For the Audi B5 S4 2.7t engine:

Springs made by PAC Racing and are wound from high grade, super clean, chrome silicone alloy. The retainers are CNC machined from 6AL4V titanium round stock.

Light weight titanium retainers lower the valve train weight changing direction. This allows higher RPM limits.

Higher closed seat pressure for consistent valve sealing at high boost pressures.

The spring pressures were tested at the most common lift profiles for the S4, RS4 and 2.8 camshafts.

Intake:

Closed seat pressure @ 1.450” installed height 72 lbs / 140% over original.

Open pressure at .301” lift (OE S4 camshaft) 115 lbs / 44% over original

Open pressure at .341” lift (2.8 camshaft) 124 lbs / 38% over original.



Exhaust:

Closed seat pressure @ 1.300” installed height 72 lbs / 16% over original.

Open pressure at .410” lift (S4, RS4 and 2.8 camshaft) 204 lbs / 54% over original.