NineLivesRacing Rear Diffuser

OptimizePrime

Goblin Guru
Does anyone have any install pictures (specifically mounting points on the Goblin) or feedback?

@dastrups I saw you had one! :)


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k.rollin

Goblin Guru
The rear wing is 69". The diffuser is probably closer to 48" wide. I don't have any feedback for the diffuser, but I did send Johnny my pylon design that works with the Exocet mount's AoA adjustment scheme (from -5° to 20°) yesterday, so those may be available in a while to go with the rear wings.
 

OptimizePrime

Goblin Guru
Ah, you're right - just saw their facebook post and thought the length was coincidentally 69" and based on their sexual overtones just went with it to be funny. I'm not a smart man
 

KSLunsfo

Well-Known Member
Making some assumptions:
12guage 5052, 32"x48" Main sheet

2.06mm x 812.8 x 1219.2 = 2,041,389 mm^3
2,041,389 * 2.7 g/ cm^3 = 5511.75g -> 12.15lbs

Another wild guess saying the ribs are all ~10% of the main sheets volume:
12.15 +1.2 = ~13.35 lbs total weight

I was going to guess 15 lbs or so...
 

SmsDetroit

Goblin Guru
Making some assumptions:
12guage 5052, 32"x48" Main sheet

2.06mm x 812.8 x 1219.2 = 2,041,389 mm^3
2,041,389 * 2.7 g/ cm^3 = 5511.75g -> 12.15lbs

Another wild guess saying the ribs are all ~10% of the main sheets volume:
12.15 +1.2 = ~13.35 lbs total weight

I was going to guess 15 lbs or so...
That’s too much math for me
 

dastrups

Well-Known Member
Kind of complicated but I measured out equal lengths right and left and then found out how far it would stick out so that the other end would overlap the floor of the cabin. Then I used several vise grips to hold it there in place and then drilled through it and into the subframe. Then I placed nutserts in the subframe. Tedious for sure. Takes time to really square it up and measure where to drill so you’re mostly centered over the subframe. Probably a better way to do it than this. Ground down some of the tabs a little without ruining the welds so that it could sit mostly flush with the subframe. Need to mount the front portion to the floorboard to make it more solid so it doesn’t catch any air underneath. So far just 4 bolts on each side.
 

Attachments

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Desert Sasqwatch

Goblin Guru
Making some assumptions:
12guage 5052, 32"x48" Main sheet

2.06mm x 812.8 x 1219.2 = 2,041,389 mm^3
2,041,389 * 2.7 g/ cm^3 = 5511.75g -> 12.15lbs

Another wild guess saying the ribs are all ~10% of the main sheets volume:
12.15 +1.2 = ~13.35 lbs total weight

I was going to guess 15 lbs or so...
Anything in carbon fiber? Thinking that someone on the forum has already thought about that, since that 12-13 pounds on the rear of the Goblin is significant (about 7% of the total weight of the car). :confused:
 

Desert Sasqwatch

Goblin Guru
Oops, you're right - too early in the day to do complicated math that involves decimals. o_O:p But still too much weight in my opinion, need that carbon fiber option!
 

OptimizePrime

Goblin Guru
Kind of complicated but I measured out equal lengths right and left and then found out how far it would stick out so that the other end would overlap the floor of the cabin. Then I used several vise grips to hold it there in place and then drilled through it and into the subframe. Then I placed nutserts in the subframe. Tedious for sure. Takes time to really square it up and measure where to drill so you’re mostly centered over the subframe. Probably a better way to do it than this. Ground down some of the tabs a little without ruining the welds so that it could sit mostly flush with the subframe. Need to mount the front portion to the floorboard to make it more solid so it doesn’t catch any air underneath. So far just 4 bolts on each side.
Interesting, seems like those side / inner mounting tabs are fairly useless then.

Anyone near Buford, GA 30518 want to offer up their subframe / Goblin for them to use for actual mounts? I have to imagine these are pretty high profit margin pieces for them, they could atleast give a steep discount and make our lives easier
 

Desert Sasqwatch

Goblin Guru
Kinda defeats the purpose of the aero at that point, no? :p
Sorry didn't catch this one on the first read through. I should have been more specific about the speedholes, not in the diffuser, but in other (non-aero) places to compensate for the added weight on the back end. I know this is possible to offset the extra 12-13 pounds of the diffuser, since I've removed more than that from my frame already. :cool:
 

r3drckt

Goblin Guru
Sorry didn't catch this one on the first read through. I should have been more specific about the speedholes, not in the diffuser, but in other (non-aero) places to compensate for the added weight on the back end. I know this is possible to offset the extra 12-13 pounds of the diffuser, since I've removed more than that from my frame already. :cool:
haha I'm really curious if you weighed all the speed hole cut outs how much you have cut total! I know there'd be a loss from the shavings but still pretty impressive all the work you've done with it. Carbon fiber may be a little on the expensive side though, might I suggest 3D printing pieces that are ~2-3mm thick and turning them into either puzzle pieces or making rivet holes (zip ties any lighter?) to secure the smaller sections together then secure to the subframe?
 

Waterdriver

Goblin Guru
haha I'm really curious if you weighed all the speed hole cut outs how much you have cut total! I know there'd be a loss from the shavings but still pretty impressive all the work you've done with it. Carbon fiber may be a little on the expensive side though, might I suggest 3D printing pieces that are ~2-3mm thick and turning them into either puzzle pieces or making rivet holes (zip ties any lighter?) to secure the smaller sections together then secure to the subframe?
Not sure a 3D printed diffuser would hold up, if assembled in that manner. If the diffuser is actually doing what it's supposed to do, there will be a suction force being applied between the road surface and the diffuser, pulling the car towards the ground. The OSB diffuser template I built (couldn't resist testing it) sucked the vertical strakes off. So there is a suction force being applied. Not that they were attached very securely in the first place, but enough to pull them off and bend the screws attaching them.
I mean it could work but you'd have to have a lot of attachment points to support it well enough.
 

r3drckt

Goblin Guru
Not sure a 3D printed diffuser would hold up, if assembled in that manner. If the diffuser is actually doing what it's supposed to do, there will be a suction force being applied between the road surface and the diffuser, pulling the car towards the ground. The OSB diffuser template I built (couldn't resist testing it) sucked the vertical strakes off. So there is a suction force being applied. Not that they were attached very securely in the first place, but enough to pull them off and bend the screws attaching them.
I mean it could work but you'd have to have a lot of attachment points to support it well enough.
This is what I love about this community, the knowledge people have combined with others who test different configurations and materials to find the best way forward.
 
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