Hood flutter on ZD8 and hood vents effect on it

[Pat]

I know hood flutter was a concern for some people on the ZD6. I put 135,000 miles on mine and didn't worry much about it. But after putting 1,000 miles on my ZD8 and passing some semis on the highway, I can see the hood flutter on this car is significantly greater than that of even the ZD6. Mine moves so much I actually pulled over to check it was properly secured.
I don't really want to drill into my new hood, but wonder if anyone out there has installed the Verus (or 86CUP) hood vent and recorded how the hood behaves before and after. I wonder if the hood would still shake this much in turbulent air if I were to install a good hood vent.
Your thoughts?

[dragoontwo]

What I tried was removing the weatherstripping at the rear of the opening. You can pop it back into place if you find the results lacking.

[Pat]

Thanks, dragoontwo. While I'm normally all for experimenting with things that are free and easily reversible, I don't think this is one of those situations. The cowl area tends to be a high-pressure area on most vehicles, which means if it did solve the hood flutter issue, it would likely not be the most effective way of doing it.
That said, I'm still a little open to that idea. Have you tried it on a ZD8? If so, what did you find?
Underhood cooling is also a consideration for me. But at this point in my ownership experience, not a major one. That could change in a few months, though. But then I'd have to worry about car classing rules for 86CUP and NASA TT, too.

[Code Monkey]

What is the 86CUP hood vent?

[Pat]

Whoops, sorry. I should have said GR Cup.
GR Cup

[KillerBMotorsport]

I've also noticed considerable hood movement at higher speeds. I did the same thing, pulled over to check that it was latched.

The easy first step here is to put some twine on the hood to see what's happening with the airflow. Like Pat, I'd be concerned with making a change for the worse from a cooling and/or aerodynamics standpoint.

Also, curious if there are any vids of these cars doing top speed runs to see how bad the flutter gets. It's not uncommon for racecars to have body panels moving around. In short, I'd rather know it's going to flutter and still be safe vs trying to solve a "problem" that doesn't exist.

[Code Monkey]

Would love to run the GR Cup vent, I was told they are not sold separately, you need to buy an entire hood.

[Pat]

The Verus hood vent is printed from ABS. Doesn't some ABS get soft when hot?
The GR Cup piece is printed from FDM Nylon 12CF. I wonder how that material differs from ABS. Here's a link about it for people much smarter than me.

[dragoontwo]

Removing the weatherstripping does not completely solve the issue, but I do believe that it helps vent a bit of pressure.

I suppose I could tape some strings. How long should they be?

[CSG Mike]

Originally Posted by dragoontwo

Removing the weatherstripping does not completely solve the issue, but I do believe that it helps vent a bit of pressure.

I suppose I could tape some strings. How long should they be?

You'll get reversion in that area. That's why it's frequently used for induction cowls and HVAC inlets.

[CSG Mike]

Originally Posted by Pat

I know hood flutter was a concern for some people on the ZD6. I put 135,000 miles on mine and didn't worry much about it. But after putting 1,000 miles on my ZD8 and passing some semis on the highway, I can see the hood flutter on this car is significantly greater than that of even the ZD6. Mine moves so much I actually pulled over to check it was properly secured.
I don't really want to drill into my new hood, but wonder if anyone out there has installed the Verus (or 86CUP) hood vent and recorded how the hood behaves before and after. I wonder if the hood would still shake this much in turbulent air if I were to install a good hood vent.
Your thoughts?

I've had the car up to the limiter without issue. It flaps, but I wouldn't stress. Add aerocatch latches if you want some extra security.

[Madisonswartz]

I was able to get rid of substantially almost all of the hood flutter using the hood adjustment knobs. For me it was rotating them counter clockwise 1-1.5 turns

[Interceptor777]

Originally Posted by CSG Mike

I've had the car up to the limiter without issue. It flaps, but I wouldn't stress. Add aerocatch latches if you want some extra security.

What's the limiter at? Mexico is high altitude so sometimes mine struggles to get there

[CSG Mike]

Originally Posted by Interceptor777

What's the limiter at? Mexico is high altitude so sometimes mine struggles to get there

iirc 143? somewhere around there. The car just stops accelerating.