my tuner is telling me that i'm maxing out 660cc injectors. he says they're at 130% duty cycle. i'm on uprev osiris.

my setup
APS ST kit
stock maf
walbro pump/660cc injectors

am i crazy?? i know i dont know much about tuning, but how could 660cc injectors be maxed out, 130%, at 4.5psi of boost. he says the car is currently making 370ish hp. does he have to redo the scaling or something? i understand the stock maf will need to be rescaled but i'm still confoosed as to why my injectors arent enough. any input is appreciated. should i find a new tuner?

 

Your MAF will be maxed out around 380whp so it doesn't matter the injector size at that point. You can't rescale it, you need a new one and a new tune to go with it. He's pegging the right side of the fuel map.

FWIW I made 420whp with 440cc and walbro (with HPX MAF), so I doubt injector size is your problem.

 

do you have a fuel return?

I have 715cc injectors and we ended up running close to 70% duty at redline. I'm guessing it was running so high because of the pressure drop since I do not have a fuel return.

I'm 5AT and making 350hp to the wheels @ 6.5 psi on a vortech V3 SC kit.

 

im not worried about the maf. i know itll peg. but hes saying that my injectors are maxed out. i do not hav a return system.

 

its ur maf..if running osiris then most have to go with the hpx maf..injectors are def. more than enough

 

What IDC in mS are they running at? The % is pretty much useless.

 

ya, 130% is an unobtainable number so the calculation is obviously off.

if you were running out of injector it would be lean under load. if it's not lean and he's just going by the incorrect 130% duty cycle then you aren't out of injector.

370hp doesn't seem near enough to max 660's.

 

You should be worried cause the MAF values control fuel and Timing. When you run out of MAF the ECU doesn't like like it, sometimes it just pulls timing and sometimes it throws a high voltage code and goes into a fail safe mode.

Either way with 660's you should be good up over 450whp. I have tuned dozens of DW600's(which is actually around 680cc's) well over 450whp with a lil room on top...

 

okay thats good news. i knew i couldn't be out of injectors. is there any difference between the pmas hpx maf and the uprev maf? are they the same thing, just rebadged? i will be gettin fully tuned once i'm out of the military and back in california. aiming for 500+whp, don't worry i'm not on a stock block :]. i jus needed something safe on the road for now. thanks for the help guys, much appreciated.

 

Uprev maf is supposedly more accurate than pmas -- if it performs as advertised that means better idle and more accuracy in boost. I also heard the pmas is no longer in production.

 

I have same S.T. setup on built short block, walbro 255, 650cc DW injectors, Uprev MAF, forge actuator with green spring and will not make more than 6-8lbs. At that boost level making a little of 400rwhp. My old setup with a Vortec was making same power on stock internals. The whole point of me going the short block route was to boost it up and shoot for 500rwhp. If you find an answer please let me know since our setup is pretty similar.

Jeremy

 

If you are using a boost controller and you can't get pressure any higher then you have either an exhaust leak or a boost leak. Nothing too bad about that. Find them and fix it. Should be an easy find if you're only getting 6psi out of it.

If you don't have a boost controller then your boost will always be spring pressure.

 

Uprev says their MAF maxes out around 600rwhp vs ~1000rwhp the PMAS is supposed to max out at. Ive heard they may be releasing a different version of their MAF to make ~800

 

They probably designed it only to 600hp to give the best resolution possible while still giving a decent amount of hp.

fact of the matter is nobody running very high hp is using osiris tuning solely. One guy on here has a thread about it. he was up around 680 something with the haltech and he wanted to see how well the osiris performed. I think he barely broke 600 after changing all his stuff around to run the osiris. that's the highest hp so far on our cars with only the osiris controlling it. So since uprev knows this why design something for a customer that doesn't exsist.

 

I think your actually referring to my post. I own a Haltech setup but wanted to see what I could get out of Osiris, yea at 600rwhp @6krpm it just misfired. But we ended adding a HKS ignition amp we had laying around and that problem was solved, i ended up making 633rwhp/664ft-lb. The day prior Z1 tuned an APS Extreme car (GT3076 w/ tiny housings) on Osiris w/HKS ignition amp and made 724rwhp. So it is possible to make big power using Osiris, especially on dual TB cars, i think GTM just made 880ish on a 370, but you have to upgrade the ignition system if running Osiris.

I will soon switch to my Haltech setup since i want the failsafes and to control my meth/N02 injection, boost etc. But right now im just enjoying having the car back on the road lol.

 

ah, maybe it was you then.

ya, with the 370 they wouldn't need to make any bigger maf's because they use 2 so it would have 2 maf's that can read 600hp worth of flow. Same concept on how the HR's don't need to upgrade their oem maf's to go over 400hp like the single maf DE cars.