1993 Lexus SC400. BFI, Exhaust

In my quest for more power I have finally ordered an S-AFC for adjusting fuel/air ratio.
From what I hear a dyno tune first; costs some money . Second: dyno tuning does not truly mimic street driving conditions and I have heard from tuners that street tune is the best.
So I’m hoping to be able to tune the unit myself.

Anyone have any experience on dong this your selfs on this engine ) ??????????

The key is that you will need a wideband o2 sensor hooked up. You could do it on the street with a wideband a safe stretch of deserted road.

Hey man,

You cannot just tune the car without a wideband - how are you going to know whether to pull fuel or add??

I don't know who told you that dyno tuning does not mimic street driving - doesn't make sense to me. When you get on the gas on the dyno is just like on the street

Jonny

Well of course I will need some sord of fuel /air maping to be able to adjust the ratios. That is why Im asking.
I read from a certain tuner that street tuning is the best.

I dont know if I would say it is the best but you can do it. Ideally you would have a passenger to help. Of course the wideband is mandatory.The passenger keeps track of the af and the rpms on each run. Then you stop and make adjustments and do it all over again.

do it on a dyno, it's simpler and will save you some headaches later on should you mistune it.

no misleading, the info was given to him to get a wideband sensor and tune it on an empty deserted street if he wants a street tune. That's all he needs.

dyno tuning is easy and allows for back to back runs in a somewhat controlled setting for consistency. It will also allow you to see a before tuning hp number and an after to see what gains were had.

Ideally street tuning would be the better way to go. Yea you have the fans blowing and stuff when you're on the dyno but that doesn't create the same type of air pressure around the car and in the engine bay as it does when you're on the road doing 60 or 70. Stick your hand out the window at 60 or 70 mph and it feels a whole lot different than sitting on the dyno even with the blowers. As soon as I get my wideband o2, I'll be street tuning too. But that won't be anytime soon

Honestly I wouldn’t do it your self unless you have a very good knowledge of what you’re doing... I was able to easily install my safc but I still didn’t dare to tune it... all I have to say is if u don’t know what your doing you could most probably expect a kaaboom, lol but more power to u...

The only problem with street tuning would be logging the o2 readings at rpms, safety and get'n caught.

get a innovate motorsports wideband with rpm logging and you're good to go

Def tune it yourself...it's a friggin SAFC!!! You're certainly not going to blow up an N/A SC400

Keys to doing this?

1) Dyno, I prefer a Mustang Dyno - it has the ability to put a load on your car...just like the real road does vs a dynojet - which will get you close and shower higher #'s

2) Wideband that you can either log yourself or a wideband on the dyno which will display your a/f under your power curve.

3) Make a pull with everything at 0% - remove fuel in small percents...i.e. don't pull -50% at once

Have fun,
Jay

I want to install the SAFC by myself and have it tuned by a professional. Any tips on how to do this install by myself?

Thanks for all the info guys!
Now I have to find a good wideband to do the tunning with.
Suggestions welcomed!

Also S-afc that I got coming is the S-AFC 1 the digital type. Whats the differences bettween the II?

For WOT tuning use a dynojet. That's pretty much all they do.

If you want real world conditions when tuning use a mustang dyno or log while driving.