out your resonator, too and do a real straight pipe?

I want to do both to mine. I've done the resonator, but been scared of the secondarys, since I don't wanna loose bottom end.

Click to expand...

I wouldn't do both on this car, mainly because I hate how 6 bangers sound and I don't want to emphasize that. I talked to Vadim here on this board and he said straightpiping the secondaries is a better option because the resonator also keeps the pressure balanced.

As for backpressure, the 350's higher compression does help it, but I'm sure I'll still lose a bit off the line, since the powerband would move to a slightly higher rpm. I'm not too worried about it though, since 1st gear winds up pretty quickly (I launch it @ 1500 rpm), and from a roll I WOT it most of the time anyway....I don't let the car bog around at low rpm.