How do 930 wastegates work?

v9ff · v9ff's Garage

Can someone explain to me how a 930 (pre-1989) wastegate works?

Are they mechanically or electronically controlled? If they can be controlled at all, I don't know.

Is the wastegate that Porsche uses on the 930 "old technology" or is there a better style one out there?

Thanks for the info!

RarlyL8 · RarlyL8's Garage

The 930 wastegate is a mechanical old-technology unit.
It works simply on spring pressure against a venting valve. The spring tension dictates presure release. You can use many types of boost controlers in concert with the stock unit to allow flexibility and better performance or function.

TurboBert · 07:58 PM

Like RarlyL8 said. Here's a picture.

You can control the boost pressure by either replacing the spring (that's the hard way) or by installing a boost controller in line between the intercooler and the wastegate.

MZ3 SBC · MZ3 SBC's Garage

but can a variable boost controller reduce the performance given the spring in the wastegate..

My sense is that the wastegate will dictate boost pressure up to its max.....and then the variable can increase boost pressure above that. Doesn't seem like a safe way to add performance unless you have EFI and tune adjusts for It dynamically.

911tracker85 · 05-04-2016, 08:56 AM

Quote:

Doesn't seem like a safe way to add performance

that is the reason one nick-name for it is dial-O-death.... turn too much and enjoy the ride up to the point your engine gernades or burns through the pistons....

increasing boost needs to be done in concert with other mods/tuning so the 'system' has integrity (not sure what work to use here), especially if it has CIS. of course the more you stress the engine it will increase the rebuild frequency.

I know a couple guys running hot-rod 930s on the track with EFI and high boost. 600+ HP, rebuild every 75 track hours..... his original plan was rebuild at 100 hrs, did not make it and it blew apart just short of that.

my 930 clone project has one installed as shown by MZ3 SBC. when I finish the full rebuild, will remove and install a new TIAL WG with .8 bar spring. fortunately I did not find any piston damage, actually a lot of carbon deposits so it would appear the motor had been running very rich.