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C4 zr-1 lowest drag most aero dynamic

 
Old 06-20-2019, 09:29 PM
  #21  
locobob
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Originally Posted by Daves obsession View Post
Underhood air is a really big effect on a C4, at 175mph you are pushing a lot of air on the fire wall. Put a fine mesh screen blocking the area that feeds the radiator. Buy a used set of gill plates and cut the gills out, take a 3.5 by 3.5 sheet to aluminum curve the front and pan from the front crash bars back.

all of the above will get you 10 mph. You welcome

Dave
10mph is a super impressive gain, I'm guessing that is on a 200+mph car right... where aero really becomes a huge deal. So the pan cuts down on undercar turbulence, the open gills reduce the air pressure in the engine compartment... but what does the front screen do? Slightly reduce the volume of air entering the engine bay? I've seen radiator screens before but always for the purpose of keeping debris from clogging up the radiator stack.
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Old 06-21-2019, 10:21 AM
  #22  
emmvette
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Here's the old article from Corvette Fever. It doesn't look great in B&W, but the file size is too large in color.
Attached Images
File Type: pdf
Wind Tunnel Testing.pdf (1.87 MB, 23 views)
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Old 06-21-2019, 02:37 PM
  #23  
Tom400CFI
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Page 38 had a chart....that is where the good info is. Looks like the C5 and C6 have the best CDA, which surprises me.
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Old 06-21-2019, 03:41 PM
  #24  
Evan70
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I was thinking the same thing. Really surprises me based on my very unscientific comparison of speeds in the different platforms and their behavior. The front lift #s do seem to back observed behavior as the C5Z gets very "light' on the front end over 170, while the C4 and C6 both feel much more planted at those speeds.
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Old 06-29-2019, 07:47 AM
  #25  
Daves obsession
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When the Beast was in for wind tunnel work the operator told me that the front lift begins when the firewall is packed and that speed is very noticeable as the fans wind up. When the front lifts the CD goes up rapidly so keeping air from entering and getting air out is critical. The screen just limits the air, The pan makes for a easier path for the air to not enter as well as reduces turbulence.
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Old 07-04-2019, 07:13 AM
  #26  
Rkreigh
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Originally Posted by Daves obsession View Post
When the Beast was in for wind tunnel work the operator told me that the front lift begins when the firewall is packed and that speed is very noticeable as the fans wind up. When the front lifts the CD goes up rapidly so keeping air from entering and getting air out is critical. The screen just limits the air, The pan makes for a easier path for the air to not enter as well as reduces turbulence.

this. the bonneville guys know aero. How is the new build coming?? good to see folks pushing the limits of the lt5 again.

I'd destroke this time and go with the 4.125 bore and let it eat.

back to the c4 aero, while he overall cd numbers aren't that great (wide bode and tires don't help) the c4 is pretty stable. JL learned with the aero body kit that reducing the front end lift and keeping the tail planted led to a 219 yellow bird number with his custom rear and a stocker front and the car drove great

the c5 did well here too during the TT testing with JL decribing hot laps at 223 which is moving it

I know Norm K. has built a "super aero" TT LPE car to try and get up over 300 which would be quite an achievement.

He's got the cubic dollars and intel but honestly I haven't seen him post for a while or heard from him.

while my TT car was being "auto swapped" at RPM, Norms stuff was on the table for the wonderbar tranny made out of unobtanium to hand the big HP needed to go that fast

Norm did wind tunnel testing to let you know how serious this effort was.

Anyone know more about this project currently? GB??
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Old 07-04-2019, 07:59 AM
  #27  
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As I got older I got slower....In my 20's I had my GSXR-1100 at 171MPH..Speedometer correction I was probably at 160.....Did this many times on upstate highways and a few stretches in long island....

With my Z I think the fastest I went was maybe 140.....For some silly reason I always felt safer at speeds on a bike than enclosed in a car....

Would like to do some half mile runs in the Z....Curious to see what it does as its modified ...Over 500 at the crank....

I'm in NY and and I really only see these in Texas or Florida....NY is a tough place for Z ownership....
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Old 07-04-2019, 03:39 PM
  #28  
Mr. Gizmo
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Originally Posted by zrc3john View Post
As I got older I got slower....In my 20's I had my GSXR-1100 at 171MPH..Speedometer correction I was probably at 160.....Did this many times on upstate highways and a few stretches in long island....

With my Z I think the fastest I went was maybe 140.....For some silly reason I always felt safer at speeds on a bike than enclosed in a car....

Would like to do some half mile runs in the Z....Curious to see what it does as its modified ...Over 500 at the crank....

I'm in NY and and I really only see these in Texas or Florida....NY is a tough place for Z ownership....
I had my 1991 zr1 up to 171 as indicated on the digital speedo. It was on a down hill incline.
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