Jump to content
HybridZ
Sign in to follow this  
seattlejester

Boost Reference Lines, What do you use?

Recommended Posts

Howdy folks, 

 

Just wondering what people are using for their turbo charged cars with regards to the boost reference lines. I have to plump hoses from my intake to my brake booster/fuel pressure regulator/blow off valve/ and to my ecu, and I was hoping to see what people have used or are using. I have 3 ~1/4 inch ports and 1 ~3/8 port.  

 

Went to the parts store and asked, and they pointed me towards fuel injection hoses for pressurized applications that can withstand oil or gas. 

 

When I had my car looked at in the past while I still had carbs, the mechanic replaced my brake booster hose with a special stiffer hose. Seems like really stiff rubber, but not silicone. No external markings. Is this a special hose, or did I get hosed in that transaction (sorry for that pun). 

 

Just wondering what people are using and if they have a preference and the reason for that preference would be greatly useful.

 

Thanks folks!

Share this post


Link to post
Share on other sites

I tend to use the standard black soft silicone/rubber flexible tubing you find on just about every car in the junkyard, went there one day and stripped oodles off for future use. I have used clear and braided PVC, it can hold the boost but will collapse under vacuum. I've even got some radiator to overflow bottle tubing on my car, with no failures at 14 psi. 

 

​My brake booster is indeed a fuel house, just because its handy and easy to get in that size. 

 

1/4 inch does seem pretty big, if its like a 1/4 inch barb fitting, no reason fuel line wouldn't work, but its expensive (especially EFI). I bet you could easily get away with basic carb fuel line, or go online and order up some silicone line off ebay.  

 

is the manifold tapped for 1/4? If it is just use a 1/8th barb fittings and 1/8th silicone rubber lines. 

 

042805445488lg.jpg

Share this post


Link to post
Share on other sites

Thanks for the response. Glad to hear that fuel injection line can work in a pinch. I have a spool or two so I may give that a shot. If it turns out not to work very well I can always switch to silicone line.

 

 I want to say it looks like the manifold is tapped for 1/8 npt fittings. The manifold came with the fittings so I'm planning on using those, unless as you suggest they may be too big and the response is compromised. 

Share this post


Link to post
Share on other sites

Keep in mind if your FPR line leaks you may blow your engine. If your waste gate line leaks you will blow your engine apart in short order. If your line to the ECU on a speed density setup leaks you may blow your engine. See a pattern? :-) I usually use braided fuel line or silicone because its cheap insurance. Clamp or double wire tie all connections. You should not be able to pull the hose off the barb without physically leaning away from it while pulling. Make sure your booster has a check valve in the line.

Share this post


Link to post
Share on other sites

I see lots of nice builds using push-lock fittings with polyethylene polyurethane lines. Here's an example:

 

http://www.b20vtec.com/forums/turbo-supercharger-nitrous-systems/700180-push-lock-vacuume-boost-kits-all-turbo-cars-no-more-boost-leaks.html

 

One of these days I'll switch.

 

In the meantime I'm using regular 6-10mm silicone hose:

 

http://www.siliconeintakes.com/index.php?cPath=18&osCsid=ab86abc7329b2918e0400f751885243b

Edited by BLOZ UP

Share this post


Link to post
Share on other sites

WizardBlack: Yes that is true, are you saying the fuel lines won't work? I mean factory lines from a lot of standard cars used rubber right? 

 

BLOZ UP: I actually have quite a bit of those push lock fittings from my pneumatic days. I know they are rated for extreme cold and high pressure, but I never looked on the hot side of things. Maybe worth looking around and investigating.

 

And thank you for the source, I think I will go buy a bit. From my math, 1/4 should be roughly 6mm, and 3/8 should be the 10mm?

Share this post


Link to post
Share on other sites

Anything over 30cm (12") really should be hardline. Long rubber hoses can deflect or collapse. You will note ECCS cars had relatively short rubber runs to Hardlines.

 

Fuel injection hose works fine, I used standard fuel hose to since 1985...I should think about replacing it, it's rated to about 21 psi, whereas fuel injection is rated higher.

 

Some of the cool VW CIS rubberised lines are rated at 100psi working pressure.

 

Silicone is all the rage, but it's. For dry systems, oil and fuel present need a special fluroelastomer lining in the silicone, it will degrade quickly exposed to rubber solvents like oil and fuel!

Share this post


Link to post
Share on other sites

Polyethelene lines will melt at underhood temps. The white-clear stuff you buy for pushlock fittings is the same stuff milk jugs are made from...

 

It starts to get very soft about 140F, and melts into goo at just over 215F.

Share this post


Link to post
Share on other sites

You can get easily misled if you just use the generic name for these materials.  PEX plumbing tubing is polyethylene based but has very different properties than milk jug polyethylene, for example.

 

http://en.wikipedia.org/wiki/Polyethylene

 

http://en.wikipedia.org/wiki/Cross-linked_polyethylene

 

"Polyurethanes" can have properties from jello-like to rock hard.  Nylons have a wide range of properties also.  And the multilayer hoses can have very different fuel resistance, inside versus outside.  Stick a piece of EFI hose in a cup of gasoline and the outside will get gooey and make your hands black if you touch it in just a short time.  The very thin inside layer has all of the fuel resistance.  That's why any sharp edges or nicks on injectors or hard lines should be smoothed before using.

 

Best to choose your specs. and make sure whatever you use meets them.  Any hose that doesn't come with specifications is probably not designed for extreme use.  Don't choose anything by its popular name.

Share this post


Link to post
Share on other sites

HDPE, high density polyethelene, melts between 225 and 240F...even UHMW doesn't make it much higher. That 300+ temp listed in the wiki is higher than I've ever seen any PE tubing listed, anywhere.

 

PEX, on the other hand, is a whole new animal. XLPE is a modified plastic, it's NOT the same material. The chemical structure is different, and it does NOT melt with heat...just gets more brittle.

 

For vacuum lines, I'm with Tony. I have 3/16" brake line tubing run for any vacuum line longer than 6" in the car, but I've yet to find any soft tubing that lasts more than one or two years.

Share this post


Link to post
Share on other sites

TonyD: Great, glad to know I didn't waste all that money on FI hose for the time being.

 

I do have some 3/16 brake hardline and 1/4 inch fuel hardline lying around. I may just couple the hard lines with rubber from the ports for the time being and look into running full hardline once the car is more permanently configured.

 

 

I just looked up the lines that I have and looks like they are Nylon 11 tubing to pushlock fittings. They are black with 1/8th npt pushlock fittings, Rated to 230F and 1500psi. The pressure part seems good, but the temps don't instill a lot of confidence. 

 

Xnke: Will definitely consider some hardline for a more permanent solution. You guys are making me want to go look at my ochem and material chem books again.

Share this post


Link to post
Share on other sites

Synapse engineering seems to sell kits for push lock/quick connect/boost connect. A little pricy, but I can't find anyone cheaper. Also, they have high temp 500 degree lines and low temp (140 degree).

 

http://synapseengineering.pinnaclecart.com/index.php?p=catalog&parent=5&pg=1

 

Found a few other place that sell these. They are called "push-to-connect" fittings.

Edited by BLOZ UP

Share this post


Link to post
Share on other sites

WizardBlack: Yes that is true, are you saying the fuel lines won't work? I mean factory lines from a lot of standard cars used rubber right? 

 

BLOZ UP: I actually have quite a bit of those push lock fittings from my pneumatic days. I know they are rated for extreme cold and high pressure, but I never looked on the hot side of things. Maybe worth looking around and investigating.

 

And thank you for the source, I think I will go buy a bit. From my math, 1/4 should be roughly 6mm, and 3/8 should be the 10mm?

Sorry to confuse. What I meant is EFI fuel lines are braided with nylon and very tough. If you tell a parts store monkey that you want fuel line they might give you the cheaper non-braided stuff for carbed cars, etc. that would not do. I use EFI fuel line from Goodyear all the time. They are harder to remove and reuse without losing the end, but they are easy to source and hold up well. Silicone is good for it as well but rather floppy. I like the temp rating on them but I tend to only order and install silicone for actual couplers anymore.

Share this post


Link to post
Share on other sites

Synapse engineering seems to sell kits for push lock/quick connect/boost connect. A little pricy, but I can't find anyone cheaper. Also, they have high temp 500 degree lines and low temp (140 degree).

 

http://synapseengineering.pinnaclecart.com/index.php?p=catalog&parent=5&pg=1

 

Found a few other place that sell these. They are called "push-to-connect" fittings.

I use those all the time at work. They are made for manufacturing, such as on pneumatically controlled robotics, etc. They work as well but are pricey. I don't see any major advantage with them, but I guess if you like the style, go for it.

You can probably get that stuff cheaper at McMaster Carr and Grainger, etc. the hose can be found at big box stores. Heck even the fitting can as well at times. Just stay away from the plastic fittings.

Edited by WizardBlack

Share this post


Link to post
Share on other sites

McMaster-Carr has plenty of sizes, they're still a bit pricy. Can't cost that much to make those damned things. In TX I used to frequent a Hydraulic Supply place that had all sorts of goodies for 1/10 the price of parts stores, online stores, etc. (Actually, the car parts stores bought them all from them, they told me.)

 

I'll probably end up doing McMaster if I can't find a cheaper place.

 

Edit: Ha, here's their (crappy) website: http://www.hydraulicsupply.com/home_a.html

Edited by BLOZ UP

Share this post


Link to post
Share on other sites

WizardBlack: Gotcha, I got fuel injection line for the interim, not carb line, I can see the nylong webbing, the gates line I bought supposedly has quite a few layers, they were charging 4$ a foot for it so hopefully it is decent. But I am leaning towards using it just as couplers and running hardline to the accessory. 

 

You can find the metal swivel 1/8 npt soft line fittings for a few dollars on pneumatic oriented sights, paintball uses them quite frequently, as do hydraulic supply stores for pneumatics as mentioned. Better spec lines can be ordered through your local hydraulics/pneumatics dealer. My local branch has been pretty helpful in trying to figure out some pretty unique compression fittings and strange pitch threads for work.

Share this post


Link to post
Share on other sites

If you're moving your reference source for the waste gate from the stock location to the intake manifold, remember that your actuator diaphragm will now be seeing vacuum as well as pressure.

 

I get around that by using a "grainier valve" for boost control which also acts as a check valve so the vacuum spike of decel at high rpms doesn't suck the life out of the actuator.

Share this post


Link to post
Share on other sites

Just ran the hardline for my boost gauge in my Suzuki Van. Adel clamps securing a 6mm tube to the support stanchion over the plenum, and a 6" length of FI Hose (suitably clamped) from hardline to plenum fitting. Runs under the floorboard, up through a grommet in the floorboard into the dash, and another 6" flexible into the gauge.

 

Should allow for engine movement no problem.

 

Realized the boost actuator on the F6A engine runs from the plenum to the turbo actuator via a hardline with 75mm flexibles on each end! Not the normal "from the scroll" typical of most early 90's turbo setups.

 

Then again, it is routed through a boost control solenoid to prevent overboost. Pretty sophisticated for a 657cc three cylinder! Hahaha

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×