Grand Prix of China

Can anyone advise how to fix this. I am going down the back straight of China GP and the car has a very fine bounce or slow up n down oscillation (2 or 3 times a second), checking motec shows the wheel loads on all four tyres are oscillating, now I would have thought on a straight under constant acceleration the the loads would increase smoothly as the aero forced the car down. Its getting very annoying, any help would be appreciated.

My car always oscillates. No clue how to fix it.

If you haven't experienced it before, then it's got to be actual undulations in the track, like a washboard. So I'd recommend softer springs. You might have the third springs in particular too stiff, because those affect how stiff the response is when both wheels at one end of the car are loaded simultaneously. On a washboard-like surface you would really feel that.

Edit: Not really noticing anything like that after some testing. Maybe I just have the cockpit vibrations turned way down. :)

It could be an aerodynamic oscillation. Sometimes they call that "porpoising". The front wing and diffuser take turns stalling and un-stalling, sort of like a see-saw. Some of the cars in GTR2 do that very badly. I would try to fix it by adding more damping to the third springs, or maybe raising the ride height a little.

This is one tough track! All last week I was barely able to get into the 1:42's and I thought I was doing great. David Fisher's 1:38.020 seemed impossible. The car just would carry me around the corners and when I did get it to turn into the corners my rear would slide out. I still haven't touched Tim's Nuerburg setup except for gears, wings, and brakes. So, I started working on the gears and wings. I wound up with a heck of a lot of wing! To compensate I lowered the gears. I also did something else that I only had an idea of in the last race. I had only been using 1st gear once at the start, and once every time I left the pits...all other times I would only drop down to 2nd. I realized that with the speed at which shifting can occur then adding another gear in the mix would improve acceleration.

And everything worked. I just turned a 1:39.787, but mostly low 1:40's. I think I've got the car almost where I want it. The track is incredibly difficult and only time is required to learn it's nuiances. There aren't many corners which were designed for straight line braking/turn in/accelerate out like with most other tracks. There are sweeping turns which require smooth braking under cornering or no braking at all with just gears to slow the car and combinations of both. And, there are a few sections which cannot be taken flat out...accelerator pedal skills required.

OK...I've uploaded my setup, but there's not much room in the description to provide tips on how to make the best use of it...so here it goes:

Turn 1: This is a wide and slowly sharpening right hander that should be taken at speed and slowly bring the speed down as you bring the car around. After crossing the finish line in top gear tap the brake at the 50 meter mark then turn the wheels and downshift into 5th (Edit: I've been shifting down to 4th now...5th was just too high, but gas has to be regulated to avoid losing the rear)...keep the gas on to carry you around for just a second in a smooth turn, then tap the brake again and downshift twice more into 3rd and keep the gas on until you are pointed toward the left edge of the Intel signs and then tap the brake and downshift into 2nd with 1/2 throttle until you can see the apex of turn 2. Ideally you should be able to downshift 1 gear at a time with partial throttle and brake to provide a more linear deceleration, but it's trickier and I find I have more control by double downshifting and staying on the gas...it may also be harder on the brakes to downshift 1 gear at a time under light braking...watch brake temps when finishing this corner.

Turn 2: This is a sharp right hander. Shift into 1st and tap the brake to bring you around and pointed to the left hander of turn 3 then get back on the gas to reach turn 3 as fast as possible.

Turn 3: This is a sharp left hander. Tap the brake to bring you around, but at the apex only give a partial throttle to avoid losing the rear...if you feel the rear come out then shift into 2nd and give it as much gas as possible until the rear starts to slip out then downshift into 3rd.

Turn 4: This is a tight left hander. The track is very forgiving here...you can stay in the middle under acceleration, or slow and cut sharp to use the curb on the left edge and the curb on the righ edge...both tactics amount to the same result coming out of this corner. Shifting into 4th as you get pointed straight.

Turn 5: This is a flat-out right hander...just stay on the gas and you should be able to hit top gear for just a moment...move toward the left edge before you get to turn 6.

Turn 6: This is a sharp right hander. Start braking after the 100 meter mark, but before the 50 meter mark. Downshift under braking all the way to 1st before turning in...get back on the gas at the apex, but watch for the rear end to slide...be gentle and stay in 1st to get the extra acceleration from that lower gear as you exit...quickly shift up under full throttle.

Turn 7: This is a wide and slowly sharpening left hander and should be taken at speed...start from the right hand curb and use the left hand curb to come around under 6th gear full throttle. Tap the brake and downshift into 4th just when you see the Intel overhead sign and get back on the gas and then shift into 5th.

Turn 8: This is a medium right hander. Tap the brakes and downshift into 3rd then get back on the gas to carry you around...try to stay off the curb, but as far to the right as possible. Use the gas to help bring you around and floor it as soon as you clear the corner...watch for the back end to swing around...manage the front wheels so you don't fishtail...don't downshift too fast unless you are pointed straight...the rear will actually want to pop back to the right and spin you counter-clockwise into the right hand wall.

Turn 9: This is a sharp left hander. Tap the brakes and downshift into 1st then back on the gas as you clear it...just like in turn 3 shift up a gear when you feel the rear slip out...you should be in 3rd heading into turn 10.

Turn 10: This is a tight left hander. Come as close to the left edge as possible at the apex...use the curb there and keep the gas on. It is important that when leaving this turn you don't shoot off the right edge into the grass...the edge will kick your car around as well as lose traction...stay on the track! Accelerate quickly up to 6th gear.

Turn 11: This is a sharp left hander. Start braking and downshifting after 100 meter but before 50 meter markers all the way to 1st...be easy on the throttle as you will want to use the left curb and get set up for turn 12.

Turn 12: This is a sharp right hander. You have a choice here...use 1st gear to get a leap ahead then shift into 2nd...hazard is loosing the rear and having to back off and waste the advantage, or shift into 2nd at the apex to help pull you around and use 1/2 throttle for more control. When exiting this corner you will be temped to floor it and accelerate as fast as possible, but if you do that then you will need to brake before entering turn 13...moderate acceleration provides more control.

Turn 13: You should be in 3rd coming out of turn 12 and accelerating. But, when you get pointed at the Petronas signs at the far left of the track then pull up off the throttle for just a moment...no need for brakes unless you didn't take it easy coming out of 12th and are going just too fast in which case you may end up sideways. Get right back on the throttle onto the longest straight. You should be shifting into 7th when you pass under the overhead sign.

Turn 14: This is a sharp right hander. Start braking and downshifting before you get to the 100 meter mark. Get all the way down into 1st gear...be gentle when getting back on the throttle as you clear the apex...then move through the gears...you should be in 5th before getting to turn 15.

Turn 15: This is a tricky left hander. There's no markers and it's hard to see what's coming especially since the pit entrance continues straight on, so there's no curb on the right until after you finish the turn. I've been trying different approaches, but so far it feels best to downshift under braking down to 2nd gear, then turn the wheels and punch the throttle...the rear will slip out some, so I'm not sure whether it is best to back off the throttle a bit and carry through the apex in 2nd at about 1/2 throttle, or shift into 3rd and get back on full throttle...6 of one and 1/2 a dozen in the other. But, it feels like more control if I'm in 3rd and sliding onto the right hand curb at the exit and pointed down the s/f straight. Get through the gears as fast as possible...keep in mind that you will be going downhill on a section and will need to shift up another gear at the bottom of the hill...sooner than you would normally shift while in that gear on the straights.

So my first timed lap of 1.37.777 is looking like a nice start then :-]

If you do that in quali or race then you will beat the record by over .3 seconds? I don't think making a run with ducts at 1 and boost at 10 with 2 laps of fuel counts. :)

That 1:38 was an awful lap btw. :-/

Yeah, it seems the awful laps are the best cause it seems like a struggle with the car going too fast. And, on the opposite side are the laps that you are sure you took too slow cause it was effortless, but turn out to be quickest.

:-]
To be honest it was my first flying lap with an unedited version of Steve's setup available here.

10 laps of fuel on soft.

Don't think softs is the way to go though. There are too many high-g corners and the first turn is gonna murder the left hand side.

Still learning the track with these cars though so we shall see.
Have another setup which is 10mph quicker down the long straight than Steve's but half a second off overall at best.

It was just an awful lap that felt bad and was very slow. Had a couple of big distractions on that lap that had me cursing at myself long before the s/f line. :-)