2020 Prius Prime- Looking for tasteful Highway aeromod

[aerohead]

Originally Posted by gregersonke

Well, I'm thinking that it's already so efficient, it won't take much to increase it by much at that speed. I'm okay with the idea of the racing discs if I can actually get 2mpg out of them at speed.

You'll never see it.

[California98Civic]

Originally Posted by gregersonke

...45 miles of my commute is at a speed of 76-80 just to keep from getting run over on California interstate...

Your speed is the biggest mod you can make. Aero drag goes up fast as speed increases gradually. A quick google search gives the below graph.

I commute on California freeways in my modified 1998 Civic daily, and I average 60-65 mph. Sometimes I am as slow as 55. I can pull around 60 mpg on average doing that (lots of technique involved). I do not get run over or cause a backup. I am in the slow lane, usually with other vehicles like trucks and other pokey cars. I imagine you are in the HOV lane and there, you get pushed by other drivers even at 70 mph, drivers who have no lawful way around you.

[vskid3]

What tires and pressure in them? My 2005 gets similar numbers at that speed with the tires at about 40PSI; even with snow tires it's still pretty close.

[oil pan 4]

I have driven on California highways. Slowing down is a bad idea. Good way to get ran off the road by someone with no insurance.

[gregersonke]

This is on interstate 5 basically going between 152 and 580. Headwinds are painful. However, some days, like yesterday, I can stick to 76mph and do pretty well. I averaged 108mpg over 72 miles using electric and gas and still had 7% of the battery left when I got home. I keep my pressure at whatever the dealer sets it at. I gotta say Toyota did a pretty good job with the Prius prime 2020.

[MetroMPG]

So, what are your modding plans?

[Yippeekyaa]

I own a 2017 prius, not a prime model and don't see the problem. Yesterday i drove two hours non stop with the cruise set on 80 mph and averaged 57 mpg. Any car that returns mpg numbers of over 45 mpg at those speeds should be nothing to complain about. Aero mods may get your more mpg at those speeds but at what cost versus payback?

Please stop depending on the dealership to set your tire pressure. The odds are very high that they set your tires to the wrong pressure. A nice digital tire gauge costs less than 10 bucks and properly used can easily improve your mpg at all speeds. Ignore what tire pressure is “recommended” by Toyota and read your tires themselves and set at max psi listed on them. For example, my prius recommends 42 psi, tires max is 50 psi. I get a 4 mpg bump at 50 vs 42.

[redpoint5]

I ask shops not to mess with the tires. They are happy to not do something and charge full price.

[Yippeekyaa]

Originally Posted by redpoint5

I ask shops not to mess with the tires. They are happy to not do something and charge full price.

My 2017 came with free oil changes for the first 3 services. 5 weeks after buying it i took it in for the first one. Yes, 10k miles in 5 weeks. Hour drive to the dealer, 2 hour wait and hour drive home. The salesmen tried to get me to pay for an alignment on the first service as in his words “toyota recommends and alignment at 15k miles”. I smiled, handed him the owners manual and asked him to show me where it says that. Furthermore, i told him that the car was just purchased 5 weeks ago and if the alignment is off it should be covered under warranty. Got a free alignment that day and the car has never been back to the dealer, even for the “free” oil changes. I can do them myself for roughly 30$ and 30 minutes of my time vs a half a day using toyota filers and mobil 1. The stealerships can pound sand.

[Ecky]

I drive a van at work. The placard in the door says (I believe) 44psi front, 48psi rear. The dealer fills them to 32.