External Wastegate piping - hotpipe or downpipe

[6btdakota]

I have a decent garrett 4294 and might want to try twins someday.

But I noticed someone had their external wastegate on a set of twins piped into the downpipe

I thought you always want to use that extra pressure to help drive the bigger charger.

What would be the reason for not doing this. Someone mentioned it being okay if your exhaust breathes well but i would like more explanation. thanks

 

[G1625S]

I 'think' in the case of big fuel and big hp, the primary is bypassed by the gate to avoid turbine overspeed. In the case of mild to moderate twins, the gate does indeed help with spool when fed to the primary.