Superchager Woes

[shinkson]

I have a 2000 VX with what I believe is an Alpine supercharger. Anyway its an Eaton M62. I was just rebuild and has a new pressure release valve. My problem is no boost . I installed a vacuum/boost guage. I get -20 on idle. Full throttle I get 0. When I blip the throttle I see the pressure release valve close momentarily and reopen and stay open. When I floor the throttle it does the same thing. I looks like there is not enough boost to allow the valve to close or too much vacuum. There may be a problem with the the way the vaccum lines are run. I have all the lines after the charger connected together (Fuel pressure reg, release valve, and intake manifold) and every thing pre-charger connected. Does anyone have clear picture of the vacuum/boost routing on a Alpine system?

[Ldub]

I have a 2000 VX with what I believe is an Alpine supercharger. Anyway its an Eaton M62. I was just rebuild and has a new pressure release valve. My problem is no boost . I installed a vacuum/boost guage. I get -20 on idle. Full throttle I get 0. When I blip the throttle I see the pressure release valve close momentarily and reopen and stay open. When I floor the throttle it does the same thing. I looks like there is not enough boost to allow the valve to close or too much vacuum. There may be a problem with the the way the vaccum lines are run. I have all the lines after the charger connected together (Fuel pressure reg, release valve, and intake manifold) and every thing pre-charger connected. Does anyone have clear picture of the vacuum/boost routing on a Alpine system?

Worry not my friend...unca dub gotcha back...



Hope that is of some help, I seem to remember that it was the missing piece of the puzzle when I experienced the same problems as you currently are.

Also I remember that the boost gauge would only register boost if hooked to a certain vac line, but right now, I don't have time to clarify.

Gonna be outta town for the weekend, so if this doesn't do it, I'll take another whack at it Monday...

[shinkson]

Yeah, I saw that pic. The only question I have about that pic is " where is the vacuum canister?" I have that line going to my vacuum manifold block. I will take a picture this weekend. Hopefully that will help you help me. So you had a no boost issue before? If so that would be good news since it sounds like you found a fix for your issue.

[WormGod]

IIRC, the vac canister is looped. Basically, plugs into itself. If we are talking about the same thing that is. See diagram: (#10)

[shinkson]

Yeah thanks. I saw that diagram also. My vac canister is looped. My query is related to the port labeled vac canister on the throttle body monifold or supercharger intake. See attached pic.

[shinkson]

I'm going to concentrate on the boost bypass valve which fails to close on WOT. I just realized that no matter what else may be wrong, there will be no boost until that is closed. I also don't think I have a leak because I am getting about -20 vacuum on idle and about 0 on WOT. That seems to be in line with a normally aspirated engine. So I will disconnect and plug the vacuum line going to the bypass valve and leave the valve open to atmosphere. This will shut the valve. At this point giving it a little throttle should result in a quantifiable amount of boost. Fingers crossed.

[xtrmes]

Have you driven it when testing? You will get no boost unless you have a load on the engine.

[shinkson]

Yeah I've driven it to work a couple of times. GUTLESS!

[Ldub]

FWIW, my boost gauge is t'd into the FPR vac line, & reads boost...

[WormGod]

FWIW, my boost gauge is t'd into the FPR vac line, & reads boost...

+1

My old gauge would not read anything over 0psi under full load. Ended up the S/C was creating boost, the gauge was just borked. New gauge, all has been good since.

[shinkson]

Hmmmm, I'll try changing the gauge

[shinkson]

Well, I changed the gauge and got the same results. The vx runs fine, just no extra power. I live in Utah so finding anyone with hands on supercharger experience is difficult. Any other suggestions?

[shinkson]

I connected my ODBII sensor for my work commute and validate that I am getting 0 boost. Does anyone know any good machanic shops in the Ogden UT area

[Ldub]

I connected my ODBII sensor for my work commute and validate that I am getting 0 boost. Does anyone know any good machanic shops in the Ogden UT area

IIRC, the stock sensor will only measure vacuum, it wasn't designed to measure boost.

Maybe try removing the S/C drive belt to see how much difference there is.

[WormGod]

What Dub said, I don't think it will reveal data over OEM load. I tried my ScanGauge once as well and it didn't reveal any added load though my gauge was showing boost.