Hellraiser

I don't know much in way of turbo's so wanted to know advantages/ disadvantages of external wastegate over internal wastegate and difference in performance between the two

All comments appreciated

nevsrevs

Greater boost control with a external at higher pressures.

Mark Shead

Give a hp est and turbo used helps.
Most of my yb run int gates and most of my evos run ext gate.

Mark

Adam-M

Any reason for the difference between the yb and shevo?

Mark Shead

The main reason is I chose to have my manifold for yb made mainly for int as it's cheaper and easier to fit and you can keep the stock heat shield and tech only a small loss in top end power but the Efr with int gate has smaller housing so tech better spool.
The Evo I buy the manifold in and the main kit is base on ext but you can get int gate but needs a diff rad on Evo 7 plus so stayed with the known route.

Mark

CrOwSoN15

Is there a rule of thumb on sizing external gates Mark?

Mark Shead

If a turbo has a sensible size exhaust housing and the flow through the gate is of good design then a 44mm tends to fit the bill well,
If the gate is to small you get boost creep as the revs rise this tends to be less of a problem as you raise the boost as the gate flows less through it th4202 e more boost you run, Again this is correct if the housing is not to small,
You tend to find odd set ups if you spec the wrong turbo,
A GTX4202 turbo will flow a flat 1.5bar with a 44mm gate if everything is correct on a YB and the gate flow much less at 2.8bar as the energy is used to raise the boost rather than bypass the turbo housing.

Mark