Hello from Tampere, Finland

[trebuchet03]

Originally Posted by DifferentPointofView

Yea, I know that, but most cars that small are usually decent at aero. It doesn't look all that bad either.

That's because they're small (not necessarily because of a low cD) For that reason, it's usually more useful to look at cDA rather than just cD. The Goodyear blimp has something like a .19 cD (or was it .09?) - it just has a freaking huge frontal area

[AndrewJ]

Wow, I never knew there were Smart Roadsters, they're very good-looking little cars.

I think the first order of business would be to find out if the "fastback" from the other smart roadster will fit on to your car.



That would take care of a lot of your problem right there. The "Del-Sol" type rear roofline isn't doing you any favors right now.

Other than that, those rear wheels (mainly the wheel wells) look like they could use some help. They're very "flared-out" looking in the pictures. I think they could benefit a lot from some wheel skirts.

Oh, and welcome to the forum!

[PeteHalo]

Originally Posted by AndrewJ

I think the first order of business would be to find out if the "fastback" from the other smart roadster will fit on to your car.

I bet that's easier said than done and I've kind of grown to like this tail end better than the glass end.

Other than that, those rear wheels (mainly the wheel wells) look like they could use some help. They're very "flared-out" looking in the pictures. I think they could benefit a lot from some wheel skirts.

I'm not so sure if I'm ready to go that far at this stage. I think I'll start with some lesser mods to see if I can improve the mileage a bit and then after evaluating the progress I decide whether to go further or to quit.

[DifferentPointofView]

I bet that's easier said than done and I've kind of grown to like this tail end better than the glass end.

I liked the way my roof racks looked, but I got rid of them anyway

Oh, pardon my rudeness, welcome to the world of tomorrow!!! lol. I got carried away talking about Cd.

I love the way those cars look though.

[diesel_john]

i have never saw a car that looked to good to start drillin' holes and riveting


on panels until now...

[MetroMPG]

Hi & welcome...

Good thing you've already discovered the right foot is the cheapest & quickest means of reducing fuel consumption. Driving technique will consistently outperform mods, in terms of total potential savings.

As for vehicle mods:

AndrewJ's right: the place to start for max drag reduction is at the back of the car. With the abrupt chop at the end of the roof, and the short deck length, the airflow likely separates at a point that's close to your max projected area, and does not re-attach on the end of the deck. Not good.

I also agree that rear skirts would help. I've tried skirts on 3 different vehicles, and my conclusion is that the closer the rear wheel is to the back of the car, the more of a benefit the skirts will have. If there's little to no bodywork "aft" of the wheel arch to shepherd flow into a somewhat clean separation, skirts are critical, I'd say.

One other area that you can go hog wild on is your car's underbody. Because of the rear engine layout, you could affix a full, smooth undertray (perhaps uninterrupted, back to the rear wheels) , since you don't have to worry about covering up exhaust components running the length of the car.

And, I trust you've had a look at the List of aero mods you can do to your vehicle for other ideas?

[andylaurence]

I've only just seen this thread, so sorry for digging up old ground. The coupe rear of the Roadster is not interchangable. The Tridion chassis is different for the coupe and the notchback (as the other version is generally known). I've not started my aero mods yet, despite having the car for a year. I've been thinking about a coupe conversion kit and it's high on my to-do list. As for an undertray, the car still has one. I'd not thought of doing wheel skirts but I might just run some coast down tests to prove the theory.