what material for flat underbody?
01-30-2012, 11:54 PM
#41
Junior Member
Join Date: Aug 2009
Posts: 186
Total Cats: 2
What's wrong with zip ties? The plastic is SO easy to work with, it's not even funny.
Anyway, here's a few vids of my diffuser BEFORE the underpanels.
I have it tested at 6.52 and 9.82 AOA.
I didn't find any differences in airflow between the two AOAs but took it to a local course as is. The following vid is at 9.82 AOA. Camera mounted underneath the muffler area, looking out towards the driver side.
Notice it is very turbulent. Despite this, I still feel a difference in rear end stability at 80-90mph speeds. In the above video, most of the turns are at about 60mph +/- so it didn't reallly matter as much.
Anyway, here's a few vids of my diffuser BEFORE the underpanels.
I have it tested at 6.52 and 9.82 AOA.
I didn't find any differences in airflow between the two AOAs but took it to a local course as is. The following vid is at 9.82 AOA. Camera mounted underneath the muffler area, looking out towards the driver side.
Notice it is very turbulent. Despite this, I still feel a difference in rear end stability at 80-90mph speeds. In the above video, most of the turns are at about 60mph +/- so it didn't reallly matter as much.
Reply
0
0
01-31-2012, 01:20 AM
#43
I epoxied the bolt on the coroplast. The undertray is in the bumper, so just put the bolts down. The good thing here, is if it comes loose I am not leaving bolts on the track. A nut is a lot less likely to damage a tire than a bolt. And also, its less likely for the undertray to fall off since the bolt is still going through the bumper hole.
Reply
0
0
01-31-2012, 10:42 AM
#44
Either way, the epoxy bolt is working fine for my undertray which I have been messing with for the last week. Plus I am doing some alignment adjustments and don't feel like cutting 11 zipties every time. and the zipties arjay is using is on underpanel stuff, not on the engine undertray.
Reply
0
0
01-31-2012, 11:35 AM
#45
Elite Member
iTrader: (2)
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,682
Total Cats: 130
What would be easier than zipties for removal? I really want to do cardboard undertray for my motor but yes I do not want to cut 1000 zip ties each time I drain the oil.
Reply
0
0
01-31-2012, 01:33 PM
#47
1) pick epoxy off shelf.
2) put epoxy in cart.
3) walk to cash register....
...
...
11732) put mixed epoxy on bolt.
11733) put bolt into hole.
11734) tighten nut onto bolt.
Reply
0
0
01-31-2012, 05:05 PM
#48
Junior Member
Join Date: Aug 2009
Posts: 186
Total Cats: 2
no critique of my stuff yet? 
by the way, bolts/nuts do have drag consequences. a normal 6-sided bolt vs a hex head bolt vs button head screws, etc. 
id like to see your pictures though, could come in handy for me to learn. i barely got my own rivet gun last wknd (thanks to 2ndchanceroadster)
i preferred the zip ties because it's still much easier than un-threading bolts under the car. it was also easier than trying to line up holes etc for hardware
I would think a front undertray (pre-front subframe) needs to be stonger than just a sheet or two or at least have a skeleton for it.
i cut a rectangle size of 2" x 4" or so for the oil pan bolt. it's like a flapping door, havne't changed the oil yet, but i don't see too much of an issue with it.
epoxy the damn bolt on there, or wait till this weekend when I unleash a goodness of photos including a muthafuckin gangster how-to on epoxying bolts.
1) pick epoxy off shelf.
2) put epoxy in cart.
3) walk to cash register....
...
...
11732) put mixed epoxy on bolt.
11733) put bolt into hole.
11734) tighten nut onto bolt.
1) pick epoxy off shelf.
2) put epoxy in cart.
3) walk to cash register....
...
...
11732) put mixed epoxy on bolt.
11733) put bolt into hole.
11734) tighten nut onto bolt.
id like to see your pictures though, could come in handy for me to learn. i barely got my own rivet gun last wknd (thanks to 2ndchanceroadster)i preferred the zip ties because it's still much easier than un-threading bolts under the car. it was also easier than trying to line up holes etc for hardware
I would think a front undertray (pre-front subframe) needs to be stonger than just a sheet or two or at least have a skeleton for it.
i cut a rectangle size of 2" x 4" or so for the oil pan bolt. it's like a flapping door, havne't changed the oil yet, but i don't see too much of an issue with it.
Reply
0
0
01-31-2012, 09:12 PM
#50
I am going to steer away from the zipties, because I personally don't give a ---- what people use to attach it. fugin put it on with bubble gum for all I care lol
Lets discuss this, anyone have theories on it? 4mmx2 is stiffer than the stock undertray. I know if there is a splitter added it needs to be stiff, but the undertray itself doesn't seem to do anything other than direct air in the engine bay.
Lets discuss this, anyone have theories on it? 4mmx2 is stiffer than the stock undertray. I know if there is a splitter added it needs to be stiff, but the undertray itself doesn't seem to do anything other than direct air in the engine bay.
Reply
0
0
02-01-2012, 03:37 AM
#51
The splitter part (that's sticking out in front) is the only thing that needs to be stiff and load bearing (be able to stand on it is a good measure if you want it to be able to transfer some pressure to the front). After the splitter part you only need strength to be able to hold the form. I don't see the ground effect suction being that high that a coroplast (Wellplast would be my local choice) with reasonable distance between zipties would get fluttering.
But testing with yarn and a gopro is knowing.
I know I can get Wellplast in sheets big enough to cover the whole car (but I might need to get bulk quantities to get them...). Make a stiff splitter and from just behind the bumper just one big undertray, with cutouts for the hot parts (and some cooling for gearbox and diff). It would be a nightmare to attach and remove though (try to find that hole somewhere in the middle)
But testing with yarn and a gopro is knowing.
I know I can get Wellplast in sheets big enough to cover the whole car (but I might need to get bulk quantities to get them...). Make a stiff splitter and from just behind the bumper just one big undertray, with cutouts for the hot parts (and some cooling for gearbox and diff). It would be a nightmare to attach and remove though (try to find that hole somewhere in the middle)
Reply
0
0
02-01-2012, 05:58 PM
#53
Junior Member
Join Date: Aug 2009
Posts: 186
Total Cats: 2
Here is the most recent status of my aero parts. I really like the balance of the car now so I am satisfied with where it's at for now, however there's so much more I CAN do. To think, aside from the entire front undertray/airdam, it is merely 2 foot wide worth of under paneling and it is far from complete.
Compare to the videos I posted at the top of this page. HUGE observable differences.
Reply
0
0
02-02-2012, 12:25 AM
#54
http://www.corrugatedplastics.net/4m...ticSheets.html
Looking into this stuff ^ Anyone ever try 2 sheets of 2mm doubled up but with the inner tubing facing different directions to add rigidity but keep it 4mm thick? I've used the 3m spray glue before and that s---- sticks like crazy. Put 2 sheets with the corregation facing opposite ways, glue together, and cut to fit. Might pick up some 48x48in sheets and use it to make radiator ducting I desperatly need to do and make a undertray for the motor. Something to replace my missing factory piece.
Looking into this stuff ^ Anyone ever try 2 sheets of 2mm doubled up but with the inner tubing facing different directions to add rigidity but keep it 4mm thick? I've used the 3m spray glue before and that s---- sticks like crazy. Put 2 sheets with the corregation facing opposite ways, glue together, and cut to fit. Might pick up some 48x48in sheets and use it to make radiator ducting I desperatly need to do and make a undertray for the motor. Something to replace my missing factory piece.
Reply
0
0
02-02-2012, 11:07 AM
#57
Elite Member
iTrader: (15)
Join Date: Dec 2007
Location: San Antonio, Texas
Posts: 4,847
Total Cats: 27
That would work, like plywood as mentioned.
Note that coroplast is a type of plastic (polypropylene) that does not take adhesives well as-is. But you can flame treat it with a propane torch (carefully) to vastly improve surface adhesion. The guys building model airplanes with coroplast seem to be the ones that figured this out.
I have flame treated myself, with coroplast and other polypropylenes, and it works. A standard hardware propane torch is all you need. Flame treat it until the glaze is gone and water no longer beads on the surface.
Note that coroplast is a type of plastic (polypropylene) that does not take adhesives well as-is. But you can flame treat it with a propane torch (carefully) to vastly improve surface adhesion. The guys building model airplanes with coroplast seem to be the ones that figured this out.
I have flame treated myself, with coroplast and other polypropylenes, and it works. A standard hardware propane torch is all you need. Flame treat it until the glaze is gone and water no longer beads on the surface.
Reply
0
0
02-02-2012, 11:18 AM
#58
That would work, like plywood as mentioned.
Note that coroplast is a type of plastic (polypropylene) that does not take adhesives well as-is. But you can flame treat it with a propane torch (carefully) to vastly improve surface adhesion. The guys building model airplanes with coroplast seem to be the ones that figured this out.
I have flame treated myself, with coroplast and other polypropylenes, and it works. A standard hardware propane torch is all you need. Flame treat it until the glaze is gone and water no longer beads on the surface.
Note that coroplast is a type of plastic (polypropylene) that does not take adhesives well as-is. But you can flame treat it with a propane torch (carefully) to vastly improve surface adhesion. The guys building model airplanes with coroplast seem to be the ones that figured this out.
I have flame treated myself, with coroplast and other polypropylenes, and it works. A standard hardware propane torch is all you need. Flame treat it until the glaze is gone and water no longer beads on the surface.
Reply
0
0
02-02-2012, 11:22 AM
#59
That would work, like plywood as mentioned.
Note that coroplast is a type of plastic (polypropylene) that does not take adhesives well as-is. But you can flame treat it with a propane torch (carefully) to vastly improve surface adhesion. The guys building model airplanes with coroplast seem to be the ones that figured this out.
I have flame treated myself, with coroplast and other polypropylenes, and it works. A standard hardware propane torch is all you need. Flame treat it until the glaze is gone and water no longer beads on the surface.
Note that coroplast is a type of plastic (polypropylene) that does not take adhesives well as-is. But you can flame treat it with a propane torch (carefully) to vastly improve surface adhesion. The guys building model airplanes with coroplast seem to be the ones that figured this out.
I have flame treated myself, with coroplast and other polypropylenes, and it works. A standard hardware propane torch is all you need. Flame treat it until the glaze is gone and water no longer beads on the surface.
Wait, huh? To what end? It heat forms the coroplast to shape? Or stiffens it? I have a hard time believing you can add a heat treat to thermoplastic...
Reply
0
0
02-02-2012, 01:16 PM
#60
Elite Member
iTrader: (15)
Join Date: Dec 2007
Location: San Antonio, Texas
Posts: 4,847
Total Cats: 27
You can most definitely heat treat thermoplastics, like for residual stress relief, but that is not what is going on here.
Reply
0
0
