External wastegates boost creep also,that's why you would use one of these or others:AEM Tru-Boost Controller Gauge Control system & Display http://cgi.ebay.com/ebaymotors/AEM-Tru-B...Q5fAccessories. I have the tru boost on my Syclone & it holds rock steady boost pressure w/my internal wastegeted turbo. Crack pressure is when the valve opens prematurely. If you use a external or internal wastegate they boost creep. Example:your internal or external wastegate will have a spring tension of say 5psi,,so when you are starting to boost up say 3 psi,,,the valve will start to open & increase the time for your turbo to spool up, (boost will be slower to rise) W/an electronic boost controller ,if you set it to say the same 5 psi,your wastegate valve will not open until the programmed 5 psi is made. If you are talking about boost spiking,that's a different scenario. When you are running high boost high HP aplications,the internal wastegate sometimes cannot maintain & controll your boost pressures,normally because the internal wastegate valve is too small.
Here is my separate wastegate, Note: the position or how far downstream I reintroduce the wastegate exhaust back into the downpipe/main exhaust system, Also note the shallow angle it comes into the downpipe,you do not want to go in @ a 90 degree angle.Key notes to make your turbo spool faster/boost faster & more power. This set-up is for my SPA manifold.
This would not be an optimun set-up for the wastegate rentering the downpipe,too close to the turbine wheel,& the angle the wastegate pipe renters the downpipe.This is also a SPA manifold. http://12bolt.com/yahoo_site_admin/assets/images/PIC00019.16952756.JPG Also note: mine is not perfect either,I did try to reduce turbulence to a minimun from the wastegate exhaust.
or another option is to run a complete separate exhaust system w/a small muffler for the wastegated exhaust.
