Subaru BRZ GT300 race car revealed for Japan's Super GT series

[Tokay444]

Originally Posted by beltax90

found some more super gt pics

I see what you did there.

[Lelandjt]

I don't get how the little engine, even with a turbo, has enough power to push all that aero through the air at a competitive speed on the straight aways.

Also, it looks like the NSX race car lost the street car's buttresses, odd.

[Quentin]

Originally Posted by Lelandjt

I don't get how the little engine, even with a turbo, has enough power to push all that aero through the air at a competitive speed on the straight aways.

Also, it looks like the NSX race car lost the street car's buttresses, odd.

Because they are circuit racing, not going for top speed runs. Splitters, sideskirts, and diffuser are basically “free aero”. Keeping that gap between the car and the road small and keeping air from rolling from the side of the car to the bottom can make a substantial impact on cornering grip.


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[MJones_RB]

Originally Posted by Lelandjt

I don't get how the little engine, even with a turbo, has enough power to push all that aero through the air at a competitive speed on the straight aways.

Also, it looks like the NSX race car lost the street car's buttresses, odd.

When you pull out all the interior pieces, install a light carbon seat, replace body panels with carbon fiber, replace glass windows with thin plexiglass, change out your transmission gears with straight-cut gears, side exit exhaust, etc. you suddenly free up all those horses to run free. The aero really keeps the car pushed to the ground now that it's so light.

[Marrk]

Originally Posted by MJones_RB

When you pull out all the interior pieces, install a light carbon seat, replace body panels with carbon fiber, replace glass windows with thin plexiglass, change out your transmission gears with straight-cut gears, side exit exhaust, etc. you suddenly free up all those horses to run free. The aero really keeps the car pushed to the ground now that it's so light.

I get all tingly when you talk power-to-weight. That's really my thing. But I would like to know at exactly what speed aero effects kick in. Any aero effects. Every time I see a road car roll by with a whale tail on the back and a splitter on the front, my "poser" alarm goes off.

[Quentin]

Originally Posted by Marrk

I get all tingly when you talk power-to-weight. That's really my thing. But I would like to know at exactly what speed aero effects kick in. Any aero effects. Every time I see a road car roll by with a whale tail on the back and a splitter on the front, my "poser" alarm goes off.

It depends on the design. There are airfoils at some angles of attack that are pretty effective at auto cross speeds. Aero isn’t an generic one size fits all. Depends on the car, track, suspension setup, etc.


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[ZDan]

Originally Posted by Marrk

I get all tingly when you talk power-to-weight. That's really my thing. But I would like to know at exactly what speed aero effects kick in. Any aero effects. Every time I see a road car roll by with a whale tail on the back and a splitter on the front, my "poser" alarm goes off.

There is no speed at which aero "kicks in". Aero effects vary with the square of speed. So if a car produces 200 lb of downforce at 100mph, it will only make about 50 lb. of downforce at 50mph.

Thing about aero is, you'll see more dramatic and bigger wings/splitters/etc in a car set up for LOW speeds than for HIGH speeds.

[scuzzy]

Aero kicks in at 88 mph . . . no wait, that's time travel. Carry on.

[Dake]

Originally Posted by ZDan

There is no speed at which aero "kicks in". Aero effects vary with the square of speed. So if a car produces 200 lb of downforce at 100mph, it will only make about 50 lb. of downforce at 50mph.

Thing about aero is, you'll see more dramatic and bigger wings/splitters/etc in a car set up for LOW speeds than for HIGH speeds.

Exactly, look at hillclimb setups. Sure, there are some longer stretches where they can get their speed up, but it's far more important to keep their speed up in switchbacks. If you have a 50 turns and you can carry an extra 5-7mph through each, it's worth trading off 2-3 mph top speed on the handful of long-enough straights.

[Lelandjt]

Originally Posted by Quentin

Splitters, sideskirts, and diffuser are basically “free aero”.

Obviously, that's why I was referring to the huge wing, dive planes, and wide fenders. It takes a lot of horsepower to push that stuff through the air over 130mph. It's gonna be noticable drag above 70mph. Maybe their tracks don't have long straights. Maybe their engines make 600hp, but I would expect much less from a 4cylinder that complies with rules and is made to last longer than a rally cross.

[ZDan]

Originally Posted by Lelandjt

I don't get how the little engine, even with a turbo, has enough power to push all that aero through the air at a competitive speed on the straight aways.

Originally Posted by Lelandjt

Obviously, that's why I was referring to the huge wing, dive planes, and wide fenders. It takes a lot of horsepower to push that stuff through the air over 130mph. It's gonna be noticable drag above 70mph. Maybe their tracks don't have long straights. Maybe their engines make 600hp, but I would expect much less from a 4cylinder that complies with rules and is made to last longer than a rally cross.

Relatively small-displacement turbos have been kicking the ass of larger-displacement n.a. engines in racing since, well, at least since the turbo revolution in F1 in the late-70s/early-80s. 1400hp in qualifying trim in a 1983 BMW 1.5 liter 4-cylinder F1 engine!

Quick search says Super GT300 power varies from 400 to 550hp.
Yes, aero downforce gives SIGNIFICANT drag on the straights, without it they'd hit MUCH higher speeds. But turning slower laps...

[Irace86.2.0]

Originally Posted by Marrk

I get all tingly when you talk power-to-weight. That's really my thing. But I would like to know at exactly what speed aero effects kick in. Any aero effects. Every time I see a road car roll by with a whale tail on the back and a splitter on the front, my "poser" alarm goes off.

That’s because they are posing. At least, that’s what I’m doing with things like that.

I owned two MKIV Supras. One was wingless. The stock wing was quoted by Toyota at providing 66lbs of downforce at 90. I could tell a difference, especially at 145. It was a big wing, but it wasn’t a wing, a diffuser, canards, a flat bottom, a rear diffuser, etc that can all really add up. It is all about surface area. Put a mattress on a car or some flat plywood and watch it fly in the air at 35. At 55, an oak armoire/wardrobe the size of a fridge that weighed probably 80-120lbs lifted into the air, flying over the gate of the bed of a truck and smashed to pieces on the highway. It had dressers and other things pressed against it, so only 50-60% of it was exposed to the air, but that is all it took.

Here is a good lesson in physics: surface area... unless that Port-o-pottie is really lighter than those kids.

[wbradley]

Holy shit!

[Jordanwolf]

Originally Posted by Irace86.2.0

That’s because they are posing. At least, that’s what I’m doing with things like that.

I owned two MKIV Supras. One was wingless. The stock wing was quoted by Toyota at providing 66lbs of downforce at 90. I could tell a difference, especially at 145. It was a big wing, but it wasn’t a wing, a diffuser, canards, a flat bottom, a rear diffuser, etc that can all really add up. It is all about surface area. Put a mattress on a car or some flat plywood and watch it fly in the air at 35. At 55, an oak armoire/wardrobe the size of a fridge that weighed probably 80-120lbs lifted into the air, flying over the gate of the bed of a truck and smashed to pieces on the highway. It had dressers and other things pressed against it, so only 50-60% of it was exposed to the air, but that is all it took.

Here is a good lesson in physics: surface area... unless that Port-o-pottie is really lighter than those kids.

I've seen this shitstorm before.