My cars behave differently on Time Trials than they do in the actual races

[Bullwinkle]

So I'm new to Gran Turismo, and so also to this forum. So far I'm loving the steep learning curve. I just got my Fanatec wheel after playing on the controller for the past month and it's a quantum leap for me, but I'm enjoying it.

The tuning, however, is driving me nuts. I made the mistake of buying the McLaren P1 GTR '16 (at $3.6 m it was a total bust) and spent all day Saturday tuning it at the Time Trials for the Catalunya 800 PP event. I'm not joking when I say all day. I easily put in 16 hours testing everything and getting deep into learning about tuning. I got it dialed in exactly how I wanted it (at least as much as a ridiculously undrivable car can be) and after dozens of test laps I was ready for the race.

I got into the first high speed turn that starts the race, right after the chicane, and flew sideways right off the track. I got back on only to slip into the gravel at the next turn, then fishtail out of the next hairpin, and . . . you get the picture. It behaved NOTHING like how I tuned it.

So my question is this: is there something different about the track on race day? Am I dreaming this, or is there a real difference? Surely it's not the slipstream from other cars since they're already dots on the horizon. It's not the weather or the time of day. Is it the track temperature? What other reasons could there be for wasting an entire day of my life to tune a car that came out even more undrivable than when I started?! HELP!

 

[Harmonic]

There's actually no fuel load in the car in time trial. Fuel load will completely change how your car handles.

 

[Bullwinkle]

There's actually no fuel load in the car in time trial. Fuel load will completely change how your car handles.

Brilliant! Thanks for that. Is there a way to know how much extra weight I’m carrying during a race so I can add ballast during tuning sessions?

 

[TumeK5]

Brilliant! Thanks for that. Is there a way to know how much extra weight I’m carrying during a race so I can add ballast during tuning sessions?

There's no way to know, unfortunately. The only thing is your car always carries a max fuel load for races

 

[Bullwinkle]

There's no way to know, unfortunately. The only thing is your car always carries a max fuel load for races

I think I’ve never noticed this because by the time the fuel load is less the tires are more worn, so there’s no sweet spot where I’m light but have fresh tires. So in terms of handling it’s a wash by the time I have to pit. Full tank and new tires just resets it to the beginning.

Anyone have even a vague idea of how much a full tank of fuel weighs? Even a rough estimate would help because I h have zero experience with racing.

 

[jack305able]

Can't really tell about the weight of the fuel. If I had to guess, Iwould say somewhere between 50-80 liters. Which should be almost equal in kg. (Don't know about pounds)

Another idea would be to start a custom race for tuning. There you can set all settings as wanted and the weight of the fuel will be considered by the game. You will have at least 1 opponent (driving alone is not possible), but just let them drive away and start your time trail once the track is free enough. Just an idea...

 

[Bullwinkle]

Can't really tell about the weight of the fuel. If I had to guess, Iwould say somewhere between 50-80 liters. Which should be almost equal in kg. (Don't know about pounds)

Another idea would be to start a custom race for tuning. There you can set all settings as wanted and the weight of the fuel will be considered by the game. You will have at least 1 opponent (driving alone is not possible), but just let them drive away and start your time trail once the track is free enough. Just an idea...

Oh snap! What an Idea! The only drawback is (I think) I'd have to quit the race to tune and then custom create a new one each time I wanted to fiddle. But I think in the long term it's a great idea for dialing in an accurate tune!

There's actually no fuel load in the car in time trial. Fuel load will completely change how your car handles.

By the way, I just saw your video on suspension tuning! Keep those videos coming! The more detailed the better. Most importantly I like how it's all spelled out in game terms. I'm curious about the order of importance, what to tune first, what's secondary, things like that.

Maybe one day you could do some videos on diagnosing specific problems? As in, a troubleshooting approach, etc.

 

[sixty4half]

Racing gasoline ranges from 6.1 to 6.6 lbs per gallon. So figure out the tank size on your test car. Example; GT300 and GT500 cars are regulated to 32 gallon tanks so if you're testing the Supra GT500 then you have between 195.2 and 211.2 lbs of extra weight at a full tank (probably at the low end of this range). A Ford Mustang '15 has a 16 gallon tank so it would use have 105+ lbs (considering it uses lower octane fuel it should be in the higher range).

I would start testing with the assumption the PD uses 1 weight for all gasoline and start my testing at 6.5 lbs of ballast per gallon

 

[Bullwinkle]

Racing gasoline ranges from 6.1 to 6.6 lbs per gallon. So figure out the tank size on your test car. Example; GT300 and GT500 cars are regulated to 32 gallon tanks so if you're testing the Supra GT500 then you have between 195.2 and 211.2 lbs of extra weight at a full tank (probably at the low end of this range). A Ford Mustang '15 has a 16 gallon tank so it would use have 105+ lbs (considering it uses lower octane fuel it should be in the higher range).

I would start testing with the assumption the PD uses 1 weight for all gasoline and start my testing at 6.5 lbs of ballast per gallon

Thanks for this. It gives me a great starting point to work from.