Drivetrain Question about the FPR line
Question about the FPR line
Question:
Does the FPR vacuum line have a restrictor in it somewhere?
Here's my story.
Recently had a cam and boost gauge installed (OEM cluster kit). After install, noticed some serious buzzing when on boost. Well, thanks to NAM, found out that the boost gauge soft vac line was connected incorrectly, ie on the pass through or top of 'T' and not on the T-bone part or bottom of the 'T' where the restrictor is.
Fixed that and buzzing is mostly gone. Still buzzes a little when at around WOT and 13-14psi. Maybe my throttle body is a little more 'erratic', or something, to produce the buzzing at high psi.
BUT HERE'S THE THING. I think it felt better before. I mean the driveability and smoothness of power delivery, not the buzzing.
Possible causes in my head for such a phenomena:
1. Adapted to cam, this is the way it is now.
2. Restrictor has smoothed the vac and boost for the FPR, and hence, a more refined feel.
So, maybe, I could go and buy another restrictor and put it inline with the FPR vac line. Hence my question. Heck, I could get another one to help with the buzzing.
Worth a try? Don't think there is any harm but blessings from the NAM community would be nice.
Current mods: 15%, JCW injectors, JCW intake, RMW tune. Cam came after all that. Tune was with everything cept cam. 2004 150k btw. 189whp at time of tune, 25-26 avg mpg.
Does the FPR vacuum line have a restrictor in it somewhere?
Here's my story.
Recently had a cam and boost gauge installed (OEM cluster kit). After install, noticed some serious buzzing when on boost. Well, thanks to NAM, found out that the boost gauge soft vac line was connected incorrectly, ie on the pass through or top of 'T' and not on the T-bone part or bottom of the 'T' where the restrictor is.
Fixed that and buzzing is mostly gone. Still buzzes a little when at around WOT and 13-14psi. Maybe my throttle body is a little more 'erratic', or something, to produce the buzzing at high psi.
BUT HERE'S THE THING. I think it felt better before. I mean the driveability and smoothness of power delivery, not the buzzing.
Possible causes in my head for such a phenomena:
1. Adapted to cam, this is the way it is now.
2. Restrictor has smoothed the vac and boost for the FPR, and hence, a more refined feel.
So, maybe, I could go and buy another restrictor and put it inline with the FPR vac line. Hence my question. Heck, I could get another one to help with the buzzing.
Worth a try? Don't think there is any harm but blessings from the NAM community would be nice.
Current mods: 15%, JCW injectors, JCW intake, RMW tune. Cam came after all that. Tune was with everything cept cam. 2004 150k btw. 189whp at time of tune, 25-26 avg mpg.
6th Gear
Joined: Nov 2004
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From: Arnold, MO.
There is no type of restrictor in the FPR vacuum line, just a straight vac. line and as long as your vac. T doesn't step down in size for one of the ends it should not matter which line is attached to which end,
If you used a standard boost gauge kit it utalizes a plastic line and most likely the buzzing you refer too is just vibration coming from that line touching the engine somewhere in its route into the cabin, and the change you experienced is simply from physically moving that line when you switched it around.
Do yourself a favor & take these steps:
1. Make sure the T you are using is the same size for all 3 of it's outputs.
2. Since you're in there, from the T itself run standard rubber vacuum hose for the gauge as far as you can toward the gauge. (in to the cabin if you can) and then either:
a. Get the proper fitting for the gauge to connect the rubber line directly.
or
b. Make the transition tto the plastic line using a simple double male ended plastic connector.
These steps will do a couple of things, first remove any chance of the plastic line from touching any vibrating parts, and second, the rubber connector that joins the plastic T or adaptor to the plastic line is sometimes made of a lesser quality rubber than a standard vacuum hose and is normally the first place leaks occur after time simply because of the heat that is present directly under the intake manifold.
As far as the performance, yes you probably need a re-tune, the ECU read a change and made adaptations accordingly, and don't forget most factory adaptations work in the favor of "uber-safe" by design. This is why a good & knowledgable tuner is worth so much.
If you used a standard boost gauge kit it utalizes a plastic line and most likely the buzzing you refer too is just vibration coming from that line touching the engine somewhere in its route into the cabin, and the change you experienced is simply from physically moving that line when you switched it around.
Do yourself a favor & take these steps:
1. Make sure the T you are using is the same size for all 3 of it's outputs.
2. Since you're in there, from the T itself run standard rubber vacuum hose for the gauge as far as you can toward the gauge. (in to the cabin if you can) and then either:
a. Get the proper fitting for the gauge to connect the rubber line directly.
or
b. Make the transition tto the plastic line using a simple double male ended plastic connector.
These steps will do a couple of things, first remove any chance of the plastic line from touching any vibrating parts, and second, the rubber connector that joins the plastic T or adaptor to the plastic line is sometimes made of a lesser quality rubber than a standard vacuum hose and is normally the first place leaks occur after time simply because of the heat that is present directly under the intake manifold.
As far as the performance, yes you probably need a re-tune, the ECU read a change and made adaptations accordingly, and don't forget most factory adaptations work in the favor of "uber-safe" by design. This is why a good & knowledgable tuner is worth so much.
There is no type of restrictor in the FPR vacuum line, just a straight vac. line and as long as your vac. T doesn't step down in size for one of the ends it should not matter which line is attached to which end,
If you used a standard boost gauge kit it utalizes a plastic line and most likely the buzzing you refer too is just vibration coming from that line touching the engine somewhere in its route into the cabin, and the change you experienced is simply from physically moving that line when you switched it around.
Do yourself a favor & take these steps:
1. Make sure the T you are using is the same size for all 3 of it's outputs.
2. Since you're in there, from the T itself run standard rubber vacuum hose for the gauge as far as you can toward the gauge. (in to the cabin if you can) and then either:
a. Get the proper fitting for the gauge to connect the rubber line directly.
or
b. Make the transition tto the plastic line using a simple double male ended plastic connector.
These steps will do a couple of things, first remove any chance of the plastic line from touching any vibrating parts, and second, the rubber connector that joins the plastic T or adaptor to the plastic line is sometimes made of a lesser quality rubber than a standard vacuum hose and is normally the first place leaks occur after time simply because of the heat that is present directly under the intake manifold.
As far as the performance, yes you probably need a re-tune, the ECU read a change and made adaptations accordingly, and don't forget most factory adaptations work in the favor of "uber-safe" by design. This is why a good & knowledgable tuner is worth so much.
If you used a standard boost gauge kit it utalizes a plastic line and most likely the buzzing you refer too is just vibration coming from that line touching the engine somewhere in its route into the cabin, and the change you experienced is simply from physically moving that line when you switched it around.
Do yourself a favor & take these steps:
1. Make sure the T you are using is the same size for all 3 of it's outputs.
2. Since you're in there, from the T itself run standard rubber vacuum hose for the gauge as far as you can toward the gauge. (in to the cabin if you can) and then either:
a. Get the proper fitting for the gauge to connect the rubber line directly.
or
b. Make the transition tto the plastic line using a simple double male ended plastic connector.
These steps will do a couple of things, first remove any chance of the plastic line from touching any vibrating parts, and second, the rubber connector that joins the plastic T or adaptor to the plastic line is sometimes made of a lesser quality rubber than a standard vacuum hose and is normally the first place leaks occur after time simply because of the heat that is present directly under the intake manifold.
As far as the performance, yes you probably need a re-tune, the ECU read a change and made adaptations accordingly, and don't forget most factory adaptations work in the favor of "uber-safe" by design. This is why a good & knowledgable tuner is worth so much.
Incidentally, the T has the same size fittings on each side. It has an integrated restrictor inside but the outer diameter 'appears' the same for the middle connector.
I believe the tubing it comes with is standard vacuum, but it is the soft kind. It is pretty soft and rubbery. Can't imagine vibration traveling along it.
It does get hot there, wonder if wrapping that fitting with exhaust wrap would be helpful.
Yeah, will retune, it is RMW without cam at the moment.
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