38Mm Wastegate Sufficient For Rb26 At 500Bhp?

[Carthik]

I am putting together a single turbo setup and need to pick a wastegate and was wondering if a 38mm external gate will do without boost creep at 500 bhp. If not what is the minimum size recommended? And if it is sufficient up to how much BHP will it be good for?

Cheers.

[Dale FZ1]

http://www.skylinesaustralia.com/forums/topic/347726-kando-dynamics-turbo/

Read this thread, gives an idea on what works for a similar output on similar engine capacity and boost requirements.

38 might be a bit undersized.

[Legionnaire]

I always wondered if internal gates, say, on GT30 series, have no problems holding boost and no boost creep problems, and usually have a flapper equal or even smaller than 38mm and located at a bad angle to gas flow, why would external wg have any problems?

[GTSBoy]

That would be because internal wastegates are a flapper valve, so the flapper progressively gets more and more "out of the way" as they open and externals are poppet valves so the head stays in the gas path (the gas has to flow around the curtain area of the valve head" so comparing them simply on diameter is not helpful.

For a 600HP anything I would have said a 45mm external was the threshold of sensible.

[STATUS]

42mm minimum, 45-47mm optimal.

[W0rp3D]

42mm minimum, 45-47mm optimal.

Agreed, can be a pain to go bigger once your done so your better off to go with some thing with plenty of flow rather than something that "might" have enough flow.

[lachlanw]

depends what turbo you have .

if the turbo isnt capable of much more than 500 hp you wont need a ver big wastegate

[R31Nismoid]

Also depends on how much boost you intend to run as to how much the gate actually needs to let past.

Read the "FI Guide", there is information on it in there.

[tridentt150v]

He also says bhp which to me says crank. 500bhp is like 300-350awkw, using the old SK formula a 42 is probably the best size.