Injectors, spark plugs, and MBC: the basics of tuning, or something

[AlphaAssault]

An aftermarket boost gauge is on the way, but i have some other questions about the setup in my GSX. I recently pulled the spark plugs and replaced them. I examined the old ones, and everything seemed to be in good order. If anything, i might be running a little on the rich side, and this is actually one of my questions: the ideal color for a spark plug after use is light tan on that center, originally white, piece. If im reading the guides correctly, if you are running lean, you get white scorch marks on the plug; where as the richer you are running, the darker the tan on that center piece. is this correct?

Assuming I am reading those spark plugs correctly, my car appears to be running about where it needs to be, though the center pieces on all 4 plugs was creeping towards a darker shade of tan; i.e. i am running a little on the rich side. What i dont understand is how i can be running somewhat rich with a small 16g turbo, with the MBC almost fully closed (more boost). Is the stock fuel system capable of completely supporting a small 16g, or is it sounding like the previous owner dropped in an aftermarket fuel pump along with the turbo? Or is there something i am completely overlooking that i should factor into this equation?

 

[kenamond]

I read plugs the same way. White=lean, orange/tan=good, black/sooty=rich. We want tan/orange.

What boost are you running?

Have you done a boost leak test recently/ever? Boost leaks will make you run rich under load.

Do you have a logger? If so, what do your trims look like at idle? If not, get one

What plugs are you using?

 

[AlphaAssault]

I not sure, at the moment, how much boost this setup is putting out. I did check for boost leaks a few weeks ago, and everything seemed good; though i dont drive the car very hard at all, so even a boost leak shouldnt have much of an impact. I dont have a logger, and im using the pretty-standard NGK bpr6es plugs.

 

[kenamond]

After you get the boost gauge installed it'll tell you how fast you're leaking air in a boost leak test. You should be able to pressurize to say 20psi and have it leak down 1psi every few seconds or longer. Loggers for a 1g are VERY cheap. Get an old Palm from eBay for cheap, an interface (cable) for super cheap, and install MMCd for free. Then you can tinker with raising boost and use the logger to know how far you can go without problems.

 

[tbhola]

Kenamond,


I was curious to see if you had any links or carnal knowledge that would give some more specific info on the capabilities of a datalogger, pros v. cons. etc.etc. Also some pricing for the components that are necessary to run a datalogger? TIA!

 

[kenamond]

Kenamond,


I was curious to see if you had any links or carnal knowledge that would give some more specific info on the capabilities of a datalogger, pros v. cons. etc.etc. Also some pricing for the components that are necessary to run a datalogger? TIA!

I have a 2g, and the loggers are different. From what I can gather, MMCd and OBDGauge are both very good and both very free. An old PalmIII logger is adequate. Color is optional but nice, backlighting is very useful for night pulls, and a rechargeable battery is highly recommended so you don't have to keep changing batteries. The 1g interface is less complicated than the 2g, and you can make it yourself or buy it cheap (the interface is the cable that goes from the PDA serial cable to the diagnostic port on the car).

I bought my refurbished PalmIIIc for $80 shipped off of eBay a couple years ago, but you could find one cheaper for sure. My wife got a PalmIIIce or something for $1 at a thrift store (doesn't have rechargeable batteries, but otherwise identical to my PalmIIIc). If you find good deals, you could probably have the whole setup for $25 or less. 2g loggers are in the $125-150 range or more depending on how cheap of a PDA you can find.