Nginx node.js express download big files stop at 1.08GB

I have this node.js app proxied by Nginx (on production). A route is something like this:

exports.download = function(req, res){

    var id = req.params.id;

    if (id && id == 'latest')
    {
        res.download(config.items.release_directory+'/<1.6GB-file>.zip', function(err){
            if (err) {
                console.log(err);
            } else {
                // do something
            }
        });
    }
    else
    {
        res.redirect(301, '/');
    }

};

So, clicking the right route/URL the browser starts to download the big file but then it stops always at 1.08GB (the file is about 1.6GB), truncating it.

I really cannot understand why. Any ideas?

EDIT: The config.items.release_directory is a static Express directory declared as:

app.use('/releases', express.static(path.join(__dirname, '..', 'releases')));

EDIT2: On development with grunt serving directly the app without Nginx it works fine.

SOLVED: read the comments below, problem is proxy_max_temp_file_size variable in Nginx

Here the matter is nginx configuration, not nodejs code.

nginx write temp files in disk before sending them to the client, it's often a good idea to disable this cache if the site is going to serve big static files, with something like:

location / {
    proxy_max_temp_file_size 0;
}

(no limit)