Vacuum line size for manual boost ontroller question

[talontsiboy24]

What size are the vacuum lines usually on a mbc 1/8" or 5/32"? im using 1/8" and i think its too tight and very hard to push it over on the mbc without force so should i go higer like 5/32" i just want it to be snug also? if u go really snug wouldnt it be harder for the pressure to run threw it?

 

[gofer]

5/32" vacuum hose is the typical size used by most MBC's I've seen, 1/8" vacuum line is the size that comes off the back of the bov going to the IM. You want a snug fit but ALWAYS zip-tie the vacuum line onto the fitting no matter how tight it may be, that way it keeps it from blowing off.

 

[talontsiboy24]

yea i think 1/8" is too tight i had to force it onto the mbc ill swap it with a 5/32".

 

[9!'clipseDOHC]

5/32" vacuum hose is the typical size used by most MBC's I've seen, 1/8" vacuum line is the size that comes off the back of the bov going to the IM. You want a snug fit but ALWAYS zip-tie the vacuum line onto the fitting no matter how tight it may be, that way it keeps it from blowing off.

4mm (just over 1/8") fits perfect for the MBC, FPR, CC, etc.

Also on a 1g at least, the BOV line is larger then the MBC lines, it's 6mm (just under 1/4").

 

[gofer]

4mm (just over 1/8") fits perfect for the MBC, FPR, CC, etc.

Also on a 1g at least, the BOV line is larger then the MBC lines, it's 6mm (just under 1/4").

I think you got your conversions mixed up...

To convert to (mm): inch size x 25.4 = size in (mm)

1/8" vacuum line = 3.17mm
5/32" vacuum line = 3.96mm
1/4" vacuum line = 6.35mm

 

[talontsiboy24]

I think you got your conversions mixed up...

To convert to (mm): inch size x 25.4 = size in (mm)

1/8" vacuum line = 3.17mm
5/32" vacuum line = 3.96mm
1/4" vacuum line = 6.35mm

yea thats why i said i needed 5/32" 1/8" was so hard to get on the mbc i had to use mad force and i think its causing the pressure not to flow fast enough.

 

[9!'clipseDOHC]

I think you got your conversions mixed up...

To convert to (mm): inch size x 25.4 = size in (mm)

1/8" vacuum line = 3.17mm
5/32" vacuum line = 3.96mm
1/4" vacuum line = 6.35mm

I looked at the first website that popped up and quoted them, I didn't do my own conversions (obviously I should have). You are correct, 5/32" is closer to (and just under) 4mm. 1/8 is closer to 3mm. However, the BOV line is still 6 mm which I correctly quoted as being just under 1/4", not 1/8" as you mentioned (unless the 2g's have a very small vacuum line).

 

[JusMX141]

Many Garrett and Holset actuators as well as most external wastegates use 1/4" nipples, so you may need a reducer to properly hook a manual boost controller to such a wastegate. Your other option is to break out the WD40 or Silicone Spray and lube the end of the 5/32" hose, get a running start, and shove it on there.

 

[talontsiboy24]

Many Garrett and Holset actuators as well as most external wastegates use 1/4" nipples, so you may need a reducer to properly hook a manual boost controller to such a wastegate. Your other option is to break out the WD40 or Silicone Spray and lube the end of the 5/32" hose, get a running start, and shove it on there.

no i just need to swap it to a 5/32" not all that u just said my mbc should have a 5/32" vacuum line on it i just got the wrong one. By the way i like using fuel lines instead of vacuum cause there stronger and dont move alot or bend.

 

[gofer]

I don't even bother pulling out the WD40, I just spit on it to lube it up and then shove the vacuum line on there and make it fit. If it wants to be a bi*** about it, I go around the back of the car and smack it in the ass and then go back under the hood and push harder... You've got to remind your DSM sometimes who its owner is!

I was using a HKS SSQV that used a 1/8" vacuum line.

 

[talontsiboy24]

I looked at the first website that popped up and quoted them, I didn't do my own conversions (obviously I should have). You are correct, 5/32" is closer to (and just under) 4mm. 1/8 is closer to 3mm. However, the BOV line is still 6 mm which I correctly quoted as being just under 1/4", not 1/8" as you mentioned (unless the 2g's have a very small vacuum line).

What about the vacuum line for the 1g bov 3/16"? the one that goes from the bov to the intake manifold?

 

[9!'clipseDOHC]

What about the vacuum line for the 1g bov 3/16"? the one that goes from the bov to the intake manifold?

You quoted the answer in your question.

I looked at the first website that popped up and quoted them, I didn't do my own conversions (obviously I should have). You are correct, 5/32" is closer to (and just under) 4mm. 1/8 is closer to 3mm. However, the BOV line is still 6 mm which I correctly quoted as being just under 1/4", not 1/8" as you mentioned (unless the 2g's have a very small vacuum line).

I used 6mm and it worked perfectly. The closest equivalent in inches would be 1/4".

 

[red_devil]

Didn't want to start a new thread..But is having a 1/8" line connecting your boost source to your WG to small? I'm getting boost spike up to 25psi on my Tial MVS with a 18psi spring. This is off the o2 housing which was ported. No vacuum leaks or pre turbo leaks.