Anthracite SC

Hey..someone just mentioned that if I got a catless exhaust, S-AFC and 02 sensors I could stay ahead of a GS400

exactly what is an S-AFC and 02 sensor? please forgive my ignorance on this.

VSsc400

iTrader: (1)

S-AFC = Super-AirFlowConverter
I think with the O2 they are reffering to Wideband O2. We already have 4 O2 sensors... 2 main and 2 sub.

Catalytic converters are most efficient and designed to work with Air fuel ratio of 14.7:1
N/A engine produces most power at air fuel ratio of 13.5:1
Thus you have to change the air/fuel ratio that your car is trying to achieve and adding more fuel. The more fuel you put in the more your catalytic converter has to work with thus building more resistance and also running hotter.
S-AFC tricks your stock ECU and lets to adjust the sensor reading of you MAF.

Lets say you want to run 13.5:1 air/fuel ratio @ 2500rpm
You would need a device to read the correct air/fuel ratio right?
This is where the O2 comes... thats Wideband O2. The factory O2 in our cars are just not accurate enough and not able to pass along enough information to the ECU. It also becomes very inaccurate as you move away from Stoich(14.7:1). A wideband O2 sensor lets you read accurately all throughout the readings from 10 to 25 or something close to that. Knowing the accurate air fuel mixture you can tune your S-AFC to so your car can be running @ 13.5:1 or any other setting you like it to be

summary
S-AFC - changes the air flow signal to trick your ECU to think that the a/f ratio is richer or leaner
wideband O2. enables you to read accurate A/F ratio

5speed300

Ive got a question on this also. Why would you want to have a different air fuel ratio at different RPMs?

VSsc400

iTrader: (1)

I don't know...... if it was me i would put it on 13.5:1 all the way...

if you are reffering to ""Lets say you want to run 13.5:1 air/fuel ratio @ 2500rpm"" I just picked that rpm in random.. but you would want to be 13.5:1 all the way through.

chrisngrod

Obviously I don't have an Lexus anymore (planning to get one in the next few years), but isn't an AFC universal? If they could figure out the pin layout on my ECU they could hook it up to a Caddy right? Thanks...

VSsc400

iTrader: (1)

yup... universal as long as you can figure out the pin layout and cylinder settings etc etc.

on the 1UZ for some reason you have to select 4cyl instead of 8cyl on the AFC.

Anthracite SC

How much do these cost? How easy is the install..
and...will it really make me gain about 50hp to stay ahead of a GS400?

VSsc400

iTrader: (1)

S-AFC new is $300 used will be $200 range
wideband O2 kit is around $450

my stuff is not tuned and never been to dyno since my performance stuff has gone on so not sure if its going to give you 50HP.... but I'm going back to the track in a month or 2 so we'll see the results then.

ciscokid

Does anyone know where you can purchase an S-AFC and what results you've gotten? Thanks.

-CK

NRG

SAFC = Super Air/Fuel Controller
its just a Piggyback Fuel Computer
when you adjust it, and tell the car to put more fuel, it has to put more air, unless you wanna run rich or lean.
more fuel and more air = more hp.
but you probably have stock injectors, and compression. so you will gain a few hp.

TGRich

How is your car going to put in more air? The SAFC tricks the ECU into thinking more or less air is coming in than really is. Then, the ECU compensates for this to run at your desired a/f mixture.
The descriptions up top are accurate too, just didn't want you to get confused.

And stock injectors and compression will make little to no difference for this mod. The stock injectors will be able to handle whatever relatively small adjustments you make to your a/f mixture. Also, 99% of people will install the SAFC way before changing these things. Sure, some people run it on their turbos, but there are even more who run them on stock engines just to maximize their potential.