Many things contribute to lag.
As you know, the turbo you choose must match the application and work optimally with the other components. To minimize lag in a stock engine with SC cams you might consider the following:
- K27/7200 or HF range turbo that can operate from 2500-6000rpm
- Short run headers
- Cam timing on the retard side
- Finely tuned A/F ratio throughout the operating rpm range.
Headers and cam timing will give you the most return on reduced lag. The choice of turbo needs to follow your chosen operating range, such as 2500-6000rpm. There may be more optimal units than the K27 series, I am not familiar with them all. Finely tuning your A/F ratio will give you 20+ HP, reduced lag, sharper throttle response, and better fuel mileage all at the same time.
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8