Everyone says the afc is only good till 12lbs.

Is this becuase in order to run the correct a/f at higher lbs you need to set the trim higher, and if you do that it throws CE???? If that is the case two other questions

1. Why does the higher correction throw CE......because of MAP?

2. If it is because of MAP could i just throw a check valve in?\

Someone that seriously knows the system, please help a brotha out.




[Modified by BorderM3, 7:23 PM 1/9/2003]

 

Bizump over the hizump to the tizop so i can bizoost.

 

I'm not sure what you mean by higher correction. Do you mean lessening the trim to say -35% from -45%? If that's so, the less correction you run, the less the AFC lowers the voltage signal from the MAP, so eventually you'll lessen the trim so much, that the voltage from the MAP will begin to show boost to the ECU, in which case the ECU freaks and throws a code.

If you throw a check valve on there, you'll prevent the MAP from ever seeing positive pressure, in which case you'll negate the purpose of the AFC hack. If the MAP doesn't see boost, the ECU won't fuel for boost, you'll go very lean and *BOOM*! The MAP needs to see boost so the ECU can fuel acordingly, but 11-12psi is the factory MAP limit, so that's the limit you can safley run on the AFC hack.

 

The exact amount of PSIs you can run depends on the correction factor, so max boost you can use will depend on how you dial it in, and what size injectors you run. If you use 390's you will not be able to even run as much PSIs as 450's. You could try 550's. Those might allow you to run more than 12psi because you would be dialing the map down more. Not sure how that would run, or if it would work well tho.

If you're running more than 12psi you probably have more money into your setup though, so going with another option may be a better idea.

 

the afc works at 12 lbs with a larger fuel pump and fmu. i would run 12 on my gsr motor(stock) on 93 octane. ran 20+ lbs on 116 octane.

 

Thanks guys... exact info i was looking for.

I have dsm fuel pump, so maybe if i put a 255lph inline on top of that i can squeeze a little more than 12psi. I am running 8 right now.

 

Actually, your DSM pump is adequate-unless your having problems with it, I'd leave it alone. I'm runnin a DSM pump as well, and with the "Hack" too much Fuel Pressure isn't good for the 450's. Do you have a FP gauge, if so what's you rail pressure?
Like I said, I'm using the DSM pump, stock rail/FPR, 450's, and have AFC trimmed at 35% across the board and can run 12psi(per the gauge) with no CEL's. GL

 

I'm not running the afc hack, but i'm using a safc, 440cc injectors, missing link and 255lph pump. We pushed 13psi. So yea, you can run over 12.

 

OK now im more confused it hgouht anytime you used the AFC with dsm inj it was a AFC hack???????(never knew why they called it a hack anyway)

Whats the difference with your setup?

 

I'm not sure about the hack, i heard about it but never wanted to use it. The fuel setup i'm using is what alot of the guys without standalones on the east coast use. Seems like nobody else uses it or recommends it, but works great for me. The injectors aren't off a dsm, they are RC engineering injectors. If you have questions, you can always call inline pro (703) 644-1788, they helped me out. The 13psi was at the track and even then, due to my fuel lines being stock and small and not having a big enough pump I was running close to lean. I normally just run 10psi daily untill i go standalone.

 

Not with the hack you can't. I'll say it again... the AFC uses the stock MAP sensor to read boost and fuel accordingly. The stock MAP can only read up to about 11.5-12psi, or better put, you can only boost as much as your stock MAP sensor will read with the AFC hack. The only other way would be to use an FMU, but running an FMU with 450's = WAAAAAAAY to rich!

 

my bad, how did i leave out that i'm also running a FMU 12:1 disk, RC 440's, SAFC, missing link, and 255lph pump. So no, my 13psi is not on the afc hack.


[Modified by autoEXturbo, 2:45 PM 1/9/2003]

 

With that setup, you must be getting 10 miles/gallon I was mad RICH using all that with my stock 240's. How much are you trimming with the AFC?

 

No, surprisingly i get mainly 240 a tank so i guess around 20+ a gallon. The car makes good power at 10psi though http://www.elite-motorsport.com/inlinedyno.jpg

 

FMU 12:1 disk, RC 440's, SAFC, missing link, and 255lph pump.

that's exactly the same setup i use. At 14psi 36deg. total timing i dynoed at 334hp 258tq

 

WOAH! 36deg timing? thats like a 6-8degree advance over a stock LS @ high rpm's. and then u have 14psi on top of that? what octane gas are u running? I run somewhere around 20degrees total timing on my car @ 12psi. but thats 93 octane.