Considering we have the same motor there is a good chance you all could be of great assistance. From all the research... it's obvious our ECUs are cancelling out any mod we put on, so I ask... what have you found worthwhile in terms of the SAFC?

Back in my Honda days... even on a Prelude with just basic bolt-ons we made some very worthwhile gains.

As for the VQ motor, I'll admit I'm not nearly as familiar and would be greatful for some expertise in this area.

Obviously the ECU is tuning out any gain that is added... so I would assume in remapping the fuel curve could be a fair mod. That seems to be the big problem now. We've (local tuning group) seemed to identify why we're losing so much power 6k+ (which the mod is already coming out to elivate this)... thou with fixing this prob, we could compensate for added/reduced fuel. I wish I could see an `03 350Z fuel chart to see exactly whats going on...

The reduction in power after 6k is causing the car to begin running real rich to compensate for the "choking" that is going on. (I'll explain in details another time) Once this problem is fixed... is our ECU intelligent enough to remap itself? Or would the SAFC be of value?

Any input is appreciated... except the "AFC is useless on NA" applications... That comment is BS... all ECUs are tuned for daily use to deliver the best fuel economy:best performance possible. Eliminate the fuel economy portion, and I guarantee you'll find power...

Thanks
Chris

 

The reduction in power after 6k is causing the car to begin running real rich to compensate for the "choking" that is going on. (I'll explain in details another time) Once this problem is fixed... is our ECU intelligent enough to remap itself? Or would the SAFC be of value?

Any input is appreciated... except the "AFC is useless on NA" applications... That comment is BS... all ECUs are tuned for daily use to deliver the best fuel economy:best performance possible. Eliminate the fuel economy portion, and I guarantee you'll find power...

Thanks
Chris [/B][/QUOTE]

i was very close to buying the apexi-safc from a shop, the owner has a superchaged anniversary edition, and he claims to have recieved a good 30+ hp gain. ive also heard that the AFC doesnt do jack squat for NA motors. Thats why im hesitant of buying it, although the owner apparently said the same thing u did, that regardless of what u have you are runing on a much richer fuel, so im quite confusd myself

 

I recently purchased a S-AFC for my 2002. In the spring I will install it and get back on the dyno. There is a way to trick the SAFC. I can't recall exactly how2 do it at the moment though, something about programing in 39% and 40%? If no one helps you I will try to find the info on this for you.

 

The SAFC modifies the signal from the MAF. It reduces or increases the signal by a percentage based on what you tell it to do at given RPMs.

First off, it doesn't do squat in closed loop. This only affects open loop (i.e. WOT).

Second, you need a good reason to fool with the factory ECU fuel map calculations. You need to be pushing more air through the motor than the ECU was designed to map. You also need to be running (to some extent) higher fuel pressure and/or bigger injectors before you can really harness the benefits of a SAFC. This all points to forced induction, or you have modded a NA motor so much that it actually can flow enough air to justify more fuel (i.e. bigger injectors and / or higher fuel pressure).

You mentioned that the ECU is canceling out any mod. I've absolutely never heard of that after working with a LOT of OBD-II cars. Nissan not being one of the ECUs I know well, I won’t go out on a limb lest I make an *** of myself, but I’d be surprised if there was something built into the ECU that somehow corrected for increased HP (i.e. a MAF reading that exceeds a certain value). The only way I can see it doing that is by yanking timing. Which leads me to….

You also mentioned that you have mods done that are causing the motor to go pig rich above 6k. Do you know why? Have you data logged the ECU to see what's up? Perhaps timing is getting yanked due to ping counts or phantom knock? All the SAFCs in the world will not correct those conditions.

 

Hey Chris,

How are you comming to this conclusion. Do you have dyno info?

 

It's from the countless dynos we've seen...

I unfortunately have not strapped up and set a baseline, I'm TOO curious... It's the number of people that have set baselines, then dyno'd low.

Utilizing an SAFC, and leaning it out as the revs climb should be fairly beneficially...

Right???

 

I'm still curious as to why the ECU is going rich at WOT??? Has anyone given a reason? There are a couple of reasons why it would go rich that an SAFC would not fix or may even aggrevate (make worse), wouldn't it be a good idea to identify the reason first before throwing on a SAFC?

 

Thats exactly what I was thinking. And if not done by a tuner on a dyno could have very bad results if it goes to lean. From the dynos we've seen it's safe to say the VQ35 likes lots of air.

I'd like to know what mods they're doing and seeing no gain or drop offs. Exhaust without intake will do no good...

 

Exactly!

I would never use a SAFC without having gauges for 02 and EGT, and I would still data log the thing a lot to make sure timing isn't getting whacked by knock.

Throwing on a SAFC at this stage amounts to a bad comb-over. Somone who understands MFI needs to sit down with a data logger and figure out exactly what is going on, then fix the actual problem.

 

This may also help. This thread is a good find by galo. It also leads me to believe that adding and tuning a SAFC one day may have much different results in the future.
I would hate to burn the rings up...

We really need to learn more about our ECUs. If we pool our resources and help woosh make a Consult-II compatible scanner we would be able to drastically shorten the learning curve.