Procharger low boost HELP

[Bmaughan]

I have an HO kit on my 15’ GT and I’m having a problem not getting boost numbers that are expected. On a 4” pulley I was making 7-7.5lbs. On now on a 3.4” I’m only making about 10lbs.
I talked with Procharger and they confirmed that I should be seeing 12-13lbs on the 3.4” and my tuner says he doesn’t see any signs of belt slip or boost leak in the logs.. so I’m a little lost at this point. Not really sure what I should be looking for.
What could be some other causes of low boost?

Any help or thought would be seriously appreciated!!!

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[80FoxCoupe]

Check all the piping from head unit to throttle body for tightness? Condition of air filter? BOV/bypass leaking? Intake manifold properly torqued down? Vacuum lines routed properly and checked for leaks? What's your elevation? Is your boost gauge accurate?Help us help you.

 

[Bmaughan]

Thank you for the quick response!

Yes all piping is all tight

air filter is brand new

BOV has been functioning up to this point but I suppose something could be wrong with it. How could I test it?

Intake is torqued down properly

It might be worth going over my vacuum setup just to make sure I didn't make a stupid mistake.

I’m only at around 1000ft

I’m using the omega boost box which I thought was pretty accurate but I could be wrong.

 

[Bigswollnasty]

I had a valve leak on my paxton car, caused me to see low boost. It was a 3.3" pulley so a similar situation. I only was seeing 8.5 psi.

 

[Jay-rod427]

The omega boost box needs to be calibrated through the nguage. Lund has very specific instructions for getting and using the correct transfer function. If it's even slightly off it will not read the correct numbers.

 

[Bmaughan]

I had a valve leak on my paxton car, caused me to see low boost. It was a 3.3" pulley so a similar situation. I only was seeing 8.5 psi.

Yikes, so just a bad valve seal? How did you determine this...compression test?

 

[Bmaughan]

The omega boost box needs to be calibrated through the nguage. Lund has very specific instructions for getting and using the correct transfer function. If it's even slightly off it will not read the correct numbers.

I followed lunds instructions and got the transfer function from their listed website. So in theory it should be working right. And honestly the seat of pants feel corresponds with the numbers I’m seeing.

 

[SolarFlare]

Whats the stock crank size? 6.75?? If so blowed speed is 61k. So should be higher. If no pipes are leaking I’m leaning towards belt slippage and bov leakage

 

[SolarFlare]

Get an Gates rpm belt

 

[Bmaughan]

Whats the stock crank size? 6.75?? If so blowed speed is 61k. So should be higher. If no pipes are leaking I’m leaning towards belt slippage and bov leakage

I think it’s 6.78... the blowers is about 65k when the motor is at 7800. So definitely should be more I would think.
Have the belt tension with just about a half an inch of travel on the factory tensioner… Does it need to be cranked down more than that?

 

[Bmaughan]

Get an Gates rpm belt

I don’t have the RPM version but I do have a brand new gates green belt on it.

 

[Bmaughan]

Is the valve leak problem common? That would really suck...

 

[80FoxCoupe]

Is the valve leak problem common? That would really suck...

What valve are you running?

 

[Bmaughan]

What valve are you running?

Maybe I misunderstood but I thought Bigswoll was referencing a intake/exhaust valve.
Good news if he wasn’t...

I have the proflo valve on it right now

 

[SolarFlare]

Id change it the proflo, maybe just me. At near max blower speed I’m sure it’s leaking a good amount.

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