Question on Vacuum/Boost Gauge

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Oh Hai
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Just installed my Boost gauge, and I am not sure how to accurately read it.

It's a mechanical Autometer Vacuum/Boost gauge reading up to 30 PSI and 30 In.HG.

When I start the car, it reads on about 15-20in.HG. I hit the gas, and it goes to 10 PSI, and no further. My stock boost gauge buries and goes about 3/4 of an inch past 10 PSI.

What is your opinion guys?

PS- Buying an Electrical Gauge is not an option at this point. Bad gauge, vacuum leak, etc?

Thanks!

-Chris
 

Zack

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Could be a bad gauge, could be a bad bypass valve on the eaton (or mis-adjusted)


OR you could be making 10 psi!
 

blck10th

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check and make sure that shitty line is not kinked anywhere
 
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Could be a bad gauge, could be a bad bypass valve on the eaton (or mis-adjusted)

With my power level and the 2.76 PSI, I am pretty sure I am making more than 10 PSI.

OR you could be making 10 psi!
check and make sure that shitty line is not kinked anywhere

The line was kinked, but I cut it and re-connected it. From what we can see, it is not kinked anywhere. I'll check the lines on the Eaton and the Bypass Valve.
 

blck10th

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what should it be at boost wise? 2.76? lower?
 
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Oh Hai
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what should it be at boost wise? 2.76? lower?

Stock Lower. With the 2.76, I should be over 14PSI.

I've never heard of a Eaton Cobra with a Pulley swap, Stock Headers, Stock Lower Pulley making 462 RWHP and 486 RWTQ.
 

blck10th

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Stock Lower. With the 2.76, I should be over 14PSI.

I've never heard of a Eaton Cobra with a Pulley swap, Stock Headers, Stock Lower Pulley making 462 RWHP and 486 RWTQ.
i only made 457. that is with stage 4 port. i need a lower. I only made 13.28 psi on the dyno
 

BlaqSnake

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2.76, stock lower, CAI, High flow mid pipe, and catback

13.3 # boost (I think) and 467 HP / 476 TQ
 

blck10th

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What size belt are you running. i think you can fit a 74" belt if you cut the tab on the tensioner. I was using the stock size belt. it slippy.
 
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Oh Hai
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Running a 74.5 inch Belt. The belt that Billetflow suggests on their site for the 2.76 and 4 idlers.

Does it matter that my car peaks at about 6250? So, I am probably running 12-13 PSI?
 

10thSVT_03

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i only made 457. that is with stage 4 port. i need a lower. I only made 13.28 psi on the dyno
I have the stage 4 port 2.76 upper 4lb lower and I made 210rwhp and 235rwtq @ 3lbs on 1 pull but was maxing out my stock injectors.. Once I get the 60lbrs we can turn it up again.. I think I am just at 190-200 now with it on a safe tune... I dont remember the belt size but it was slightly smaller than the Cobra Bob website recommended..
 

blck10th

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I have the stage 4 port 2.76 upper 4lb lower and I made 510rwhp and 535rwtq @ 18lbs on 1 pull but was maxing out my stock injectors.. Once I get the 60lbrs we can turn it up again.. I think I am just at 490-500 now with it on a safe tune... I dont remember the belt size but it was slightly smaller than the Cobra Bob website recommended..
yeah i did not know i should get a lower when i did it:-o
 

10thSVT_03

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have had the 60's and just got the carbon fiber cai from jlt
Yeah I wish would have bought them before my tune.. :( The JLT I bought from Kurgan when I got the tune.... I'm curious as to how my car will do when I get a new clutch also.. High revving its hard to get in gear....
 

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