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Old 01-31-2012, 12:54 AM   #41
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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.
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Old 01-31-2012, 01:40 AM   #42
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nothings wrong with zipties for your application

I am using 2mm thick aluminium.
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Old 01-31-2012, 02:20 AM   #43
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Quote:
Originally Posted by Track View Post
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.
Zip tie the damn thing and be done with it. If you rip the zip ties you got bigger issues.
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Old 01-31-2012, 11:42 AM   #44
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Originally Posted by triple88a View Post
Zip tie the damn thing and be done with it. If you rip the zip ties you got bigger issues.
I didn't say there was anything wrong with zipties! Use them if you want, or don't if you don't!

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.
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Old 01-31-2012, 12:35 PM   #45
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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.
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Old 01-31-2012, 12:38 PM   #46
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Transparent aluminium.
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Old 01-31-2012, 02:33 PM   #47
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Originally Posted by Faeflora View Post
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.
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.
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Old 01-31-2012, 06:05 PM   #48
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no critique of my stuff yet?

Quote:
Originally Posted by Track View Post
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.
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.

Quote:
Originally Posted by Faeflora View Post
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.
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.
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Old 01-31-2012, 06:13 PM   #49
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Quote:
Originally Posted by greeenteeee View Post
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.
Well that is just unacceptable... zipties will cause unwanted drag.

"trollface.jpg"
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Old 01-31-2012, 10:12 PM   #50
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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

Quote:
Originally Posted by greeenteeee View Post
no critique of my stuff yet?

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.
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.
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Old 02-01-2012, 04:37 AM   #51
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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)
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Old 02-01-2012, 06:29 AM   #52
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Quote:
Originally Posted by hustler View Post
Transparent aluminium.
I think Scotty remembers the formula for that.
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Old 02-01-2012, 06:58 PM   #53
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Quote:
Originally Posted by NiklasFalk View Post
. 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)
Do you happen to know what surface temps for the diff and tranny case that would be within tolerance? I last recorded 170 deg on the diff case from daily driving, never recorded before the under panels. I know the cylinder head can easily get over 200 degrees when it is running at operating temp.

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.
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Old 02-02-2012, 01:25 AM   #54
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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.
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Old 02-02-2012, 09:56 AM   #55
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do it, it sounds fine. the whole reason I got 4mm was exactly for that reason. I could double or triple up and cross the patterns for rigidity, but still keep it within a reasonable thickness.
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Old 02-02-2012, 11:02 AM   #56
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That is how plywood is made. They criss-cross the layers with the wood grain 90 degrees each time to make it stronger.
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Old 02-02-2012, 12:07 PM   #57
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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.
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Old 02-02-2012, 12:18 PM   #58
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Quote:
Originally Posted by ZX-Tex View Post
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.
greatly appreciate this, I did have to gob the ---- out of the epoxy which had me worried.
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Old 02-02-2012, 12:22 PM   #59
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Quote:
Originally Posted by ZX-Tex View Post
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.

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...
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Old 02-02-2012, 02:16 PM   #60
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Quote:
Originally Posted by vehicular View Post
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...
The flame treatment changes the surface chemistry of the plastic allowing the adhesives to stick. You only need to flame treat the surface with a very quick flame application since too much heat will deform or damage the underlying material. it takes a little practice but it is not that difficult.

You can most definitely heat treat thermoplastics, like for residual stress relief, but that is not what is going on here.
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