External wastegate on only 1/2 the cyl?

O

okish

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Due to packaging reasons, it would be extremely easy to run a gate on only the front 3 cyl of the manifold. I don't see this as an issue, but if there is one, I still can put it in the collector and gate both runners, it would be alot more work of course. Gate is. 44mm jgs and top turbine housing is a twin volute .85ar 65mm s300.
 
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I believe hx35's only gate one volute, so in theory you should be fine.

I had a similar issue with a previous setup, ended up welding a external gate to a exhaust housing, keeping it divided up to the gate, worked very well.
 
Yea they were gated only on the rear volute and people commonly drill the divider to vent both. I'm worried that if I wastegate only the front cylinders, drive pressure will rise on the rear as the gate opens. I'll prolly just place the gate flange on the center of the manifold and have flow from both volutes. I don't want to put the gate on the housing in case I swap housings.
 
There is not much difference in backpressure between volutes when only other side is gated, they both share same turbine..

Yes, someone has actually measured it.
 
Leiffi said:
There is not much difference in backpressure between volutes when only other side is gated, they both share same turbine..

Yes, someone has actually measured it.
Click to expand...

Hmm. I know a little about thermodynamics and I know that at a given shaft hp for the compressor to keep up, pressure would increase on the non gated side since the turbine and compressor would start slowing. Of course there's like 500 more variables so I'm unsure if that actually happens in real life. If a few more can chime in about it and say it doesn't matter then I'll just vent the front cylinders to the hot pipe.
 
I think your control would be limited, depending on how much how much flow you are trying to gate.

The best control I experienced, is the above mentioned setup, you can see why.
 

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ill be putting it on the collector. if it doesn't work out. the turbine housing will be next. i figure if i swap housings/turbo's i wont have to redo the wastegate mounting. i see alot of the flanges have a divider all the way to the valve. any reason that no divider will harm anything?
 
Maybe not a huge difference, certainly wouldn’t hurt though. I’ve played around with twin scroll vs undivided housings, mostly noticeable off idle.
 
This is what we came up with. I think it is the best solution, especially if I want to run different housings etc... I'll post a pic after it's all welded up

1fk3YHWh.jpg

IleFV8bh.jpg
 
Are you going to weld a plate up the middle to keep it divided? Or are you basically just going to turn your manifold into a non-divided manifold?
 
Gonna Fab up a plate to run up the middle of the pipe and butt up against the bottom of the manifold. It won't be welded to the manifold because we ground out all the cast to be able to get enough flow. It will be formed to the floor but not water tight. I think it will be fine.
1NQHHaCh.jpg
 
Very nice, should work well for you. May be worth grabbing something like a knife sharpening block and go over the gate flange, looks like it could of warped.
 
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