My car: 2003 G35 Sedan, Mods: 5/16 motordyne spacer, throttle body spacer, clutch fan delete, OBX Exhaust (knockoff).

Dyno done on DynoJet with tailpipe sniffer to read AFR
Tunning was done using S-AFC

Over all I'm disappointed with low gains around 8whp or so, but I guess it looked like I was a bit lean so now AFR is in much safer range.

 

what you guys think?

 

Which is the tuned AFR? I'm hoping that the 14.86 isn't a tuned AFR. Even the 13.42 is in the upper safety limits of what we'd tune for.

 

the 13.42 it sounds like is the new. thats not really very lean if you consider that this was with a tailsniffer and still has the cats, so its reading leaner that it probly is

not sure why youre disappointed, you made gains everywhere and you only tuned the AFR, from not being that far off to start with. you should be happy with how much you picked up throughout the powerband

 

so sniffer will read leaner than actual?
by how much?
so did they correct too much at tunning if im at 13.4 now?
also how r those power numbers too low or normal?

 

tail sniffer will always read leaner but the dyno will compensate for that. i think tail sniffer tend to read 1 point leaner especially with cat but by the time you see it on you dyno sheet, the dyno already made the correction. you are not really playing with the ignition so why do you expect to much/ you are basically just playing with the fuel right.

sorry my shift button is not working so i couldn't use any capital letter...lol

 

Those numbers aren't too bad. Respectable for a sedan. The S-AFC is the Apex'i unit, correct?

 

yes Apexi

 

the dyno does not make any correction for the 02 sensor location, it's just reading the signal the sensor outputs

The SAFC absolutely alters timing because of how it alters fuel. It is rescaling the mass air, and the net result of taking fuel away means advanced timing, and adding fuel means reduced timing. This is one of the reasons, among others, why it's a less than desirable method of tuning.

 

so we have added up to 8% of fuel on top
how much does it take for the ecu to retard timing?

 

sorry I don't know

 

huh?.... The sedan should be putting out similar numbers to the coupe and Z. the engines are the same but Inifiniti rated the sedan engine's output lower to make the coupe appear to be the faster of the 2.

To me, those numbers seem low.......but I don't know if that's a 5AT or a 6MT. low for a 6MT....good for a 5AT.

 

you lost at least 1, maybe 2 degrees. it depends on what cell you are starting in though, if youre on the edge you could lose a lot with a little. but i didnt realize the early 03 g ECU did that. drop in slightly larger injectors, tune the extra fuel out and get that timing back

 

Car is Auto

How much would injectors cost me? if its more than $200 it would not be worth is since I could just get an emanage for that much and tune timing as well...But maybe there is an advantage of injector upgrade?

 

the only advantage on an NA car, and this only applies to cars where the ECU doesnt self learn fuel trims on WOT, is that by taking out the fuel that bigger injectors adds (remove via safc) is that the ecu reads less air intake and will as a result provide more air. if you can get get, used top feed injectors in the range of 350-380cc then it is a good use, not to mention that the EU doesnt really play nice with vq35 software (that is unless you consider burnt coils nice)

 

For that kind of time and money he could just do a real tune and sell his SAFC. And he'd end up with a more reliable and better running system, with more power and better fuel economy. Plus he'd be able to see his current unit to make a few bucks.

 

cost me something like $60 to get another few points of timing this way. if he already has the safc and can get the injectors used its certainly cheaper. plus the gas mileage isnt hurt because in closed loop the ECU tunes out the extra fuel, or you can go to the SAFC and do your best to make it run lean (15:1 @ light throttle here, obviously 14.7:1 cruising as no matter what if the stock ECU is controlling thats the target). either way, its obviously BETTER if you can get a utec or equivalent (not EU) and tune that way. but if he doesnt have 400+ tuning to spend, then its not a bad choice.

 

Not going to argue an invalid point. Half assing something to make something work that doesn't do anything but trick another item into working is not the correct way to do something (wow thats a lot of nonsense). You are free to do things wrong all you'd like but recommending that to someone who may not understand or be able to judge the facts for whatever reason is not a very polite or good thing to do.

Adding used parts of unknown variables on to parts that are making things work incorrectly to fix the things that are working incorrectly, instead of doing the right thing does cost more. Even a set of decent used injectors, along with the cost of the SAFC itself is going to be well over $400, what we charge for a mail in flash, and is very likely to cost more than the $700 for a full tune with data logging software.

 

like i said, i got my injectors for 60 and he already has an safc so adding that cost ft?? its not "work incorrectly to fix the things that are working incorrectly", whatever that even means. theres nothing wrong with tricking the computer. like i said, i would suggest getting a real tune anyway, but if he could pick up a set of bigger injectors for cheap, then IT WILL BE BENEFICIAL. you cant argue that it doesnt help. im not sure why youre so adament against it, its one thing to not want to do it to your own car, but saying that its wrong, half assed or such when you dont seem to know the specifics is a little bit off. this is something ive been dealing with for a long time so i know a bit here

BTW, forgot to post this earlier, but at least for my ECU its about 1 degree for every 3% removed/added so with your +8% youre looking at 2-3 degrees lost

 

hmmm thanks,,, I like the idea of getting bigger injectors ,,,
Whats the flow rate on OEM? How big should I get?