At What Speeds to Aero Mods Take Effect?

[95metro]

Originally Posted by Matt Timion

For around the town driving the height/aerodynamics really don't matter too much.

I have read statements similar to Matt's a number of times and it has me wondering at what point aero mods do matter.

As a vehicle travels it is pushing air. At low speeds the air flows easily around the vehicle, but as the vehicle's speed increases the air in front of it begins to compress and becomes a "wall" that must be push through...at least this is my understanding of things.

Obviously every vehicle is different thus similar aero mods will have different affects at different speeds, but is there a way of determining what that speed might be for a particular vehicle. Obviously CdA would come into an equation here.

[Matt Timion]

Originally Posted by 95metro

I have read statements similar to Matt's a number of times and it has me wondering at what point aero mods do matter.

As a vehicle travels it is pushing air. At low speeds the air flows easily around the vehicle, but as the vehicle's speed increases the air in front of it begins to compress and becomes a "wall" that must be push through...at least this is my understanding of things.

Obviously every vehicle is different thus similar aero mods will have different affects at different speeds, but is there a way of determining what that speed might be for a particular vehicle. Obviously CdA would come into an equation here.

Someone posted a graph here a while back. I believe that aerodynamics took effect somewhere over 40mph, but I'm totally guessing. I remember seeing that for "around the town" driving rolling resistance was the only issue.

[krousdb]

http://www.gassavers.org/showthread....highlight=tool

Ben was hosting it but the linky is brokey. I still have it.

[SVOboy]

It's on darin's site now isn't it?

[Matt Timion]

Originally Posted by SVOboy

It's on darin's site now isn't it?

Yes, but I remember someone posting an actual graph. I think it was actually you SVOBoy. Am I just making this up?

[SVOboy]

I posted a graph of my speed vs mpg, but I didn't make any mention of aero mods or anything like that.

[95metro]

Thanks guys - that's a good thread. To think, I've spent tons of time surfing MetroMpg.com and I've never come across that chart page...oh well.

[kickflipjr]

I have heard that at 35mph The engine is working more for wind resistance then tire resistance.

[95metro]

According to the chart: http://metrompg.com/tool-aero-rr.htm my car matches what you have heard kickflipjr.

I am assuming that some vehicles would be lower and some higher.

So, in the 70 km/h (45 mph) zones that I travel often I would see some marginal benefit from aero mods even in town.

[zpiloto]

Originally Posted by 95metro

According to the chart: http://metrompg.com/tool-aero-rr.htm my car matches what you have heard kickflipjr.

I am assuming that some vehicles would be lower and some higher.

So, in the 70 km/h (45 mph) zones that I travel often I would see some marginal benefit from aero mods even in town.

Don't overlook the effects of surface winds.