Vacuum lines popping off at 15psi. Which ones can I remove?

[tekdeus]

Yep, the previous owner removed the charcoal can. Does the BVSV open when it gets hot? So I would get a boost leak that I missed when testing cold?

Also, just wondering what the big vac line that goes near the power steering is for? Mine is an '87

 

[Rennat]

yeah i've seen too many collapsed vacuum lines now... especially the big diameter ones that are used on the BOV and things of that nature.

im going with a few rolls of good year emission/ vacuum lines next time around. and there black... so there more stealth than the "bling bling" red/blue/yellow ones...

 

[jdub]

Yep, the previous owner removed the charcoal can. Does the BVSV open when it gets hot? So I would get a boost leak that I missed when testing cold?

Also, just wondering what the big vac line that goes near the power steering is for? Mine is an '87

I see you're on a "clean-up the engine bay" crusade :3d_frown:

I very rarely see these turn out very well. Right now, with no charcoal canister, you've either eliminated the positive pressure on the tank (vented gas cap) or you're venting gas vapor some where in the forward area of the car. No EGR = NOT GOOD...I'm not even going to start on this again. No hot start idle up VSV = start problems in the summer, especially after a hard run.

IMO...you're begging for a problem, especially since you seem to only have a vague idea of what all this stuff does. BTW - it's all in the TSRM....I'm thinking it's time you figured this out for yourself. It seems I'm just helping you create a problem.

 

[tekdeus]

yeah i've seen too many collapsed vacuum lines now... especially the big diameter ones that are used on the BOV and things of that nature.

im going with a few rolls of good year emission/ vacuum lines next time around. and there black... so there more stealth than the "bling bling" red/blue/yellow ones...

I suppose the best silicone hoses are the ones that have really thick walls?

 

[Rennat]

look at the wall thickness for sure!

my little one are all ok, but like the ones for my power steering kinda crimp... so i need to replace them.

 

[tekdeus]

Jdub: The previous owner installed a JDM block (no EGR) and removed the charcoal can. I may look into a smaller 1JZ charcoal can, if it works the same way? I never had any hot start problems since I owned the car with the inoperable fuel pressure up VSV, so I won't miss it. Thanks again for the info you have supplied!

 

[Poodles]

Not a fan of silicone vacuum hoses at all myself... There aren't any advantages to them other than them being colored.

 

[jdub]

Jdub: The previous owner installed a JDM block (no EGR) and removed the charcoal can. I may look into a smaller 1JZ charcoal can, if it works the same way? I never had any hot start problems since I owned the car with the inoperable fuel pressure up VSV, so I won't miss it. Thanks again for the info you have supplied!

The fuel pump needs the pressure differential (~2 psi) the charcoal canister provides to prevent cavitation. The 1JZ canister works exactly the same and can be mounted under the rear wheel well under the plastic liner.

I highly suggest going with a standalone EMS if you're not going to run an EGR. Or, tune it rich for mid throttle.

 

[Rennat]

Not a fan of silicone vacuum hoses at all myself... There aren't any advantages to them other than them being colored.

sadly i fell to the scheme of the awesome colors... :3d_frown:

 

[tekdeus]

I just want black lines. What material is the best for holding vac and up to 30psi of boost reliably??

I highly suggest going with a standalone EMS if you're not going to run an EGR. Or, tune it rich for mid throttle.

I think my wideband reads around stoich at mid throttle, and was dyno tuned at Titan motorsports by the previous owner. Does the lack of the EGR make it lean at mid throttle? It's pretty easy to hit moderate boost up a hill at half throttle.

 

[IJ.]

Plain rubber is fine at 30psi.

 

[tekdeus]

Plain rubber is fine at 30psi.

As long as it's new? I burst an OEM line at 17psi, and it's not like mine are brittle or cracking.

 

[IJ.]

The stuff I use has been fine up to 30psi, it's just a bulk buy thing off a roll at my hose supplier so it may be thicker wall than the stock stuff.
(damn sight less expensive)

 

[jdub]

I think my wideband reads around stoich at mid throttle, and was dyno tuned at Titan motorsports by the previous owner. Does the lack of the EGR make it lean at mid throttle? It's pretty easy to hit moderate boost up a hill at half throttle.

The EGR functions above idle to ~4500 RPM. The ECU is tuned for it...timing and fuel. With no exhaust gas in the combustion chambers, temps go up and additional air takes it's place....you can easily go lean. Under load is where you can detonate (up hill), especially if you go into boost.

 

[rayall01]

I will upgrade to silicone hoses soon, but was I was wondering which vacuum lines I could eliminate, as they sometimes pop off under boost.

What are the VSV's under the intake manifold for? Part #'s 17650 and 25860?

Also, I was trying to see where hose 17344 goes, and it seems to loop back up to the hardline to the BOV. Is this true?

I can say that the small cable ties work fine on mine! :biglaugh: