Offroad-Express

collecting parts for my saf turbo convo will be aiming for around 15-200kw boosting a hx35,what size wastage should I be going for?38mm to small?

I'm not familiar with turbo TD42s, but I am familiar with turbos, and if you want to run high boost, a small waste gate is fine. Even a 38mm gate can bleed plenty of exhaust with a well designed manifold.
BTW the holset hx35 on my tractor (around 6 litre diesel) has no waste gate at all.

true,mmm got me thinking though when I took my 300kw r32 for a tune the tuner mentioned that my 44m wastgate was to small and it was causing boost creep, just wondering if because I'm going for a smaller power figer on my td42 if I would get away with a smaller gate

Less worry in a diesel other than boost creep dragging your afr lean. As blake said most tractors trucks run nothing but the turbos work in a narrow powerband governed by the pump. Personally ill try without on my next buildup. But im running twinscroll and two wastegates would be necessary if it does spool up enough.

ahh I see,sweet so sounds like a 45mm will be more than sufficant,cheers for the help