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Internal to External Wastegate?
Rallye_Mark - 13/12/10 at 08:35 PM

Hey everyone,

for my turbo to fit nearly within the standard bodywork I would need to remove the Internal wastegate and actuator as it is the actuator that will poke out to far. I've been doing some reading but would like to know other peoples opinions is it as simple as...

Remove the internal flaps from the wastegate and remove the shaft that it runs on, weld the small hole up, then fit an external wastegate to the exhaust manifold before the turbo?

Also for IVA, would the flow from the external wastegate need to be fed back into the exhaust system or could I have it running into the atmosphere/screamer pipe?

Cheers Mark.


PSpirine - 13/12/10 at 09:36 PM

I thought you weld the flap up, not remove it! (otherwise you'll get gasses bypassing the turbine)

As for how you vent it, you need to consider the noise of an open wastegate at full chatter..


Antnicuk - 13/12/10 at 10:09 PM

i dont think you would get through the iva without the screamer plumbed in. As for the actuator, you can move them around a bit as its only a bar operating an arm so you have quite a range of movement, it just means making a longer/shorter arm and new brackets.

Thats what i did with my first turbo but then i went for an external w/g, which as you say is just taken off the manifold before the turbo, but you need to take into account the flow direction of the exhaust gasses. On the internal w/g, I just attached a flat piece of metal with a hole in it over the waste gate door lever and then welded the other end to the exhaust housing holding it shut, that way if i wanted to revert back i just need to grind the flat bar off. If you remove the door you wont spool the turbo as the gasses will go through the hole instead of through the turbine wheel.


Stott - 13/12/10 at 10:13 PM

For IVA then you would deffo need the waste put back into the exhaust. It would prob pass noise as it would be off boost at the no load 3/4 max rpm test but the fact the tester could see there is an un silenced exhaust part and the fact that the emmisions at this point would be un catalysed (if necessary) would cause them to fail it IMO.


StrikerChris - 13/12/10 at 10:14 PM

I think in theory your correct,a screamer pipe is called that for a reason tho!be bloody loud (and annoying) in an open top car!I was amazed how loud my standard wastegate sounds!


richardR1 - 13/12/10 at 11:19 PM

Would definitely say you need the pipes feeding back into the exhaust for IVA as others have said. Have just bought a highly tuned Skyline which has external wastegates and screamer pipes and it sounds awesome but i think an IVA inspector would have heart failure


CNHSS1 - 14/12/10 at 09:34 AM

with a decent ext WG, it should never open when the engines running unless it hits the boost threshold, so it becomes just a redundant tube. Depends how alert the IVA guy is i guess


coyoteboy - 14/12/10 at 10:24 AM

quote:
ith a decent ext WG, it should never open when the engines running unless it hits the boost threshold, so it becomes just a redundant tube. Depends how alert the IVA guy is i guess



Unless you have a good boost controller which actually blocks the pressure signal before the actuator, any WG will begin to open before the threshold, at least from my experience. Significant early boost gains can be had by fitting a blocking boost controller which holds the WG shut until the crack pressure, then ramming it open as much as needed.


CNHSS1 - 14/12/10 at 10:58 AM

i was assuming a boost controller would be used. in my experience, the cheap ext WGs work OK in terms of conrolling boost, but often 'chuff' at idle which sounds pants (and could upset your IVA guy or a scrutineer...). The beauty of an ext WG design over a std internal penny and actuator, is that pressure is fed to both sides of the gate, so that its sucked open and pushed shut if that makes sense.


coyoteboy - 14/12/10 at 11:11 AM

quote:
The beauty of an ext WG design over a std internal penny and actuator, is that pressure is fed to both sides of the gate, so that its sucked open and pushed shut if that makes sense.


Fair point, even if it has an amusing mental image


CNHSS1 - 14/12/10 at 11:13 AM

Oooh errr Missus, fnaar, fnaar, nudge, nudge, wink, wink