View Single Post
safe safe is offline
Registered User
 
safe's Avatar
 
Join Date: Feb 2004
Location: Sweden
Posts: 3,406
Garage
I have no practical experience with turbos, but as i'm thinking of buying a 930 I have been doing some reading.

What I have gathered is that a primary length of 20 inches is a good start, diameter is a trade of between spool up and power.
Also you want the exhaust pulses to come as separated as possible to the turbo, that is what makes a twin-turbo spool faster; more separated pulses not a smaller turbine.

But maybe twin-turbos are becoming old school, with new engine management and anti-lag systems big single turbos might be coming back.

With a soft rpm-limiter at ~4000 rpm actuated by the clutch pedal you keep the right foot planted and when you clutch you cut the spark, limiting rpm dumping fuel through the turbo keeping it revved up, but much more gentle to the turbo than with retarded ignition. The throttle is wide open, nothing that slows down the compressor. While a big turbo i slow to speed up, its also slower to stop!
__________________
Magnus
911 Silver Targa -77, 3.2 -84 with custom ITBs and EFI
911T Coupe -69, 3.6, G50, "RSR", track day.
Old 07-08-2010, 01:45 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #76 (permalink)