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Easy fab: brackets for Vibrant 12800 intercooler into NA chassis

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Easy fab: brackets for Vibrant 12800 intercooler into NA chassis

Old 09-11-2017, 01:57 PM
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Default Easy fab: brackets for Vibrant 12800 intercooler into NA chassis

I have this in my build thread, but figured I'd post it here for ease of future search

Design Goals:
- stable mounting of Vibrant 12800 intercooler into NA chassis. Better quality than Ebay intercoolers, available at reasonable price from Amazon Prime:

- use fabrication materials, tools, and methods available to cheap hobbyist types like me (no welding, complex cutting or forming)

- Intercooler placement that maintains good air flow and cooling by keeping compatibility with factory undertray, air guide, bumper and radiator. There are many ways to mount intercoolers, but if you look at many of the build threads, they had to pitch the undertray or air guide because of interference with the intercooler. Many have had to go back later and add improvements for air flow.

- use existing mounting points in chassis. In this case, flange in front of radiator bottom mount with M6 nut already welded in, shown in the bottom right of the photo here (radiator has been removed). Note that if you have A/C, I don't think these mounting points are available.

- 6x18" 16Ga sheet steel, in stock at your local Home Depot:
Everbilt 6 in. x 18 in. 16-Gauge Plain Steel Sheet Metal-801467 - The Home Depot

- two 5/16" 4 1/2"hex bolts and nuts, to go with the mounting hardware that Vibrant provided. Also from Home Depot

- M6x1 25mm flange bolts. Good Grade 9 ones here:

- spray paint of your choice, so your brackets don't get rusty. I used Rustoleum engine paint (500 degrees).

Tools Required
- drill and drill bits
-angle grinder with cutoff, grinding wheels
- bench vice

Cut the outside dimensions with the angle grinder.

Mark the lines to bend the stiffening flanges; clamp in bench vice, and beat hell out of it with your hammer. This is work.

Mark the spots for the intercooler holes from the actual intercooler. Drill 5/16" holes. Mount the flanges on the intercooler with the bolts. Remove the radiator (trust me here). Hold the assembly up to the mounting points and mark drill locations on the midline of your brackets (Q tip and a dab of grease works well to mark the spot). Drill 15/64" holes and paint brackets.

Mount brackets finger-tight to mounting points.

If you wish, drill the intercooler end tank for IAT sensor and wastegate reference. I used a 3/8" thread to 1/4" barb for the wastegate reference, so I could use the same drill/tap.

Mount intercooler to brackets, tighten all mounting bolts.

Intercooler is clear of bottom undertray and bumper/air guide assembly.

This also seems to locate the intercooler pretty well for routing the piping. The undertray and part of the air guide will need to be trimmed.

Last edited by Schroedinger; 09-11-2017 at 02:28 PM.
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Old 09-11-2017, 02:05 PM
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Clever solution for those who ditch AC. Do you notice any oscillation fore and aft or pitch oscillation since the condenser mount isn't as reinforced. Intercooler just has more mass than the condenser and extends further inducing a moment on just the lower mount. Probably more than fine, especially with piping attached. Just curious if it'll bob enough to fatigue under resonance/vibration.
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Old 09-11-2017, 02:27 PM
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I'm still routing the piping and installing the turbo, so I haven't driven it to know if there will be any oscillation/resonance. What I do know is that the brackets are damn stiff with the bent edges, and the mounting points are also very stiff. When mounted, the IC is very secure. I figure the intercooler pipes will also add mass/damping to the system, so I'd be pretty surprised if I have any oscillation/vibration issues. In the worst case, if the mounting points break off due to fatigue, they are bolt in/out and replaceable from a junkyard car.

M6 is not very big, and there are only two bolts holding this thing up, so I felt compelled to go with Grade 9 hardware from McMaster rather than Home Depot stuff. We'll see if it lasts. Because it's bolted up tight to the mounting tab, the moment arm is pretty short.

Great point about A/C. I don't have it, so I never think about people who do!
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Old 09-11-2017, 02:35 PM
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I have the same intercooler and mounted mine in the same location. I welded my brackets to the intercooler. It fits extremely well in that location.
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Old 09-11-2017, 06:23 PM
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How NOT to tap very thin metal:

Tapping thin metal is risky at best.
Using locking pliers to screw the tap in instead is the easiest way to screw up the 2 threads you'll actually tap, use the proper tool.
Please don't do this again.

- other than that, love your work!
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Old 09-11-2017, 06:34 PM
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^yeah, you caught me. Sad part is that I've worked in a machine shop, I know better. My tap handle isn't big enough for that honkin' square end, and I was too lazy to get another one. Fortunately I've tapped a lot of holes, and it's nothing that a steady hand can't overcome.

Vice grips. The wrong tool for every job.
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Old 09-11-2017, 06:37 PM
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being a Miata owner, of course you tapped a lot of holes
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Old 09-11-2017, 08:44 PM
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^ LOL'd. Well played sir.
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Old 09-11-2017, 09:31 PM
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Great work man, Good job. Super simple and gets the job done, a great DIY lesson.

Taps that big suck, you need like a 4 foot handle. F it, I just hold a steady center and crank away at it with an adjustable wrench. The beauty of NPT threads.
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