I have a question about ECU tuning. With out a SAFC or anything to tell the ECU to add more AIR or Fuel. How much boost will the ECU be able to tune its self for.

Basicly Im asking if I add bigger injectors bigger turbo like a skyline T28 and a 255. And turn up the PSI to 16 for track or a race, and then turn it back down to 12 for daily driving. Will i need a SAFC to re-tune everytime I do that, or can the ECU do it on it's own.

BTW it is a S13 Redtop and I have done tuning before with a wideband and a SAFC. Im jsut no really familiar with the S13 ECU stock programming.

The stock ECU cannot run different injectors without having it retuned. You will also need a different MAFS as the stock unit can't read very high boost figures. As I recall, the Skyline turbos (at least from the GTRs) will not bolt up to your stock manifold either and they aren't good are producing high boost. An S15 silvia turbo would be a better choice as its got near stock fitment, and is a ball bearing turbo and can handle higher boost numbers. The T28s that I know will fit were found on the S14s and the GTI-Rs.

You should have a 255lph Fuel pump if you are running a turbo at all, the stock pump can barely keep up with the stock 7 psi and many times doesn't. You had also better be running a FMIC or an upgraded sidemount if you plan to run much over 10psi safely.

If you have the knowledge (real knowledge) to tune on your own then you might want to look in to a bikiboard for your ECU. It lets you do all the tuning you need in the car and has added features like a 2 stage rev limiter and N20 control.

Just to give you an idea what it could cost to do the upgrades you want;

Walbro 255: $100S15 turbo: $800ish new550cc-740cc drop in injectors: $500Z32 MAFS w/plug = $125ishProfessional ECU tune =$500

Assuming you've already installed a quality 3" exhaust and a FMIC, and can install parts yourself, you're looking at roughly $2,000 to put you in the 300hp range.

Once your setup is tuned for the larger injectors, z32 MAFS, and the turbo of your choice, it doesn't matter if you run boost lower than you were tuned for, the ECU can deal with it.

The info you just gave me is great and thank you. I knew most of it except the part about the Turbo hehe thx. My real question is though. I know an SAFC can only handle injectors up to 550cc.

But I bought some 480's which I know can handle up to around 350hp. Im only wanting to run around 300rwhp. And actually I tottaly forgot about the mafs.

I guess my real question is. After I tune my car with the safc to run with all those mods. at 14 psi. How would the ECU react to me switching for instance to17psi for the track. Would I need to retune to 17 or would the ECU adjust it's self for that?

definately need to read some of the faqs

Tune for the higher boost level and when you run the lower level everything should be fine without retuning. My ECU is tuned for 19psi but the car has no problems when I turn the boost down to 14, or even turning off the boost controller and letting the internal wastegate open at 11.5psi

FYI, I was making 360RWHP with a GT2871R with the stock S15 MAF and ECU. Only had an SAFC2 for tuning. I have been told the MAF makes a big difference, but with my turbo, the stock maf worked just fine so upgrading the maf could probably wait, depending on money situations. Just giving out my information that I know, not telling anyone what to do..........

Its doubtful he has an S15 engine. An S15 runs larger injectors and a higher flowing MAFS from the factory. You were also using an SAFC to tune the car. The S13 MAFS is only good for around 250hp before it maxes out as I recall and the injectors are about the same. It is not safe to run a car with its injectors and mafs maxed or close to maxed out as you run a higher chance of hitting a lean situation and screwing up the motor.

Also, do you happen to have a dyno sheet for your run, I'm curious to see what your curve looks like compared to an S13 with basically the same setup.

Just wondering, are you asking me for the dyno? or who are you directing the question to?

My bad, I think that I should of stated that I was told that a (Z32 maf) makes a big difference. I do have an S15 set up. Sorry for any confusion that might of been caused.

You don't technically gain any power with the z32 MAFS, but it allows you to make more power since it can read more airflow. If you aren't maxing your current MAFS, theres no reason to upgrade to a larger one.