2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

stock boost gauge

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Old Oct 27, 2003 | 07:38 PM
  #1  
JackoliciousLegs's Avatar
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haiO
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From: mmsports.org
stock boost gauge

hmmm... i never knew that 250mmHg = 9psi?!!? Well, actually it doesn't. That's just what my stock boost gauge told me.

I hate the stock boost gauge! It's a PIECE of SH*T!!!!!! After all this time (thanks to all that helped by responding to my posts) I am in fact boosting fully! 9psi actually with cat-back exhaust! A month of hardcore worrying! DONE! Next step... intake/FCD/downpipe/cat

Thank you autometer!

Jack
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Old Oct 27, 2003 | 10:39 PM
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If the stock boost gauge only gets up to 250mmHg when you're actually boosting to 9psi (465mmHg), then your pressure sensor may be the problem. If that's the case the ECU will be receiving incorrect info, and won't think you're boosting as high as you are. Check to see the pressure sensor is within spec.

BTW, you list of proposed mods will put you dangerously close to disaster unless you replace the fuel pump AND port the wastegate first.
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Old Oct 29, 2003 | 09:48 AM
  #3  
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will do on the pressure sensor
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Old Oct 29, 2003 | 09:50 AM
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now wait a minute... i posted this question before and everyone told me i'd be fine as long as i got a fcd!

Last edited by JackoliciousLegs; Oct 29, 2003 at 10:05 AM.
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Old Oct 29, 2003 | 10:01 AM
  #5  
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oh, about the boost registering low... it also registers atmospheric pressure low, so maybe the gauge is just out of line (which i think it is)... is that still bad?
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Old Oct 29, 2003 | 11:26 PM
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If it's the gauge, no. If it's the sensor, yes.

This could be caused by the FCD. The better ones send an unmodified signal to the ECU but clamp it just before fuel cut, but some simply reduce the signal by a fixed percentage all the time, which isn't nearly as good. If yours is one of the latter ones, the boost gauge will always read low.
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Old Oct 29, 2003 | 11:35 PM
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well if you are going to do your suggested mods do not boost more than 10psi without fuel pump and injectors, youwill be in dagerous territory; my suggested in the following order would be;

FCD/High Flow Fuel Pump same time;
Intake,
larger secondaries and way to tune them
DP + CAT,
that way you will most likely always be safe!
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Old Oct 29, 2003 | 11:52 PM
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if you have a FCD installed i thought that tricked your ECU into thinking that the boost was lower than it actually was subsequently your gauge reading lower than your actual boost is?

is that correct or am i wrong?


edit: sorry for sounding repetitive, i noticed this point already brought up.
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Old Oct 30, 2003 | 12:12 AM
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it does for the most part but the better ones only do that at the upper range of boost ie 9-10 lbs but some do it through the entier rance it 0-10, the ones that only clamp near 9-10 are the better ones, the ones that clamp the whole range aren't the better ones and can be potentially time bombs!
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Old Oct 30, 2003 | 12:21 AM
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well i have always believed you should install a direct gauge anyhow. for more accurate and dependable pressure readings.
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Old Oct 30, 2003 | 12:32 AM
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agreed! I don't rely on the stock guage at all!
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Old Oct 30, 2003 | 02:27 AM
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Originally posted by jreynish
larger secondaries and way to tune them
For 10psi boost larger injectors are not necessary. The fuel pump is mandatory and a fuel controller is a very good idea, but you don't need bigger injectors until injector duty cycle gets too high.
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Old Oct 30, 2003 | 06:31 AM
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From: ste-marthe
does any 1 have the fuel map in the ecu ?

I just curious to see !

chicoutimi
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