Boost Gauge Vacuum Line. Which is best?

[revolution337]

So this may have been covered elsewhere on AZ, but I did search and I didn't really find any information. I was wondering which vacuum line is best to get a clean/non-interuptive signal for a boost gauge. Some installations say to use the FPR line, but others say that doing so can affect the fuel pressure. How about the DV line? Any suggestions? Thanks !

[SnowBum124]

i tapping into my DV line and it works like a charm. if that's any help

[Seerlah]

I used the line in front of the IM, which is basically the dv line.

[RTe]

So this may have been covered elsewhere on AZ, but I did search and I didn't really find any information. I was wondering which vacuum line is best to get a clean/non-interuptive signal for a boost gauge. Some installations say to use the FPR line, but others say that doing so can affect the fuel pressure. How about the DV line? Any suggestions? Thanks !

Check here. http://forums.vwvortex.com/zerothread?id=2365126
That's how I installed it on my car (by that DIY)

[SVB5]

I used the FPR line, works like a charm. I went with that one 'cause it's closer to the firewall.

[revolution337]

I used the FPR line, works like a charm. I went with that one 'cause it's closer to the firewall.

yeah, thats what i was thinking

[Polski]

i have a question regarding this....i tapped into the line that comes out of the turbo...the bottom one....and i have a boost/vaccum gauge and it dosent show the vaccum..could i be tapped in the wrong line?

[jpcallmotor]

The line to the fuel pressure regulator is the best, for one thing it is closest to the firewall which makes the install look much cleaner.

Polski, is your gauge capable of reading vaacum. In other words there are some gauges that only monitor boost. Upload some pics of the gauge/ the line you tapped.

[Polski]

Sorry took a little while, heres the gauge:



And this is were i tapped in:





Also this is were the line that i tapped in goes to in the turbo:

[Polski]

ttt

[jpcallmotor]

Looks like you tapped the line to the diverter valve. Try tapping the FPR hose, I have been using that line with no problems for over a year, I build boost just find and the reading on the gauge is bang on. You should have absolutely no problems if you go from that line, not to mention the FPR line is in a better location and access to the inside cabin is easy to achieve, oh and the setup just looks cleaner.

[walky_talky20]

No, it appears he tapped the line that goes from the compressor housing to the N75 (boost control solenoid).

That particular line sees boost only. It will never see vacuum, which is why your gauge is not showing it. The only place you will find vacuum is in the intake manifold, behind the throttle body. The line you tapped is in front of the throttle body. The 2 easy places to tap in, as suggested above, are the FPR line or the DV line. Good Luck.

[RTe]

Polsky
Tap it here:

[gotboost]

tap at the intake manifold, then you see how much boost the engine is getting

[djwimbo]

Some installations say to use the FPR line, but others say that doing so can affect the fuel pressure. How about the DV line? Any suggestions? Thanks !

Either or.

The FPR line never had any problems for myself or dozens of other owners.
Ideally, the closer you get to the manifold, the more accurate your numbers will be (in response time).

The FPR line was the easiest to get to, and the easiest for routing.

Polsky
Tap it here:

OR, do it on the back of the manifold, it does the exact same thing, but you have to buy a foot less vacuum line, and it looks cleaner.

[revolution337]

thanks for in info guys. im installing mine this weekend. how about power taps? is there an empty fuse that has switched power? (i.e comes on with DLR and headlights)?

[Fukenfast]

thanks for in info guys. im installing mine this weekend. how about power taps? is there an empty fuse that has switched power? (i.e comes on with DLR and headlights)?

I hooked up the power to terminal 75X, which turns the light on when the key is in the ignition. To get to this remove the 4 screws of the driver side knee bolster right below the steering column.

[revolution337]

I hooked up the power to terminal 75X, which turns the light on when the key is in the ignition. To get to this remove the 4 screws of the driver side knee bolster right below the steering column.

thanks but i was looking more for power source that turns on with the interior lights and instrument panel, like when you click the stalk.

[big-L]

thanks but i was looking more for power source that turns on with the interior lights and instrument panel, like when you click the stalk.

yeah i'd like to know how to wire it to the light stalk also

[walky_talky20]

You have to tap one of the fuses that comes on with the device you want. So tap the tail lamp fuse if you want the gauge to light with parking lights and head lamps. If you only want the gauge to light with the head lamps on, tap into one of the low beam fuses. Here are some examples of fuse taps:

[walky_talky20]

EDIT: stupid double post. Never did this before the "update"...

[revolution337]

cool, thanks for the info.

edit: kinda off topic, but how do you get the light bulb out of the back of the gauge on the VDO gauge? i bought an LED to use, but i can't figure out how to remove the light housing?

[fbdohc]

i will be installing mine soon and what i'm wondering is how the hell you get the wire or the hose passe trough the dash and firewall to the intake manifold

[revolution337]

i will be installing mine soon and what i'm wondering is how the hell you get the wire or the hose passe trough the dash and firewall to the intake manifold

cut a hole in the 2 rubber grommets located next to the brake booster.

[fbdohc]

and this goes down under the steering wheel ?

[revolution337]

correct.

Back to my other question: does anyone know how to remove the light bulb from the VDO gauge?

[Seerlah]

Sorry took a little while, heres the gauge:

15psi? Get a different gauge.

To the OP, to get to the VDO bulb, just pop off that black cap on the bck, where the posotive/negative wire connects. It may look like it won't want to come out, but it will (just apply more force). And if you do mess it up somehow, I have an extra one I can send you. I thought I lost mine (well, I really did and found it later) when I was changing my bulb and ordered a new socket for it.

Also, in referance to tapping into the fuse, I just wrapped the wire around the fuse and I didn't have an issue with it. Of course, this is not the proper way to go about it but I had no issues doing it this way.

[revolution337]

15psi? Get a different gauge.

To the OP, to get to the VDO bulb, just pop off that black cap on the bck, where the posotive/negative wire connects. It may look like it won't want to come out, but it will (just apply more force). And if you do mess it up somehow, I have an extra one I can send you. I thought I lost mine (well, I really did and found it later) when I was changing my bulb and ordered a new socket for it.

Also, in referance to tapping into the fuse, I just wrapped the wire around the fuse and I didn't have an issue with it. Of course, this is not the proper way to go about it but I had no issues doing it this way.

just pull it straight off? no clips or anything? i say this because im pulling really hard, i even got some pliers, and it doesnt want to come off.

EDIT: nevermind, i finally got it off. thanks for the help seerlah

[SVB5]

thanks for in info guys. im installing mine this weekend. how about power taps? is there an empty fuse that has switched power? (i.e comes on with DLR and headlights)?

I used the fuse that controls the license plate lights. I'm not sure which one it was(i looked in the owners manual). Red lead to the fuse and black to ground, used a screw in the fuse panel to get the ground. works great,
the gauge and the facelift center vent (i got off ebay) both light up when I turn the lights on. I'm sure there is a better way, but this works for me.

[Polski]

well i'm only boosting 5 psi right now and about 18-19 vaccum at idle...is there something wrong about that gauge?
Or is 15 psi not enough?

[Seerlah]

You supercharged? For the turbocharged guys (which I thought you had), 15psi is not enough. Most tunes will bring them into the 18psi range, and that is with the stock turbo.

[Polski]

oh ok, i see.
I have the 1.8t stock everything..i guess i will change gauge when i get to the higher psi levels

[OLAbeLincoln]

Hey I have a B5 s4 and I tapped into the FPR line.. and I'm not sure if this the cause or not but when I get on it now in 2 or 3 or any gear really itsorry like the car revs high or something then rpm gauge shoots over and I almost feels like when I get on it its slipping... but I never smell a clutch burning or anything... any ideas

[Seerlah]

Wrong section to post in, and relevance to thread topic is slim. But seems like you just have a slipping clutch. Don't need a burning smell to accompany it. If clamp load isn't enough, it will slip. If you have a boost controller to manage boost pressure control, try dialing it down by 1 psi increments to see if at a certain boost level it stops.

This is basically just a test to see if your clutch really is slipping, because from your posts that is what it seems. Has nothing to do with your boost gauge install. Or you are explaining your situation in a manner I am analysing incorrectly, and you really do have an issue associated with the install?!?! But a gauge install should always be a tapped configuration that should effect nothing it was tapped into unless a longer line set plays a factor. Or if your tap (gauge) install has a leak involved.

The fpr line is nothing but a reference line for a rising rate fueling system. All it does is provide a reference line to the fpr so it can increase fuel pressure accordingly as the boost pressure increases, supplied directly from the source being the intake manifold.

I would first confirm no leaks on your gauge install, then test to confirm your clutch slipping or not. And remember, your clutch is rated and operates off torque from the crankshaft. Depending how the torque is applied can cause the clutch to slip or not to slip. So that means that it can slip at some times and not at others, depending how tq is appied.

What many I think do is take it to a highway, place it in a higher gear with lower rpm, and go wot. At this time, the tq load applied to the clutch this way reveals if the clutch is slipping or not as rpm and clamp load increases. That is if you don't have a way to lower boost pressure for testing.