Trans Am Tires

[Eunos_Cosmo]

GT7 could definitely use some historic tire compounds. First time out with the Porsche 904 I bought from LCD, I was shocked out how stiff and grippy it felt. It came on RH tires! I'm not even sure the 904's suspension components could even take the forces of modern race compounds. I put it on CS tires immediately afterward, but as @Marcus Garvey notes, these still don't feel right.

 

[hawkeyez]

GT7 could definitely use some historic tire compounds. First time out with the Porsche 904 I bought from LCD, I was shocked out how stiff and grippy it felt. It came on RH tires! I'm not even sure the 904's suspension components could even take the forces of modern race compounds. I put it on CS tires immediately afterward, but as @Marcus Garvey notes, these still don't feel right.

I could have swore I have that car stock and it had CS on it. It slides around a lot for me?

 

[Eunos_Cosmo]

I could have swore I have that car stock and it had CS on it. It slides around a lot for me?

Maybe I am misremembering, but I felt like it handled on rails when I first drove it.

 

[hawkeyez]

Maybe I am misremembering, but I felt like it handled on rails when I first drove it.

You can just add sheet in the settings page and see what tires it throws on it as that reverts it all back to stock.

I wouldn’t say it handles like it’s on rails, but I would say it’s very predictable in its handling even though it doesn’t have a ton of traction. Or perhaps I just drive it harder than I need to. Lol

I love that car at goodwood, lots of predictable drifting.

 

[Marcus Garvey]

Haven’t gotten around to trying comfort mediums yet. Is that 2600lbs correct?n I thought that was the weight of the Sunoco Camaro that they were told to never bring it to the track again? I thought they were more in the 2900lbs range?

The 1967 car they got down to 2550 lbs that they were told not to bring back, they kept running through 1968. They just swapped the nose so it looked like a 68 lol. They would swap number plates to run the cars through tech to avoid rolling thr lightweight car over the scales. Even after all the teams got caught acid dipping by 1968, they just slowly reintroduced lightweight parts over time to get the cars back where they were by 1969. Even in 1970 the Autodynamics Challenger driven by Sam Posey got nabbed dipping. That was part of the popularity in vinyl roof coverings on the cars, to hide the oil canning. Sam talks about it in this interview - start around 2:20 and then Sam begins talking about his car at 3:00.

Attached are a couple of excerpts from The Unfair Advantage detailing some of their efforts in getting the lightweight cars through. Apologies for the cell phone pics of the book lol

By 1969 the SCCA rulebook had the trans am cars at 2900lbs, though as you'll see in Sam's interview I linked, they were running much lighter cars in the races. Iirc the Penske's secondary car was around 2700lbs, not quite as light as the primary car. Nowadays SVRA rules put the Camaro at 3000lbs for historic trans am, but they're well over 500hp.

I think CM are closest to real life but CS are probably the sweet spot for the most drivability.

 

[hawkeyez]

The 1967 car they got down to 2550 lbs that they were told not to bring back, they kept running through 1968. They just swapped the nose so it looked like a 68 lol. They would swap number plates to run the cars through tech to avoid rolling thr lightweight car over the scales. Even after all the teams got caught acid dipping by 1968, they just slowly reintroduced lightweight parts over time to get the cars back where they were by 1969. Even in 1970 the Autodynamics Challenger driven by Sam Posey got nabbed dipping. That was part of the popularity in vinyl roof coverings on the cars, to hide the oil canning. Sam talks about it in this interview - start around 2:20 and then Sam begins talking about his car at 3:00.

Attached are a couple of excerpts from The Unfair Advantage detailing some of their efforts in getting the lightweight cars through. Apologies for the cell phone pics of the book lol

By 1969 the SCCA rulebook had the trans am cars at 2900lbs, though as you'll see in Sam's interview I linked, they were running much lighter cars in the races. Iirc the Penske's secondary car was around 2700lbs, not quite as light as the primary car. Nowadays SVRA rules put the Camaro at 3000lbs for historic trans am, but they're well over 500hp.

I think CM are closest to real life but CS are probably the sweet spot for the most drivability.

Well I may buy another Camaro next time it comes up and copy what I have and then lighten some more just to compare.

 

[wheelhp]

without reading too much I'd honestly try to tune for a tyre swap. Something like CS front and SH rear. Or SH front and SM rear then make the rear swing out more on turns with ballast and suspension changes, install a differential but make it very poor and open, that should do it. You're correct that GT7 tyres do not hook up at all realistically. This is a fault of the physics engine and tyre model

 

[hawkeyez]

I’d do that but then if I want to run it in our room with pp and tire limits, I’d have to open up the tire restriction.

It’s pretty good now, I’m getting used of it. Another couple weeks and I’ll probably share it. Hard part with be getting the challenger and boss to match. I’m sure they’ll come in a little under in pp.