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Old 09-28-2006, 11:55 PM   #1
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Talking Yet another DIY Intercooler

I’ve gotten a couple of PMs from people with regard to my recent DIY intercooler system, with particular regard to cost and vendors. So I thought I’d do a full writeup on it so everyone can see.

Unless otherwise noted, all pieces were purchased off fleabay, and the prices shown include shipping, since that’s a big percentage of most of these type of sales.

First came the intercooler. $101 from a seller called autosquare. Avoid this guy like the plague. It was advertised as a bar & plate with 2.5” ends, but turned out to be a tube and fin with 70mm (2.75”) ends. I didn’t want to risk trying to get a refund from this scam artist, so I just cut the ends down and lived with it. Here’s a link to the auction so you can see what not to buy. http://tinyurl.com/oqy4o

To mount it, I fabricated a bracket that mounts to where the A/C condenser used to be. The vertical pieces are 3/4” x 3/16” flat steel, the horizontal pieces are 2” x 2” x 1/8” steel L-channel.

Next the aluminum pipe. This came from veccohighperformance, and totaled about $130. Three pieces of 2.5” 90°, one piece of 2.25” 90°, one piece of 2” 45° and three pieces of 2” 90°. I also bought the two silicone 90° elbows from him, total of $54 for those.

I bought two silicone reducers from seller622, a 2” to 2.25” and a 2.25” to 2.5” These totaled $40, and came with some surprizingly high-quality T-bolt clamps.

For the rest of the silicone couplers, rather than buy individual pieces I just ordered foot-long pieces of 2” and 2.5” from verociousmotorsports, totaling $36. The clamps I bought from a local speed shop (VW Paradise in San Marcos, CA) and they were about $30 in total. This stuff turned out to be very hard to cut. Unless you own a bandsaw, just buy the pre-cut pieces. If you order from seller622, he'll include free clamps.

I have an FM BOV which I wanted to mount remotely due to size and interference concerns. It has 1.375” OD fittings, which are tough to match. I wound up using couplers for 1.25” copper plumbing pipe from Home Depot, which have a 1.5” OD. I brazed a straight coupler to the side of the pipe which feeds the I.M., and used a pair of 45° fittings to make the turns. It’s all held together with a total of 12” of 1.5” silicone, purchased locally from VW Paradise as well. Figure about $50 for all that stuff. (copper has gotten expensive.) To do the brazing, I ordered a few sticks of muggy-weld, which is a low temperature alloy rod that will join most non-ferrous metals. It works, but it's very different from normal brazing. After this stuff melts, it's got the consistancy of water.

And that’s about it. All told, a total of nearly $500 for everything. The moral of the story? Unless you just absolutely have to be able to tell your friends with a straight face that you built the whole thing yourself, don’t waste your time. Just buy Stripes’ kit.

Pictures to follow…

Last edited by Joe Perez; 09-29-2006 at 12:10 AM.
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Old 09-28-2006, 11:58 PM   #2
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Here's the bracket being fabricated. I cut the pieces roughly to length first, then clamped them in place on the car and tack-welded. I then moved to the bench for finish cutting and welding.
Attached Images
File Type: jpg bracket1.jpg (56.3 KB, 555 views)
File Type: jpg bracket2.jpg (59.4 KB, 439 views)
File Type: jpg bracket3.jpg (38.8 KB, 462 views)
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Old 09-28-2006, 11:59 PM   #3
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The intercooler mounted in its new home.
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File Type: jpg IC1.jpg (60.1 KB, 506 views)
File Type: jpg IC2.jpg (148.5 KB, 652 views)
File Type: jpg IC3.jpg (84.5 KB, 804 views)
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Old 09-29-2006, 12:00 AM   #4
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and I thought my one bent up aluminum bracket was over the top
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Old 09-29-2006, 12:00 AM   #5
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Plumbing from the turbo outlet to the I/C inlet. Where the pipe passes between the P/S pump and the sway bar, I fabricated a little bracket which mounts to the lower radiator fan bolts and holds the pipe steady.
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File Type: jpg pipe_dr_1.jpg (109.7 KB, 869 views)
File Type: jpg pipe_dr_2.jpg (83.9 KB, 730 views)
File Type: jpg pipe_dr_3.jpg (84.1 KB, 659 views)

Last edited by Joe Perez; 09-29-2006 at 12:36 AM.
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Old 09-29-2006, 12:01 AM   #6
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And finally, the I/C out to the throttle body.
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File Type: jpg pipe_pax_1.jpg (85.4 KB, 583 views)
File Type: jpg pipe_pax_2.jpg (101.8 KB, 611 views)
File Type: jpg pipe_pax_3.jpg (100.3 KB, 653 views)

Last edited by Joe Perez; 09-29-2006 at 12:35 AM.
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Old 09-29-2006, 12:42 AM   #7
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Quote:
Originally Posted by braineack View Post
and I thought my one bent up aluminum bracket was over the top
Hehehe. Thanks.

I've managed so far to do this whole project in the one car garage of my apartment, which is in sort of a snooty upper-class neighborhood. Between the air compressor, the chop saw, the MIG welder, the drill press, the die grinder, the angle grinder, the band saw, the profanity, the constant engine revving, and seeing my hairy legs sticking out from under the car into the late hours of the night, it's a wonder the neighbors haven't had me tarred and feathered.
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Old 09-29-2006, 01:15 AM   #8
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your car is freaking amazing so clean so DIY so good looking under the hood i wish i had your mad skillz
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Old 10-08-2006, 02:02 PM   #9
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Thanks, Lunatic. Honestly, the only reason I do this stuff is to stay busy. I'm afraid of what will happen when this project is finished, I'll probably have to buy another vehicle to modify.

And now, a follow-up after one full week of driving.

First, my fears of the tube-type ebay intercooler seem to have been allayed. I have not yet touched the wastegate or added the MBC in, because I wanted to see what kind of pressure drop I was going to get. Before the I/C, I was usually seeing about 5.5 PSI according to my cheap mechanical boost gauge. Afterwards, I'm seeing around 5 to 5.25 PSI. Assuming this relationship remains linear, I expect less than 1 PSI of loss once I get up to 12 PSI. (actually, it may not even be that much, since going from 6 PSI to 12 PSI isn't a doubling of absolute airflow- more like 25%)

I haven't yet attached the thermocouples, but it seems to be cooling adequately. I've added back about 3 degrees of base advance back in, and still no pinging. (previously, I'd taken 3 degrees out, due to moderate pinging going uphill on boost).

Now, the bad news. That pipe which goes up and into the intake manifold has two fittings on it- BOV and idle air bypass. I thought I could get away with using Muggy-Weld (a low temp aluminum brazing alloy) to join copper fittings to the aluminum elbow. This has proved false. On the second day out, the fitting to the idle air hose popped off, so I re-brazed that, and then the very next day the big BOV fitting popped off. Needless to say, the engine didn't run well with a 1.25" hole in the plumbing. I had a rudimentary MAP-AFM substitution map for the EMU on the tablet PC as an emergency measure (I've been working towards AFM removal), and it worked, but the fuel pump kept shutting off as there was no airflow through the AFM at idle, and of course I wasn't carrying a paperclip at the time to jumper it on.

What's surprising is that in both cases, the brazing alloy stayed firmly attached to the copper, but pulled cleanly away from the aluminum. I've attached a close-up of the edge of the 1.25" hole where the BOV fitting was- you can see that the brazing allow just plain came unstuck from the pipe, leaving very little behind. I'd followed Muggy's directions concerning surface prep, heat and flux to a tee, but I guess there's just something about these pipes.

So anyway, I had to make a whole new piece out of steel, which has the advantage of being easily mig-welded. Bought a piece of mandrel-belt uncoated steel exhaust pipe from Summit Racing, 2.5" dia, 90 degree, 4" radius. Also a 3/4" heater hose nipple (for the idle hose) and a piece of 1.5" exhaust pipe for the BOV fitting. (I really want to know what kind of car uses 1.5" exhaust pipe...) I sprayed the finished product with plasti-kote aluminized/ceramic hi-temp exhaust paint, and it looks ok, but it's not nearly as shiny and cool as the aluminum was...

And, with the additional cost of the exhaust pipes, the fitting, and overnight shipping from Summit, I have now spent more on this debacle than Stripes is selling his kit for.
Attached Images
File Type: jpg Weld_1.jpg (74.0 KB, 389 views)
File Type: jpg NewPipe.jpg (23.6 KB, 464 views)
File Type: jpg MigWelds.jpg (67.6 KB, 473 views)
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Old 10-08-2006, 03:48 PM   #10
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very nice.

I really wish all you guys were around 4~5 years ago when i started my greddy project on my old car.
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Old 10-08-2006, 04:36 PM   #11
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Bracket????? I see a subframe!!!!!
I love it.
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Old 10-08-2006, 05:59 PM   #12
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Joe, thanks for sharing the angles you used!
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Old 10-08-2006, 07:41 PM   #13
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JB weld works really well for attaching the idle valve hose.
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Old 10-08-2006, 07:57 PM   #14
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Very, very nice writeup, and the pics/explanation of the bends used is awesome!!!
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Old 10-08-2006, 08:30 PM   #15
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so you would just say go buy stripes kit?
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Old 10-08-2006, 11:28 PM   #16
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Buying a cheaper grade steel would save a considerable sum of money I would imagine.
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Old 10-09-2006, 01:33 AM   #17
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BTW: Verocious is where I got all my exhaust tubing, great prices, fast shipping.
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Old 10-09-2006, 01:33 PM   #18
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Thanks again, all.

The aluminum pipes weren't exactly cheap, but at about $130 for eight bends, I don't think they were outrageously expensive. That only comes to about $16 each, shipping included. If there was a shop in town where I could have custom bends done on steel I probably could have saved a few dollars (and eliminated a few couplers) but since I was stuck with using pre-formed standard pieces there's probably not a whole lot that would have been saved by going steel from what I've seen.

I considered JB-Weld, briefly. Two things turned me off of that. One, of course, is looks. I have a general aversion to using duct-tape or epoxy on my car. The only area of the car where I've applied JB-weld is on the threaded NPT to -8AN fitting on the oil pan, and even there I used so little that you can barely see it even if you know it's there.

The other concern was safety. I've used JB weld in other applications before, and it seems to become slightly brittle with age, heat, and petrochemicals. My fear was that should the fitting break (as mine did) that chunks of JB weld might tend to be drawn into the manifold, through the engine, and then exhausted out through the turbine wheel, possibly causing harm in the process. I realize the turbine is made of meatier stuff then the compressor, but I didn't want to take any chances.

So far the steel up-pipe has worked well. As you can see, I'm not the world's most talented welder, and all I have to work with is a cheap flux-core rig, but it does seem to be holding. I flogged it pretty hard on the way to work this morning and nothing fell off, which is more than I've been able to say thus far. Hopefully my luck will hold on the way home this evening. And tomorrow. And the next day... If everything holds together, I'm planning to install the MBC this weekend.

After welding the fittings onto the pipe, I sprayed it with a few layers of Dupli-Color 1606 high-heat ceramic-aluminum paint, and baked it in the oven for a couple hours. The result is not as bad as I'd feared. It doesn't match the other pipes, but it does have a decent-looking finish to it. I'd previously used this paint on the lower half of my Tony DP (the upper half I had professionally coated) and that piece has held up well.

Someone asked in PM how I cut the 1.5" piece to fit the 2.5" pipe precisely. Very simple, actually. I built a little wooden fixture to hold the 1.5" pipe steady (just a board with some 2x4s nailed to it) then I mounted that on the drill press and used a 2.5" hole saw to cut the 1.5" pipe in half right down the middle. I think HF sells a jig for doing this, but my way was cheaper.

Firedog- I looked at Verocious for tubing, and while he's got some great prices on the straight stuff, his bends seem really expensive, and also have very short legs. The stuff I got from Vecco had long enough legs on it that I didn't have to use any straight pieces between them, it's all one bend directly to the next. Cut down on the number of couplers that would have been required in the longer sections, particularly the vertical sections.
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Old 10-09-2006, 01:39 PM   #19
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I am doing an intercooler on my car right now, just taking a little break. As long as I can use all the pipes that I have and dont have to buy any extra then I should be at around 300 for my kit total. 130 for the IC shipped, and 170 for the pipes and sillicon. BTW....I ordered my IC from CXRacing, a very very good ebay company unlike autosquare. I got a 28x8x3.5in bar and plate IC for that cheap, and its REALLY nice actually.
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Old 10-09-2006, 06:01 PM   #20
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Joe, please link everyone you bought from! Thanks!
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