Most people say keep stock sr turbos below 14psi. That's pushing it though. Stay 13psi for safety on 93 octane if you have stock tune and stock injectors. If you have a journal bearing turbo or have ceramic comp/turbine blades, you don't wanna spin them to death lol. (faster rpm's come with higher boost levels)
This is in a nutshell speak. Search search search will yield muuch more extensive discussions.
Just because you have a built bottom end doesn't mean it can take more engine knock if you don't have upgraded injectors/tune/pump/fuel system in general. That's your limiting factor. Maybe s14 injectors can stomach more increase and have more cc of flow from the factory than s13 sr20det's, but I am not familiar w/ that... search sayss
http://www.drift-connection.com/sr20det-specs.php
If this is a reliable source, and you check your ECU number to verify what car your SR20 came from, and have at it!
Specifications for the S14 Black Top SR20DET with VTC
(Found on the 95-98 Silvia)
- Horsepower: 220hp @ 6000rpm
- Torque: 203 ft/lbs @ 4800rpm
- Turbo Specs:
- Compressor: T-28, 60 trim 60mm BCI-1 compressor in T-04B housing
- Turbine: T-25, 62 trim 53.8mm 0.64 A/R turbine housing.
- Center Section: Ball Bearing
- S14 SR20DET's use a different ECU and harness, these are extremely expensive and hard to find.
- Variable valve timing system and a different turbo are the significant changes from the S13 SR20DET engines.
- The S13 uses a "low port" intake design vs. the S14 "high port" design.
- Performance:
The stock turbo will be safe to 13-15 psi. After that, the turbo is past its efficiency range, and power increases will fall off and are not worth the risk of turbo damage. The stock engine should produce 250-260 RWHP at safe boost using stock turbo. Upgrading turbo, fuel and rest of need parts will yield 300-375.