miata gas mileage vs. festiva gas mileage.

[htchbck]

I had been trying to figure this out for a long time. My BP festy gets close to 40MPG on the highway, and my roommate's '91 Miata (B6D, 5-speed) only gets around 32 if she's lucky. Didn't make any sense to me cause the miata doesn't weigh much more than the festiva, and its certainly a lot more aerodymanic (plus the B6D is a smaller motor). I thought maybe there was just something wrong with her car that was causing it to have that low of mileage but after checking into it thats about what the B6D miatas are supposed to get. I kinda forgot about it till the other day when she hurt her foot at a friend's house and I had to go pick up her and her car cause she couldn't drive it back. I'd driven her car before but only on the twisties up and down the mountains (nothing over 50MPH). But on the way back to the apartment I got to take it out on highway, and my question of gas mileage was answered. At 50MPH in 5th gear the tach was reading 3K... by 70 it was well above 4K. In the festy cruising at 70MPH in 5th is only about 3K RPMs. So apparently the reason the miata gets such sucky highway mileage compared to the festy is because the gearing is a lot lower, espcially for fifth gear.

[leapin]

My uncle complains of the same thing...that short ratio box...like I say...you gotta pay to play

[htchbck]

lol yep, once I get a miata its just gonna be a mountain car... I'll save the festy for the highway And I'm still not sure what my LTD is best suited for :lol: I guess just towing and hauling. Close to 300ft/lb of torque, but still only as much HP as my festiva :lol:

[leapin]

He uses his miata to run around town and autoX...his supercharged SHO is for the highway

[joey48442]

Yup. I get around 30 in both my Miatas. Plus, they only look aerodynamic.


Its all in the gearing.


Joey

[leapin]

Just pop up the air brakes...i mean headlights to slow down!

[htchbck]

^^ yeah thats the next mod we're doing to her car, a guy at her college has fixed his where the lights only pop halfway up and he has two small HID bulbs (one always on, the other is the high beam) side by side mounted in each one and we're gonna copy that. Looks awesome at night and only sticks up 2 1/2" instead of 8" like stock

[jglutz]

Re: miata gas mileage vs. festiva gas mileage.

I So apparently the reason the miata gets such sucky highway mileage compared to the festy is because the gearing is a lot lower, espcially for fifth gear.

You answered your own question.....

I do not know the actual gear box ratios but do not forget that in addition to the actual gear ratio, the differential gear ratio and tire size are also part of the equation.

Peppy car usually have gear ratios that aide in acceleration....as a result, the engines usually wind up more. Also I would not be surprised if the HP curve in the computer allows more fuel thru.

I'm not a mazda expert...just trying to say that alot of factors answer your question.

[htchbck]

could be true about the computer allowing more fuel... as for tire size differences there is none... we're running the same size wheel and tire, and our speedos are both accurate, and when we're running side by side they match each other. I'm guessing the reason the festiva is geared so much taller is so it could actually achieve 75MPH on the poor little stock B3 lol. As for trans ratios vs. diff ratios I think the trans is probably gear similarly in both, I'm guessing its the miata's rear diff that is geared lower than the festy's diff