MINI Cooper S rear diffuser w/ underpanel

[khafra]

Interesting--that increased the variance again, but also pulled up the mean enough that we have a p-value of .0348; or 3.5%. If we'd done the experiment under rigorous conditions and documented it thoroughly, that'd be good enough for journal publication. Well, also if we'd used a more appropriate statistical test and had a lot more data.

Given those results, I just might have to get me some airtabs.

Right now, I'm recording the mpg of every highway-only trip I take, which is a pretty decent amount since I live next to a freeway onramp. As long as traffic allows me to drive ~70mph most of the way, I record the mpg right before I decelerate for the offramp. I figure that'll help isolate the effects of drag as much as possible.

If I do buy airtabs, I will write my conclusions and methods up in a post here. I will also probably point to that post in an argument against the useless A-B-A test method that somehow rules the ecomodder forum

[InsightfulRay]

Originally Posted by khafra

Interesting--that increased the variance again, but also pulled up the mean enough that we have a p-value of .0348; or 3.5%. If we'd done the experiment under rigorous conditions and documented it thoroughly, that'd be good enough for journal publication. Well, also if we'd used a more appropriate statistical test and had a lot more data.

Given those results, I just might have to get me some airtabs.

Right now, I'm recording the mpg of every highway-only trip I take, which is a pretty decent amount since I live next to a freeway onramp. As long as traffic allows me to drive ~70mph most of the way, I record the mpg right before I decelerate for the offramp. I figure that'll help isolate the effects of drag as much as possible.

If I do buy airtabs, I will write my conclusions and methods up in a post here. I will also probably point to that post in an argument against the useless A-B-A test method that somehow rules the ecomodder forum

Thanks for posting the upshot of the last set of data. It occurred to me that a tank's worth of consumption over several hundred miles of driving really represents quite a number of data points. This despite our considering only the end result distance/consumption result as a SINGLE data point.

[vkash1208]

I just notice that you can't use the stock exhaust. :/

[curv872]

Originally Posted by vkash1208

I just notice that you can't use the stock exhaust. :/

Stock exhaust = heavy & restrictive

[vkash1208]

aftermarket = too much moola. Was thinking of doing the One Ball Exhaust Mod, wonder if there is any other gains besides better exhaust note.

[curv872]

Originally Posted by vkash1208

aftermarket = too much moola. Was thinking of doing the One Ball Exhaust Mod, wonder if there is any other gains besides better exhaust note.

1 ball is also lighter, but yeah, the exhaust note will change, some say it's too raspy...it will be louder than stock for sure.

[vkash1208]

Easy to do on my own? or better for a shop to do it? something to play around with until I save enough money for a Miltek

[curv872]

Originally Posted by vkash1208

Easy to do on my own? or better for a shop to do it? something to play around with until I save enough money for a Miltek

Unless your a skilled welder, I would have a shop do it.
If you haven't already, check this out:
Do It Yourself DIY One-Ball Exhaust

[Ladogaboy]

Nice job! I'm curious about how this diffuser is holding up. My main concern is the heat from the exhaust melting the diffuser.

My car has a stock rear diffuser, but I think I might try extending the paneling underneath.

[curv872]

After almost a year on the car its holding up very well. No problems with heat, since the top side is covered with an application of aluminum duct tape.