Post some C4's with rear diffusers!
Thread Starter
Le Mans Master
Joined: Sep 2009
Posts: 6,937
Likes: 348
From: My interests are mobile
Post some C4's with rear diffusers!
I've seen one so far, but can't even find that. Anyone have any pics of C4's, race prepped or not, that have rear diffusers installed.
Race Director
Joined: Jun 2004
Posts: 13,960
Likes: 707
From: WI
There are two cars with pix in this thread:
http://forums.corvetteforum.com/c4-z...-diffuser.html
I'm going to make one as well. The empty spare area has got to be dragalicous.
http://forums.corvetteforum.com/c4-z...-diffuser.html
I'm going to make one as well. The empty spare area has got to be dragalicous.
Team Owner
Joined: Mar 2001
Posts: 30,856
Likes: 293
From: Boston, Dallas, Detroit, SoCal, back to Boston MA
It's an option with the Greenwood kits.
Thinking of loosing the spare and cutting the rear lip on the bumper cover to make a larger one. Don't know if it will go with the class rules.
Thinking of loosing the spare and cutting the rear lip on the bumper cover to make a larger one. Don't know if it will go with the class rules.
Thread Starter
Le Mans Master
Joined: Sep 2009
Posts: 6,937
Likes: 348
From: My interests are mobile
Aardwolf...that's the pic I was lookin for! I forgot it was in the ZR1 forum.
Any more?
I've got 27 feet of 12k x 12k twill weave carbon and nothing to do with it!
Any more?
I've got 27 feet of 12k x 12k twill weave carbon and nothing to do with it!
Melting Slicks
Joined: Mar 2008
Posts: 3,022
Likes: 3
From: Chandler Arizona
i am curious to know how effective the greenwood unit is. it might be worth the effort to purchase the greenwood unit to study the shape, and than improve the design (if there is room for improvement).
I would say that a diffuser is definitely a nice aftermarket piece, but i would want to keep it "reversable" (i.e. for the owners that don't want to do anything that would be permanent, and can be reversed back to stock for resale etc).
I would say that a diffuser is definitely a nice aftermarket piece, but i would want to keep it "reversable" (i.e. for the owners that don't want to do anything that would be permanent, and can be reversed back to stock for resale etc).
Tech Contributor
Joined: Jun 2004
Posts: 20,905
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
There are two cars with pix in this thread:
http://forums.corvetteforum.com/c4-z...-diffuser.html
I'm going to make one as well. The empty spare area has got to be dragalicous.
http://forums.corvetteforum.com/c4-z...-diffuser.html
I'm going to make one as well. The empty spare area has got to be dragalicous.
All ears here.
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Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
I have the Greenwood one on my '87. It is trimmed very tight to the components in the area (i.e. Flowmaster 40s and the rear Y pipe). It definitely closes up the spare tire storage area. Painted body color....
Thread Starter
Le Mans Master
Joined: Sep 2009
Posts: 6,937
Likes: 348
From: My interests are mobile
Not to say the Greenwood one doesn't appear functional on some level, but diffusers produced in that manner appear to much for "show" for my taste. Simple carbon units are what I'm looking for such as the Callaway unit or the ZR1 via the link.
Anyone have any other C4's to show here?
Anyone have any other C4's to show here?
Melting Slicks
Joined: Oct 2006
Posts: 2,238
Likes: 10
From: College Station TX
Rear diffusers look fun, and I agree the Greenwood, like almost all their products, looks far more for show than go. I don't have mufflers in the stock location, so I have plenty of space back there to setup a diffuser (if I only had the time).
Race Director
Joined: Jun 2004
Posts: 13,960
Likes: 707
From: WI
Between running a big block in my '69 and a turbo in my '84, I've never lost sleep over drag issues. I kind of hoped the drag would help slow me down better coming into the corners. However, if I heard about a setup that produced some measurable downforce on an otherwise stock bodied car, I'd consider installing one.
All ears here.
All ears here.
Tech Contributor
Joined: Jun 2004
Posts: 20,905
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
But aren't you still limited on deceleration by the tires grip? Deceleration is a sum of the tire's grip and the aero drag. Adding more drag isn't going to help track threshold braking. As long as the drag doesn't have a lift component, there's no downside I'm aware of. Drag will just cause lower top speeds in the straights, lowering lap times. I'm not lacking for horsepower in either car. My experience has been that I generally have more speed than brakes, as it were, so any help in the deceleration department just lets me brake later into the corner. A diffuser will lower drag and help down force.
Thread Starter
Le Mans Master
Joined: Sep 2009
Posts: 6,937
Likes: 348
From: My interests are mobile
I don't want this thread to turn into a debate over whether or not they work. I think their function has been proven. I want to see pics of Vettes that have them installed.
Safety Car
Joined: Feb 2000
Posts: 4,564
Likes: 110
From: Austin Texas
Rick Doria did a lot of modifications to his C4 to make it average >200 mph for the Open Road Race events. There's some good information in this Chevy High Performance article...
He set the speed record at 227 mph in his car in 2003.
I don't know what he is doing these days (besides testing for Shelby)...
I'm sure if you contacted Rick's restaurant ( Doria's Haus of Pizza ) they can get you in touch with Rick. I heard he had wrecked the C4 doing over 190 mph, but I don't know if it was totaled. He'll have lots of pictures of it though...
Melting Slicks
Joined: Oct 2006
Posts: 2,238
Likes: 10
From: College Station TX
Rick Doria did a lot of modifications to his C4 to make it average >200 mph for the Open Road Race events. There's some good information in this Chevy High Performance article...
He set the speed record at 227 mph in his car in 2003.
I don't know what he is doing these days (besides testing for Shelby)...
I'm sure if you contacted Rick's restaurant ( Doria's Haus of Pizza ) they can get you in touch with Rick. I heard he had wrecked the C4 doing over 190 mph, but I don't know if it was totaled. He'll have lots of pictures of it though...
Melting Slicks
Joined: Mar 2008
Posts: 3,022
Likes: 3
From: Chandler Arizona
this ZR1 is just flat out SICK! I would love to mimic the stance, wheels, brakes, rear-diffusor.
this is something that looked appealing, it's also in the same thread as the home-made diffusor.
the greenwood might look "show", but it certainly looks to have the proper curvature to create downforce. Keep in mind, shape is also critical, not just the closure of the rear-spare area (although this is important too).
this is something that looked appealing, it's also in the same thread as the home-made diffusor.
the greenwood might look "show", but it certainly looks to have the proper curvature to create downforce. Keep in mind, shape is also critical, not just the closure of the rear-spare area (although this is important too).
Melting Slicks
Joined: Mar 2008
Posts: 3,022
Likes: 3
From: Chandler Arizona
this ZR1 is just flat out SICK! I would love to mimic the stance, wheels, brakes, rear-diffusor.
this is something that looked appealing, it's also in the same thread as the home-made diffusor.
the greenwood might look "show", but it certainly looks to have the proper curvature to create downforce. Keep in mind, shape is also critical, not just the closure of the rear-spare area (although this is important too).
this is something that looked appealing, it's also in the same thread as the home-made diffusor.
the greenwood might look "show", but it certainly looks to have the proper curvature to create downforce. Keep in mind, shape is also critical, not just the closure of the rear-spare area (although this is important too).
did anyone ever consider the greenwood kit just painted flat-black to get away from the "show" look? I think this is by far, the best idea.
Melting Slicks
Joined: Mar 2004
Posts: 2,141
Likes: 2
From: Pittsburgh Pa