IntegxX

iTrader: (6)

Im about to install the safc II and want to tune at 25 psi boost. Would i need to get bigger injectors (720cc) in order to safely boost 25 when i take it to get tuned or would the stock injectors with the 255 walbro fuel pump be fine?

Warrtalon

iTrader: (6)

Stock injectors with Walbro will be fine for running 25psi. The S-AFC portion of that is not relevant, but I would certainly not recommend using an S-AFC as your tuning advice if you're going to rely on someone else to tune it. The S-AFC is for tuning yourself and is mainly for low power applications, since it can't control timing. A flash or more advanced piggyback will give you a far better tune, especially since you're talking about running full-time on meth or race gas (re: 25psi). Please reconsider if you still can...

MitsuEvoIIX

iTrader: (11)

I wouldnt suggest you running 25psi unless you have alky of course

IntegxX

iTrader: (6)

I plan to get alochol injection in spring. But for now im running a dual stage boost controller (so its not going to be running full time on 25psi) so i want to tune on my high boost (25psi) with the walbro and the safc. (its going to be tuned by a shop). What do you think about getting a flash, then tuning the safc on top of that? Also, what can i buy to control the timing and tie it in with the safc tuning? thanks

Warrtalon

iTrader: (6)

Uh, you can't run 25psi without alky. That's just dumb. You should not go trying to tune on high boost like that with pump gas when you'll later have alky, because the tune will change. It's not like you can go tune it now and just slap on the alky later and think it will work. That's absurd. I also told you there's no reason to purchase/use an S-AFC if you're just having a shop tune it. That's a waste of money and a waste of a mod.

I now run my S-AFC on top of a base flash. I think that works great, because your timing is already set by the flash for the mid-range (can't do this with s-afc), but you are able to fine-tune with the S-AFC, especially when at the track and using race gas.

There's nothing for your last question. If you want to control timing, which you should want to do, then you don't get an S-AFC. The S-AFC is for basic tuning with basic mods.

IntegxX

iTrader: (6)

The thing is i already have an safc from my previous car and i dont think i should just leave it to waste. Also, i didnt plan on slapping on the alky kit and thinking it would work, i was planning on tuning on high boost then when adding the alky kit, re-tune, but now i know i cant run 25 psi without the alky kit, thanks. So i should just wait until i get the alky kit in order to get the flash/run higher boost, then use the safc to fine tune ontop of that flash? Also, would i need bigger injectors to support the 25psi/alky injec. or would the stock injec. work fine with the walbro fuel pump? Thanks

Warrtalon

iTrader: (6)

I already answered that in my first response:

Yes, I suggest getting the alky and a flash for all of your mods, then install the S-AFC and use it to fine-tune. Be sure you have a wideband O2 for accurate AFR readings, and a logging device to watch your timing.

mchuang

iTrader: (11)

If you have a pretty conservative base flash with afc..at like 21psi..and still using stock ecu..wont the ecu yank timing if the knock sensor voltage gets in the range where knock is about to occur

Warrtalon

iTrader: (6)

Having a flash means you have the stock ECU.

Yes, if the ECU detects knock, it will retard timing, but what is your real question? That didn't really have anything to do with a flash or S-AFC...it's just a basic ECU function.

Inn-Tune

iTrader: (33)

Nobody has said anything about the fact that boost level doesn't determine fueling requirements alone.

25 psi on stock cams is not the same as 25 psi on 272s
25 psi on stock exhaust is not the same as 25 psi on a catless turboback
and while I think you're assuming this is on the stock turbo...
25 psi on the stock turbo is not 25 psi on another turbo

Airflow is the key. You need fuel to match the airflow you're pushing in the ratio you want (air/fuel ratio). As an example...If you have big cams you're going to max the stock injectors a couple pounds of boost lower than a car without them on an otherwise identical setup at the same air/fuel ratio. Head work, oversized valves, and other mods that aid in airflow all require extra fueling.

Watch your injector duty cycles, wideband, knock, and EGT readings.

-Mike

IntegxX

iTrader: (6)

Thanks for the info warrtalon and mike. i was also wondering... lets say i get the alky kit, boost 25 (on the dual stage boost controller), stock turbo/cams, tbe, ss manifold, turbosmart bov, intake, 255 fuel pump.. and i get a tune on 25 (high) psi/alky kit, then i fine tune with the safc after that. wat would happen if i switch back to stock psi on my low setting on the boost controller for daily driving? will it drive fine so when i just want to turn up the boost/turn on the alky injec. itll work fine?

Warrtalon

iTrader: (6)

No, you would run terribly rich, but if you have the S-AFC II, it has 2 maps. You could use one map for one boost setting and another map for the other boost setting. But the point of alky is that you're able to run 25psi all the time everywhere, so you typically get tuned for that and never turn the boost down. There's just no need to do that, but if you want to for some reason, then set up 2 maps.

Inn-Tune

iTrader: (33)

Like he said, get a map tuned for each setting. It can hold two.

Lowering the boost and turning off the alcohol injection while running your high boost + alky injection tune could actually make the car run lean and detonate.

-Mike

IntegxX

iTrader: (6)

Alrite thanks. So u just switch between the 2 maps inside the safc then huh. See , I wanted to do the 2 maps because i use the car as a daily driver so i dont want to be constantly pushing 25psi and wearing down the engine. But thanks for the info, it helped alot.

Inn-Tune

iTrader: (33)

Yup it's real easy to switch back and forth. That would be the best bet. Good luck!

-Mike