I'm running 30psi through my 1G Magnus intake manifold and haven't needed to put a "danger to manifold" sticker on it.
I know Joey's welds started to pull with over 30psi and NOS on his Magnus. But you've got to remember that NOS is a whole different ballgame.
The Magnus is also 1/2 to 1/3 the capacity/size of some of the larger intake manifolds and yet it still flows a lot for its size. Is it really a case of 'bigger is better?'
Those tests show different results to other tests carried out by BAZ a few years back. Baz also tested the JMF intakes and noted nothing about turbulence in them.
Word to the wise, I wouldn't care too much about these 'tests' as they're going to differ wherever or whoever does the test and with whatever equipment they use.
The aftermarket industry's fallacy of 'bigger is better' is not always the case. Improving performance in one respect, usually has a counteracting effect to another.
If you can get a cast manifold it will be the strongest and will handle 40+psi.
GVR4 Cyclone intakes are restrictive. Swap it out for an OEM Australian delivered ECI Multi intake manifold and I reckon with some porting it'll do just fine.
EVO owners need not even bother changing intakes unless theyre making some pretty high power. We've seen several guys put 30-40psi through them and they still make the power (edit: unless of course they have done a big port job and need bigger intake runners lol).
