Delkevic's 4:1 Exhaust System

[radare]

Delkevic has an exhaust system listed for the Seca II. It's a 4:1 system. Delkevic has shown an improvement of 3 hp across the RPM band with this exhaust. I find this surprising as early reports on Vance & Hines and Yoshimura 4:1 systems barely showed a single HP increase. Do you all think Delkevic has figured something out or do you think they're BS'ing us?

http://www.ebay.com/itm/SECAII-XJ600S-X ... 2a&vxp=mtr