I'm curious what you guys have found to be the best approach to speed runs! Every run I've done I seem to find myself following about the same angles down wind as I would upwind. So if I'm tacking though 100 degrees upwind (for example), I'd be gybing downwind through about the same angles, with max speed on the downwind runs.

I notice that when I'm heading upwind, and start to fall off to build up speed, if I try to stop at a broad reach (90 degrees off the wind) the forces load up in a hurry and I'd be really hard on edge to hold my ground, so I continue to fall off further down wind. I'm using skis on snow/ice but I'm sure you buggy pilots have the same issues.

So that's the big question, what angle off the wind have you found to give the fastest speed? I'll continue to play around and experiment with this, but frankly the local ice conditions are never that smooth, and going fast is usually borderline out of control with legs flying all over the place on the bumpy lake.

it's similar when I'm on hard pack snow to being in a buggy - but more differences in a buggy when there is a lot of room like the playa. On the dry lake when i wanted to do a speed run I would start as far upwind as i could get and into corner of the lake to give max room down the centre of the lake - anyway in the buggy I would start on a beam reach then as speed starts to build I ease toward a broad reach (angling slightly more downwind) and then as kite builds up max pressure and i seem to be going as fast as I can i then angle downwind a few degrees more that takes a bit of pressure off the kite but you don't loose any speed and then start to work the kite a bit that again builds more pressure and again if the kite is fast enough that it builds max pressure angle off a bit more and work the kite slightly and again i've increased speed until I'm running downwind - then when you feel you are going as fast as hell you start to turn into the wind again and BAM slingshot of pressure and power and you need to look fast at how much room you have left anywhere and decide to start burning rubber to slow down.
From and overhead view it's a long very shallow S curve
Similar on skis that I gradually go more and more downwind but it all depends on kite speed and how much pressure and whether I'm getting any more out of the kite.

That's pretty much what I do as well. I'm curious if I hold a little hotter angle (where you feel that big increase in pressure) if that will actually give me more speed, or if I'm just fighting the kite at that point.

The cell phone app I use generates polar plots for your sessions and it's really neat to check that kind of info out.

Exactly what Mark says. The only thing I've done differently sometimes is if I can't edge upwind to slow down, I have turned so much downwind that I flirt with the angle that the kite will barely fly. This will bleed off 20-30 mph and then the pressure on the kite will be reduced enough that you can turn upwind and slow down.

It's amazing how much real estate you burn through when it's time to slow down and turn, definitely have to plan ahead! Can't imagine what it's like at 60+.

I do pretty much as Mark describes. I'll run 90 degrees to the wind to build apparent until my legs can't hold an edge anymore. At this point I'll start to veer down wind. When starting to haul down wind I'll pull in the bar to give me an additional boost of power. This will propel me even further down wind but with a lot more speed. This timed with a strong gust sets things up. To me, speed runs feel similar to being catapulted. Slingshot effect. We have giant lakes around here with room to run. On a speed day I will cruise across a lake hunting for those peak gusts and then act on them. Typically my fastest runs are right away when my legs are still fresh. The more power you can convert to forward motion, the faster you can go I'm thinking. Of course luck plays a giant part as well. Having the right kite, right winds, proper surface, nerves, and proper moon phase all adds to the correct recipe. Chris Krug should chime in, he's our resident speed expert on skis. I've been trying to figure out the speed "secret" for years. I used to think it was all about the kite, but that's far from it. The consistently fast guys in the speed ranking are not using race kites. I noticed my speeds really getting faster when I started using LEI's. Not because it's an LEI per say, but because they made me really comfortable going out in bigger winds. More wind = more speed.

one of the things I always found fascinating - and loved, on the playa was getting into those troughs of wind that seem to ripple and roll down the middle of the lake - you can hook into one and just go blasting by someone that is a few hundred feet away almost standing still and especially on the playa you can pass people sitting in their buggy, kite on the ground with zero wind and you are ripping by - the danger is you'll end up miles away and turn to come back and into nothing. You catch the good gusts in the winter too but it'll usually been when everyone has some wind and then you catch a good gust and go for it.

I haven't had any issues on skis, usually a sliding stop unless it's a bit rougher conditions. An ice buggy is more like being on the playa with the added danger or having a sagging line drag under a blade. But with blades i can still kick out the back end and slough of speed quickly if I need to.

Bobby makes a good point, there could be a whole second discussion on techniques for slowing down. If you have the room the nice gradual arc upwind will pass through a period of more pressure but if you play the able right you won't burn tires and then all of the sudden you are heading upwind and slow down fast. There are times when I've also taken the kite overhead and then gradually ease it back behind me to work as a drag chute but you really gotta watch where you put the kite ever so slowly turning it to point the opposite direction. The kite essentially ends up at what would be the other edge of the wind window so it's stalled and you are pulling it along - it's not trying to move across the wind window and rip you out of the seat backward, but do it carefully.
I remember a few times at Ivanpah running down the lake (I guess it's actually heading north toward Primm) and then going to turn downwind to take the pressure off the kite and found i was getting really close to the edge of the lake and not loosing speed. To avoid running into the scrub brush at full speed (or marker posts) turning back onto the lake into the wind, picking up even more speed and the next thing I know I'm down at the hydro lines - good times!

Its possible of course to return to your starting position carrying the same amount of speed, this would produce an image similar to that of the infinity symbol. I rarely do this however, for me going left to right takes less thought processes.
I don't like to mess around in strong gusty winds, preferring instead to cannonball in one direction only, the one I'm used to.

Does anyone else have a left to right bias ?

This diagram represents my GPS data and latest outing with a max speed of 64mph over 230m.
Markite mentioned a long shallow S curve and that's what you see here too, but its a relatively short S curve given the short distance.

Don't tell anyone, but I suspect that the longer and shallower the S curve the faster you'll go. This of course requires plenty of space, good wind and a small kite.
If I remember correctly, the fastest guy on skis did 82mph using a 6m Cabrinha Switchblade.