Twin Rotrex 3.2 VR6.

    Twin Rotrex Supercharged R32 - 3.2 V6

    We've been working with Rotrex superchargers for years now and working with the R32 3.2 VR6 engine for just as long.

    We were winning awards with a Supercharged R32 project car back in 2006, but not being one for sitting still Storm Developments decided to take it to an all new level by taking an R32 engine and adding not just the one Rotrex superchargers, but two.

    A combination of two differently sized chargers creates excellent efficiency, the smaller blower generates immediate good boost at low rpm, then the larger unit continues to push it right on through to the red line with devastating effect...

    The Installation

    Installing two superchargers was a logistical nightmare in itself, requiring amongst other bespoke solutions a custom built front subframe. We at Storm Developments try to avoid cutting away any of a car if it's at all possible and this development was no exception. We mounted one supercharger at the top of the head and the other in place of the air conditioning pump. The auxiliary belt driving these superchargers is a stock VW part also found on the Porsche Cayman, it's well over 2 meters long. This required a serious belt route and again with this supercharger system we've managed to employ a clever belt tensioning system to counteract belt slip at the same time as avoiding over-stressing any pulley or bearing. Be wary of any supercharger system that does not employ a sprung tensioner of some description.

    The boost from one Supercharger is cooled by an intercooler and the other by means of a chargecooler. The already cool charge temperatures are dropped to an icy cold level with an Aquamist water injection system that runs a 50/50 mix of methanol for it's additional beneficial properties. After a hard run the inlet manifold is cold.

    Each Rotrex Supercharger has a standalone oil system incorporating it's own oil cooler; this keeps the superchargers and engine oils physically and thermally separate. Engine oil is not a good gearbox oil and vice-versa.

    The R32 engine is thermally excellent, but a large radiator with twin race fans and a lower temperature thermostat keeps the water system nice and cool. Although not strictly required an oil cooler assists the engine oil temperatures on those extra hot days. Along side all of this is an intercooler and another separate radiator for the chargecooler.

    Free from the excessive heat generated by turbo'ing a car, the twin Rotrex Supercharged R32 stays surprisingly cool.

    The engine is run on Storm Developments standalone engine management for forced induction R32 as designed and built by Storm Developments.

    With the single supercharger the power was measured at approx 590 bhp. Power is now estimated at 650bhp.