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Discussion Starter · #1 ·
SO i've read all the threads on how the factory limits boost in 1st and 2nd to around 10 psi or less. So I install my boost gauge last night and load and behold...I'm getting close to 15 psi in 1st (WOT) and definitely solid 15 psi in 2nd...and needless to say solid 15 (not a bit more) psi in 3rd, 4th, and 5th. So that tells me that the boost gauge isn't like totally off (since we're suppose to get 15 at 4th and 5th stock, right?).

I'm bone stock as for engine mods. No BC of any kind or resistor mod (whatever that is).

Anybody have any explanations?

And if it's true, then I guess I won't get much of a diff by adding a BC???
 

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Is it spiking and then dropping down or is it holding that high? I actually have a problem with spiking in first and second gear, not as bad as it was when I had the 3/16 connetor in, but it still spikes to about .94 bar in 2nd and then drops to .75 bar. If anyone can help us both, that would be great. Sorry I can't personally help you QuickSilver.

-joe
 

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Discussion Starter · #3 ·
How can you tell between spiking and real boost?

When I go near WOT, the gauge climbs to 15 psi as I accelerate (butt dyno) and holds, for what seems to be awhile..a second maybe (relative)...the needle isn't just jumping around. And I have to hit her hard...doesn't even come close to 15 PSI at normal driving accelerations.
 

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What I mean by spiking is the needle (in your case, I have the Dual TT so it is a bit easier to notice on the digital read out for me) jumps to the higher number and the quickly drops down again and builds slowly to the max. Something like, spike to 15 psi, drop to 10 psi and then build back up to the max, whatever that might be. If you have no spiking, the needle will just climb up the max and stick there until boost trails off as you approach the redline. In my case, in 2nd gear, WOT, it jumps to .94 then falls to .7 and builds up to .75. I spike to about 1.02 in 3rd and then fall back to about .9 and build to my max of .94-.97. Ok, that is about all I can help with, time for someone else to chime in and actually make some sense of this.

-joe
 

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What type/brand of boost guage?

Where did you tap it?

If you actually are getting a factory warranteed 15psi, don't complain :p

VV
 

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I am using the Blitz Dual TT as it has a built in boost guage. I tapped the BOV and all my connections are nice and tight with hose clamps. I am not getting 15 psi in 2nd, but I am definately spiking badly in 1rst, 2nd and a bit in 3rd.

-joe
 

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Does the tubing for the Blitz come with an inline restrictor? The factory boost guage utilizes a very small restrictor in the line to reduce the apparent spiking/wavering.

I have no idea if the Dual TT is supposed to have accurate boost measurement. You tapped the right line btw. I thought maybe you were seeing pre-intercooler boost.

VV

NJwrbT-WRX said:
I am using the Blitz Dual TT as it has a built in boost guage. I tapped the BOV and all my connections are nice and tight with hose clamps. I am not getting 15 psi in 2nd, but I am definately spiking badly in 1rst, 2nd and a bit in 3rd.

-joe
 

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I do not think the Blitz came with and inline resistor, but I am pretty sure that it is accurate. I read more than a few accounts of its accuracy here in these pages, and the boost readings after the spiking are pretty much right on the money. I never spike about 1.02 so I guess I am not doing any damage and there is nothing to worry about.

-joe
 

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So you spike to 1.02? What does it settle down to?

Easiest way to check this is a 4th gear pull from 3000 - 5500 rpms. Look sustained boost around torque peak at 4400 rpms. .85 - .95 bar sustained seems to be the typical range for stock.

VV

NJwrbT-WRX said:
I do not think the Blitz came with and inline resistor, but I am pretty sure that it is accurate. I read more than a few accounts of its accuracy here in these pages, and the boost readings after the spiking are pretty much right on the money. I never spike about 1.02 so I guess I am not doing any damage and there is nothing to worry about.

-joe
 

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I settle to about .95 bar, which is good, and I am comfortable with that. I am worried about when I put in my MBC and my spikes may be higher, I do not want to be spiking too high, even if I settle to an acceptable pressure.

-joe
 

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The spiking and then settling down is more a byproduct of the factory boost controller. A good MBC will be much more accurate and consistent. With my HPMBC, I don't remember seeing a spike higher than .02 bar...if that.

VV

NJwrbT-WRX said:
I settle to about .95 bar, which is good, and I am comfortable with that. I am worried about when I put in my MBC and my spikes may be higher, I do not want to be spiking too high, even if I settle to an acceptable pressure.

-joe
 
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