Performance for Automatic transmission?

[jllnet]

I got a 95 240SX (S14) Automatic Transmission and I'm looking for affordable ways of increasing performance, specially gas management. The car seems to choke when fast accelerating, and I know that people out there have computers, and stuff to override the car's factory fuel system.

Any good suggestions?

Thanks !

[180fan]

S-AFC II my friend. Use that to tune up your fuel system and you might want to install a 300zx fuel filter too. I noticed that at higher RPM's, that's where the benefit of the 300zx fuel filter came in. I too have an auto for now and the afc works great. If not, you can try a more expensive, but built for auto (changes shift points) piggy back computer from buddy club. Check out http://www.takakaira.com for that one. For me, as I'm going mt summer, it wasn't in my best interest to get the piggy back from buddy club, so I went with the afc.

[89240sx]

hmm, how much knowledge do you need as far as fuel systems do you need to know how to install and/or adjust one of these S-AFC II systems? And are they worth the money?

[[s3]]

Its only worth the $, if you have time and access to a dyno. Every car is different and you can' t always use the same settings for every car (mods considered)

Its not hard to program a SAFC, it just takes a while to get over that you are only making 5 to 10HP extra while using it.

You will also have to make a lot of dyno runs to find out which program gets you the most power.

Or you can do it the ghetto way and butt dyno every change you make.

Also, if you don't know what you're doing, you can serioulsy blow your motor by fubaring up the SAFC settings.

[89240sx]

Thanks for the reply!

[jllnet]

So what is the S-AFC? Automatic Fuel Controller?How does it get implemented. I understand the fuel filter because it is a canister and I have replaced it before so I assume that it doesn't take much to replace it.

But, the S-AFC is something else, right? Can someone provide more details. I'm a novice at this.

Thanks for the help

[sxseguy]

After you get your car running right, you should get the torque converter modified for a higher stall speed. It'll mean some down time for the car, becuase you have to remove the converter and ship it out, then put it back in. If you can get your hands on a used converter, then you could ship that and then a shop in town could swap it in when it gets back. Then you'd only be without your car for a day. Of course, if it's not a daily driver, then down time doesn't really matter.

For converters, check out: JMO, Level Ten, and Precision Industries.

3000 RPM is a good stall speed for a 240. It's still drives pretty much like normal, but gets you up into the powerband quicker in first gear.

[[s3]]

So what is the S-AFC? Automatic Fuel Controller?How does it get implemented. I understand the fuel filter because it is a canister and I have replaced it before so I assume that it doesn't take much to replace it.

But, the S-AFC is something else, right? Can someone provide more details. I'm a novice at this.

Thanks for the help

SAFC is a Air/Fuel Controller, has nothing to do with transmissions etc.

Its a piggyback computer which is soldered into the ECU wiring and monitors Throttle/RPM/Fuel injection/MAS sensors to calculate fuel/air mixtures.

Once you have it installed, you can adjust at 500 RPM intervals of the air/fuel mixture.

It also has playback and record features. Its a great tool to tune the car when running a turbo for maximum gains.

For a NA car the gains are much less.

[Toast]

Hey this wount help the stalling part (or maybe it will) but look under the FAQ section from 240sx.org and there is a faq about how to disable the part of your transmision that makes it shift smoother/longer. I did this to my car to act sort of like a shift kit. Its very easy to do all you need to do is pop your hood and look at the drivers side strut tower and there will be a little grey plug, then unhook it. and now the transmission will shift faster/rougher (only rough from first to second IMO). It will also not damage your transmissions because we have the same transmission as the 300zx just with a different bellhousing and the 300zx dosnt have the smooth shift thing. So good luck.

[89240sx]

are you sure that does not damage the transmission??

Can maybe Nistech confirm or deny this?

[Toast]

I would like to know for sure too, what I have said is what I have been told. To my knowlage all The unit's purpose is to regulate the transmission fluid pressure, to soften the shifting for comfort purposes. So I see no way it would harm the transmission but I would like to know.

[89240sx]

Yes ... some say it hurts the transmission and others say it does not ,.... I had it done to mine for a while but decided to put it back because I got nervous that it may destroy my transmission before I have the money to do something about it.

[89240sx]

anyone?

[Nismo_Freak]

Not an expert on an auto transmission but typically the higher the line pressures the higher the shock to the valve body when you shift. This in turn wears out the transmission faster and can break components, and blow out seals due to the added stress of shifting harder.

As for the S-AFC II, it doesn't monitor A/F ratios. It takes an incoming signal from the MAF and allows you to convert it. Which in turn allows you to change the amount of air the ECU is reading. Thats how it changes your fuel curve... you then supply the, assumingly, correct correction factors for your target a/f ratio. It will read and display airflow, tps, knock (ver. II only), and rpm parameters.