I recently got a third-party dyno at Specialty-Z to verify my numbers. I was just as concerned about my AFRs since I've had some fuel issues lately. Everything looks OK through most of the pull (probably too rich from 4800 to 5800), but we noticed the car started to lean out after 5,800 rpms.



AFR leans out at a constant rate starting around 5,650rpm, and since this part of the curve is very linear, I have to assume its directly related to linear increase in boost created by the supercharger (I maxed out just over 13psi on this run). I have a walbro 255 in tank pump & 600cc DW injectors, but the rest of my fuel system is stock. The walbro can't increase pressure / pump more fuel beyond a certain point (please correct me if i'm wrong), so my guess is that it can't keep up beyond a certain manifold pressure.

Do you guys recommend a RFS in this situation? All of the searching I did on here before starting my build indicated a RFS wouldn't be needed at my power level, but the graph doesn't lie. My tuner is still out of the country so I haven't been able to discuss this with him yet or find out if he can simply dump more fuel. You guys have seen pretty much everything so I figured I'd ask here too

 

Did you do the fuel basket, fuel regulator and swirl jet modifications?

 

yeah, all that stuff was done by technosquare right before the initial tune

 

i dont feel u should be having any issues with fuel with ur current setup or need a fuel return for what ur going for as long as the pump was installed right...with that pump and those injectors with the 2.87 u should be set....what ems are u using?

also as far as numbers i know that dynos are all different and many things factor in, but i pulled 410whp/350ft. lbs. on a dynojet in 96 degree weather very heat soaked after about 10 dyno pulls with stock injectors and just the 3.12 pulley on hitting a max of 9.5 psi....have u thought about taking the car somewhere else maybe?

 

yeah ur a/f graph also needs to be smoothed out quite a bit it is pretty rich in parts and pretty lean in others..not a very solid tune id say...i sit high 11's to a 12.0 on a hit at a low rpm and it will level off in the mid 11's for my a/f as the rpms increase to redline..the way ur tune is now u are loosing low end torque and midrange power that i can see at just under 5k and on and not safe to take over 6k

 

i'm tuned with a technosquare reflash. as for the power numbers, i have a 5AT so that sucks up some power, plus i'm sure the car was pulling lots of timing as the mix leaned out above 5,800. i'll have the car dyno'd again if/when my tuner is able to make the adjustments in the upper RPMs. also, fwiw, my STD corrected DJ numbers are at 409, but i figured everybody posts the unsmoothed SAE numbers here...

 

One of the last things I would skimp on during a FI build is any part of the fuel delivery. Just my humble opinion.

 

well i would def. go with a good ems and thats the whole reason i still havent gone to the 2.87 pulley yet...i wouldnt run that flash but thats just me, id at least opt for a utec minimum or emanage ultimate or something along those lines..yes the 5AT will suck up some power and yeah im sure it is pulling timing....and as far as the numbers yeah thats what i meant my numbers are unsmoothed SAE also..i dont even know my corrected numbers so it really seems like u are lacking a good tune and a good ems so far....good luck with everything, if ur driving it id be careful with that tune....also with the reflash, do u have any knock detection to even pull timing above 5k? seems like it wouldnt...

 

Your MAF looks maxed out in the upper RPMs hence the linear increase in AF ratio. In other words, the MAF is reading the same value for all RPM's above a certain amount...

You need to upgrade the MAF then retune. Overall your tune looks terrible, and I wouldn't drive it much if at all until fixed.

 

I believe you are experiencing exactly what 96sleeper experienced with his vortech VQ35 swap in to his car. You need to convert to return style.

http://forums.maxima.org/supercharge...tyle-vq35.html

Beyond that, your tune is in pretty bad shape. That big dip in the mid range corresponds perfectly with your AFR being pegged rich and going into the 9s or even lower. Just that AFR to a more accepetable number will pick you up a good bit of power in the mid range, and of course you'll need to fix the lean condition above 5800.

 

one would think that you'd have PLENTY of fuel for your set up with your current fuel supply mods. but overall, your tune looks like ****. who tuned it?

 

like someone else mentioned, if this car doesnt have an aftermarket MAF, thats the problem right there. Its pegging the voltage and theres no way to tune past that.
+1 on the poor tune though.

You are way too rich thru the entire map. before 3500 should be mid 12s, slowly working to high 11's at redline

 

thanks for the comments guys, i'll address with the tuner whenever he gets back in the country

 

I ran out of room with my 550 injectors at about 16psi with a return fuel system . The AT5 loses alot of whp ..more than you would think . Did you tune your car in the summer ? Take it back to Technosquare and have them retune it .

 

^^yes exactly how the tune should be and what i was trying to say up above, this tune is all over like my first tune i had done and i had flat spots where it felt like i ran into a wall cause it would get so rich, that would be my first clue to take the car elsewhere like i did and now i coudnt be happier..


yes def. could be the maf...i think chef had one on here for sale not sure if it still is or not, i def. think there should be no issue on getting enough fuel so it is prolly the maf, but still dont see why the tune would be so crappy even before the fuel issue....good luck im sure it will get sorted out, hopefully soon for u

 

chef sold his MAF a while back. i had considered buying it, but neither of the big tuners around here (including TS) thought it was necessary. as for a retune, i plan to stick with TS. they've done much more complex builds and have reflashed the stock ecu for far more power than i'll ever see.
hey man, i had the car tuned in early november. and i completely agree on the 5AT...i didn't think i'd get anywhere near 400, especially with only a catback and HFCs. i'll see what tadashi at TS can do when he gets back from japan.

 

ya there is no issue with the tuning software/method, they just need to start over on your particular car.

 

Also, you don't have a fuel pressure regulator. Most guys running the vortech kit run the vortech FMU which raises fuel pressure after 5psi of boost. 8lbs of pressure for every 1psi of boost. That makes a huge difference.

You could either add that or do a return system which adds a rising rate fuel pressure regulator.

I agree on needing a larger maf. HPX PMAS

 

bigc's Christmas wish list:
- pmas MAF
- stage 1 return fuel system
- meth kit

 

Merry Christmas...I was thinking of getting this as a spare but you can have it...

https://my350z.com/forum/intake/467502-hpx-maf.html