i took this from RPW australia... sounds interesting...
For all engines from 1.0 - 1.5 litre, especially the smaller 8 and 12 valve engines we recommend :-
* For 90% of people with mild modifications a 2" press bent system would do the job perfectly. Mandrel bent would produce no credible gains for your application other than giving you a larger bill.
* For those with larger modifications like some of our stage 2 upwards modifications, 2" mandrel bent is the perfect size where air flow volume is a lot greater with items like twin throttle bodies, or camshafts stage 2 etc.
* For those with race style system in naturally aspirated form like a quad TB system, 60mm Twin TB system etc, then a 2 1/4" mandrel bent system is as large as you would want to go.
* For those with our turbocharger kits you would be recommended to run either a 2 1/4" mandrel bent system or a 2 1/2" press bent system. Any larger is again, a waste of time and money.
cheers
