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no more vacuum leaks for me...

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Old 10-06-09, 03:16 AM
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no more vacuum leaks for me...

I C&P this from the 2nd gen section because this applies to the FD UIM.

The car is a FC with a FD UIM. UIM is tapped with 3/8 npt which will run upto the vacuum manifold on 1/2" line. All other connectors will be the instant fittings (these are a hell of a lot cheaper than braided stainless line and -an connectors) with a plastic hose. I found a good deal on them from: http://www.stc9.com/Stainless_Steel_Fitting.htm
The manifold was machined out of 1" thick 6061 aluminum. The support bracket is made of 1/4" 6061. The manifold ended up being slightly smaller than a pack of cards. I made 7 1/8" npt ports and 3 3/8" npt ports on the manifold. I am planning on running 1/4" hose to everything that needs vacuum signal and 1/2" to the brake booster. If i can not figure out some way to thread the nipple on my GM map sensor i will run a hose barb in one of the 1/8 npt ports with a hose clamp.

pictures:







The black square is covering the ugliest plug weld known to man (i am to embarrassed to display that to the public). That is also where the uim is tapped.
Old 10-06-09, 08:42 PM
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Don't be so hard on yourself. Welding on mazda manifolds is hard, the base metal is junk...Nice setup, it will come in handy when you get above 20psi too...
Old 10-06-09, 08:56 PM
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Are these fittings the correct size?

Tial wastegate is M10x1.0
Greddy BOV is 1/8"npt

2x M10x1 -> 1/8npt adapter $8.95 each from summit
4x 1/8"npt -> instant hose fitting 90 degree $3.04/per
6x 1/8"npt -> instant hose fitting straight $1.39/per
1x 1/4"hose barb -> 1/8" npt fitting $3.99 from summit
2x 3/16" hose barb ->1/8" npt $3.99 from summit
2x 3/8npt->1/2" hose 90 degree $5.02/per
1x 1/2" elbow union $4.49/per
1x 3/8npt - 3/8" hose barb $3.39 from summit
40' of part #5156K87 1/4" polyethylene tube from mcmaster $0.22/ft
max operating temp 175F
1' of 5156K89 - 1/2" polyethelyne tube from mcmaster $0.76/ft

Total for fittings=$77.85

$77.85 isnt bad for something that isnt going to leak.

I will probably order a few extra straight and 90 degree fittings just in case i cant get something to fit how i want it.

I should get around to ordering the fittings and tubing sometime this week, ill post an update once i get it all plumbed.
Old 10-08-09, 12:02 AM
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77.85 how much for the cnc plate? and y when you can drill and tap the uim.
Old 10-08-09, 06:32 AM
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What was causing your vacuum leak problems? I guess...what led you to do all this?
Old 10-08-09, 05:08 PM
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I did not actually have a vacuum leak but with this setup i will never have to deal with any vacuum leaks on the hoses or fittings (i suppose my thread title was rather misleading).

My motivation for all this was that I saw a thread by Howard Coleman about checking your vacuum lines to your map and fuel pressure regulator. I went out to the garage and my map line had started working its way loose...only about half the nipple had the hose still on it. If that hose had come loose.... there is a chance of kablamo. $80 now and a couple hours of my time is better than possibly killing my motor in the future. Since i was planning on converting to the FD mani i decided that i would modify it so that i would never have to worry about blowing off hoses again.

I made the bracket and plate myself $5 in metal (scrap that i had) + a couple hours of my time. I did it on a manual bridgeport, no cnc. I did create a cad file for this but i my CNC guy did not want to make a single part. I doubt it would cost more than $40 to have the manifold cut if i had wanted to have several made.

I did not drill and tap b.c:
1. I wanted to make sure that everything was drawing its vacuum and map signals from the same place.
2. it did not leave me enough room to run all of the instant fittings that i wanted to run without having and splices in the vacuum lines.
3. I have to much time on my hands. I figured if i was already polishing/porting/welding up and cutting out double throttle/smoothing the uim i might as well plumb a vacuum manifold while i was at it.
Old 10-08-09, 11:07 PM
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most of the cars I see with vacuum manifolds are Hondas because they don't have many vacuum ports on the factory plumbing.

i found that a little bit of Krazy Glue solves any of the smaller vacuum lines blowing off over 20psi, and the larger ones can use hose clamps. it's a minor inconvenience for removing them but not a big deal

I wanted to make sure that everything was drawing its vacuum and map signals from the same place.
two different pressure sensors (one for an EBC, one for your ECU) are never going to agree completely unless they can both be scaled/calibrated in the exact same way. You can hook an AVC-R pressure sensor to the same place as your MAP sensor and it's not going to read the same because the AVC-R sensor calibration cannot be adjusted. Even having the FPR signal on a different port than the MAP signal is not going to have a noticeable affect on the tune as long as the line doesn't blow off.

It sounds like you did a nice custom project and you had the resources to do it easily but I don't see it being beneficial for most people. If you use appropriately sized hoses the lines aren't going to come off until you get over 16-17psi. They're not going to melt either unless you are using cheap rubber hoses, or you let the lines touch the exhaust. The only stainless steel air hose I have is for the side port of my external wastegate. One of the main problems people have is that they use autozone vacuum caps. Those tend to fail.
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