Corsa-B.uk - Vauxhall, Opel and Holden Corsa B Owners Club

http://www.uucmotorwerks.com/html_produ ... uemyth.htm

So i came across this a but ago and had a read through
Ive always thought that you needed back pressure as when a mate of mine removed his middle box
It slowed down quite a bit.
Anyone know a bit more on the subject?

i wud also like 2 know a bit more about this subject as well - in my corsa i fitted a huge backbox and took the middle box out and didnt notice a drop in power but there might of been a subtle loss. wud like 2 know as i love the noise even a small engine makes without a middle box and wud be looking at removing the one on my next car as well

think it depends on exhaust. i had the middle box and cat took out. didnt notice any difference.. apart from the sound.