A Z4 Targa?

[ZippyZed4]

Thanks! Yeah I know what you mean ref heavy… all parts for the real thing are genuine BMW parts… I’m thinking maybe a bodywork trim piece on the pillar next to window may balance out the look…

 

[ZippyZed4]

Love your work on this. The rear looks quite heavy in the photos, but maybe it’s just the camera angle. Are you going to need stronger B pillar or targa roll (old 911 targa like) hoop on the real thing?

 

[Richard29]

I like it

 

[Zephyr]

What is the height difference between that front pillar beam (windshield) and what will be left of the rear?
I’ve had an MR2 Targa and wind turbulence in the cabin from 60km up to 90km was unbearable. So were the cracking noises with the top on.

 

[ZippyZed4]

What is the height difference between that front pillar beam (windshield) and what will be left of the rear?
I’ve had an MR2 Targa and wind turbulence in the cabin from 60km up to 90km was unbearable. So were the cracking noises with the top on.

So very apt you’re mentioning this as I am looking at this right now, it has been a concern yet met with que sera attitude, the model shows the rear being a smidge taller which does suggest it’s going to be as aerodynamic as a parachute … the car will be intended as a tourer more than racer so for myself personally I don’t mind finding noise solutions…very worst case scenario i will put a permanent roof on … if noise isn’t an issue I’m also toying with a cross bar from A to B/C pillar just in case the soft “targa” top has issues with storage when removed I can make two removable rooftops like the mk1 MR2 / corvette and similar…. Thing is, so far this is really quite cheap and just for fun… were the MR2 known for this issue then?

 

[Pingu]

So very apt you’re mentioning this as I am looking at this right now, it has been a concern yet met with que sera attitude, the model shows the rear being a smidge taller which does suggest it’s going to be as aerodynamic as a parachute … the car will be intended as a tourer more than racer so for myself personally I don’t mind finding noise solutions…very worst case scenario i will put a permanent roof on … if noise isn’t an issue I’m also toying with a cross bar from A to B/C pillar just in case the soft “targa” top has issues with storage when removed I can make two removable rooftops like the mk1 MR2 / corvette and similar…. Thing is, so far this is really quite cheap and just for fun… were the MR2 known for this issue then?

The drone noise is the air in the rear collapsing and then filling. Fast flowing air has lower pressure than static air - this is why it collapses. The void it leaves has to be filled. This is why it fills. You can't stop it filling, so you have to control how it leaves. If it empties and fills at the wrong frequency, you get "drone". I get this in my Range Rover when the rear windows are open at above 50mph. The solution for the Range Rover is to either open the sunroof, or open one of the front windows about an inch. They know about it, because the solution is in the owners' manual

You may find that just raising the windows may stop it, as this will prevent air leaving around the B pillar.

You would have to be Adrian Newey to design the solution before you build it.

If it were me, I'd build it, then see how bad it is. You can use smoke to see the air flow. I think that I would use a smoke machine and a video camera, and go for a drive.

The solution could be as simple as a Gurney flap up the inside of the B pillars and across the inside of the targa opening.

 

[Zephyr]

were the MR2 known for this issue then?

Most of them had the T-tops glued and sealed.
It leaked, did not align properly and it was noisy.
Many will try to prove me wrong about this, but with the MR2 being the “best car ever” I understand its an “MR2 thing”.
(one of the worst cars I ever had in terms of comfort and quality. Also rusted like a can left in a field, at the most unbelievable areas).