Friday, December 11, 2009 - 05:04 pm, by: Mike Bradberry(Halflife)
I read the whole article Ben, and of course it makes sense, but I still feel that a lot of it is going to be guesswork and/or experimentation on individual vehicles. There were certainly some good basics and guidelines to get started though. I always wondered about oversized pipes not necessarily giving best performance. His article backs that up.
Saturday, December 12, 2009 - 03:21 pm, by: Cihan Aday(Cihan)
Can be replicated in Engine Analyzer 3.5, standard 1UZ vs Std 1UZ + optimised headers and 1100cfm exhaust (twin 2.5inch with x pipe).
The NA 1UZ i'm thinking about building uses this '5th cycle' principal ;) Makes up for lax midrange compliments of intake tuning and big cams.
Graph 1: You can see the difference in pressure over the standard headers either side of TDC. Something like up to -13psi vacuum during overlap (green vs red line). The two blue lines show intake side pressure, the effect of exhaust scavenging is clear between TDC & 450 degrees.
Graph 2: Light blue (torque) example is a reasonable application, dark blue is an extreme example that's not as easy to implement as pipe sizing is a little large etc.
Tuesday, December 15, 2009 - 08:29 pm, by: Cihan Aday(Cihan)
Thanks Peter!
I've made the decision to build the 1UZ VVTI in NA trim, in favour of the 2J + single im currently running. Looking for an engine at the moment. Once thats found i'll fly up to Brisbane, sit down with Cameron, tear it apart and work out what can be done.