Is there anything I can do to speed up dl speeds for large (4-6 gig) files? I only average around 15kbs on large well seeded files, yet on smaller files of 100 megs I can get up to 150 kbs.

Large files take a lot longer to get in gear. Some files may take up to 45 minutes to get the share ratio up. Could also be that there are no seeders in Thailand for these large files or that the seeders in general are just poor. It's a toss-up with torrents.

Steelepulse,

Use BitComet for your downloads, when typing in search box in top right corner, always choose Piratebay search engine. Results that come out will download very fast. Their servers are really good. Till recently I used different search engines and took ages to download....

Servers have little to do with torrent download speed.

I am with DTTK, it is all to do with the seeders.

I have a couple of large torrents 4 & 5 Gb that have been going for over a month now and still not complete,

both from Pirate Bay.

Also once you download a large file you need to keep it available for some time to allow others to share

It's unlikely you'll get fast download speeds on a torrent tracked by a public tracker unless there are hundreds of seeds/leechers. This is why public trackers are only really useful for new and, generally, mainstream crap. Most seeders (the ones that even bother seeding back) will have their upload speeds capped, since they're looking to provide availability rather than speed. The massive speeds you get on new torrents are generally a result of the combination of up to 100 or so connected peers hitting you at 3-4kbps each. On an old torrent you might have something like 10 or so seeders if you're lucky and a few leechers all typically capped at 1k or so, giving you rubbish downstream speeds. Private trackers provide the solution, but also present their own unique set of issues (ratio rules, having to compete with seedboxes etc.).