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fredmeister fredmeister is offline
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Join Date: Oct 2002
Location: Baltimore, MD, USA
Posts: 2,235
Originally Posted by 911nut View Post
All you experts are avoiding answering one question: If a shorter spring is a stiffer spring, why is the .8 bar factory spring longer than the .7 bar factory spring?

So, whoever thinks they can explain the in's and out's (and I don't mean providing links to other pages; do it in your own words) of spring mechanics to us all, have at it.
Simple answer from one of the experts.....
Stiffness and force are 2 separate issues. When you increase the wastegate blow off or opening pressure you are increasing the force acting on the wastegate diaphragm via the spring inside the housing. How you get there is the question. You can get the same force from 2 different springs of different stiffness by compressing them different amounts via Hookes Law.
You need to look at all the dimensions of the spring not just its uncompressed length to determine the end result of the force it exerts when compressed in the housing. This cannot be explained easily without looking at the equations and having an understanding of what is going on in the wastegate design.
My original response early on was not meant to insult or hurt feelings but was said in order to prevent the author of this post from doing lots of expensive damage...if I did not care to help I would not have said anything at all.
1979 930 Turbo....3.4L, 7.5to1 comp, SC cams, B&B intercooler, Snow Perf water/meth injection, Rarlyl8 headers, Garret GTX turbo, 36mm ported intakes, Innovate Auxbox/LM-1, custom Manually Adjustable wastegate housing (0.8-1.1bar),--running 0.7bar max
---"When you're racing it's life! Anything else either before or after, is just waiting"
Old 02-22-2009, 06:38 PM
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