Wow the Prius c gets quite dirty in the back

Did you ever find that thread? Where did you get your spoiler and how complicated was it?

 

I don't know..
My Honda Fit had the "spoiler"...of course it Always had the spoiler, so I can't compare how it would of been without it.- But The Spoiler didn't seem to make much a difference as far as dust and dirt.

I think most of that comes up from the tires, from below where a spoiler is anyway.

The "spoiler" on my Standard Prius sure doesn't seem to help in keeping the second vertical insert clean below it....

May actually deflect a degree of rain...rain that might actually clean off the window. So I'm not sure if a spoiler doesn't potentially make the problem worse. Doesn't block dust and dirt from below....does block rain from above....

I think it's perfectly justified to want a spoiler for looks and potential aerodynamics....but I wouldn't install one thinking it's going to keep the back significantly cleaner.

 

Garm sells the spoiler and it's extremely simple to change.

 

Previous thread would be this one:

Aftermarket OEM spoiler | PriusChat

 

Trust me. The sport style spoiler makes a DRAMATIC improvement to how clean the back of the C and rear window stay. In fact, after a week of driving I'm often surprised to find the back of the car barely more hazey than the rest of the vehicle.

I was surprised by this as I only bought the new spoiler for looks... I had not anticipated the added benefit of keeping the rear windshield so clean.

SCH-I535 ?

 

SCH-I535 ?

 

Believe what you want to believe about the "spoiler". But I live in an area that gets a lot of rain. And I had the Honda Fit with the spoiler...very similar to The Prius c's dimensions and set up.

I did not credit the spoiler with much improvement.

Think about it. Most of the dirt, rain, is coming UP from below the spoiler..not falling down on the window from above. IMO there is no way the spoiler can make that big of a difference as far as keeping dirt off the window. I think the majority of it is coming up from the tires and street below. When you go to clean it? You'll notice a lot of dirt, dust build up on the underside of the spoiler.

It's my opinion, and it certainly could be wrong, but I wouldn't purchase a spoiler with the idea that it is much of a cleaning aide. Purchase it for all the other reasons someone might want a spoiler, but if you are expecting that addition of a spoiler is going to leave your rear hatch window significantly cleaner I think you will be disappointed.

I didn't think it helped much with the Fit.
I don't think the rather massive "spoiler" on the regular Prius helps much either. The vertical piece just below it get's dirty real fast. So obviously having that lip above it isn't doing much as far as keeping it clean.

 

Ok, let's approach this logically.

I have the actual Prius C touring spoiler that you're theorizing about... and I first had the stock spoiler so I have direct, first-hand, fact-based experience. Yet you're debating me because you had a similar spoiler on a different vehicle?

First off, my impressions of the cleaner rear windshield are not opinion or theory... it was an objective, dramatic, unquestionable improvement. And I had the stock spoiler for over a year, so I was very aware how differently the dust build up behavior changed the day I put on the new spoiler (and every day thereafter).

I'm sure there are valid reasons why the experience is so different from what you experienced on your Honda FIT with a similar sized spoiler. But rather than try to compare/contrast, let me explain why I suspect this touring spoiler works as it does.

The spoiler has air-vents that channel air from the roofline down along the back of the vehicle, so rather than getting that "vacuum pocket" behind the car where dust and road grime accumulate, they are constantly flushed away by the moving airstream down the back of the car surface. This also affects rain... rather than being "sheltered" from rain as the with the stock spoiler, the rear windshield now gets very wet because the rain is pulled down with the air stream onto the glass. This also helps keep the rear windshield much cleaner because during rain you're getting a constant gentle washing by the fresh water being pulled from above the car downwards over the rear.

Did the larger Honda FIT spoiler have a similar air-vent to channel air from the roofline down accross the back of the vehicle? I wonder if this issue may be one reason why the C touring spoiler acts differently than what you experienced.

And to clarify, my rationale about "how" the spoiler is keeping the rear of the car so clean is a theory/opinion, but the fact that the spoiler *is* keeping the rear of the car clean is a real observation from having owned the stock spoiler for over a year and from having the new spoiler almost as long.

 

No..I have to admit none of the spoilers I am talking about or have experience with have the "touring spoiler" vent in them. So perhaps that does aide in channeling rain down on the windshield and keeping it cleaner.

You'll just have to excuse my continued skepticism that any spoiler is going to make a significant difference. Because my experience is simply that hatch-backs get dirty. But I will admit, I have no experience with the specific design of your vented spoiler.

 

I can be a second voucher for the fact that the touring spoiler does work at keeping the back cleaner. Not sure why (and in my case it doesn't matter as she gets cleaned a lot either way), but it does help dramatically. It's not just some quasi-perceived thing, it's actually quite significant of a change.

 

Ugh, I may have to get that cute vented spoiler, after all. Black hatchback = much dirt. This is a stupid question, but someone above mentioned not using paper towels because those can damage the paint--is that a real thing?

 

Yes. Paper towels are rough. If you are going to wipe the car down you need a microfiber cloth. But even then the dirt will scratch the clear coat if the car isn't wet.

 

Okay...I concede... I must..I've never had a spoiler with that vented design.

The people have spoken.....

 

I think the back is staying cleaner as he stated above because the water is going thru the openings on the top of the spoiler, washing the back as it cascade thru the opening all over the back. On the normal spoiler it keeps the water from coming down the window and keep in all the dust basically trapped in the back of the car. I believe if there were no spoiler will be seeing same results as with the aftermarket spoiler.

 

Mayhaps... but it stays cleaner in the dry weather as well.

 

I did a quick and dirty sim with RealFlow to get an idea of what's going on, and best that I can tell, given that it's not a perfectly accurate model (just some polygons in the rough shape and dimensions of the car and spoiler laid out in 20 minutes), and all I know about fluid dynamics is mostly forgotten, from a 2nd year engineering class taken over 20 years ago, and that the RealFlow tool, while using real fluid dynamics models, is not really meant as a perfectly accurate scientific modeling tool, but is rather used for creating realistic effects for the computer animation industry, is that the rear of the vehicle gets dirty because of some nasty vortex effects behind the vehicle: you've got air from both the top and the underside of the vehicle swirling behind it, and this obviously deposits on the rear surfaces.. When you just extend the spoiler, the airflow over the top stays a bit smoother over the extended surface, but then still swirls back towards the rear, and it doesn't do anything for the flows coming from under the vehicle.. But when you put in the vents, at certain speeds you can get enough downflow over at least the upper portion of the rear window which seems to move the location where the vortexes swirl back onto the vehicle body downwards . If the simulation is at all accurate, this would suggest that the rear window should indeed be clearer, but there should still be a fair bit of dirt deposited on the bumper and rear hatch surfaces (ie, everything below the window).. Can anyone with the extended spoiler confirm?

On something like a Honda Fit, if you change the model to have a more vertical rear surface, a spoiler, even with vents wouldn't help you much unless you put a big angle on the vent to really force the air down and then you'd get a lot of upwards turbulence (and probably a big hit on drag as well if I remember my fluid dynamics class correctly: I do remember one of the exercises assigned was to estimate the drag coefficient on a Saab, which the prof claimed, that at the time, had the best drag coefficient in the whole auto industry).. In any case, the sim seems to say that: different car, different design and geometry, different effects from a spoiler..

 

I am still getting dirt, but I'd say that more is accumulating on the hatch portion of the car and not the glass anymore. I honestly don't know if it's more dirt or the same amount of dirt. So take that for what it's worth.

 

Yeah, I think the lil spoiler over the back window makes dirt collect even faster.

 

Hand washed today for the first time in months (hey, don't judge me ) and the back wasn't nearly as dirty as the sides - the lower part of the door panels and the strip below the doors easily had the worst build up of dirt.

 

I have noticed small leaves etc gets in the door jam of the hatchback.