NASCAR nationwide rear spoiler

[Federico]

Why the rear spoiler of nationwide cars is vertical? How can generate downforce? Is it uses Venturi effect slowing down the air above so the air under the car is much more fast?

And I have another question: what is the purpose of the "blade" on the roof? Slowing down the car?

[qw56q]

Why the rear spoiler of nationwide cars is vertical? How can generate downforce? Is it uses Venturi effect slowing down the air above so the air under the car is much more fast?

And I have another question: what is the purpose of the "blade" on the roof? Slowing down the car?

can you post a picture i doubt any one here watches nascar

[Federico]

can you post a picture i doubt any one here watches nascar

Here we are:

[qw56q]

can you post a picture i doubt any one here watches nascar

Here we are:

those blades seem to channel the air towards that wall on the back of the car. that spoiler just seems to force it up

[Federico]

those blades seem to channel the air towards that wall on the back of the ca

Unluckyly I can't find a photo with the "blade" I speaking about, the blade I saw at Talladega is positioned in the other direction (perpendicular to the blades showed in the photo).

[qw56q]

those blades seem to channel the air towards that wall on the back of the ca

Unluckyly I can't find a photo with the "blade" I speaking about, the blade I saw at Talladega is positioned in the other direction (perpendicular to the blades showed in the photo).

oh i though you meant those

[wesley123]

i think it just works as a huge gurney.

such a 'spoiler' is imo a bad way to create the downforce as the air heaps up at the start, it is cuasing much more drag.

[Scotracer]

i think it just works as a huge gurney.

such a 'spoiler' is imo a bad way to create the downforce as the air heaps up at the start, it is cuasing much more drag.

Pretty much. They are near-vertical but that creates an effective angle of attack that produces some useful downforce but a lot of drag with it (which they use to try and keep the cars at sane speeds).

[DaveKillens]

x

[Federico]

thank you dave, fantastic explanation

[ISLAMATRON]

alot of that stuff on top of the roofs of Nascar racers is to keep the cars from flying when they get sideways or backwards

[tk421]

i'll just post it here instead of starting a new thread, but i was watching the nationwide race at circuit gilles villeneuve (jacques finished fourth, btw), and the last 11 laps were just terrible. nobody except the top few drivers knew what they were doing in the wet, and those 11 laps took almost an hour to complete because the safety car came out nearly every lap...i love hard racing and side by side/door to door action, but when 11 laps take that long because of all the yellows, it becomes incredibly boring. i must credit the montreal fans though: very faithful, very passionate, and very patient!! btw the ALMS race at Mosport was great, though it was sad seeing the Dyson Lola/Mazda drop out of the championship....

[hpras]

Well, this not really a defense of what happened in Montreal, but those cars are not at all designed to run in the wet. The wipers and the defoggers are bolt-on's and an afterthought. Also, most of the regular drivers in the series do a road race 3 times a year and spend the rest of the time turning left at a very high speed. The road races are the only chance they ever have of running in the wet.

Islamatron is very correct when he says the at the strakes on the top of the roof are there to help prevent the cars from getting airborne when turned sideways. At the wrong slip angle/angle of attack, the car does tend to become a wing. There are also flaps in the roof that will open when the car gets turned sideways, work like the spoilers on an airplane.

One thing to ponder. At Daytona and Talledega, the cars are restricted with a throttle plate. The full out Sprint Cup cars are knocked back by about 350hp. 800->450. 1987 was the last Daytona 500 that ran with out this restrictor. The pole speed was 210mph, vs around 185 now. For all their tractor like technology, they are still able to go quite quickly in a roughly straight line.

[Federico]

One thing to ponder. At Daytona and Talledega, the cars are restricted with a throttle plate. The full out Sprint Cup cars are knocked back by about 350hp. 800->450. 1987 was the last Daytona 500 that ran with out this restrictor. The pole speed was 210mph, vs around 185 now. For all their tractor like technology, they are still able to go quite quickly in a roughly straight line.

I think it's because the highest gear rate they can utilize is a 1:1 and since they use enormous V8 from the '70 they can't revv past 7600-7700 rpm. So the 800+ hp is not very useful compared to today 450

[Ray]

One thing to ponder. At Daytona and Talledega, the cars are restricted with a throttle plate. The full out Sprint Cup cars are knocked back by about 350hp. 800->450. 1987 was the last Daytona 500 that ran with out this restrictor. The pole speed was 210mph, vs around 185 now. For all their tractor like technology, they are still able to go quite quickly in a roughly straight line.

I think it's because the highest gear rate they can utilize is a 1:1 and since they use enormous V8 from the '70 they can't revv past 7600-7700 rpm. So the 800+ hp is not very useful compared to today 450

Wrong. Those car easily exceed that amount
of rpm. They touch almost 10k at alot of mile and a half or longer tracks. They are not V8s from the 70's. Not even close. They make almost 2 1/2 horsepower per cubic inch N/A. Do you even watch this series? Most claim these facts and it's simple to find the truth.