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What is the purpose for a Boost Gauge?


Patrik
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to look at how much boost ur FI is running in...normally in PSI readings....

some can be set to ur own preference...

example ur car max boost is 10psi....

den u can set it to anything lower than dat...ie:6psi so it will not exceed dat...

not 100% sure...ha ha... [thumbsup]

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Neutral Newbie

The stock boost gauge is not the most accurate one in the world. Many modifications you make will increase boost even if you don't think they will. As a result, you need to be sure that you are able to accurately know how much boost you are creating. The result of over boosting will be detonation and eventually damage.

 

The stock "boost gauge" does not actually measure pressure. The ECU "calculates" the boost based on information it gets from the Mass Airflow Sensor, temperature, barometric pressure, engine RPM, and some efficiency assumptions. The problem is this is those assumptions are thrown out the window when you mod the car and the ecu is not set up to understand flows above the stock levels.

 

An aftermarket boost gauge measures actual pressure in either psi or bar(kg/cm2) at the manifold. Choose the one that best suits your needs. There are two basic kinds: Boost and Boost/Vac gauges. I recommend the Boost/Vac gauge since vacuum variations can help indicate problems which might be hard to diagnose. It also lets you see the whole range of the turbo's behavior (spool up). Typical gauges read from 30mmHg to either 20, 25, or 30 PSI. I recommend 25 at a minimum for large cc cars. Anything lower will just prove useless in the future

Edited by Kax2
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Hahahha... ok to actually answer your question, the boost gauge is there to tell you how much boost your turbo is making.

 

turbonetics>> for your injectors, you need software that plugs into your ecu (or can read it) to tell you the injector duty cycle to tell you how they're working.

Edited by Elfenstar
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yup, you're right i forgot abt superchargers... a vacuum gauge would be good for a NA car, though I don't know the co-relation between power and amount of vacuum.

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Neutral Newbie

low vacuum = high load/power

high vacuum = low load/power

 

Vacuum is directly related to how much you step on accelerator. If you see low vacuum, it means that you step on it, high vacuum means your throttle is almost closed.

 

The vacuum exists because of the following reasons..

 

During low throttle:

The throttle plate is almost closed, and engine continues to suck air from intake manifold, leading to high vacuum. (or low pressure)

 

During high throttle:

The throttle plate is opened, then air flows freely from intake into intake manifold, lead to low vacuum. (higher pressure, comparative to previous case)

 

Note that both "high" and "low" vacuum are lower than atmospheric pressure due to moving air, thus the word "vacuum" is used, rather than "pressure", which usually mean compressed air.

 

IMO, why need a gauge to gauge your foot position? [laugh]

Edited by Zrun
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IMO, why need a gauge to gauge your foot position? laugh.gif

 

Could be a diagnostic tool (which it is anyway) if the car is really old. Consider it a cheapoman's AFR monitor or OBD reader.

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Neutral Newbie
The stock boost gauge is not the most accurate one in the world. Many modifications you make will increase boost even if you don't think they will. As a result, you need to be sure that you are able to accurately know how much boost you are creating. The result of over boosting will be detonation and eventually damage.

 

The stock "boost gauge" does not actually measure pressure. The ECU "calculates" the boost based on information it gets from the Mass Airflow Sensor, temperature, barometric pressure, engine RPM, and some efficiency assumptions. The problem is this is those assumptions are thrown out the window when you mod the car and the ecu is not set up to understand flows above the stock levels.

 

An aftermarket boost gauge measures actual pressure in either psi or bar(kg/cm2) at the manifold. Choose the one that best suits your needs. There are two basic kinds: Boost and Boost/Vac gauges. I recommend the Boost/Vac gauge since vacuum variations can help indicate problems which might be hard to diagnose. It also lets you see the whole range of the turbo's behavior (spool up). Typical gauges read from 30mmHg to either 20, 25, or 30 PSI. I recommend 25 at a minimum for large cc cars. Anything lower will just prove useless in the future

 

Where did you copy-paste this from? It contains a lot of outright errors.

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Neutral Newbie
turbonetics>> for your injectors, you need software that plugs into your ecu (or can read it) to tell you the injector duty cycle to tell you how they're working.

 

Not necessary. You can just use a DSO.

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Neutral Newbie
IMO, why need a gauge to gauge your foot position?

 

Because although boost is related to throttle position, it is not the same thing. e.g. for cars running with antilag, TPS has low voltage, yet car is already making boost...

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Neutral Newbie
Could be a diagnostic tool (which it is anyway) if the car is really old. Consider it a cheapoman's AFR monitor or OBD reader.

 

Use the right tool for the job. Just because a spanner is hard, doesn't mean that you should use it to hammer nails.

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low vacuum = high load/power

high vacuum = low load/power

 

IMO, why need a gauge to gauge your foot position? [laugh]

 

The level of vacuum can also determine your FC/how efficiently you are driving. Low vacuum = more fuel is burnt. High vacuum = less fuel consumed

 

foot position? i dunno [laugh]

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u can check at most car accessory shops. they should carry it as its quite a common item. If u are not brand conscious (n go for delpi brand) the jap/taiwanese bands go for 40-70 bucks.. depending on the type of function (water temp, volt, vacuum, boost etc)

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Neutral Newbie

For NA cars, any vacuum condition is on part throttle. ZERO Vacuum or atmospheric is considered WOT.

 

For FI, any reading above atmospheric is boost condition. More fuel will be injected and viola; torque.

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