I'm deciding what gauge to get first. I have the boost and the useless A/F and now I need to further monitor my car. I have no way of tuning the fuel since I have the standard FMU with a 12:1 disk. Is it worth it to get the SFMU to tune the fuel curve? I'm running on stock injectors and a Walbro 225 inline pump. I'm thinking the fuel pressure monitors what's going into the cylinders and can identify major problems..then again the EGT monitors what's inside the cylinder, but then you can get high EGTs from going lean or going rich, so how do you know. PLease help me out..thanks
Alvin

96 RST

Star Stage I turbo kit /Starion I/C w/ 2" chrome piping / GReddy Type-S BOV / Missing Link / Custom APEXi- GReddy 2.5" exhaust / 55mm ARD TB/ Nology wires / APEXi EL mech boost gauge / Autometer A/F gauge / Southland Dual Friction clutch

EGT, definately.

fuel pressure is nice to know but once you set it, its set. EGT's on the other hand constantly change, its not MORE important necessarily, its just more practical to use the EGT on a daily basis.

example: 4th gear pull on the freeway, who gives a shit if you're at 80 psi of fuel? you could be at 1600 degrees and you dont even know it :nono

edit: the EGT shows exhaust gas temperature, not the temperature inside the cylinder. put it on the 3rd runner on the manifold, the rest is all in the search ;)
_________
96 talon esi-t
san clemente, ca

EGT definately. your setup isnt in need of a FP gauge since its simply stage 1.

EDIT: and i would definately get oil pressure before fuel pressure. you could save your turbo one day with it, or your engine ;-)

get a good egt gauge first, and just use a mechan kind of fp gauge in the engine bay for now. I did not get a full sweep fp gauge for inside the car till i had extra cash.
Michael
99gs HRC Stage IV 8-Injector Setup
2GNT Member #32

Cool..thanks everybody
Alvin

96 RST

Star Stage I turbo kit /Starion I/C w/ 2" chrome piping / GReddy Type-S BOV / Missing Link / Custom APEXi- GReddy 2.5" exhaust / 55mm ARD TB/ Nology wires / APEXi EL mech boost gauge / Autometer A/F gauge / Southland Dual Friction clutch

Get BOTH. Knowing your fuel pressure can be very, very helpful, not to mention an engine life saver..I would never turbo a car without an EGT, boost, and fuel pressure gauge. A/F is pretty worthless IMO. Lets say your car starts running like crap..lets say its the fuel pressure as the problem..you would never have known that unless you had a fuel pressure gauge. Yeah, once you set the FP, its set, but you never know when something can happen to upset that fuel pressure. LOTS of things can happen with the fuel system..way to important.

damn, i better get an EGT, ive had my turbo on since the beginng of the year with only a boost gauage!:o by the way, how much is an EGT guage?

both.



14.5 @ 95mph / 7psi 185hp/180tq :thumbsdown My car sucks

how is the AF ratio gauge useless? It tells you how much fuel your dumping in the car. Its a great tuning tool.

The EGT is important too, it lets you know how long you can push it for.

FP is import too I guess, helps you tune, where could I get a small gauge that attaches to that test port on the fuel rail? One that reads high enough anyway.

Originally posted by HadesOmega
how is the AF ratio gauge useless? It tells you how much fuel your dumping in the car. Its a great tuning tool.

On our cars, its not a good tuning tool. Knowing the exact A/F ratio under WOT full boost is very important, assuming you have the proper tools to measure it. The A/F gauges we use, weather it be the blinky light, or the numeric readout, all measure off of the stock o2 sensor, which is NOT very accurate. Its accuracy is meant to measure stoichiometric values, not a 11.5:1 A/F ratio. There is no way in hell i would tune by an A/F gauge using the stock o2 sensor. Its more of a "ballpark" type of reading, which is pretty useless IMO. I dont think I have ever looked at my A/F gauge when i'm full out boosting it hard. My eyes stay planted on the EGT gauge. I also listen to the motor. I listen if its starting to break up, or hear any small amounts of detonation. If so, then richen it up. I look at the EGT, and just watch it. If it goes up slowly, and at the top of 4th gear at WOT, the EGT is not above 1550, then I know its got enough fuel. If the EGT rises quickly, and gets real hot, much faster, then its too lean. I have never tuned using the A/F gauge or the stock o2. Its just not very accurate. Now, using a wideband o2 sensor, that is the BEST way to tune. My eyes are always on the EGT gauge when I'm full boosting it hard.. An EGT gauge will tell you damn near everything you need to know about how much fuel the motor is getting. Knowing how to use it, and how to interpret what you are seeing is very important to do it right.

If your EGTs can rise if you go too lean and if you go too rich..how do you tell which is which? Hearing detonation = lean and smelling fuel = rich??
Alvin

96 RST

Star Stage I turbo kit /Starion I/C w/ 2" chrome piping / GReddy Type-S BOV / Missing Link / Custom APEXi- GReddy 2.5" exhaust / 55mm ARD TB/ Nology wires / APEXi EL mech boost gauge / Autometer A/F gauge / Southland Dual Friction clutch

Originally posted by Semperboost
If your EGTs can rise if you go too lean and if you go too rich..how do you tell which is which? Hearing detonation = lean and smelling fuel = rich??

If your EGT's are rising because of afterburn(wayyy to rich), then you will know it. If its that rich to cause that, then the car will be very sluggish, and black smoke pouring out the exhaust. Its normal though to have a bit of black smoke out the exhaust, because we do need to run pretty rich under boost. Also, a quick look at your spark plugs will tell you just as much info also. Learn to read your plugs, as that is a great tuning tool also.

so how long does it take for the spark plugs to change conditions (from say, tuning lean, to rich, to just right).

i'm at 5psi so is my af gauge useless (i have the apexi tt); how about the 02 gauge on the apexi tt. i've read that the af gauge is a theoretical calculation, but the 02 is real time, so should i tune with the 02?

-------jezreel
hrc stage 1, sfmu, ml, prokits, egt, boost gauge, apexi tt, costum dp, dynotune fp gauge. gst muff, turbo spoiler

Originally posted by jsupetran
so how long does it take for the spark plugs to change conditions (from say, tuning lean, to rich, to just right). i'm at 5psi so is my af gauge useless (i have the apexi tt); how about the 02 gauge on the apexi tt. i've read that the af gauge is a theoretical calculation, but the 02 is real time, so should i tune with the 02?

Wont take too long for the plugs to show how its running. If you are running really rich, then they will get black pretty quick, within 50 miles I would think. For normal wear on the plug, give it a few hundred miles to check em out. A/F gauges and o2 gauges, whichever, all run off of the stock o2 sensor, and both give the same readings really. Now if you are talking about a "wideband" o2 sensor, like dyno shops use, then yes, that is real time, and very, very accurate to measure your true A/F ratio.