Hey everybody. I would like to buy some gauges but I am not sure if I should buy the Mechanical or the electrical ones. Which different gauges would you suggest that I buy? I know that I will be purchasing a Boost gauge but am unsure on the rest. My WRX is stock for right now but I plan on moddifying her with larger turbo, I/C, Injectors, and so on. What gauges would you suggest that I buy? I know this sounds really stupid but I could really use some good advice. Also how hard are the gauges to install? Thanks in advance.

Boost and EGT to start....You might consider a PSI*3 S.E.C.S. unit (a search may find it...) or...

http://quantum-racing.com/shopsite_sc/store/html/Electronics.html

I went with boost, EGT, and oil pressure. I'd highly recommend at least boost and egt. Be sure whatever gauges u get are electrical. They are fairly simple to install but if you're unsure or have problems there are some very good instructions floating around here and on www.scoobymods.com (http://www.scoobymods.com)
As far as brand goes thats up to you, but i'd personally pay a little more to get a better quality gauge like greddy or blitz...i went with greddy:D

I got the omori gauges from www.gruppe-s.com

I am very pleased with them. if i didn't do omori, i would have went with defi.

I would at opt for a Turbo gauge (Boost/vaccuum), Oil Pressure and EGT (considering your future modifications).

As far as brands, what are you looking for (i.e. stock looking, flashy, etc.)? I went with Omori gauges since they matched the stock gauge cluster really well (green backlit, yellow needles......red for the '04). I've been very pleased with their performance.

- Kean

Definitely get Boost and EGT, and then oil or water temp if you like. I had Autometers and HATED them, so I switched to 60mm Greddy P/H/W Electrical gauges. They also match the dash lighting extremely well and work flawlessly. Huge improvement over autometer.

Boost and EGT are the musts. Get electrical gauges, you are better off in the long run.

Whatever you do... don't waste money on an air/fuel gauge.. they're not at all accurate.

And what's the difference between mech and elec gauges?

Mech takes whatever you're measuring to the gauges. Ex: Oil pressure will actually bring oil to your gauges.

Electrical just uses sensors to bring the signal to your gauges.

Electrical is better cause if your mech oil pressure gauge breaks, you'll have to deal with oil in your cabin :p

Electical is better... Mechanical is better...

Good lord, it really depends on what you want and what you're doing.

One difference between these two that is FACT is that ALL electrical gauges will have only 90 degrees of sweep in their measurement. (Don't start in with "A tach is an electrical gauge!" Those work on a completely different principle, and are not part of this discussion.) They will only make a quarter turn, usually from about 10 to 2 if you imagine a clock face.
http://www.sw-performance.com/Im-bas/ElGaCol1.jpg

A mechancanical gauge will give you a much larger amount of sweep, perhaps 270 degrees. Like so:
http://www.sw-performance.com/Im-bas/MechCol.jpg

Pros of mechanical gauges:
-greater resolution due to greater swept area
-they work without any electricity, like when the car is off or when your electrical system is f@#ked
-if they show anything, the reading is very likely "real"

Cons of mechanical gauges:
-whatever they measure has to be routed to the back of the gauge. This is not an install for the timid or inexperienced. Imagine a fuel pressure gauge: one wrong move and it's spraying gas all over you.

Pros of electrical gauges:
-no need to route oil, coolant, gas or whatever into the inside of the cabin.
-routing a wire is easier than routing a tube or hose

Cons of electrical gauges:
-poor connections can make a gauge read crazy. You think it's working, because the gauge is moving, but it's not accurate anymore because of a bad connection. Surely we've all experienced a gas gauge in an old car that never reads full or never reads empty? That's the problem with electrical gauges.
-You also need sensors. These sensors usually have a degree of non-linearity to them. Does the gauge make up for this? Maybe.

So it comes back to: what do you want, what are you trying to do, and how skilled are you?

Cheers,
Anders

Originally posted by anders8
Electical is better... Mechanical is better... Good lord, it really depends on what you want and what you're doing.
Agreed.

Originally posted by anders8
One difference between these two that is FACT is that ALL electrical gauges will have only 90 degrees of sweep in their measurement. (Don't start in with "A tach is an electrical gauge!" Those work on a completely different principle, and are not part of this discussion.) They will only make a quarter turn, usually from about 10 to 2 if you imagine a clock face.
http://www.sw-performance.com/Im-bas/ElGaCol1.jpg

A mechancanical gauge will give you a much larger amount of sweep, perhaps 270 degrees. Like so:
http://www.sw-performance.com/Im-bas/MechCol.jpg
False. Here are some examples:
http://www.omoriusa.com/gauge_pictures/aeco-225-bz.gif
http://www.omoriusa.com/gauge_pictures/aeho-222-bz.gif
http://www.omoriusa.com/gauge_pictures/aep-215-bz.gif

Originally posted by anders8
Pros of mechanical gauges:
-greater resolution due to greater swept area
-they work without any electricity, like when the car is off or when your electrical system is f@#ked
-if they show anything, the reading is very likely "real"
- False (see above)
- True. This is why they are primarily found in racing applications (no electrical draw). However, in a street application you will still need to wire the gauges for lighting purposes. Personally, I don't see what you would want to monitor when the engine off in your car so I don't see this as an advantage.
- True, but this is the same for any modern, well built electrical gauge.
Also, mechanical gauges are usually less expensive than their counterparts.

Originally posted by anders8
Cons of mechanical gauges:
-whatever they measure has to be routed to the back of the gauge. This is not an install for the timid or inexperienced. Imagine a fuel pressure gauge: one wrong move and it's spraying gas all over you.
- True. Although gauges such as "boost/turbo" are quite safe and easy to install (provided you don't kink the line).
Since a fuel pressure gauge isn't a common item to add to your car, a better example would be oil. Mechanical gauges require that you bring engine fluids into the cabin. This is a potential problem if a line gets cut, cracks, or otherwise leaks (very messy).

Originally posted by anders8
Pros of electrical gauges:
-no need to route oil, coolant, gas or whatever into the inside of the cabin.
-routing a wire is easier than routing a tube or hose
- True.
- True.

Originally posted by anders8
Cons of electrical gauges:
-poor connections can make a gauge read crazy. You think it's working, because the gauge is moving, but it's not accurate anymore because of a bad connection. Surely we've all experienced a gas gauge in an old car that never reads full or never reads empty? That's the problem with electrical gauges.
-You also need sensors. These sensors usually have a degree of non-linearity to them. Does the gauge make up for this? Maybe.
- True. ....but do the job right and you shouldn't have a problem. Problems with mechanical gauges can also be attributed to improper installation.
- True/False. Again, it depends on the quality of the product. Modern sensors can be very reliable and consistent.
Also, you could consider the price of electrical gauges as a "con" since they tend to be more than mechanicals.

btw, what made you revise a month old thread? =)

- Kean

Hey Kean,

False. Here are some examples:

I would classify those as "electronic" gauges, not "electrical" gauges, which is only my personal differentiation for those devices which employ silicon / microprocessors.

Old school toaster: electrical device
Microwave with processor: electronic device

The only way a "traditional" "electrical" guage works is applying more and more current, creating a larger and larger magnetic field, pulling the element (needle). You can't get more than 90 degrees out of that system.

Now, of course, put a small stepper motor and a microprocessor, and you can do whatever you want. :) Lots of high end tachs work that way, since these guages seem to have other features built in to them, I'd suspect microprocessors, but who knows, I couldn't find much info.



-they work without any electricity, like when the car is off or when your electrical system is f@#ked
- True. This is why they are primarily found in racing applications (no electrical draw). However, in a street application you will still need to wire the gauges for lighting purposes. Personally, I don't see what you would want to monitor when the engine off in your car so I don't see this as an advantage.


Oh, this is easy. I only put guages in race cars. For oil pressure, which I feel is really the more important 'safety' gauge, I like mechanical. For street cars, gauges are mostly toys (fun toys) so I wouldn't care too much.

btw, what made you revise a month old thread? =)

I was searching for info on the thread size of the oil pressure sensor. For those that are interested, my engine (EZ30) uses a 1/8 BSPT, 28tpi. Not to be confused with a 1/8 BSPP, or the more common 1/8 NTP (27tpi). Curiously, no one else has mentioned any trouble, so I'm guessing that 1.8, 2.0, 2.2, 2.5 blocks use something else.

Anders

Originally posted by anders8
Hey Kean, I would classify those as "electronic" gauges, not "electrical" gauges, which is only my personal differentiation for those devices which employ silicon / microprocessors.

Old school toaster: electrical device
Microwave with processor: electronic device

The only way a "traditional" "electrical" guage works is applying more and more current, creating a larger and larger magnetic field, pulling the element (needle). You can't get more than 90 degrees out of that system.

Now, of course, put a small stepper motor and a microprocessor, and you can do whatever you want. :) Lots of high end tachs work that way, since these guages seem to have other features built in to them, I'd suspect microprocessors, but who knows, I couldn't find much info. Hi Anders, I can't debate about the difference that you speak of because I'm not intimately familiar with electric/electronic gauge design. GReddy calls them electronic, Omori calls them "electrical", and manufacturers like Autometer refer to them as electric (who happen to offer a "full sweep, electric" gauge). Either way, my point was that not all electric/electronic/electrical gauges are limited to the shallow sweep you spoke of.

Originally posted by anders8
Oh, this is easy. I only put guages in race cars. For oil pressure, which I feel is really the more important 'safety' gauge, I like mechanical. For street cars, gauges are mostly toys (fun toys) so I wouldn't care too much. Gauges can provide a useful function in a "street" car (not just for racing applications). All gauges serve a purpose and they all have a level of usefulness. Sometimes their usefulness can change depending on what you do with your car. It seems some folks are under the impression that your engine's vital functions are only worth monitoring if you modify/race. Does this mean that folks who modify their vehicles are the only one's who will run their cars hard.....or have problems......or want to get the most from their car's performance/economy? Don't get me wrong. The justifications for modified/race cars are usually stronger (for example): The chances of a system failure is increased as you upgrade the engine's performance and the importance of keeping an eye on "vitals" is greater. Also, some gauge types can be indispensable for tuning/monitoring purposes after modification. A couple examples of practical use in a street/occasional track application:

- Boost Gauge: can alert you of potential problems (i.e. loss of boost, erratic readings, etc), but it's also a valuable tool to get the most performance/economy from your engine. I use mine to change my driving habits when I want to get the best fuel economy (I stay out of boost). It's also been an awesome tool in helping me with my driving technique to obtain the best performance from my car.

- Oil Pressure: oil is your car's life blood. Leaks, temperature, oil level, etc. can affect your readings. With a high performance, turbo charged vehicle, it's value is greater. I have an Omori gauge with an adjustable warning light. I currently have it set ~20 psi. Basically, an oil pressure gauge can alert you to potential problems way before the "idiot" light illuminates. I now know what my engine's normal operating ranges are and what to expect. If something is not right, I'll know about it.

- Oil Temp: it's the best indicator as to when your engine is up to it's normal operating range and can alert you of over-heating problems. You'll notice that it takes several minutes longer for the oil to reach temperature after the water does. It's a great tool to make sure you car is fully warmed up before running your car hard and to make sure it's cool enough before you shut it off after a hard run.

- Kean

Without reading all the above posts casue some are too long, i'll throw in my 2 cents...

If you want inexpensive gagues that match the factory gagues almost perfectly go with VDO. Their green bulb condom matches well, it's just the needle color that is off (on the 03 wrx anyway).

I would say boost, oil pressure and EGT. Oil temp is sorta unecessary because as your oil warms up your pressure at idel drops, so you know when your oil is at its operating temp. On a track car i would want both oil temp and press.


For the EGT and oil pressure get electrical...for boost it doesn't matter much.

Originally posted by Kwyjibo
Oil temp is sorta unecessary because as your oil warms up your pressure at idel drops, so you know when your oil is at its operating temp. Shortly after installing my Oil Pressure gauge, I discovered this as well. This is what I use in the mornings (I don't have an Oil Temp gauge).