03maximaguy

what is the right size injector to balance out a 3.5 or 4 inch maf housing upgrade on a 3.5 liter max? Is there a plug and play Nissan injector that works great with a 3.5 or 4 inch maf? Ive read threads around here on this subject but didn't see any that specified a injector size for maf housing size.
I remember back in the day when I was into third gen supras we would upgrade to the bigger lexus v8 maf housing. aprox 25% bigger than the supras. Paired with 550cc injectors, aprox 25% bigger than stock they balanced each other out..almost..Not much tuning was needed due to this.

MrEous

iTrader: (11)

You can technically get away with z33 injectors. I was running them at 92% duty cycle @6k...I'd just rather be safe than sorry so I put RC 440cc injectors in and ran at 75% DC.

Bought some GTR injectors (570cc) for a better OEM fit. Overkill?...Yup but they were cheaper than aftermarket and I love an OEM fitment.

03maximaguy

Are you having to pull a lot of afm signal out with the 570cc injectors? will the z32 twin turbo injectors plug and play on our cars? think those are 370cc if memory is correct.

VQ'ed

iTrader: (2)

no definitive answer yet but id gladly appreciate an upcoming on that subject.

NmexMAX

iTrader: (22)

If wondering about teh 570's here it is.:

I thought I gave you my input?

Idle cold:
+4 = 10.9 AFR

Idle warm:
+4% no AC = 14.7 - 15.1 AFR
0 required w/AC on = 14.5 - 15.0 AFR
+4% w/AC on = 12.5 - 13.1 AFR

Cruising 60 - 90MPH
1800 - 3000 RPM 0 - +3% = 14.7 - 15.5 AFR I have my Ne points @1800 - 2200 lo throttle since it used to be leaner than I'd like (16+) at those cruising speeds so I used those points for better resolution at those RPM’s.

WOT
1000 – 7100 RPM + 10 - 12% = 12.9 - 13.2 (steadily) AFR

Around town, varies, but nothing demented as in it stays in the 12.5 (throttle tip in) to the leaner side (15.5 when cruising a 25 MPH straight)

Are you using the VAFCII or SAFCII? If using the VAFC your settings will vary quite a bit since it really hasn't been too definitive as far as VAFC set-up for MAF scaling is concerned. IIRC Ceffy posted about it or someone actually confirmed maybe it was the Altima forums, either way, it's not widely knows if the VAFC can scale MAF's like the SAFC.


I've also had Z33 (335cc) injectors and 440's, so if you have any questions on those, let me know. All with 3" MAF, 3.5" MAF and now 4" MAF.

VQ'ed

iTrader: (2)

Thanks for sharing my friend!! that is pretty nice. Im using a V-AFC2. I will post my inputs shortly. Instead of pushing the duty cycle on the oe injectors, I read a lot on using these GTR injectors to keep the timing in the right range with less correction percentages.

NmexMAX

iTrader: (22)

Yes, I would do that first and foremost. Don't be me and get 335's then need to get 440's then need to get 570's, go that way the first time. My timing was crappy with the 335's and 3.5" intake, got it back with the 440's and 3.5", then went to 4" and bam, back to square one with the low timing. Dyno's even reflected it.

I was +27-30% with the 440's and 4", timing was a good (-)4-6 throughout the curve and I'm fairly proud of my "good" timing curve.