e-Golf rear belly pan advice

[Vman455]

Here's the Leaf's diffuser:



It has a pronounced upward curve. I measured the diffuser panel on my Prius at 10 degrees from horizontal.

[freebeard]

^^ That's a nice part. I'll bet wrecking yards have a supply of them.

[JulianEdgar]

Originally Posted by Vman455

I measured the diffuser panel on my Prius at 10 degrees from horizontal.

Yes, I used 10 degrees on my Insight, the figure based on the SAE paper research I did when writing my book.

Note that this figure is dramatically different from the 'rule of thumb' that has been disseminated here over many years.

[IRONICK]

Originally Posted by JulianEdgar

Yes, I used 10 degrees on my Insight, the figure based on the SAE paper research I did when writing my book.

Note that this figure is dramatically different from the 'rule of thumb' that has been disseminated here over many years.

The degree of the diffuser also depends on the angle of the car's roof when combining flows.
But obviously it has to be like you in the book.

[Vman455]

Originally Posted by IRONICK

The degree of the diffuser also depends on the angle of the car's roof when combining flows.

Yes, you're exactly right--the optimum diffuser angle will depend on the shape of the particular car in question, which is why you should test it. The "2 degree diffuser angle is always best" rule has been bandied about here for a long time, but that clearly isn't the case given that low-drag production cars sometimes use much steeper angles!

Originally Posted by IRONICK

But obviously it has to be like you in the book.

And now you've devolved into (unfounded) personal jabs.

[IRONICK]

Originally Posted by Vman455

Yes, you're exactly right--the optimum diffuser angle will depend on the shape of the particular car in question, which is why you should test it.

I'm already testing it, but not on the electrical model.

[IRONICK]

Originally Posted by Vman455

And now you've devolved into (unfounded) personal jabs.

Maybe a little respect for colleagues on the forum and less advertising, it doesn't hurt.

[aerohead]

Originally Posted by Vman455

Here's the Leaf's diffuser:



It has a pronounced upward curve. I measured the diffuser panel on my Prius at 10 degrees from horizontal.

Could the 10-degrees have anything to do with SAE departure angle clearance requirement for that overhang ?

[freebeard]

No-one has explained to me whether the x-degree angle is at the leading edge, trailing edge or average of the camber.

[JulianEdgar]

Originally Posted by freebeard

No-one has explained to me whether the x-degree angle is at the leading edge, trailing edge or average of the camber.

It doesn't have to be cambered. Mine on the Insight is non-cambered after the undertray/diffuser transition, so the 10 degrees (approx) applies to the inclination of the straight panel.