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As the summer come and go, it seems less and less likely that my car would hit the paint booth this year. The flares are a couple of days away from completed but I still have the rear window mod on my list.
So, considering I may have one more winter to spend on the body, I'm starting to list additional modification I could do before next spring.
So far I have :
LT-1 hood scoop, '68 gill and vented rear bumper cover.
And that's on the lastest I'm asking for your inputs, technical and/or aesthetic.
Did anyone tried that?
How big is the "parachute ***" effect it? / How big should be the opening to prevent it?
What is you favorite vented rear bumper design?
maybe others know what you are working on but Im unclear and can only assume you are talking about a 74 to 82 car with a non-metal bumper. What are you trying to accomplish by "venting" it. Would a rear spoiler achieve your goal? When you say LT-1, do you mean install a big block hood?
maybe others know what you are working on but Im unclear and can only assume you are talking about a 74 to 82 car with a non-metal bumper. What are you trying to accomplish by "venting" it. Would a rear spoiler achieve your goal? When you say LT-1, do you mean install a big block hood?
My resto mod is a '76.
By design the rear bumper cover act as a parachute, slowing the car and making the back ligher, so the idea is letting air flow through it.
My idea so far is a opening in the center with a grill, à la Ferrari.
Other option I see it like the C7, openings on each side, beside the taillight.
I did mention the LT-1 mod just give a broader idea on what I'm working on, seems it make my post more confusing, Sorry for that.
Yeah, it's just about grafting a LT-1 hood scoop on a '76 hood, just because I find them much more sexy than the usual L88 scoop, but that's another story.
2020 Corvette of the Year Finalist (appearance mods)
C3 of Year Winner (appearance mods) 2019
I know what you are going for and trying to picture a good way to do it.
Would another option be a pan under the back .. Used to be called a wake modifier at one point. It could bolt on after the body is on. I know ideally they need to be really well engineered to get the air to attach to the underside of them as it exits, but it seems like just keeping it from going up into the "parachute" would make a big difference. Then again, if poorly designed, I guess that could create lift also.
Just throwing it out there.
One thing to keep in mind though: if you do go ahead and do it, it will affect your resale value since the car won't be original anymore.
I know what you are going for and trying to picture a good way to do it.
Would another option be a pan under the back .. Used to be called a wake modifier at one point. It could bolt on after the body is on. I know ideally they need to be really well engineered to get the air to attach to the underside of them as it exits, but it seems like just keeping it from going up into the "parachute" would make a big difference. Then again, if poorly designed, I guess that could create lift also.
Just throwing it out there.
One thing to keep in mind though: if you do go ahead and do it, it will affect your resale value since the car won't be original anymore.
Thanks for chimming in Brent.
I will have to look for that wake modifier thing, so far a quick googling don't bring out that much.
Concerning the resale value, I almost spilled my tea laughing
I'm having trouble finding a part that come from a '76... in my '76
It just can't get worse.
Thanks for chimming in Brent.
I will have to look for that wake modifier thing, so far a quick googling don't bring out that much.
Concerning the resale value, I almost spilled my tea laughing
I'm having trouble finding a part that come from a '76... in my '76
It just can't get worse.
Did you look in the "AIM"????
What about something like this- I dig the hair on the "model"....
It looks as though there is plenty of room between each "bumper" and the license plate to add a pair of grills.....
something similar to these......
There are also some honeycomb grills shown in Corvette stores on-line.
This is definitely where I plan to put it, I already have some pointer for Ebay stores that sell all kind of shape of grill.
Honeycomb is indeed my favorite shape.
It's more about the design of the opening itself that I'm looking for ideas.
2020 Corvette of the Year Finalist (appearance mods)
C3 of Year Winner (appearance mods) 2019
Don't listen to Richard. He will have you installing an electric door that opens at speed to relieve pressure. :-)
The one diffuser pictured with the huge fins is a bit much for me, and also I think added drag from the paint cans would out weigh any advantage gained from the lower aero drag.
Seriously, though, I like the one with the panels that cover it up. Not so obvious, but seems like it would work well..
As far as venting I wondered this: ( keep in mind I am not an engineer and I don't go all that fast anyway ). So if you vent the back it would make less drag by allowing the air to flow through the parachute. I wondered if it would also be beneficial because it would be dumping that air out the back to reduce the low pressure behind that car that creates a lot of drag.
i lost concentration at "resale value" i think a diffuser would be a good idea, the one with the paint cans is too extreme, the fins need to be cut down. that would allow the paint cans to function
Don't listen to Richard. He will have you installing an electric door that opens at speed to relieve pressure. :-)
The one diffuser pictured with the huge fins is a bit much for me, and also I think added drag from the paint cans would out weigh any advantage gained from the lower aero drag.
Seriously, though, I like the one with the panels that cover it up. Not so obvious, but seems like it would work well..
As far as venting I wondered this: ( keep in mind I am not an engineer and I don't go all that fast anyway ). So if you vent the back it would make less drag by allowing the air to flow through the parachute. I wondered if it would also be beneficial because it would be dumping that air out the back to reduce the low pressure behind that car that creates a lot of drag.
Maybe Richard could do a "Hinged Electric License Plate Mod" with a hidden opening behind the plate!!!!!!!!!!!
But seriously............Exiting all that hot air from the exhaust system wouldn't hurt a thing either!
Maybe Richard could do a "Hinged Electric License Plate Mod" with a hidden opening behind the plate!!!!!!!!!!!
no need to complicate the process with electrics,
just cut out the area behind the number plate and hinge the plate along the top.
that way the faster you go, the more it would open..
also has the advantage that a speed camera wont be able to read the plate.....
i have c'n on funny cars and doorslamers, they have their tail lights hinged to stop the parachute effect.
no need to complicate the process with electrics,
just cut out the area behind the number plate and hinge the plate along the top.
that way the faster you go, the more it would open..
also has the advantage that a speed camera wont be able to read the plate.....
i have c'n on funny cars and doorslamers, they have their tail lights hinged to stop the parachute effect.
Well.....since Bubba installed a late '70s tail light clip on my '68 project.....I may as well volunteer to hinge my license plate until I install the '68 clip. I may have to install a light-spring-loaded hinge to help it open above 30 mph.....no sense in holding all that traffic light heat under there while driving in town!
Last edited by doorgunner; 08-01-2014 at 11:16 PM.
No, it's not a problem at all. We cars guys just like putting louvers and vents where they don't belong.
Is that sarcasm?
Let me ask you since your such a "car guy"
Do you have any technical data on the amount of drag and or lift effect that rear bumper causes and at what speed it causes it?
And if so is the effect significant enough to warrant installing what looks like an HVAC floor vent on the back of your ride?
Ok, look I'm not the only one who choked at Richard's "resell value" point.
You were tricking us right?
Thanks you all for the input so far.
I didn't know about the serie of hole technique. I don't find it that sexy, it's like pure function, zero aesthetic, well IMHO.
May I shoot some ideas of mine:
I like the upper vent shape
Here is two render I did :
In this one the idea would be to join the two taillight holes, and mesh the bottom, so air could flow around and between the taillight.
Here are idea of more subtle vent, above the taillight, of beside.
07-31-2014, 01:37 PM
Brainstorming a vented rear bumper cover
DSCN4422 
i think a diffuser would be a good idea, the one with the paint cans is too extreme, the fins need to be cut down. that would allow the paint cans to function
