Shaun41178(2) wrote:The exhaust pressure isn't enough to open the wastegate. Take your boost reference line off the wastegate, and let me know when the wastegate cracks open under boost. IT will be well after you see 35 psi.
Maybe not by itself, but added to manifold pressure, it opens the valve prematurely, because it now has 2 forces working together to open it - despite only needing the one.
Not only but the wastegate itself won't last long with the heat generated by the exhaust if turned around backwards. You would burn the diaphragm and everything else up in short time.
also I don't see a pic.
What you are describing as the wastegate opening before its preset spring pressure can be addressed with a electronic boost controller. So there are already fixes to this problem.
Again, maybe. The housing is made to take the heat. EGTs are fairly low most of the time, so the only time it will get really hot is when you're on the throttle hard, boosting. But that's the same for the normal operation too. I think it'd last, there are cars out there that get the entire wastegate glowing, with only one dyno run, and these same cars running full boost for hours straight in racing apps. We're not getting our's
nearly that hot.
Pic works fine, your comp is fucked dude. My pics are generic photobuckets, with img wraps. Everyone else sees them.
So why spend $300 for this, when my $20 MBC and the WG I already have will do the same thing?
The Dark Side of Will wrote:
Backpressure is higher than boost in any streetable application.
If this is true, and at the same RPM, then my theory would be completely correct, and the exhaust would be opening the WG well before the engine has max boost. I don't think this is quite correct Will, as it'd take forever to get to max boost, because the WG would be held wide open before the engine is at max boost.
What would open the wastegate if exhaust gas is holding it closed?
Manifold pressure is supposed to be what opens the wastegate. You have a reference line (Blue in my pic), go from the manifold to the bottom of the WG. You would have a boost spike, not sure how much, as it gets to max boost, but it would fall back down to your spring pressure fairly quickly. If it's only a pound or two, I'd have no problems with that if the response was noticeably better.
Under normal operation, a spring holds it closed and boost opens it. If the spring AND the turbo backpressure are holding it closed, it'll never open because backpressure goes up faster than boost.
Also, as Shaun said, it's probably not meant for that continual exposure to heat and pressure. What's the housing made of?
But if backpressure is pushing it open, won't it open fully before your engine ever gets to max boost? I have a 8.7psi spring. If my backpressure gets to 8.7, it will open the wastegate fully. Then there won't be enough exhaust flow to the turbine to even get the engine to 8.7psi. So how am I seeing 8.7psi?
Paste from TiAL's website:
- 347 Stainless Steel Alloy is used for valve and valve housing.
- High temperature silicone Nomex reinforced actuator diaphragm.
- 17-7 PH Stainless Steel actuator spring gives consistent pressure at high temperature, resists "relaxing" at temperature to 900F (483C).
- Nitronic 60 Stainless Steel is used for the valve seat, and valve bushing the same material used in the higher level gates for reliability and longevity.
- CNC Machined 304L 12mm thick weld flanges.
- Color anodized 6061-T651 aluminum actuator (Silver, Red, Blue, Purple, Black).
