Richard
I have a 3.9 Hotwire +8, which originally came with the standard cast iron manifolds (an abominable botch up , they are too crude to call a design) and stock silencers.
I fitted the Librands "cross-over" exhaust manifolds with Librands silencers and resonators on the tail pipes, and I continued to run the cats. I did immediately notice the extra horses released (difficult not to with the original design so poor) and I was pretty pleased with the conversion (even if the price made my eyes water a bit)
The exhaust note definitely changed, for the better. To my mind it is still a little too subdued BUT it is really very relaxing when cruising to have all the noise going out behind us.
I have toyed with the idea of trying to release a bit more "rumble" from the V8, and I have considered the following:
1 ) Cat delete pipes , and tune resistor (Problem is that this makes it technically illegal to drive on UK roads and would need changing back before each MoT)
2) Doing away with the resonators ( this entails changing the entire tail pipe, or possibly inserting a close fitting internal pipe to cover the resonator holes)
3) Doing away with the tail pipes and using side exhausts like the Aero based cars) I am told this would be VERY noisy. (very cheap option)
4) Using much more loosely packed silencers, to allow more flow and absorb less noise (only issue here is cost)
I have not really decided which path to take , and I expect that I will choose between options 1 and 4.
BTW I am not aware of Tornado doing an ECU, do you mean chips?
I assume you are aware a GEMS engine needs 2 chips , one for fuel and one for ignition, as well as the knock sensors.
Last edited by MOG 615; 01/11/16 07:42 PM. Reason: Poor proof reading