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Discussion Starter #1
Short of the big C5-R wing, are there any functional front and rear aero aids that can be added to our C5Z cars? Who makes them? I am talking about creating some front and rear downforce in a manner that does not unbalance the car or cause unnecesary drag.
 

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ACP, a Forum Supporting Vendor,
<-----------OVER THERE
has the best selection. LG Motorsports also has kits. Others that have aero body parts & kits are Specter Werks & Mallett.

The best improvements are WC front fascia, an evacuator hood such as Metro Mold or ACP's louvered hood and rear fascia with spoiler or spoiler extension.
There is an approved GM kit but it is not sold by GM and is similar to the WC kit with a spoiler that attatches to the rear OEM fascia.
Both ACP and Specter Werks have wide body kits as well.

Other small things that can be done to aid Aero are:
- keep or add the Body Side Moldings (many remove them unknowingly)
- Carravaggio front strakes OR
- Add Gurney Lips to front fender well leading edge. I experimented with these and used the mounts for my Speed Lingerie Bra, inverted so they stick out. These will now appear on the C6 Z06 since they work so well.
- Remove side vent interior close out to evacuate air
- Front hood seal
- C5R lights
- improve rear fascia venting by opening up new vents
- lowering car with proper rake will also aid Aero
 

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DJ do you have any data that BSM's are Aerodynamic Aid? :screwy:
 

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I've read about it too. They help keep the boundry layer that forms on the side of the car from spilling all the way down the sides. In other words more air goes over the top, instead of coming off the side.

Sorry I have no idea where I read this though.
 

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Yes, otherwise I wouldn't state it as so.

Mallett did preliminary studies & wind tunnel tests with Chevy at GM's wind tunnel facilities in Troy, Michigan when they were developing the WC body kits and GM's C5 Aero kit. What they noticed was a difference in rear end lift (or downforce, depending on your perspective) between cars with and without the BSM's.

They found that cars WITH BSM's had better rear downforce numbers with Aero aids and less rear end lift on cars without Aero aids.
- On further investigation it was found that the BSM's greatest advantage was to aid and improve Laminar Flow along the sides of the car. What the improved laminar flow did was prevent the spilling of air off the side of the hood at the cowl. This added downforce at the windshield.
- The improved side body Laminar Flow also reduced the amount air wrapping under the car (in front of the rear wheels and thus reduced rear end lift. Without the BSM's the reduced Laminar Flow and increased Hood Cowl spill resulted in and almost doubled the amount of air getting under the rear.
Note that the laminar flow starts to become effective around 100 MPH and increases after that.
- There is a small downforce componant of the BSM's due to their angle of attack. There is a very small but discernable positive effect above 150 MPH. Like the Laminar Flow there is probably an effect at around 100 MPH but it is very small but builds with speed.

Other things that were assumed but not measured was that the improved Laminar Flow:
- Increased air extraction of the front & rear wheel wells and
- Improved brake cooling
- Improved air extraction from functional side vents
- Improved underhood air extraction from evacuator hoods

Note that this concept of improved side laminar flow was designed into the C6 & C6 Z06 and therefore they do not require or need BSM's.

Another benefit of the BSM's is evidenced if you look on the bottom of them. You will notice as time goes on a large number of chips and dings on their underside. Had they not been there the stones and road grit would have been thrown up on the upper door, upper fender, top of rear fascia and the trunk lid and could have promoted scratches, chips & dings on these more conspicuous places.

This side laminar Flow investigation also lead to the research and investigation of Gurney Lips on the leading edge of the front wheel well. We inverted the Lexan mounting strip for a Speed Lingerie bra (when not using it on the track) so that they stuck out. We found out that:
- brake temps were reduced 100-200 degrees
- front downforce increased
- Side laminar Flow was not effected or interrupted (did not improve or decrease).
- drag was not significantly increased

Although not measured it is assumed that the negative pressure generated just behind the front fender lip
- increases cooling air to the brakes thru the ducts
- increases cooling air to enter the well from the bottom
- increases ground effect in the front
- increases air extraction from the wheel well
- increases air extraction from a functional side vent

This is why you wil see Gurney Lips on the front wheel well leading edge on the C6 Z06.

We do not recomend installing Gurney Lips on the rear wheel well leading edge as it upsets the side Laminar Flow which evacuates the rear wheel well adaquately.
 

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That is amazing. I never would have thought the BSM would make any difference. Makes you wonder if they planned it, or if it is a funny side effect.
 

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I'm going to find the picture of John Lingenfelter C5 that went 225+MPH and see if it BSM's. I know from talking to John L. that the stock C5 has very poor Aerodynamic's above 180 compared to the stock C4. :cheers:
 

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IT L GO said:
I'm going to find the picture of John Lingenfelter C5 that went 225+MPH and see if it BSM's. I know from talking to John L. that the stock C5 has very poor Aerodynamic's above 180 compared to the stock C4. :cheers:

 

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Thanks DJ,
Great info!!!! But I liked them before this good stuff you just shared, they have stayed on since picking up the car. And will continue to be there.
 

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Notice that the LPE car is a Coupe and not a FRC/Z06...it appears that he doesn't have BSM. The coupe has better Aero than the FRC.

But what he does have significantly is about 1,000 HP from the twin turbo. That tends to over compensate everything else.
 

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I have a bunch of things done to my car some are obvious and some not. When you funnel air in and out of areas of the car you create drag which is a trade off for downforce. The top speed at Pocono is 165 which it was before many of the mods. Difference now is Nascar turn 1 is 125 at the lowest speed and lap times are down. Even though I am carring more speed around the corner the mods create drag down the straight. I'll be running it this weekend and next Friday at Pocono with a few more mods I'll keep you posted.
 

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Discussion Starter #16
SEE MY QUESTIONS IN CAPS

DJWorm said:
ACP, a Forum Supporting Vendor,
<-----------OVER THERE
has the best selection. LG Motorsports also has kits. Others that have aero body parts & kits are Specter Werks & Mallett.

The best improvements are WC front fascia, an evacuator hood such as Metro Mold or ACP's louvered hood and rear fascia with spoiler or spoiler extension. IS THERE ONE CONFIGUATION AND ANGLE THAT IS SUPERIOR AS A COMPROMISE BETWEEN DRAG AND DOWNFORCE?
There is an approved GM kit but it is not sold by GM and is similar to the WC kit with a spoiler that attatches to the rear OEM fascia.
Both ACP and Specter Werks have wide body kits as well.

Other small things that can be done to aid Aero are:
- keep or add the Body Side Moldings (many remove them unknowingly)
- Carravaggio front strakes OR
- Add Gurney Lips to front fender well leading edge. I experimented with these and used the mounts for my Speed Lingerie Bra, inverted so they stick out. These will now appear on the C6 Z06 since they work so well.
- Remove side vent interior close out to evacuate air I DO NOT FOLLOW THIS ONE--YOU DO NOT WANT THE AIR TO EVACUATE?
- Front hood seal YOU WANT TO REMOVE THIS SEAL?
- C5R lights IF YOU RUN WITH HIDDEN LIGHTS IN THE DOWN POSITION, THAT SHOULD BE BETTER THAN C5R LIGHTS, CORRECT?-I DO NOT RUN AT NIGHT ON THE TRACK.
- improve rear fascia venting by opening up new vents WHERE WOULD YOU PUT THEM?
- lowering car with proper rake will also aid Aero
 

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No, the width, length, angle and wehther or not a wicker bill is needed and what size it should be are all dependant on top speed. General rule is the slower you want the down force to be effective the larger the spoiler and greater the angle of attack needs to be. For example low speed Modifidied AutoX cars need to carry a large rear spoiler with high angle of attack and drag is not that great...however that type of spoiler would generate too much drag on a high speed car where a low angle of attack, short chord wing produces just as much downforce.

The interior close out panel in front of the side air vent makes it almost non functional. By removing it you can make it functional, evacuate air, reduce under hood lift and improve cooling. The aim is to vent the under hood engine bay...not the fender well.

I recommend adding a front hood seal. The car doesn't have one...only on the sides and rear. This aids in improving cold air into the OEM airbox and airflow over the hood.

Some remove the rear hood seal for low speed events but I do not recommend it for high speed as this area becomes a high pressure area.

With C5R lights you can actually seal the lights with thin rubber sheeting, thus improving hood air flow.

I first saw the rear fascia vents on '64 grand sports and Can Am cars. You can effectively vent a C5 rear fascia by drilling holes high on the rear panel between the headlights and then screening them. You can also relieve pressure by opening up the license plate area and screening it off....the C6R uses this technique.
 

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Although we have "graphix'd" the snot outta the Cancer Corvette, at DJ's assertion, we left the BSM's on....along with a few of the enhancements mentioned above (full carbon-fiber ACP Widebody/wing/front splitter-tray). Depending on the height of wickerbill used on the WC wing, this thing STICKS...
More on the body conversion in the July '05 issue of VETTE Magazine, due out in about 2-3 weeks...
BTW, DJ is a clearly acknowledged expert on race-conversion stock-body Z06's. Please heed his advice...we sure do!
 

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DJWorm said:
No, the width, length, angle and wehther or not a wicker bill is needed and what size it should be are all dependant on top speed. General rule is the slower you want the down force to be effective the larger the spoiler and greater the angle of attack needs to be. For example low speed Modifidied AutoX cars need to carry a large rear spoiler with high angle of attack and drag is not that great...however that type of spoiler would generate too much drag on a high speed car where a low angle of attack, short chord wing produces just as much downforce.

The interior close out panel in front of the side air vent makes it almost non functional. By removing it you can make it functional, evacuate air, reduce under hood lift and improve cooling. The aim is to vent the under hood engine bay...not the fender well.

I recommend adding a front hood seal. The car doesn't have one...only on the sides and rear. This aids in improving cold air into the OEM airbox and airflow over the hood.

Some remove the rear hood seal for low speed events but I do not recommend it for high speed as this area becomes a high pressure area.

With C5R lights you can actually seal the lights with thin rubber sheeting, thus improving hood air flow.

I first saw the rear fascia vents on '64 grand sports and Can Am cars. You can effectively vent a C5 rear fascia by drilling holes high on the rear panel between the headlights and then screening them. You can also relieve pressure by opening up the license plate area and screening it off....the C6R uses this technique.

I thought the fender well is a high pressure area? The Bulgatti that does 240+ had to place vents that automatically open at certain speeds to prevent lift. The more places you funnel air in and out of the more drag you create, no? My fender wells are vented at the top through the ACP hood and now through the rear and out the side vent of the body.
 
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