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spuggy spuggy is offline
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Join Date: Jul 2003
Location: Glorious Pac NW
Posts: 2,831
Originally Posted by gsmith660 View Post
I am curious about this also as I dont want to run more than .5 bar and sometimes less
Like mb911 says, boost controller blocks the boost signal from reaching the wastegate, so that the wastegate doesn't (e.g.) "see" .8 bar until the boost controller "sees" the pressure it's set to regulate at.

So it would be useful to run (say) 1.0 bar on a factory wastegate without swapping springs. (If your fuel and ignition maps were set up to run that safely - there's a reason these are called "dial 'o death" when cockpit-adjustable...)

You want to run a lower spring pressure than stock. Some people say that wastegates can start to open prematurely as they're close to opening pressure, and that running a boost controller set to the same opening pressure as the wastegate can be a good way to avoid this - as the wastegate only "sees" the opening pressure/signal when it's there, and thus doesn't "flap" at close to the rated value.

I've also heard that lower settings tend to be more prone to this issue - that the lower mechanical spring pressures involved only increases the tendency of the wastegate valve to prematurely open.

I don't know what the lower bounds of operation of the factory wastegate are. And you'd probably have an issue sourcing a .5 bar spring for it, as the factory spec was higher than that.

But mb911 stocks/supplies the 44mm Tials (which more-or-less bolt straight onto a 930 exhaust system, depending on exactly what you have).

Tial's web site lists a wide range of spring settings for their F44 wastegates, including .2, .3 & .4 bar springs, you could probably run one of those with a boost controller.
'77 S with '78 930 power and a few other things.
Old 01-03-2009, 07:24 PM
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