what gauges are NEEDED or a must have???

Generally the big three are boost, egt, and oil pressure.

Generally the big three are boost, egt, and oil pressure.

No, I don't think EGT and oil pressure are necessarry. The problem with those gauges is that by the time they give you a bad reading, the damage has already been done -- a dramatic climb in EGT or drop in oil pressure can end the life of a turbo or engine in mere seconds. By the time you noticed a drop in oil pressure, that engine could be welded it itself. You can use an oil pressure gauge to tell if you are low on oil, but by the time you've lost enough to make a significant difference in average oil pressure you should have checked your level by the manual means (dipstick) several times. I know I check my oil level at least once a week -- you can't squeeze 285hp out of 2.0 liters and not burn through your fluids.

EGT levels are more trivial knowledge than anything else; if your EGTs climb to dangerous levels (1500 and above) you've got a host of other problems and a car that is seriously out of tune -- EGTs are a symptom, not a cause. I've got an ECUtek ODBII monitor, and it shows my EGTs vary from 1,000 to 1,400 regularly, and at the low 800s sitting at a stoplight. That's a pretty broad range of data, and it would take a real expert to keep an eye on those numbers and determine whether a particular mod was causing an overall trend that was going to become a problem. Again, by the time those EGTs reach a dangerous level you could have cooked your turbo, cats or gaskets already.

What gauges you need are determined by what you are going to do with the car. If you are going to mod the car and race it on a track or off-road for long periods of time, I'd say a very accurate coolant temp gauge (not the junk that comes stock in the dash) and an oil temp gauge, as well as boost, battery voltage and fuel pressure. Fuel pressure is the most neglected gauge for some reason, but it is the most important data you could possibly need for racing -- being lean is much more destructive to an engine than being 1 or 2 psi low on oil. A drop in fuel pressure would give you a chance to save a car (pull over and turn it off!) that other gauges would not.

If it is going to be modded for street, and tinkered with more than once in its lifetime, you can get by with boost, a/f ratio, coolant temp and perhaps oil temp. An ODBII/ECU reader like I have, or even better an ODBII logger, is a much better tool for keeping track of how mods are affecting the car than trying to read a gague on your dash while driving; that is what the road tuners use, and they aren't more expensive than a few gauges and a dash pod.

If the car is just going to be used for some brisk driving, get a boost gauge and stop there -- the extra data won't do you any good.

thats is exactly what i needed to find out! thenx meilers! i dont think anyone else can beat that answer

They use EGT's to aid in tuning. Gauges are for monitoring your set up, not a fail safe for bigger problems.

That's my point exactly. EGTs are a great tuning tool on the dyno or for a road tune, but in daily driving not much use except to the most discerning expert.

I've got an ECUTek Data Monitor in my 02 WRX, and it monitors 14 different parameters from the car's ECU through the ODBII port; one of the things I have discovered, after three months of keeping an eye on the settings, is how amazingly consistent and stable the readings are -- what a nice piece of engineering the boxer engine is! It is fun having all that data, but if I'm not tweaking my hardware or software on a weekly basis it is more trivia than anything else. The major failure points of the car are coolant temp, oil pressure, fuel pressure and oil temp; a variance of +/- 10 or so degrees is not a big deal, but a spike or a drop is -- thus, they are indeed failsafes. If a tune creates unsafe conditions, that should show up on the dyno (unless you have a idiot for a mechanic/tuner!) before you ever get out on the road.

I think the one condition that I would really want to know my EGTs, A/F ratio, injector duty cycle and other data would be if I was using a unichip or Accessport and doing all my mods in my own garage -- and if I was really pushing the car to its edge.

egts in stock cars driven hard will reach excessive temperatures. see posts by azscoobie on nasioc.

meiler's assertion that a measurement of exhaust gas temperature flies in the face of years of engine tuning by hosts of experts. ime, it is by no means "trivial knowledge." you are free to make your own decisions.

I think you misread my post slightly. I didn't say EGT was always trivial information, it is just not necessary for the average stock driver. Certainly if the car was going to spend a long time under boost (on a track, for example) then EGT would become a necessity -- but I already said that befrore. In a stock car (or even lightly modded car) which will never see track time or seriously hard driving, an EGT gauge is more of a "vanity" mod; like I said, if it hits 1500+ you've got other problems to worry about (such as detonation) that you'll probably notice first.

if you think your stock/lightly modded car doesn't see 1500 degree exhaust gas temperatures on a regular basis, you're mistaken.