Throttle stop vs coast down testing
 

Has anyone done both?

I tried Coast down testing with before and after windows down at around 60 mph. Literally no difference surprisingly. I heard that it’s only really effective at super high speeds, over 90 mph and higher

Was going to try the throttle stop testing next, with windows up and down, but my pedal barely moves and I don’t need to push down on it hard ti maintain a high speed. So no idea what it’ll do

Throttle stop testing doesn't work for cars with electronic throttles. Being a 2019 ioniq it probably has electronic throttle.

so whats the best test? coast down at super high speeds probably? i wish i just had an accurate way to measure aero mods and their impact and how sensitive it is

I don't know the answer to that. I don't have anything with electronic throttle so I haven't had to deal with it. You could use pressure testing, but I don't think it is a straight forward answer since you will have to consider more factors.

You could just try the window up/down coast test at high speeds to see if the difference is more pronounced.

If you can log speed vs time on multiple coast down tests you should be able to see a trend in the data (if there is a meaningful difference).

Do you have a scangauge or anything like it? Perhaps you could monitor power or load with cruise control set at a certain speed and see how much it changes with the windows down vs up. Just make sure you also monitor the battery state of charge to make sure you're comparing apples to apples (and not a run which charged the battery against a run that depleted the battery)

scangauge wont work with the ioniq and how it shuts the engine off and goes full ev mode then switches back to engine to charge the battery then switches back to ev and so on

if electronic throttle is an issue, then i guess coast down tests going 90mph versus 60 may do something

Why doesn't it work with throttle-by-wire? I understand that throttle position is a suggestion to the computer, but it's one that should be consistent in testing.

I only repeated what others had expressed when they tried it. No reason to wonder. Try it and let us know. I only know of one case, having multiple sources would help confirm.

My understanding is that the electronic throttle is good for a hybrid for obvious reasons. I've read that its purpose for gas only models make the car feel better than it is, for example if you are going up a hill while holding the throttle steady it will adjust throttle to maintain that speed.

nope. def have to push down harder to maintain same speed going up hill.

only time you hear the throttle rev going up hill is if you use cruise control

I meant it makes small changes to keep speed, not full on maintain speed on a hill. Watch the tps and you can see it change a few percent is what they were reporting. So the ECM increases throttle when the vehicle slowed.