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Meat Popsicle
91 CRX Si
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Discussion Starter #1
Looking for a new boost gauge but the one I would like to get is $193 because it includes a MAP sensor.

What's the advantage of having a electrical vs a mechanical sending unit for my boost gauge?
 

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Meat Popsicle
91 CRX Si
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Discussion Starter #3
Well right I get that part...but what is the advantage of running one vs the other?

Is the digital sending unit more accurate?
 

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1988 Honda CRX
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Mechanical gauges are generally more robust and accurate, but it depends on quality. A good electrical beats a shitty mechanical.

Electrical is easiest to fit and in some cases safer. Fuel pressure for instance.
 

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Mechanical gauges are generally more robust and accurate, but it depends on quality. A good electrical beats a shitty mechanical.

Electrical is easiest to fit and in some cases safer. Fuel pressure for instance.
I wouldn't be as concerned about accurate compared to safety wise. It's obviously going to be off somewhat, but you really only use gauges as reference not exact readings. So to answer your question, get which ever one that fits your budget. But if you are thinking about running something liquid like oil pressure or fuel. Always stick with electrical, I would much rather have it leak outside of the car. I used a mechanical oil pressure gauge twice and they both leaked inside my dash. But if you really want to know how accurate in terms of boost you are seeing just read right off the MAP sensor using your ems.
 

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ej8
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Call me old fashioned, but I generally prefer mechanical gauges.

Besides, they are usually cheaper.

:smile:
same here electrical tend to mess up or weaken due to wires, but somethings are a must for electrical gauge like oil and fuel pressures.

Im using a mechanical boost aways have and aways will.
 

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88 hatch
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I will never again use a electrical oil pressure gauge. Especially a autometer to one. If you run a mechanical oil psi gauge to do it right you are suppose to run a -3 or -4 an line to it for the most accurate reading. AN lines and fitting tend to be much better at sealing and being long lasting than that gay 1/8 plastic crap that comes with the gauge.

Also run a mech gauge they are close enough to be useful to keep an eye on things while driving. When tuning though rely on the map sensor reading for boost.
 

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See above...
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If installed correctly, a mechanical would have less failure and no leakage. I loved my Autometer 3" mechanical!

For an electrical, you either have to hang that large sending unit off at an angle or rig up a nice remote setup. Obviously no chance for leaking inside the cabin.

Personally I prefer a mechanical.
 

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A mechanical will tell you what's in your manifold....the electrical will tess you what your map sensor reads....mechanical gauges generally are much more accurate....although on map based engines, like ours, electrical is better from what I understand
 

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1988 Honda CRX
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On a race car I actually normally use industrial quality gauges like used on chemical process plants. They are tough and accurate. They are not pretty though.
 

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ej8
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Boost - Mechanical.

Everything else, electrical. Too dangerous to have that stuff in the car.
+1
Seen a guy have a car crash and gauge busted then oil went everyway. Also you can get a leak or bad gauge
 

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Meat Popsicle
91 CRX Si
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Discussion Starter #16 (Edited)
Thanks for all the input guys. I think I'm going to have to end up splurging and going for the electrical. I want this gauge:



But it's only available in an electrical version.

I can't seem to find any mechanical boost gauges that have the layout in terms of the 2.5psi tick marks. Anyone know of one that has a similar look? I'm only going to be running 10-12 lbs of boost so I'm looking for a gauge that shows more detail between 0-5, 5-10, etc..
 

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1988 Honda CRX
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I have never worried about safety with a mechanical oil pressure gauge or with a boost gauge where the fuel is injected downstream of the gauge.

Fuel is a whole different story for several reasons.

1) If the gauge sprays fuel into the cabin a fire can start. This is unlikely with oil.

2) In a crash the engine most likely stall and oil is not pumped, but the electric fuel pump keeps going.

3) If oil leaks it is normally a slow leak and it takes quite a while for dangerously hot oil to come out the gauge or line. Even with a disconnected line, it has to be hot oil and has to hit you directly to cause damage to you. A small amount of fuel burning in the cabin can hurt you even if it sprays some distance from you.

That is kinda why sanctioning bodies allow mechanical oil pressure gauges in the cabin, but not fuel pressure gauges without a firewall isolator fitting.
 

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honda/firebird form.
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+1
Seen a guy have a car crash and gauge busted then oil went everyway. Also you can get a leak or bad gauge
in a serious car crash the last thing i would be worried about is some oil getting on you... esp after a serious front end crash, the engine will shut off, and therefore no oil getting inside...

mechanical hands down is the best and most accurate way to go..

there are too many ways for a electrical gauge to fail...

use copper line with the mechanical gauge and they will be no chances of anything bursting... thats the only type of line i would ever use on a mechanical gauge.
 

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97 honda coupe
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im all for the electric gauges, for everything from oil to boost.

Mainly im using the oil pressure gauge for a general idea of my oil pressure, and my dummy light is a backup to that. If im getting 0psi dummy light comes on and gauge should match, if im getting 50 or 60 im over 10psi obviously and if im 1 or 2 psi off in either direction im ok with that.
 

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How about using an isolator? At least on a mechanical fuel gauge.
 
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