Is x torq just Husqvarnas terminology for auto tune? Will the saw automatically tune if I run 40:1? I may be buying a 450, that looks as if it has never run, I just don't know how these x torq saws work.
I don't know exactly what defines an X Torq saw, but X Torq is NOT Auto Tune.
There are lots of Non Auto Tune, X Torque saws, it seems that all of the Auto tune saws are in the "5" series, but not all the "5" series are Auto tune, the 543XP, does show as being Auto Tune, and the 576XP is available both with and without Auto Tune.
Pretty much the entire "4" series of saws, from the 435 through the 465 are all X Torque, but none show listed as Auto Tune.
As I understand it super basically, X-torq uses fresh air to blow out the burned exhaust gases before the atomized fuel from the crank is forced in through the transfers. Thus saving emissions supposedly as un-burned fuel is not coming out the exhaust.
From the Husqvarna Site Glossary AutoTune
AutoTune technology uses a computer chip to control the flow of fuel to the engine. This enables automatic optimization of performance, which in turn reduces fuel consumption and emissions. The new chainsaw 576 XP AutoTune, which was launched in 2009 is a technological and environmental break through for professional chainsaws.
Husqvarna's latest technology for two-stroke engines, which reduces fuel consumption by up to 20% and emissions by up to 60%. The engine technology increases torque over a wider rpm range, providing maximum cutting power. X-TORQ® is used in E-TECH II engines for chainsaws, clearing saws, trimmers and leaf blowers.