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Old 06-27-2020, 01:12 PM   #47 (permalink)
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Accord - '12 Honda Accord sedan EX-L
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Originally Posted by MeteorGray View Post
Interesting four-wheel alignment on that car, or is it the wide-angle lens distorting things?
Not funny or constructive. This is exactly why I give zero credibility to post count #s like your car's odometer is rarely an indicator of how good or fast of a driver you are.

Originally Posted by Vman455 View Post
Of course not. They're completely invisible to anyone looking at the car unless they kneel and peer under it, yet most if not all manufacturers of passenger vehicles today use rear diffuser panels or, as is becoming more common in the last 2-3 years, a centrally-mounted muffler shaped to function as a diffuser panel. Toyota uses straightening vanes on all its cars since the 2010 Prius was introduced.
I guess I should have posted a picture instead of assuming everyone who wants to talk about car aero could Google for 5 seconds instead of side tracking and posting completely unrelated study from its grave because I mentioned it as a side note.. Glad it's back on track now.

Originally Posted by Vman455 View Post
The idea that one has to have a full, smooth belly pan before even considering a rear diffuser is bogus. You can glean as much from Hucho's book; in particular the discussion of the Opel Calibra's front air dam cutout and rear diffuser (p. 189-90 in the 4th edition), where he writes:
(emphasis added)
As well as from the example of nearly every current production car (and a fair number of SUVs/crossovers) in the world.
I don't know how you remember which pages to quote but thanks a lot. I was thinking the exact same thing but what does a 20-post-count kid know? lol

This is the best I can do to add for anyone thinking one needs a full belly pan before diffuser, yeah he's just a youtuber so take it or leave it.

I recommend you focus on the parts where he explains how the air from mid section of the car goes into the diffuser, not the diffuser itself.
For cars without smooth belly pan, a diffuser design used on full belly pan cars would be considered "poor diffuser design". Not "no diffuser will work without smooth belly pan". So Toyota made the design suitable for each car they put it on as you can obviously see some differences between models.

Doesn't this resemble the one used under Camry? (the one with trailer hitch) VGs don't have to be paper thin to be efficient. Actually bump VGs are less draggy IIRC.

But since I have no ability or superficial hourly expense to verify my idea/question scientifically, I look at pictures like these. (for you wind-tunnel fanatics, there are also studies showing significant difference between wind tunnel vs real life and concluding road test is mandatory to optimize airflow around a car)

I can't tuft-test those and I don't have a Toyota. So now I'm really curious if they are straightening strakes and/or variable angle VG (to crosswind). Also I want to know why they have some thickness to it as opposed to tire spoilers which are just a panel of plastic.

What would the angle of attack on those underbody strakes do? Since there is always some crosswind IRL and cars don't always drive in straight line??

A tube-fed version of those who don't understand why I posted the video in #1.

Now that I think we cleaned up that the idea I got from Toyota wasn't from a "styling gimmick" I hope it continues in constructive direction trying to suppress flow detachment on the downside of crosswind over the A pillar and roof line.

Originally Posted by JulianEdgar View Post
2. Separated flow on the downwind side of the car will, however also cause instability
in this post he tested them on the side of A pillar's curvature so I plan to test them on the front side of A pillar, parallel to tufts I will attach to the very outer edge of windshield when the they dance over and around A pillar. I don't have those equipments sadly.
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