Help, get rid of side drafting, ideas?

[Mista Bone]

Originally Posted by doviatt

Why would you de-tune a race car? Race cars are supposed to be fast and fun.
Get another car if you need efficiency and don't race it- mod-it for economy.

Why when you can have both in the same car?

Thanks to modern tuning it is possible.

[Mario_Marques]

Thanks aerohead, i think you are all sure, but i was shoking because it never happened to me before, nobody ever raced head to head whit me, so, i'm like 30years old drafting virgin, everything is new to me.lol
I think most of you guys never feel this, believe me, it's scary, it's like you hit your brakes very hard or an anchor.lol
So, there's no way to avoid this, the only way is to block the passes for everycar.

[NachtRitter]

EDIT: aerohead already posted even better information about nose-to-tail drafting!

OK. Then I would be interested to understand the physics behind the "side drafting". When the physics is understood, then the solution to prevent it could be found.

I believe the nose-to-tail drafting advantage is well proven; a good discussion is here: HowStuffWorks "How NASCAR Drafting Works". While the article covers NASCAR, the drafting advantage to the front vehicle is not limited to NASCAR.

So it seems clear from what is known that you will notice a sudden increase in drag when a car which is drafting you pulls out from behind you and tries to go next to you... especially at 215km/h.

But it is not clear what is happening when the car is coming next to your rear wheel. What might be happening, if the other car is very close, is that it is disrupting the smooth flow of air along the side of your car, creating even more drag than normal. Maybe this is your 2nd noticeable increase in drag (it is not the engine braking hard, but the aero drag increasing which means more engine power is needed to keep the current speed)

[Mario_Marques]

Originally Posted by Mista Bone

Why when you can have both in the same car?

Thanks to modern tuning it is possible.

Not possible with my country laws, believe me, my car has 115hp stock, and it's diesel, with diesel comes noise and smoke, i hate noise and smoke on streets, not fair with other people, they dont need my smoke and noise.

https://www.youtube.com/watch?v=WtZ5dYLvyd4

My engine was tuned like the one in the video, the sound was the same, the smoke was the same.

[NachtRitter]

This quote from the Ten80 site seems to align with your description very well:

But when the trailing car gets out of line to go around the lead car, suddenly there's a low pressure area behind the lead car and the drag force on the front car suddenly increases by as much as 400 lbs. This has the same effect as throwing an anchor out, it slows the lead car by as much as 5 mph almost instantly.

[NachtRitter]

Originally Posted by Mario_Marques

I think most of you guys never feel this, believe me, it's scary, it's like you hit your brakes very hard or an anchor.lol
So, there's no way to avoid this, the only way is to block the passes for everycar.

That is why I asked about what aero modifications you are allowed to make on the car when at the race track. If you are allowed to add something like a Kamm-back on your car, then you might be able to reduce the effect of the sudden drag when a car moves out from behind you and goes next to you. Of course, the Kamm-back will help you around the entire track. And it could be removable if it is not allowed to have these kinds of attachments for driving legally on the road.

[wmjinman]

This may not apply, but I've noticed when a semi truck passes me, there is a time about when his front end pulls even with my back end when it feels like he's sucking me backwards. I don't know why this would be, unless the increased velocity of the air moving around him causes a corresponding low pressure area around it. Then when that low pressure area is directly behind me, it causes the increase in drag. ???

Of course, this quickly transitions to a feeling of a crosswind when he's about halfway up my car length. I attribute that to the air he's pushing aside hitting me in the side. Then of course, once his front is cleanly in front of me, that sensation goes away...

I wonder if that's the same thing that happens when you're racing???

[Mario_Marques]

In road, at my country, it's not allowed any kind of modifications, if the cops know that you have mods, you gonna have problems for sure...
In track i can do what i want, i can do a kamm-back, but i want to go for a most discrete as possible way, something that other drivers dont care about.