gauges...what are they for to be specific?

[rizalhoo]

:oops: i hate to ask this coz it makes me sound like an idiot but i wanna learn so here goes:

i know a boost gauge is for so that you can watch you boost and not overboost it (sorry if im wrong)

but what a a/f gauge for? what is its safe reading (lets say if I get one so what reading should I be getting that tells me that im in a safe range?)

oil temp...whats it for? what is its safe reading? same goes as what water temp,exhaust gas temp for and all other gauges...

Thanks for in advance for teaching me all these stuff :wink: :) :D

[rizalhoo]

i also noticed that mostly people getting 3 gauges, what are they? im sure boost gauge are one and the rest? sorry for asking so many dumb questions....

[Howie]

I have spoken to Adam at Z1 Performance.. and this is what he had to say:

-------------------------

A mechanical gauge is the simlest form (also least expensive to produce). Simply put, it takes a reading of whatever you are measuring (lets say boost) and directly feeds that reading to the gauge. For boost, you would have a vacuum line running directly from your intake manifold to the back of the gauge, and the gauge takes its pressure reading directly from the vacuum line. For boost, this type works just fine, and is plenty accurate. However, lets say you also want to measure oil pressure. A mechanical gauge would have a hose that connects to an oil pressure source via a fitting, and would send oil directly to the back of the gauge, thus giving you your reading. Not a good idea to have hot, pressurized oil running into the car though!!!! Same would be for fuel pressure - its dangerous, tends to smell, and is not something you would do. Mechanical gauges are good for iunstalling under the hood, where they can be isolated and monitered quickly while doing minor tweaks, etc.

Some mechanical gauges use a quaise-sending unit where they have oil running into the sending unit, then that oil is used to pressurize some other liquid, and that liquid runs to the back of the gauge. While it works in theory, the same downsides are there - you tend to smell the oil or fuel you are monitering, and if the line should ever rupture, its a mess inside the car, near all the wires, etc.

An electronic gauge (as all GReddy gauges are) uses an electric sensor which converts the unit you are measuring (oil pressure, oil temperature, water temperature, exhaust gas temperature, etc) from a mechanical reading to an electronic signal. So rather than having oil, fuel, etc lines running into the car, those lines simply run into a sending unit, and that sending unit converts it from a mechanical reading to an electric signal, so you only have wires running into the back of the gauge. Much safer, much less hassel and all around just "better".

The most popular gauges for turbo cars tend to be boost, EGT and oil pressure. As you may already know, oil is the lifeblood of the motor. The turbo relies on oil to keep it properly lubricated as well as maintain a certain temperature level (oil is used as a coolant for the turbo). Its important to have good oil pressure for the simple reason that without it, the upper portion of your motor (the head, cams, turbo, etc) will not be properly cooled or lubrictaed, and can overheat and eventually fail. This is becuase the oil pump is located at the bottom of the motor, but it has to pump oil sufficiently so it reaches the upper portion of the motor. An oil pressure gauge allows you to moniter this, which in a turbo car is especially important.

Fuel pressure is important for similar reasons. Any car relies on proper fuel pressure to mee tht fuel demends of that engine. For a turbo car, its especially important becuase the fuel system takes an input from the turbo system. The fuel pressure regulator (whose job it is to maintain the proper fuel pressure is present), is connected to the intake manifold as well. When there is no boost, the fuel demands of the motor are less, so the regulator relzes things and keeps fuel pressure down, giving better fuel economy, etc. etc. When boost is present, it increases fuel pressure to ensure that as you rev the car towards redline, the fuel injectors are all receiving an equalized amount of pressure, so that they can deliver the reuqired amount of fuel (the cars computer plays a huge role in this as well, mine is a simplified description). As you increase boost levels via a boost controller, etc, it becomes useful to watch fuel pressure so you can see if it remains constant or if it trails off as boost is present and rpms increase. If it remains constant, it means your fuel pump is adequate to flow the amount of fuel the motor demands for the boost level and rpm range you are running in. Often times, when you start turning up the boost on these cars beyond 21 or so pounds, fuel pressure will start to trail off at the upper rpm ranges, meaning the fuel pump is "running out of steam" so to speak and can not adequately supply the volume of fuel the motor requires. The solution of course is to fit a high volume fuel pump. Without a fuel pressure gauge, you might not know this is occurring though. For most people, you can do without fuel pressure as a gauge till you start getting into the larger turbos or really start running particularly high boost pressures.

Temperature is important for the sheer sake of the fact that oil operates best in a certain temperature range. In that range is where it flows the best, and where its chemical properties remain constant and can have a decent lifespan. If oil temperature is allowed to get too hot, the oil breaks down prematurely, and its ability to cool and lubricate diminsh rapidly. Generally speaking, your oil temperature should be a bit hotter than water temperature, so anywhere in the 190 to 220 range is acceptable for a street car. Obviously as you change the viscosity of your oil (its weight, or thickness), these factors might change. While monitering oil temperature is great, its really not needed except on cars that see alot of track time (lap after lap of on boost situations makes the temps rise much much faster than simple street driving or stoplight races! It's alos beneficial again for guys with higher level of modifications.

Usually we do boost, EGT oil pressure as the first three, then fuel pressure and oil temperature together as the last 2. For guys who track their cars alot, an aftermarket water temperature gauge is a nice ide, though not 100% necessary, depending on a variety of factors.

[Anonymous]

Wait what is exceptable temparture for the oil? I know the cooler the better, but also when i push my car to high speeds it goes from 65 to 75 farrenheit. Im sure that oil going past 90 is baddd, but everytime i change oil filter it makes temp go down? what is normal temp?

[mprtklr]

if you have the sport kit it is 65-75 Celsius, your oil is NEVER at 65-75 farhnheit.

[Anonymous]

i need to learn more i guess, lol

[xxfairenoughxx]

Speaking of gauges has anyone seen the ralliart gauges yet? I saw a picture of them in a sport compact tuner or one of those magazines and they look pretty sweet anyone know when and if they are available because the stock cluster sucks.

[ItsStockOfficer]

I like water temp guages alot. I have had more coolant issues then oil issues.

My oil temp is 65 degrees before I start my car in 65 degree weather...

[AD_LIB]

the ralli art guages are Uk/Jap only (KM/hr) and they reset your odometer :(...oy ya and they cost an arm and a leg too

[rizalhoo]

hey guys, how u peeps doing :)

anyhow i noticed that some gauges like the a/f gauge offers like the 02 sensor or something to do with o2, by the way, thats that for? and do i really need to purchase the o2 sensor to get an a/f gauge or whatsoever gauge ?

[han74j]

hey howie thats a very informative post thx