Originally Posted by
Roelof
To make it legal?
If you look closely it seems it was cut open.
INS Box (no matter what: Serpent, Xceed, OS, ...) they're made in two halves and secured with screws because its assembled around the intake engine filter (I suppose that putting tape on those locations was a try to not upset laminar flow around the box). I remember seeing Serpent INS box that originally came with some adhesive tape to 'seal' the two halves. But that was about 25 years ago.
Takahata MRX3 with INS-Box attached
Remember to have read (żEFRA/IFMAR?) that any physical modifications to the INS box renders it illegal.
Originally Posted by
Roelof
The insbox was a Serpent solution to lower the noise where the EFRA was hunting for. It is true that the inlet noise can be loud too but the effect with every engine can be different. You US guys have different environment laws than we Europeans do and so for us it is important to keep the noise level within the limits of the law so the track will not be closed down.
Unfortunately, this happens everywhere, so the unique solution is to reduce noise emissions (in some places, tree huggers start to target nitro cars as source of noise and pollution) so better to stay under their radar.