A worrisome development

[Darth Vader]

So, I stuck a boost gauge on the car and took it out and, I can't for the life of me get this thing to do better than 14 pounds of boost, obtained in 5th, full load, starting at 3000 rpm and running to redline.

It's 20 degrees Centigrade out, 101.94 baro pressure, I blocked off the manifold port to the BOV with a gasket material plate and got similar results. The only mod to the car is an AEM CAI and the boost gauge.

Where/what to do next? Any ideers?

BTW, I checked the obvious stuff like leaking intake tubes as well, nothing seems wrong and all were tight.

 

[derspi]

In 5th, that should be about right for a stock MS3 I believe.

Same results for all the other gears?

 

[Kain]

Which boost gauge?

 

[Darth Vader]

It went no higher in ANY gear. 5th was the best, hitting 14. Closer to 13 psi was on order in the other gears. The boost gauge is a cheap one, yes, a Trico but, two of them came up with the same results.

 

[Bravnik]

What was the average boost you saw? If 10psi then I would have to say you're running waste gate only which should be around 10psi max. If this is the case then you have something wrong somewhere and more questions are needed.

1. Did you buy the car new?
2. Did you ever have an MBC hooked up
3. Did you replace your turbo inlet
4. Did you replace your stock BPV

Right off I would check the following

1. Tighten all clamps on the tube coming off the TMIC
2. Tighten the clamp going to the Turbo Inlet
3. Check the hoses to your Waste Gate and ensure they are not capped. (If you purchased the car used).

 

[Darth Vader]

The car made around 13 psig for the most part.

No MBC ever used.

Turbo inlet and everything under the hood, save the CAI, is all stock.

The car was bought lightly second hand, i.e. under 10,000 miles on it. I have checked everything listed.

Isn't this car supposed to be pushing out 15.6 pounds?

 

[Mid_Life_Crisis]

Where is the boost gauge tapped? If it`s on the wrong line, it will not be accurate.

 

[eg6motion]

What elevation are you? or where are you located?

 

[Darth Vader]

Boost gauge in line to the BPV.

550 feet above sea level at the end of my driveway.

 

[Bravnik]

Is it a mechanical or electrical? If mechanical, is there any chance of a kink in the line as it went through the firewall, maybe a cut causing a leak?

 

[Darth Vader]

It's mechanical. No chance of damage to the hose. Strong solid vacuum at the head end of the line and careful routing underhood.

 

[aaronc7]

perhaps there was a disturbance in the force and thus your boost readings are off???

 

[Speed3Rookie]

How much vacuum are you seeing at idle?

 

[ericrapp]

Stock boost tubes leak for sure. Some have reported the stock valve leaks a little. Any spiking or was that the peak value?

 

[Darth Vader]

Vac at idle is about 22 inches, verified with dash gauge and my Snap-On fuel pressure tester from my carb days.

As far as I can see, the BPV can't be the source of the problem, as I tried a block-off plate and got the same readings.

No spikes, that was the peak value.

 

[SPEED305]

if no questions are left to answer, than you have no choice but to try a different gauge. i coundnt even find the one you listed!

 

[Sphincter]

Go out and get a DashHawk, pretty useful tool.

 

[ericrapp]

im your father luke

perhaps there was a disturbance in the force and thus your boost readings are off???

just got it. nice humor there mister. The reason i asked about fluctuations in boost are that my hot side ic tube got very soft and was expanding and contracting. I was having trouble with my stock valve and replaced with a forge unit and the tubes with street units heavier ply hose ( i would prefer solid but all in good time ) i was making twelve to 15 in fourth gear before these were replaced. that is all i know. I would hope the experts will chime in here soon Mr. Vader sir

 

[Darth Vader]

I found the issue and here's a hint: Just because you checked something a couple days ago, don't assume it's still fine. a few days ago I checked all the clamps for the pressure side hoses and they were mostly tight. I snugged them a little more and good. Then, I get this boost gauge and it tells me 14 pounds. I worry but, don't recheck the hoses because I just tightened them a few days before. Today I check and the goddamn IC out hose is totally slacked off again and boost is blowing out there. Tighten it up and the cheapass gauge now reads 16 pounds like it should. I think T-bolts are in my future.

Worm clamps :flip:

 

[derspi]

Not the first time this has happened I tell ya.

Glad you figured it out.