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View Full Version : All this talk about external wastegates!



benp
05-30-2007, 06:05 AM
Well I cheated a little bit, heres my swingvalve wastegate dump. For what reason? I guess cuz loud is cool but im hoping this will also eliminate boost creep.
http://i89.photobucket.com/albums/k217/benjaminpogoda/DSC08389copy.jpg
http://i89.photobucket.com/albums/k217/benjaminpogoda/DSC08378copy.jpg
http://i89.photobucket.com/albums/k217/benjaminpogoda/DSC08381copy.jpg

Skibbe
05-30-2007, 08:09 AM
Probably won't cure boost creep on that end of the swingvalve. Porting the wastegate hole would be the only help there.

The nice thing about a true external gate is that it's pulling pressure out of the exhaust manifold before it has to go in the turbo at all.

1FastCSX289
05-30-2007, 10:12 AM
Whats the reason for the divider? Arent you sealing off the turbine by doing that and losing control that the wastegate has over it?

Turbodave
05-30-2007, 11:44 AM
By putting the divider in I'm guessing it should act like a typical external wastegate by diverting the exhaust flow before it gets to the turbine. Or at least that's the theory behind it.

What type of calibrations are people with the external wastegates running? I'm guessing something that doesn't need 02 feedback?

Skibbe
05-30-2007, 12:19 PM
By putting the divider in I'm guessing it should act like a typical external wastegate by diverting the exhaust flow before it gets to the turbine. Or at least that's the theory behind it.

What type of calibrations are people with the external wastegates running? I'm guessing something that doesn't need 02 feedback?

This is still an internal gate and operates just like it would stock. The divider and new dump are just not tied into the exhaust housing anymore. I don't know if he plans on tieing them into the downpipe further downstream, or if he wants to keep them divided.

My external gate set-up pulls the exhaust gas out of the exhaust manifold, before it goes into the turbo. The exit on the external gate ties into the downpipe, before the O2 sensor, so stock electronics are fine.

I don't know that having a divided wastegate dump would affect the O2 readings at all. Exhaust should still have the same mixture, just less volume if some is sent out the wastegate dump.

turbovanmanČ
05-30-2007, 01:08 PM
By putting the divider in I'm guessing it should act like a typical external wastegate by diverting the exhaust flow before it gets to the turbine. Or at least that's the theory behind it.

What type of calibrations are people with the external wastegates running? I'm guessing something that doesn't need 02 feedback?

Oxygen sensor readings are a moot point as there not used in boost, :thumb:

I am having a hard time trying to figure out how that will work, you've shut off the boost control from the flow of exhaust so as it sits, you have no control over boost.

OnLooker
05-30-2007, 01:29 PM
He is still going to be using it like a stock internal wastegate but it will be vented externally instead of mixing with the other gasses in the swingvalve area. It still reduces pressure before it goes through the turbo just like factory but being vented externally.

Skibbe
05-30-2007, 01:34 PM
I am having a hard time trying to figure out how that will work, you've shut off the boost control from the flow of exhaust so as it sits, you have no control over boost.

Same boost control as any internal gate... needs an actuator on the swing valve. The only thing that has changed is where the wastegate exhaust goes. Instead of into the downpipe, it now has it's own exit.

I don't know what the perceived benefit would be... other than the OP wanting it to be loud.

tryingbe
05-30-2007, 01:54 PM
Honestly, I don't think it's going to help. The wastegate hole is still very small.

TII vs TIII punk.
http://www.thelostartof.net/tryingbe/forsale/cosworth2.jpg

turbovanmanČ
05-30-2007, 02:15 PM
Same boost control as any internal gate... needs an actuator on the swing valve. The only thing that has changed is where the wastegate exhaust goes. Instead of into the downpipe, it now has it's own exit.

I don't know what the perceived benefit would be... other than the OP wanting it to be loud.


Ok, I see how it will still vent. I thought it was sealed off from the exhaust gas's but forgot it still has the passage to the turbine, :nod:

moparzrule
06-05-2007, 08:10 PM
If you cut off the flapper, ported the hole a good bit bigger and installed an actual external gate like a tial or greddy or something then it might do some good. But still using the stock flapper theres no point.

The Pope
06-08-2007, 10:20 AM
if your going to cut into cast iron, add the wastegate to the exhaust manifold between 1&2. Then your removing backwash and gaining flow out of the engine. Going though the work and getting a gain from your trouble is important.

2.216VTurbo
06-08-2007, 05:03 PM
I think the folks who are down on your idea need to read up a bit on why Mitsu chose to do a 'divorced wastegate path' on thier Evo 8&9 motors. One of the benefits they found was that the turbulence from the wastegate exhaust didn't disrupt the flow from the 'engine' exhaust. If it didn't work, would they have spent the extra development time and $$ on it. There was more logic listed (IIRC it was Dave Colemans Technobable section in Sport Compact Car Magazine) but I can't remember waht it was:o