2017 Toyota Corolla LLE aero mods

[woodstock74]

And just like that, Johnny Cash is no more and I have a new car. The transmission took a dump; 3rd issue with the gearbox in 5 years, so took the opportunity to wash my hands of it as this time it wasn't covered under warranty and the reality was long term this is the achilles heel of the Darts.

And viola, I'm the new owner of a 2017 Toyota Corolla. New car, new machinations...First thing I note, factory .cd is .29 (Dart was .285). So in the ballpark. Second thing I note, Corolla LE Eco's .cd is .28...the only difference I can tell; trunk trailing edge spoiler. And these can be had for cheap on eBay, like $40. So I might go ahead and get it, because even if that isn't the only aero difference (it's the only external topside difference I can see and so far I haven't found any underfloor shots), it's a contributor. Though a .01 reduction from the addition of a spoiler isn't unreasonable I shouldn't think.

Tomorrow I'm having a look at hood sealing to the engine bay. There are some gaps there that some weather striping would seal. So we're already off to the races.

[Vman455]

If yours is an LE, the LE Eco also has different wheels--15 x 6.0 steel versus your 16 x 6.5. Congrats on the new car!

[woodstock74]

Originally Posted by Vman455

If yours is an LE, the LE Eco also has different wheels--15 x 6.0 steel versus your 16 x 6.5. Congrats on the new car!

Yes, I was looking at that. However...would mean new rubber and the tires on it have lots of life left. Not something I could justify at the moment.

Thanks! The funny thing is, I realllly like the Dart. However, and this is the truth with me and always has been, my favorite car is always the car I'm currently driving. So while there's been some separation anxiety, I've already moved on. I realllly like the Corolla...now, just need to perform my flush wheel cover trick (this will be the 3rd car I've done this on and I only JUST finished the Dart's like 3 weeks ago...ugh).

[mpg_numbers_guy]

Congrats on the new car! Got any pics? What color is it?

Originally Posted by woodstock74

...now, just need to perform my flush wheel cover trick (this will be the 3rd car I've done this on and I only JUST finished the Dart's like 3 weeks ago...ugh).

Couldn't you have used the aero caps from the Dart, or are the wheels different sizes?

[woodstock74]

Originally Posted by mpg_numbers_guy

Congrats on the new car! Got any pics? What color is it?



Couldn't you have used the aero caps from the Dart, or are the wheels different sizes?

Yes, I'll post up a pic probably tomorrow. She's white.

No, different lug pattern unfortunately.

[woodstock74]

Thar she blows....

Was looking over the car and spotted this aero device at the trailing edge of the rear fender:


Any ideas what it does? Separates the flow so it reattaches and energises before the outboard sharp edge quarter panel/bumper trailing edge?

Also found this image of the underfloor of the LE Eco:


From what I can tell, the LE (version I have) doesn't have the 5 panels in the center. At about $100 a pop I don't think I'll be buying them...

Close up of the trailing edge underfloor panel:



Has two interesting aero shapes of unknown function. Anyone enlightened/familiar with what they might do?

[Vman455]

Originally Posted by woodstock74

Was looking over the car and spotted this aero device at the trailing edge of the rear fender:


Any ideas what it does? Separates the flow so it reattaches and energises before the outboard sharp edge quarter panel/bumper trailing edge?

I first noticed these at an auto show a couple years ago and was curious about their function. Turns out it isn't an aerodynamic device at all, but is required to meet a FMVSS requirement that rear tires remain inboard of bodywork to 50 degrees past vertical. Some manufacturers use a small plastic add-on:


2018 Mazda Miata

But at this year's Chicago show I noticed some of these are being molded into bumper covers now rather than added as a separate piece:


2019 Jaguar F-Pace


2019 Lexus NX

Originally Posted by woodstock74

Close up of the trailing edge underfloor panel:



Has two interesting aero shapes of unknown function. Anyone enlightened/familiar with what they might do?

Toyota includes those fins for stability on all their cars. Generally, airflow under a car spreads outward and these help straighten the flow at the back (unlike the faux "diffuser" vanes seen on a lot of rear bumper covers these days).


2018 Toyota Camry


2018 Toyota Sienna


2020 Toyota Corolla Hybrid

[woodstock74]

Originally Posted by Vman455

I first noticed these at an auto show a couple years ago and was curious about their function. Turns out it isn't an aerodynamic device at all, but is required to meet a FMVSS requirement that rear tires remain inboard of bodywork to 50 degrees past vertical. Some manufacturers use a small plastic add-on:


2018 Mazda Miata

But at this year's Chicago show I noticed some of these are being molded into bumper covers now rather than added as a separate piece:


2019 Jaguar F-Pace


2019 Lexus NX

Thanks for pointing out that those are regulations compliance features. I lanced it off the car at lunch time. Based on that it certainly wasn't helping aero. So off it went.

[IRONICK]

Originally Posted by Vman455

is required to meet a FMVSS requirement that rear tires remain inboard of bodywork to 50 degrees past vertical. Some manufacturers use a small plastic add-on

Do you have the documentation for that? Thank you in advance

[Vman455]

Originally Posted by IRONICK

Do you have the documentation for that? Thank you in advance

My mistake--it's an EU regulation, not FMVSS (I had mis-remembered). It varies state by state in the US, with most states having a more aggressive regulation that requires coverage of tire tread to 75 degrees past vertical, like Washington: "Coverage of the tire tread circumference must be from at least fifteen degrees in front and to at least seventy-five degrees to the rear of the vertical centerline at each wheel measured from the center of the wheel rotation." I suspect this is mostly so they can crack down on lifted trucks and fender-less Jeeps.

The relevant EU statute is Commission Regulation (EU) No 1009/2010, Annex II, 2.1.1: "In the part formed by radial planes at an angle of 30° towards the front and 50° towards the rear of the centre of the wheels (see Figure 1), the overall width (q) of the wheel guard shall be at least sufficient to cover the total tyre width (b) taking into account the tyre envelope as well as the extremes of the tyre/wheel combination(s) as specified by the manufacturer."

This regulation is also referenced in this Car&Driver article, "How Regulations Dictate the Look of New Cars," which also explains why we still get those little plastic bits on cars in the US.