Holy Headwind batman

[FSANE]

Driving today on the highway with headwind around 30-40 mph. Flooring it and barely maintaining 74mph. Any less, I started to lose speed.

I need more hp for my next daily driven car.


And don't get me stared with crosswinds :(


End of rant.

[severous01]

yeah....crosswinds suck. i got some ideas though. a lot of ppl say the rear swaybar upgrade helps tons. and that the narrow wheels is bad for winds too. so i'll be steppin up to at least a 195, hopefully a 205 soon.

other thing is, you can get the under body woks stuff from garm and get an aerodynamics enhancement. the aluminum panels...and you could lower it and add ground effects to eliminate drag also...but that's a ton of money for a little help...not even horsepower.

[fnkngrv]

my sedan has become HUGELY more stable since I lowered it, put on 205s, and added the rear sway bar.

[SailDesign]

The important things for side-winds is the height of the sidewall. You need larger wheels to reduce sidewall height, which doesn't allow the wall to flex so much.
IMNSFHO :smile:

[.Kevin.]

How much is 140 kmh in miles? I was getting that on my yaris going UP hill, and I only got a sway bar.

[Slick]

I can attest that lowering springs + rear sway bar make a HUGE, MASSIVE, difference when it comes to crosswinds. It's barely noticeable in 20+ mph side wind gusts

[djct_watt]

74MPH (120KPH) with a 30-40MPH headwind means you had an airspeed of up to 114MPH, which is approximately the Yaris' top drag/power limited speed.

I'm too lazy to do the math, some I'm going to quote a stupid wiki page, but increasing power 10% does not net a 10% increase in top speed. (Nobody is doing it here), but I love it when newbs say that their air intake boosted their top speed by 10MPH, when it gave them a 3HP gain, IF EVEN that.

Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome air drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW). With a doubling of speed the drag (force) quadruples per the formula. Exerting four times the force over a fixed distance produces four times as much work. At twice the speed the work (resulting in displacement over a fixed distance) is done twice as fast. Since power is the rate of doing work, four times the work done in half the time requires eight times the power.

If you want to increase top speed and/or reduce the effect of headwind, lower your car and look into aero mods that REDUCE drag. Rice spoilers and most body kits need not apply. Look at a Prius for inspiration; seal up the under carriage, reduce cooling intake, etc. However, all this kind of modification isn't necessarily good for the car, nor is it necessarily safe. Reducing drag may end up increasing lift. EG, the Bugatti Veyron (set on high speed mode) reduces spoiler height to minimize drag. . . that means LESS stability at the benefit of higher speed.

In terms of a sway bar, it will do nothing for a HEADWIND, as the OP stated was the problem, but it will make a HUGE difference in CROSSwind. A sway bar will only increase underbody turbulence and weight (but you would probably never notice the difference).

Another mod for overcoming headwinds would be skinnier low resistance tires. . . skinny=less aerodrag and friction.

[djct_watt]

^ Sorry, I made the assumption the Yaris is drag limited, but I'm actually not sure about that. I don't recall hitting a limiter. . . it just kinda runs out of juice around 190KPH for me. If it is electronically limited, there's not much power left at all; it's already near the drag limit.

[.Kevin.]

I got to 140 kmh like I said, 90ish mph? And I was smelling burnt rubber was going up hill too messing with some guy who was trying to race me but couldn't out handle me on the curbs so he just stayed behind lol I felt bad for the car afterwards though.

[djct_watt]

A good tool for the future is google. Just type in convert XXXkm to mi or vice versa ;-). But you're right on at about 90.

I had an xA (same motor and transmission) that I beat up in the USA. I drove from SF to LA (leaving at 2.00AM for a 400 mile trip) and maintained a steady 110MPH throughout except for the dangerous areas (grapevine mountain pass as well as 580/5 mountains). The car had no problems at all and handled like a champ. I was expecting to overheat at least once due to the high revs, but it didn't happen. I regularly do trips out here in Thailand that take about 40mins to 1.25 hours, and it's on an elevated highway which is SUPER smooth. I honestly just hold down the gas pedal for the entire trip. I average 180-190. . . I don't know it will eventually kill the car (possibly me, but I slow down for absolutely any and everything), but man, so far it's been indestructible. What's nice is that the major roads here work like an autobahn, and people don't sit in the fast lane; it's for passing only. It's actually much easier to get a ticket for driving in the fast lane than it is for speeding. It's nice because fast cars keep to their side of the road and slower ones almost ALWAYS move over.

FSANE, not to preach, because I obviously speed as well, but a 30-40 MPH wind is fairly dangerous. Crosswinds can pick up at anytime, and the wind sometimes has a mind of it's own. Please be careful. 74MPH with a 40MPH headwind can easily turn into a 40MPH crosswind which would EASILY blow the Yaris into the next lane. Remember that no matter how good your suspension is, high speeds inherently produce lift which make the car handle even lighter. Wind just adds to that. . . I'm not judging you for it, just saying (from experience) to be cautious and not underestimate the wind.

[WeeYari]

A good tool for the future is google. Just type in convert XXXkm to mi or vice versa ;-). But you're right on at about 90.

An even easier tool for him, just look at his speedo. It's marked in both kph and mph.

[djct_watt]

Actually no. I could be wrong, but those of us with PROPER speedos only have KPH listed, sans MPH, at least it's that way in the Asia spec'd Yarii, and most cars here. The "mile" and most imperial measurements are the most arbitrary and ambiguous
measurements ever... with retarded conversions. I'm
American by birth and nationality, but I prefer the metric system.

[djct_watt]

Oops, my bad, you're Canadian too, so I guess you guys have both KPH and MPH? Either way, I meant the suggestion for offroad use. I can't imagine anyone driving and googling. You can't always have ur speedo nearby. I only use google to be super accurate. I still calculate my maintainence intervals in miles and not KPH, so I have to convert.

[Vioz]

yea yesterdays winds in long island, ny were crazy looked like i was driving drunk my car was all over the highway and i was only doing 70