I'm planning on buying an sti UTEC soon, but before I do that I need to install some gauges. I like the look of the autometer center dash pod, but with only Boost + EGT gauges I'm left with one hole to fill up. Anyone have any opinions on what to put in there?

I've seen some people mention oil temp and oil pressure gauges, but I'm wondering if these are actually directly applicable to tuning or if people just get these for general engine monitoring. If they really are useful I'll get one, otherwise I'm just going to get a 52mm clock and call it done :D

Thanks in advance...

The oil temp guage is nice because it tells you when the car is really warmed up enough to get on it. When the oil temp goes too high it can be an indicator that you should let off a little.

oil pressure
or fuel pressure

if nothing else fuel pressure moves alot (blinky light factor)

You can put a fuel pressure gauge in the engine bay. Although it cant be readily seen, I dont think it is as important. So, I would say either of the guages for oil.

Hmm, then between oil pressure and oil temp, which would be more useful? I'm still kind of unclear on what I would use an oil pressure gauge for.

Thanks a lot for the help guys, it's much appreciated :)

I believe that the oil pressure would be best for something like blowing a gasket or something. You would loose pressure and power, but you probably wouldn't need a gauge to tell you something was wrong. I would probably go with the oil temp. myself. Especially if you are going to try and reach high hp numbers, because it would give you a better idea of how quickly your car cools. Plus, the oil temp and the water temp are usually about the same, so it is almost like getting two guages for one. But dont fully rely on it for the water temp.;)
EDIT: This is what my knowledge on the subject is. It is limited, so apply wisely.

Excellent, thanks all. One last question: I found an oil temp gauge that reads between 150-300 degrees F. Is that sufficient range?

IMO, I think that the oil pressure gauge is more important than the oil temp gauge.

Oil temp isn't really an issue with the WRX because of the excellent oil-water cooler it has. Oil temp is fine about a minute or two after the water temp gets up to normal.

Now, oil pressure will also give you an indication of the oil temp (oil is thicker when cold, you will notice the oil pressure gauge peg the meter when cold). After a short while, you will easily be able to tell if the oil is warmed up by looking at the oil pressure gauge (assuming that everything else is normal with the car).

Additionally, oil pressure will let you know of the health of your oil pump, and bearings, and if you are getting any oil starvation in high G corners.

Originally posted by drees
Additionally, oil pressure will let you know of the health of your oil pump, and bearings, and if you are getting any oil starvation in high G corners.
Good point, but this would depend on his application. I believe oil temp might be better for drag racing and oil pressure for autoX.

If I had to choose between oil pressure or temp, I would choose oil pressure whether I was drag racing, autoXing, tracking it, or daily driving it. Your oil is not going to overheat unless your coolant is also boiling over, the WRX oil cooling system is that good. However, if you experience some detonation while racing, you want to know if your oil pressure dropped because you damaged the bearings.

Good point again. Makes sense.;)

No one's said anything about a/f ratio?? I'm not the most experienced tuner in the world, but I've heard this is a fairly important indicator. Anyone have any other input on air to fuel??

Unless it gives you an exact read out, it is just a fancy light show.

From what I have been reading and hearing an AF gauge acts as a cheap substitute for the EGT gauge. But he already has an EGT gauge, and lets say his EGT's are high, I guess his A/F ratio is messed up and he wont need an actual A/F guage to tell him that. Kinda redundent. With an AFC you would tune until the EGT's are good and you should be able to safely assume that your A/F ratio is good.

my 3.5 cents

Since my wrx came with the boost gauge on the steering column, I put EGT, A/F, and oil pressure in my pod. Just like on here nobody I talked to could agree on the third gauge. The greatest Idea was a guy somehow fitted the stock clock back in the third hole. Does that help?

Originally posted by 5spdfrk
Unless it gives you an exact read out, it is just a fancy light show. Yep, you need a wide-band to get any really useful information out of an A/F gauge.

a/f - blinky lights .. unless you can log it, in comapirson with the rest of your engine paramiters.. aka worthless

fuel pressure gage in the engine bay is pretty much useless unluess your running a carborator.. you need to see it when the car is makeing boost to make sure that the pressure ratio is maintained

or you coudl just buy a huge honkin pump and not worry about it

I wish I could find a clock that would fit in the gauge pod.. it sucks not having a time piece in the car.. but I'd go with oil pressure instead of the fuel pressure that's currently in my gauge pod (along with boost and EGT).

Originally posted by Jaxx
fuel pressure gage in the engine bay is pretty much useless unluess your running a carborator
Not true, I have one in my NA car and before I got it I was getting some knocking. I got the gauge and it was reading that I was 20-22psi when I was needing 40-41psi, but I only needed it because I upgraded my stock fuel system with some AEM pieces.

Oil pressure.

oil pressure

Originally posted by PeteDucati
I wish I could find a clock that would fit in the gauge pod.. it sucks not having a time piece in the car.. but I'd go with oil pressure instead of the fuel pressure that's currently in my gauge pod (along with boost and EGT).

VDO makes a nice one in 52mm.

http://www.egauges.com/vdo_mult.asp?Type=Clock&Series=Vision&Cart=

Originally posted by nhluhr
VDO makes a nice one in 52mm.

http://www.egauges.com/vdo_mult.asp?Type=Clock&Series=Vision&Cart=

Thanks! I'm there, dude.

Yeah, I was going to get the same thing, until I noticed this (from the same page):

"Notes: Quartz movement, with sweep second hand. This part has been discontinued. Available only until stock is depleted."

:(

The Autometer Z-Series clock looks almost the same: http://www.egauges.com/vdo_mult.asp?Type=Clock&Series=Z-Series&Cart=

And it's $10 cheaper! :disco:

www.summitracing.com has by far the least expensive gauges. that egauges wanted 30 bucks for the vdo fuel pressure, summit wanted 20 bucks.