fpbig28 and s-afc tunning basics

[sethtroy]

any help would be greatly appreciated i am new to dsms and just got started with my 99 gst. i was thinking of getting a dyno tune but everyone says i should do it my self it is easy. so i am here to ask for some advice on setting the s-afc. my mods consist of:

fpbig28
greddy big fmic
550 injectors
magnecore wires
walbro 255 fuel pump
greddy type S bov
greddy upper and lower ic pipping
stock ported o2
3 inch downpipe
3 inch exhaust
injen intake
greddy turbo timer
greddy profec-b
apexi s-afc
egt guage
air/fuel mixture guage
boost guage

also i am running about 15 lbs. of boost right now. what would you think the most i can boost on the 550's i was hoping for 20 lbs. with everything tuned. manly looking for a mid 13 sec daily driver. thanks for any help dsm tuners i here is the best for advice so here i am.

 

[Blk_99gst]

Nice setup; but I hope you haven't put the 550's in yet. The NUMBER ONE mod everyone needs to get early on in the process is a tuning device, especially before going with a safc and bigger injectors. I think a logger and a safc should be sold together.

So if you don't have a logger; get one immediately. Go to www.pocketlogger.com; it's under 200 bucks but you'll need a palm device. At least you have an EGT gauge so you're not completely in the dark. Scrap the blinky air fuel meter unless you like the light show; but it doesn't serve any purpose.

I have other friends with 2g gst's with fp big28's who are boosting 19-20psi. I think it can be done, but I would be careful; it's very easy for the big28 to push hot useable air at that kind of pressure.

Best thing to do is to get a datalogger. Learn how to use it, capture some logs and if you need help post the logs up on here for opinions (To find out how to log just search throught the tuning section). Once you get things reasonably tuned via the pocketlogger, then it would probably be worth taking the car to a dyno and having them put a wideband o2 sensor on and see what your exact air/fuel radio is. Then you could squeak out a few extra ponies using that. Good luck; and get a logger soon!

 

[kpt4321]

He nailed it right on the head.

I want to back up his suggestion that you get a logger. Without a logger, tuning is just a very iffy guess. (Even with a logger, you're still guessing to some extent)

Once you get a logger, check out this little guide I have typed up:

http://home.attbi.com/~tarryo/kyle/tuning.html

It's not all-inclusive, but it should help you get on your way, and probably will answer some questions you have.

With the Big28, I think you should probably shoot for about 18 psi on pump gas. With tuning, 18 psi will pull damned hard.

....Kyle T.
93 TSi AWD "TURBO4"
14b - 12.8 @ 108