I started logging my mpg's a while back for the sole purpose to determine if the aerodynamic of the hardtop actually help with better mileage,

my null hypothesis- there is no relationship between the miles per gallon of my ap2 and the difference between driving with a hardtop or soft(top up)

Basically, after crunching the numbers I reject my null hypothesis (rejected at α 95 sig)

-This test wasn't 100% fault proof, but I did take the same route every day over the test period and I kept my driving habit the same for both runs.

If anyone cares I had plenty of vtec action and wasn't being a 'hyper miler', 50/50 highway/city

2mpg increase with hardtop

 

That's interesting, & what I would expect, with modern laid back windscreens.

I did something similar, but different many years ago, with a Morgan +4 that I used for a mixture of road & track.

For racing I usually removed the windscreen & fitted a single aero screen on the drivers side.

One of the tracks I raced at regularly decided to have a closed sports car race. When they did not get a full field of entries, they invited about 10 of us open car boys to enter, but we had to run with our hoods/tops up. Did that cost most of us some performance!

I was almost 2.5 seconds slower in my lap time, & I lost 16 MPH top speed at the end of the main straight. That was with a car that was in the same trim as it's previous race there, but for the hood. I then did some runs with the windscreen in place, with & without the hood/top. On a full 2 mile run there was no difference in top speed, so I decided the main difference was the change to aero screen.

 

To that end, I wonder if the CR cowl would change those results. There's a lot less cabin wind buffering.

 

With the convertible top, your numbers are more like, 1184 miles/54 gallons = 22 avg mpg. ?!?

 

you are right if you account indented and regular data, the non indented data was aggressive track like driving so I left it out of the consideration. Basically I only used data for commuting.

I will keep compiling the mileage for the next couple of month, but I am getting more miles per tank with the hardtop on.

 

That would be interesting to compare the CR vs soft top/hardtop mpg's.

 

You're a stats major aren't you? lol.. Stats is an awesome class. It's one of the few classes that makes real-world sense, as evident by your research. What method did you use?

 

Haha, just a chem/bio major but I always love testing things, especially when it's something I enjoy.

I am gona keep the hardtop going till the end of the month and then switch back to soft top to accrue more data, after I am satisfied and my 2mpg gain is solidified I will do the top down testing.

 

I've been getting around 27 mpg with 50 mixed with my soft top mostly up. Interesting that you get better mileage with the hard top.

 

oem hard top? o0