View Single Post
Old 02-25-2021, 10:11 AM   #590 (permalink)
Ecky
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: New Zealand
Posts: 5,005

ND Miata - '15 Mazda MX-5 Special Package
90 day: 42.54 mpg (US)
Thanks: 2,866
Thanked 2,501 Times in 1,547 Posts
Got my new pulley installed. I needed a new belt as well, and decided to go with one that had one fewer rib (6 vs 7) while I was at it. The belt's effective length was 66 inches, but I would probably have picked out one @ 66.25" if it were available.

Preliminary results:

Earlier this week I had a commute where the outside temperature was nearly 40F. The roads were damp, but clear. Nobody was on the road, and I was able to maximize EOC I arrived at work with 53mpg on the gauge.

This morning it was 26F. The roads were a bit slushy. There was some traffic, and I wasn't able to EOC nearly as much. I arrived at work with... 53mpg on the gauge.

Yesterday after swapping out the pulley, I made a trip to and from my local auto parts store, to return a belt I didn't need. I averaged 55mpg on the way there, and 56mpg on the way back. I don't think I've beat those numbers on that trip, even in the height of summer.

It's tough to draw any conclusions based on such limited data, but I know for certain that my biggest single waster of fuel is the "minimum load" or parasitic drag from the engine - it's relatively thirsty even when idle, and that caps my maximum achievable fuel economy without heavy EOC at around 65mpg. This is the sort of mod that helps with that.



  Reply With Quote
The Following 2 Users Say Thank You to Ecky For This Useful Post:
Joggernot (02-26-2021), redpoint5 (02-25-2021)