I've been away from the forums for a while, and I still have not gotten around to installing a boost guage on my Roush'd 2008 F-150 Limited. I saw an Autometer guage yesterday at Pep Boys that would match my existing Limited guages perfectly: brushed aluminum face, black lettering, with red needle. However, the Autometer guage installs via a fitting that must be drilled into my intake manifold (or so said the Pep Boy salesman). I really don't want to drill into my manifold if there's an easier way to install. Isn't there a way to "Tee" into one of the boost/vacuum lines on the back of the supercharger somewhere?

Thanks,
CW

 

not familiar with your year of truck but.. look for the vacuum line that runs into your Fuel pressure regulator witch should be on your drivers side fuel rail just t that line and you will be just fine..

 

CW Cobra: I agree with "01Lightning". I have my boost gauge mounted to a custom made "Pod" on my driver's side front sill.
The only thing needed is to "T" tap a suitable vacuum line that is as close to the manifold as possible. Since I was already replacing my "Spaghetti-Tubing"; I arranged for a brass, "T" tap; off of the tube leading away from the manifold (98, Romeo, 4.6Ltr.). On my engine that feed is on the manifold, right below the T-Body,on the L-side of the engine.
I used high temp. emission hose for the part of the run that is over the engine. Then I extended the vacuum line up to my front piller (funny I forget how to spell that).by going down the wheel well, and up the weather stripping until I reach the mounting pod.
I provided a pass way for the vacuum tube by drilling a suitable hole at the bottom of the cable channel which runs under the doorway. I did use a water-proof bulk head penetration to clamp the hose, and prevent moisture,water entrance.
You can tap into the IP Lighting Circuit for power to operate the internal light of the gauge. I don't know what color that circuit is in a F-150, but in an Expy. it is Lt.Blue/red. If it is not the same in a F-150; check the lamp in the ash tray for the appropriate color pair. Maybe you can even tap the power from there.

Have a nice weekend.
"98X"

 

im not sure about your roush setup, but my non-ic has a vacuum line capped off coming out of the rear of the manifold. in the installation instructions, i believe it said that this was a place for mounting a boost guage.

now that being said, i installed my boost guage to the line and i dont get correct readings on my guage. at idle it reads a big vacuum and just gets to 0 or 1 psi of boost at WOT. it also shows a decent vacuum even when the motor is off, which im not sure is normal or not. i dont know if this is because of the line being incorrect or just a faulty guage. i think i remember trying a different vacuum line and getting the same results. maybe someone else with a roush will chime in...

dont drill any holes though, that guy didnt know what he was talking about...

oh by the way, are these the guages you have?

 

dude this is very easy if you pop your hood look at the drivers side of the blower pretty much all the way to the fire wall you will see a T fitting with a little black cap or plug you simply side you nylon boost line into it i know i didnt think it would stay but mine has bin there for like a year now no issues if you cant find it pm.

 

thanks, ill try to find a different line to tap into. i dont care if it its messed up when its off if it gives accurate readings while running, but it may be bad all together, we'll see...

 

I agree with Crash!...from the looks of that pic, that boost gauge is definitely way off. I had an Autometer Lunar series boost gauge that used to sit at 5" vacuum when the truck was off. I always thought it was normal until I noticed I was getting low boost at WOT. I called up Autometer and they said it's definitely supposed to sit in the "0" box when the vehicle is off. Caused my boost reading to be about 5 psi lower as a result. Got a new boost gauge from Autometer, it sits in the "0" box, and all is well. Call up Autometer and tell them what the gauge is doing...they have excellent customer service and should replace it free of charge

 

thats cool if they will replace it, it was like $60 new... ill give them a call!

i cant remember what it reads at idle but its either 14 or 19 psi of vacuum. but yes it does sit at 9 psi at off...

if it was 9 psi off at all times, i would be showing 9psi of boost at WOT(assuming its hooked up correctly) and im only running 6...

i bought some T fittings today, so ill try finding another vacuum line first to make sure it is where it needs to be.

 

this is the vacuum harness that you tie into the boost gage

and it plugs in to the nipple just to the right if the intercooler lines

 

Anywhere post-throttle body should give you and accurate reading. I T'd into the main vacuum line going to the vac. reservoir on my truck. It's not difficult to find a large line coming off the lower manifold to tap into. Do not tap into a vacuum line that is routed to any sensor like EGR or FPR, that's just asking for trouble. I also did what Crash recommended with a $15 parts store manifold gauge to make sure my Boost gauge is reading correctly.

Idle reading:

 

[QUOTE=justjames80;3672534] Do not tap into a vacuum line that is routed to any sensor like EGR or FPR, that's just asking for trouble. QUOTE]

The nipple going to the FPR is the only option I have on my blower and is were the instructions say to tap for it ... I totaly understand why you wouldn't want it there.. I guess when I had the S/C off last time to drill and tap for a IAT sensor I should have drilled a port for the boost gauge....

 

what about in a saleen supercharger,...what do you hook up to what???

 

ok well i think i got it straightened out. I did apparently have it connected to the right line(s). i think i just have a bad gauge. My friend had a cheap harbor freight boost/vac gauge that i hooked up to the same line and i show 5-5.5 lbs of boost at WOT which should be right on considering im running LT headers and no mufflers right now. interesting thing is that im showing 22 lbs of vacuum at idle....

anyway here are the 2 locations i tried to run the signal line. they connect at a port on the back side of the intake manifold. i dont know if its the same setup on the intercooled roush though...

 

Here is how I have mine mounted.

http://store.roushperformance.com/detail.aspx?ID=1076

 

ok,..forgive my ignorance,..nut still don't know how to connect my gages..sorry,..any info would help,..thanks alot crash for your info