Ride Height Mods - Effect on speed/aerodynamics

[MrMazda92]

I keep seeing all these lowered Hon-duhs in my city, and it got me thinking about the pros and cons of a lowered vehicle. I'm not talking about the obvious ones, like cornering ability and bottoming out, but the ones people don't tend to think about. For example, has anybody on here actually done windtunnel testing on an MX-3, to see how ride height(or any other) mods affected the aerodynamics of their car? I'm of the opinion that Mazda didn't choose our ride height randomly, but there's almost always room for improvement. That being said, has anybody had a measurable increase/decrease in fuel economy, 1/4 mile times, or even road noise levels from adjusting the ride height?

[Ryan]

You will see increase in MPG from being lowered. Less frontal area = lower COD. As long as you don't go disturbing the boundary over the bottom of your car, or just dumping the front (higher COD).

The ride height would have been chosen as a function of preformance, comfort, and fitting it into the styling and overall design, like Mazda's interchangeability (323/pro/escort/etc).

1/4 mile will be improved from more of the power being put down, and less into loading the suspension. Also, the COD thing.

Road noise should remain unchanged, as the majority of the noise comes through the suspension members, and lowering doesn't really affect the overall strut/spring/control arm mass. Some does come through the wheel wells, and that may be increased from the tire being closer to the car.

Cons are pretty much just ride comfort and longevity of all suspension components.

Wind tunnel time is ridiculously expensive and no one in the MX-3 circle with any sanity will put the money into it. People dedicate PhD's and lifetimes of research just into COD's of one type of things, like buildings, bullets, trucks, or cars.

[MrMazda92]

I figured the MPG would go up marginally, but to what point? In other words, if you receive the same benefit from dropping it 3/4" as you do from 1", at what point does the cost outweigh the benefit? I can't help but laugh when I see the local shitvics bottoming out even when they take speed bumps at extreme angles.

[mikeetown]

You will see increase in MPG from being lowered. Less frontal area = lower COD. As long as you don't go disturbing the boundary over the bottom of your car, or just dumping the front (higher COD).

The ride height would have been chosen as a function of preformance, comfort, and fitting it into the styling and overall design, like Mazda's interchangeability (323/pro/escort/etc).

1/4 mile will be improved from more of the power being put down, and less into loading the suspension. Also, the COD thing.

Road noise should remain unchanged, as the majority of the noise comes through the suspension members, and lowering doesn't really affect the overall strut/spring/control arm mass. Some does come through the wheel wells, and that may be increased from the tire being closer to the car.

Cons are pretty much just ride comfort and longevity of all suspension components.

Wind tunnel time is ridiculously expensive and no one in the MX-3 circle with any sanity will put the money into it. People dedicate PhD's and lifetimes of research just into COD's of one type of things, like buildings, bullets, trucks, or cars.

took the words right outa my mouth. (physics but without the numbers lol)

A super low car well get really good gas mileage on highway basically.

[Ryan]

I don't know how to determine how low is too low, but Formula cars go with <1inch clearance all day, but they're also designed to shove the air OVER the car for downforce, ours have a tendency to suck it under with the shape of the front end. A jutting lip or a splitter would help with that. I believe a lot of Honda aftermarket bumpers take that into account.









The best thing for any car would to have a full undertray diffuser... the suspension and wheels are the greatest points of drag on a formula car. Our rear bumper is also pretty much a parachute.



Edit, I just realized that COD is a tradeoff with downforce, so just remove "formular 1 car" from whatever I said and throw in NASCAR or something. lol. COD on some forumla cars is > 1, which is pretty much like driving with a vertical 4x8 sheet of plywood vertically out of your sunroof. (or another MX-3 on your roof)

ALSO, another thing to note is that the shape of the end of the car is more important than the nose. Any shape that would create less of a vacuum behind the car will be much better.

[Sleeper6]

Also Im pretty sure heated air has a big effect on aerodynamics as well, hence why alot of supercars have center exhaust exits to help eliminate the dead space behind the vehicle by filling it with heated air to "extend" the body in a way to make it more aero friendly. Another big area you could make gains on would be eliminating the mirrors.

[MrMazda92]

Good input guys!! Thanks!

[youdirtyfox]

My front wind splitter has made a difference in
better straight line speed stability, and my
acceleration has improved from being lowered
70mm on coilovers

couldnt tell you about juice yet as we've just had
another petrol price rise!

I also invested in some vitaloni california
wing mirrors to improve it even more ...

[MrMazda92]

Good point on stability at high speed, thanks for mentioning it. Do you mean the original one, or the one you made?

By the way I liked your build thread youdirtyfox, you put a lot of hard work into your car.

[youdirtyfox]

Yes I meant the one I made, and thanks

braking should also improve by lowering i think too