Two Suzuki S1600 rally cars with custom designed light weight composite body kits secured ‘Winner’ and ‘Runner up’ positions in the 2013 Spanish Rally Championship. Both cars competed this season in the two-wheel drive, 1640cc 4-cylinder engine ‘Super 1600’ formula rally class. 

The re-engineered composite body panels were supplied to the Suzuki-Repsol team by Karbonius Composites, a Spanish fabricator which specialises in designing and moulding bespoke carbon and Aramid fibre reinforced parts for Motorsports applications.

A 55% weight reduction was achieved by switching the production process to vacuum bagging and fabricating new front and rear bumpers, the four inner wing sections, two mirrors, and the front fog light housings using Crestapol 1250LV high performance acrylic resin reinforced with Aramid and Silionne glass fibre fabrics. 

The new Suzuki S1600 body panels also used white pigmented Crystic LS 97PA, an isophthalic marine approved spray gelcoat, which is able to provide superior UV weathering performance and gloss retention to cope with the intense sunshine conditions typical for Spain during the summer.

Karbonius Composites, located in Lestado, near the famous Santiago de Compostela in the Galician region of Spain, has been designing and manufacturing specialist automotive FRP components for many years.  The founder and owner of the company, David Segade, is an engineer at heart and always on the lookout for innovative new materials and production techniques to keep ahead of the game in the rapidly moving and highly competitive world of Motorsports.

Until now, Karbonius has used a vinyl ester (VE) or epoxy infusion resin, depending on the application. Previous body panels supplied for the Suzuki S1600 rally cars had been fabricated by hand lay-up, first using a VE resin laminate with three layers of Silionne glass fabric, which proved too heavy. 

A replacement set of body kit panels were then fabricated by infusion, this time using an epoxy resin with three layers of the same Silionne glass fabric. In use, this epoxy glass option proved to have insufficient impact resistance; the front bumper was badly damaged during a race and cost them time.  In preparation for the 2013 rally season, the Suzuki-Repsol team set Karbonius the challenge of redesigning the body kit for their S1600 cars in line with FIA rules to further reduce weight and improve impact resistance, particularly for the front bumper. 

With this in mind, David Segade attended JEC Europe 2013 back in March. He was recommended by Dr Alejandro Castro of Resinas Castro, S.L., a long standing Scott Bader distributor for the north west of Spain, to find out more at the show about Crestapol 1250LV acrylic resin, as he knew it to be a very tough resin which can be closed moulded with high performance carbon and Aramid fibres reinforcement fabrics. Following a meeting on the Scott Bader stand at JEC Europe, Resinas Castro supplied samples of Crestapol 1250LV to Karbonius. 

The Karbonius team also attended a Carbon Composite training course in Porriño, near Vigo, which was run by Resinas Castro; the training course provided best practices for resin infusion and vacuum bagging of Crestapol and other resins with carbon and Aramid fibres to produce high quality FRP parts.

Following the course, a new set of Suzuki S1600 body panels were vacuum bag infused by Karbonius using a new, much tougher laminate design. This new laminate design comprised of Crestapol 1250LV with two layers of twill Aramid fibre fabric (200 g/m2) and one layer of Silionne glass fabric (245 g/m2).  Due to the high mechanical properties of the Crestapol resin plus the greater moulding control possible with vacuum infusion, less resin was needed. As such, a thinner and lighter laminate could be moulded. 

The total weight of the new Aramid-glass Crestapol 1250LV body panel kit was only 10.8 kg, a reduction of 13.2kg (55%) from the 24kg weight of the original VE Silionne glass body panels.  Alongside a major weight reduction, was the significantly improved impact properties of the body panels due to a combination of the much tougher Crestapol 1250LV resin and the Aramid fibres.

After seven gruelling races, all the new Crestapol body panels are still in good shape on the two cars. David Segade commented: “It is amazing what these vacuum infused parts made with Crestapol 1250LV resin can withstand. The glass fibre epoxy resin front bumper only lasted one race! I am very impressed with the significantly lower weight and improved toughness of these Aramid-glass fibre Crestapol body panels, as is the Suzuki-Repsol team.”

For Karbonius, there have also been significant manufacturing productivity benefits in switching from an epoxy resin to Crestapol 1250LV. Segade went on to explain why: “When compared with the epoxy resin, we reduced our overall production time by more than six hours. This is because Crestapol 1250LV resin, in addition to being easy to infuse, cures at room temperature and so can be de-moulded in only few hours.

"When we manufactured body panels with epoxy resin, the parts typically needed to be post cured at a minimum of 65 ºC for up to 12 hours.  For Motorsport body panel applications, I personally think Crestapol 1250LV is probably the best product currently available on the market.  It is certainly the best resin for high performance FRP parts that I have used.”