BayGS2200

question for the experts.
if you have the basic intake(srt with ecu) and exhaust upgrage would it make a noticable performance difference by changing the srt ecu with an unit like apex sfc or hks pro or a stand alone ems(if any is made for this car)
we hear a lot about properly tuning the car for extracting most hp........so would these be the tools needed
to do the tuning
experts please enlighten us on this issue:
the primary goal is to extract most hp
even at some everyday drivability compromises
thanx
sean
99 gs400

cyberseano

This is something that I've been wondering also.

I've also wondered if there was anything else we could do to our engines such as:
Intake manifold
Cams
Blueprinting
Boreing
Polishing
Balancing
Headers
New Pistons
Crankshaft

I can't find ANYWHERE where someone has done anything more to their GS400 then just an Intake and exhaust.

Neo

iTrader: (3)

But less than turbo or SC right?

cyberseano

YEP

Guru

S-AFC II works great on the GS400 and especially when you have an intake and other mods. I have so many mods to finish on my GS400 and I'll have dyno charts for you guys. I've been super busy with work and my car is always the last thing my mechanics touch around here.

cyberseano

S-AFC II??

BayGS2200

air fuel ratio controller
more air and more fuel into the combustion chamber = more hp
upgraded intake=more air
need for more fuel is where some sort of aftermarket device comes in.
well the choice of the said device is where it gets a little complicated and hence this post

cyberseano

Thanks airtrackk.

I did a search and found out pretty quick what it was

I understand how air/fuel mixture works for the most part.

My question is: If the SRT intake gives MORE air and the SRT Race ECU compensates and makes adjustments for the larger intake and more air then what exactly would the S-AFC II do to improve on things?

Does the S-AFC II actually allow you to adjust for MORE Air AND Fuel?

I haven’t heard of anyone with a GS400 using an S-AFC II. I’m sure I’ve just overlooked it since I really didn’t know what it was.

If this is something that can add a nice amount of HP I’m ALL FOR IT!!

I’d like to hear more info on this.

Does it take any special installation for a GS400 compared to other vehicles?
Is it something that would be easy to adjust or should a professional at a DYNO shop handle all the adjusting?

Lots of questions now

jawnthen

From my understanding, the S-AFC II controls the fuel side of things. So depending on what means you get more air into your car, be it intake, FI or NOS, the S-AFC allows you to add or reduce the fuel at different RPM settings. I believe that runing too rich and running too lean will hurt your engine, so unless you know what you're doing, a shop preferrably with a dyno should do the tuning for you.

BayGS2200

i do know that the key part in tuning is make fuel/air ratio maps for the entire rpm band so the engine
gets a perfect mix of air/fuel thru out the range. i personally doubt a preset piggyback with no user/tuner adjustability would work in the entire band as good as an more sophiticated/expensive unit ...............i honestly did never feel an improvment after installing the srt intake ecu combo, first i thought it wasn't installed properly and had someone take a look at it and it was set up the way it was supposed to, so at best it seems to be an decent intake.
yeah cyber it would be nice to be able to get to the bottom of this issue, i did some searching but never could find a post with a deninitive answer

broke_gs

SAFC - Super Air Flow Converter

What it does is take the readings from Mass Air Flow Sensor (I think more commonly called MAP) and modifies it making the ECU believe that there is more/less air than there actually is. This change in the reading causes the ECU to adjust to the new readings adding more/less fuel because it thinks there is more/less air.

Guru

THe most important way to get the most out of whatever you buy is to make SURE to dyno tune it properly with a proper wideband O2. I prefer S-AFC II to any kinf of preprogrammed unit because you can actualy tune the unit to your specific car. All cars are different so the setitings will always differ from car to car. INtakes will also vary in terms of airflow changes. I would HIGHLY recommend you get a fuel ECU of some kind BEFORE you get an intake as an intake just causes detonation on these cars and wil damage motor over time.

jmecbr900

Guru: They all have the piggy back that comes with the SRT intake. They're wanting to know if using the AFC would make it any BETTER.

Personally, I'm running the S-AFCII and I swear by it. Will it do more than the piggy back that comes with the SRT??? Hard to say. I would tend to think that logically the answer would be yes if for no other reason than the fact that the AFC is user programable and the SRT isn't.

All tuning for the AFC or any other bigger piggy back management should be done at the dyno on the wideband. There really is no other way around it. Every car is different, as Guru mentioned, and should have individual settings that fit the car. Setting the AFC wrong WILL cause engine damage.

cyberseano

Thanks guys!

Yes, that was my main question.

If I already have the SRT and piggy back ECU whould the S-AFC II help?
Could you even install the S-AFC II with the SRT piggy back ECU installed? Would if conflict with it?

Guru

Actually the S-AFC would replace the SRT ECU. I would use a basic intake of your choice and get an S-AFC II. Even with tuning and install you're probably still less than the SRT and you'll have better results since it is tuned for your car. I think a lot of Lexus folks like the SRT just because it is plug and play but I believe in getting the most for my money. I took a used RMM intake and am adding a Blitz SUS filter and possibly making my custom intake pipe then tuning with S-AFC. I am also making custom test pipes/downpipes with my Fujitsubo exhaust. Should flow substantially better I think but tuning it is the key.