650cc and AFC

[DSM_GSX4life]

Do you have to install a S-afc with 650cc injectors??? or do you need a tuning device with big injectors?

 

[johnh]

Yes you will need some sort of fuel correction. The 650cc injectors flow almost 50% more fuel than the factory 450cc's do. Look into a SAFC or an HKS VPC. I am not sure of the price of the HKS, but I know that the new SAFC II is around $300 and does a lot more than just a/f corrections. You can find them in the parts catalog in the main menu.

 

[kpt4321]

What else does it do besides airflow corrections? Nothing that I can think of, except display things you could see on your logger anyway.

You need something to tune with the second you change you injector flow rate.

 

[DSM_GSX4life]

ok thanks guys. I have a s-afc to go with the injectors. Are they hard to tune. I dont really know how or what to do. Is there a web site that would tell me how?

 

[sp00ln]

ok thanks guys. I have a s-afc to go with the injectors. Are they hard to tune. I dont really know how or what to do.

Yes. I'd go with 550s with your turbo and get a data logger.

 

[DSM_GSX4life]

I already have the 650s as well as a big16g that is wait to go in. The turbo has to get fixed so thats all I am waiting for. Also where did all u guys with AFC's install them?? it looks too complicated for me.

 

[burldude]

There not hard to tune or install as long as you have the knock count calibrated right you can tune your car really easy with an safc . If you have a 2g car I have heard that you cannot hook up the knock feature . I dont know . It would really help to be able to data log your car and set the safc high points where your o2 is low or where you have knock in the power band . In your case with larger injectors you will just need to lean it out in the lower rpm range and depending on the amount of boost richen or lean it out in the 4k plus range . It is really simple once you start doing it . I put my Safc in place in 2 hours , the only problem I had was removing the computer . I have heard there is also an o2 function with the safc 2 but I have yet to use it ,or find it . Duh more research.

Edit Please do not use the o2 voltage readings if doing the blue wire mod . After research it is proven that the blue wire mod is useless and unreliable or vice versu.

 

[ltho98]

You will need an SAFC and datalogger to tune those injectors down to what you need.

For starters.. stock are 450cc's.. yours are 650cc's.. that means that you need to start off with about -30% across the low throttle just to keep your low fuel trims in a somewhat sober area.

Second.. leave it zero'd out in the high throttle and open it up in 3rd gear until you begin to develop boost. I hope you have friends with a wideband because this will help with a lot of headaches. Once you open it up and BEGIN to develop boost-- let off, it should be dumping so much fuel you'll be sputtering, take out fuel at that rpm point until the sputtering stops, note that percentage.. continue doing that and pulling more fuel at that rpm point until you begin to register knock. Then set the percentage of correction between the point at which it sputters and the point where knock registers. Then go to a higher rpm before you let off and take away/add fuel as needed. Complete for all rpm points and you're golden.. and you're going to eat a lot of fuel and time when doing this.. good luck.

 

[DSM_GSX4life]

ok thanks!

 

[diambo4life]

You are going to have very high advanced timing (easily in the mid 20's) due to your AFC settings being "so negative." Not a good thing. I would bump down your fuel pressure while keeping an eye on your IDC's or get a Keydiver chip to compensate for the 650cc's (best way to do it.)

At the track last year, my timing would peak at 28* with ~-28% taken out.