Rear Diffuser
Thread Starter
Safety Car
Joined: Dec 2008
Posts: 3,588
Likes: 10
From: North New Jersey
Rear Diffuser
Hey, I was wondering if anyone has ever made or bought a rear diffuser for the C4? I see they have them for the C5s and C6s and thought about making one for the C4.
I was also wondering if anyone had any experience with splitters for the front? Another downforce application...
Anyone know about C4 downforce or aerodynamics for the C4? Does anyone know anything about the correct way to make a diffuser so it will work properly?
Lets see some pics if possible!
I was also wondering if anyone had any experience with splitters for the front? Another downforce application...
Anyone know about C4 downforce or aerodynamics for the C4? Does anyone know anything about the correct way to make a diffuser so it will work properly?
Lets see some pics if possible!
Race Director
Joined: Jun 2004
Posts: 13,895
Likes: 691
From: WI
I've been planning to make one for mine, when time allows. I don't expect a big gain but a little help adds up, also partly for filling in the area where the spare tire was. In your first picture you can see how the whole under body is aero. Adding just a diffuser without the rest isn't a complete system.
There was a thread in the C4 ZR1 section with pix of a diffuser being made and several others too IIRC. There was also just a topic in the race section about making a diffuser. Check those threads and also get a decent aero book.
Some pix I saved:
There was a thread in the C4 ZR1 section with pix of a diffuser being made and several others too IIRC. There was also just a topic in the race section about making a diffuser. Check those threads and also get a decent aero book.
Some pix I saved:
Safety Car
Joined: Oct 2008
Posts: 4,689
Likes: 4
From: Yucaipa CA
Used to be a company that made them for C4's that came in a complete body kit. Thought it was sold through ecklers or one of the vette suppliers. Don't remember the company that made them though but was a nice setup.
aci but they refer to it as a tunnel
aci but they refer to it as a tunnel
Last edited by jeffp1167; Jan 31, 2011 at 11:55 AM.
Thread Starter
Safety Car
Joined: Dec 2008
Posts: 3,588
Likes: 10
From: North New Jersey
I've been planning to make one for mine, when time allows. I don't expect a big gain but a little help adds up, also partly for filling in the area where the spare tire was. In your first picture you can see how the whole under body is aero. Adding just a diffuser without the rest isn't a complete system.
There was a thread in the C4 ZR1 section with pix of a diffuser being made and several others too IIRC. There was also just a topic in the race section about making a diffuser. Check those threads and also get a decent aero book.
Some pix I saved:
There was a thread in the C4 ZR1 section with pix of a diffuser being made and several others too IIRC. There was also just a topic in the race section about making a diffuser. Check those threads and also get a decent aero book.
Some pix I saved:
Burning Brakes
Joined: Aug 2010
Posts: 833
Likes: 1
Shouldn't be too hard to make a rear diffuser if you have the right skills. That greenwood kit That jeffp posted up is more for aesthetics than aerodynamics. I've actually seen a splitter for the front of a C4 that bolts in place of the spoiler and had reinforcements bolted to the bottom of the front bumper. However, these aero devices don't really work unless you have them as close to the ground as possible.
Race Director
Joined: Jun 2004
Posts: 13,895
Likes: 691
From: WI
I forgot to comment on the splitter, there was just a topic in the race section on that too.
http://forums.corvetteforum.com/auto...-race-car.html
As for the front end my friend has the mold and he has them made as ordered.
He also got the hood and the wing for me.
He knows his shet when if comes to corvettes.
His name is Mike and runs Mike Poupart Motorsports.
You can contact him at (504)472-0400
He can get you any info on the front end, hood or the wing that you need.
http://forums.corvetteforum.com/auto...-race-car.html
As for the front end my friend has the mold and he has them made as ordered.
He also got the hood and the wing for me.
He knows his shet when if comes to corvettes.
His name is Mike and runs Mike Poupart Motorsports.
You can contact him at (504)472-0400
He can get you any info on the front end, hood or the wing that you need.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Greenwood was the company. You could get different levels of the kit; rocker panels alone, spoiler alone, rockers and diffuser, or all of the pieces. IIRC, the Greenwood diffuser fit over the spare tire carrier, but it was a royal PITA to get to the spare. The diffuser used something like Dzus fasteners to hold it in place and you had to remove the entire piece to get to the spare.
Melting Slicks
Joined: Aug 2009
Posts: 3,028
Likes: 2,105
From: Schaller Iowa
Ok...I really hope I'm not the only one on CF that has no idea what a diffuser is for. I gather it's for a racing application. Does it somehow add downforce to the rear end?
astepup said that
astepup said that
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Thread Starter
Safety Car
Joined: Dec 2008
Posts: 3,588
Likes: 10
From: North New Jersey
I dont race my car but I am gonna need something to get me some attention at shows this year so I am thinking of fabricating my own diffuser out of fiberglass. I want to make it a bolt on to the spare carrier so it can be taken off if needed...
Thanks for all the info guys!
Burning Brakes
Joined: Aug 2010
Posts: 833
Likes: 1
Yes, it is mainly for racing applications. A diffuser works by lowering the pressure underneath the car. In a normal car there's all kinds of stuff just hanging underneath the car which creates pressure. On a race car, people usually cover all this up and add a diffuser. This helps to make a huge amount of downforce.
Thread Starter
Safety Car
Joined: Dec 2008
Posts: 3,588
Likes: 10
From: North New Jersey
Yes, it is mainly for racing applications. A diffuser works by lowering the pressure underneath the car. In a normal car there's all kinds of stuff just hanging underneath the car which creates pressure. On a race car, people usually cover all this up and add a diffuser. This helps to make a huge amount of downforce.
Thread Starter
Safety Car
Joined: Dec 2008
Posts: 3,588
Likes: 10
From: North New Jersey
OK, so if I start designing my own diffuser what are some key parts of the design?
So far I am thinking 4 or 5 fins that are about 5in high and are the length from the rear differential to the bumper. The diffuser is going to seal pretty much the whole rear so its going to cover the mufflers and gas tank. Im going to use a dynomat or something to prevent excess heat from destroying the diffuser. Its going to slope pretty much the same way the rear tire carrier slopes.
Any other points or ideas? Is it a good idea to cover the mufflers? This is a daily driver and not a track car.
So far I am thinking 4 or 5 fins that are about 5in high and are the length from the rear differential to the bumper. The diffuser is going to seal pretty much the whole rear so its going to cover the mufflers and gas tank. Im going to use a dynomat or something to prevent excess heat from destroying the diffuser. Its going to slope pretty much the same way the rear tire carrier slopes.
Any other points or ideas? Is it a good idea to cover the mufflers? This is a daily driver and not a track car.
Thread Starter
Safety Car
Joined: Dec 2008
Posts: 3,588
Likes: 10
From: North New Jersey
School has been keeping me too busy to try and make a cardboard fab but I was thinking of making it go from the cats back to the exhaust so the whole bottom is smooth and helps aerodynamics... Boost my downforce and fuel economy.
Racer
Joined: Sep 2010
Posts: 379
Likes: 0
From: Kingsland GA
I have the greenwood on mine. It looks good but probably has minimal airflow effect. Most of the diffusers that have legitimate performance gains go down to the ground which is not good for a street car. Can anyone say pothole.
