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Getting 10PSI+ on stock S/C....

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Old 11-08-2007, 06:15 AM
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Getting 10PSI+ on stock S/C....

Yesterday I was driving home from school and pinned it to merge onto US19. And i saw my boost guage and it was over 10PSI+ Like somewhere around 11PSI. And it started to stutter/ bogg down like it was running out of fuel. My friend told me that the injectors can only handle up to 8PSI then they wont be sufficent for more than 8psi of boost.

1st of all why is my truck getting over than 8PSI on the stock S/C???
What can I do to keep it under 8PSI???

Thanks
 
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Old 11-08-2007, 11:20 AM
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First, your friend has no clue what he's talking about. Injectors are not rated by how much boost the engine makes. Yes, a lot of highly modified/built Lightnings have fuel upgrades that include using 60lb Siemens Deka injectors, but your stock injectors will still flow enough fuel for a moderately modified Lightning.

Sure, when you add an aftermarket supercharger and start pushing a lot of boost through the engine, you'll need to upgrade the injectors to stay safely within the envelope of safety, but the stock injectors are not rated by boost.

Second, please post a complete list of your mods. Simple things like a CAI will cause your stock boost gauge to record a higher than stock reading. The average reading from the addition of a CAI unit will be 1.5 to 2 lbs of boost.

One last thing, are you going by your stock boost gauge, or an aftermarket gauge?

What was the outside temps when this happened?

Stewart
 
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Old 11-08-2007, 01:36 PM
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Shouldn't you lose boost as you remove restrictions?
 
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Old 11-08-2007, 01:56 PM
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I agree that your friend is clueless.

Many stock L's will indicate over 10 psi stock. The more dense the air is to begin with the more boost the gauge will show. My truck typically peaks at 8 or 9 in the summer and will go to where 12 or 13 should be in the winter. I've got stock pullies and blower. BTW, the stock gauge sucks. It is fairly precise, but its accuracy is poor.

Whether or not you lose boost when you remove a restriction depends on where the restriction is. If it's downstream of the blower you should see a reduction in boost. If it's upstream you should see an increase.
 
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Old 11-08-2007, 01:57 PM
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Originally Posted by Stewart_H
First, your friend has no clue what he's talking about. Injectors are not rated by how much boost the engine makes. Yes, a lot of highly modified/built Lightnings have fuel upgrades that include using 60lb Siemens Deka injectors, but your stock injectors will still flow enough fuel for a moderately modified Lightning.

Sure, when you add an aftermarket supercharger and start pushing a lot of boost through the engine, you'll need to upgrade the injectors to stay safely within the envelope of safety, but the stock injectors are not rated by boost.

Second, please post a complete list of your mods. Simple things like a CAI will cause your stock boost gauge to record a higher than stock reading. The average reading from the addition of a CAI unit will be 1.5 to 2 lbs of boost.

One last thing, are you going by your stock boost gauge, or an aftermarket gauge?

What was the outside temps when this happened?

Stewart
-It has a K&N Intake & a Borla Cat-Back...

-Stock Boost Gauge

-The Temps were around 65*F-70*F. But it has happened when it was warmer also.(80*F-90*F)
 
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Old 11-08-2007, 02:15 PM
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Originally Posted by Silver Streak
Whether or not you lose boost when you remove a restriction depends on where the restriction is. If it's downstream of the blower you should see a reduction in boost. If it's upstream you should see an increase.
d'oh! I must've turned my brain off or something.

Its always kind of interesting to hear people talk about losing boost when they install free-er flowing heads, exhaust, etc and then complain about it. All it means is that your engine moves air more efficiently.
 




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