Whispering Swedes

22nd September 1972, Page 98

22nd September 1972

Page 98

Page 98, 22nd September 1972 — Whispering Swedes

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• Full-throttle noise levels as low as 84 dBA in calm conditions, and in-cab levels "more typical of saloon cars than of lorries" are recorded in a report on noise tests on Volvo F86 and F88 tractive units, undertaken by an independent testing organization in the UK, at the request of Ailsa Trucks.

Put through the BS maximumacceleration test in 6th gear, the 192 bhp Volvo F86 and the 250 bhp F88 both produced figures around 84 dBA for external noise. They had manual eight-speed range-change gearboxes arid were coupled to 33ft semi-trailers having special rubber suspension to cut trailer clatter.

Figures on this test varied from 84.25 dBA on the upwind side to 85.8 on the downwind. The results compare with present UK limits of 92 dBA for new vehicles at the F88's power, and 89 dBA for the F86 type. If proposed reductions in the legal limits are introduced, these would become 89 and 86 dBA respectively.

When the vehicles were given free-acceleration tests while stationary, the F86 produced a maximum of 86 dBA, the F88 87 dBA.

During steady-engine-speed tests with the vehicles stationary, the maximum in-cab noise level with the F86 was 76.25 dBA at the max-power speed of 2400 rpm; at 1000 rpm the noise was about 63 dBA. In the F88's cab a steady engine speed of 2200 rpm produced only 73.75 dBA, and 68 dBA at 1500 rpm.

Concludes the report: "These two vehicles were very quiet for their power."