Duty cycle 90+%, dsm 450's, 10psi wtf??
 

alright heres my dilema...
my setup,
built y8 block
stock z6 head
dsm 450's
crome Pro
walbro 255
t3/t04e
10.5 psi

at around 6500 rpms my duty cycle on teh 450's was around 105% with teh stock fuel pump (3rd gear) so i ddi some research and most people said that putting a walbro in had cured similiar problems...ok so i put the walbro in and this morning on the way to work i got on it in 2nd gear...only took it to 6k at 10.5 psi and the log on crome pro said the duty cyle was at 90% again....

i know that teh dsm's are good to around 300hp and i know im not anymore than 220 or so...so whats going on here? are they really maxed out???

another weird thing is if i go control f to the fuel multipler...my original injector size says 240 and my new injector size says 240 even though my map is for 450's....shouldnt the begining injector size say 450? would this have anything to do with my duty cycle not being correct??

oh and all this is on stock fuel pressure i dont have an adjustable regulator.

so whats going on here i really want to turn up the boost to around 15psi but with it saying my duty cycle is not safe, its making me scurred. Any insight would be appreciated!!

Re: Duty cycle 90+%, dsm 450's, 10psi wtf??
 

a/f ratio??

Re: Duty cycle 90+%, dsm 450's, 10psi wtf??
 

I know this is not on topic but, I am building that exact setup and was wondering how that turbo spools?

Re: Duty cycle 90+%, dsm 450's, 10psi wtf??
 

if you didn't retune then you're maps are going to show the same duty cycle as before.

regarding the fuel multiplier look and see if the multiplier is at 1 or a # less than 1. if it's less than 1 then it has it saved.

i always hear this 300 out of dsm 450's, but i've never seen it. i've seen 250-275whp, but not 300whp.

Re: Duty cycle 90+%, dsm 450's, 10psi wtf??
 

you posted this on pgmfi.org also, right?

Re: Duty cycle 90+%, dsm 450's, 10psi wtf??
 

yea i did...
a/f's are good...a little on the rich side actually...high 10's low 11's in boost...richer as the revs go up...
i get full boost at around 5200 (10PSI) with spool starting at around 3800...its weird i get a 6-7 psi instantly at about 35-3800 then it takes till 52 or so to get to 10psi.

BUT i didnt want to have to worry about all this, so i just went and bought some Precision 780cc injectors last night :6

Re: Duty cycle 90+%, dsm 450's, 10psi wtf??
 

if you can still richen the maps, then you havent maxed the injectors.

my suggestion is just run with it, when you get to the point you cant richen the maps anymore, you're maxed, and back it off.

Re: Duty cycle 90+%, dsm 450's, 10psi wtf??
 

Whats your fuel pressure looking like?

Re: Duty cycle 90+%, dsm 450's, 10psi wtf??
 

Fuel pressure will play a big role in this too, like CSaddict said. I have tuned setups using 440cc injectors and over 300WHP by bumping base fuel pressure up (adjustable regulator) and keeping the duty cycle under control.

Re: Duty cycle 90+%, dsm 450's, 10psi wtf??
 

I made 300 on DSM, stockish fuel pressure...

Are you looking at the live duty cycle or logged reading in Crome or are you looking at the maps in terms of duty cycle? I have noticed that while live tuning, Crome is WAY off although the maps show duty cycle a little closer....

Keep in mind this isnt all exact science and you cant ASSume that Crome is 100% exactly correct either...use your best judgement...

Re: Duty cycle 90+%, dsm 450's, 10psi wtf??
 

i agree about the duty cycles not being accurate in uber and crome. i've pushed injectors into the 125% range before and not truely maxed them.

Re: Duty cycle 90+%, dsm 450's, 10psi wtf??
 

bumping fuel pressure does allow you to take injectors further, but i always err on the conservative side and try not to push injectors close to the limit of duty. as in any electronic or mechanical device...the harder you push them the more likely they are to fail.

i've always seen adjustable fpr as a band aid device instead of getting a larger pump or injectors. however, if someone comes with a car to tune i'll tune it with what they have and push it as far as it can go as long as they are aware of what i'm doing or intending to do.

Re: Duty cycle 90+%, dsm 450's, 10psi wtf??
 

He's running high 10 and lower a/f ratios, that's the problem ;) That's way to much fuel for only 10psi. Lower the duty cycles in boost untill your a/f is closer to 12.1

Re: Duty cycle 90+%, dsm 450's, 10psi wtf??
 

CROME dlog reported duty cycles are way off. Look at your injector M/S in 2d view to gauge how much injector you have left.
As far as 300whp on 450's, Ive personally seen 350whp on 450's. Yes they were maxed, the 2d fuel curve in Uber was off the screen, lol.
Ive also seen 321whp on an LSvtec on 450's.

Both cars had a Walbro. Pretty sure both were on stock FPR's. Although, Im a big fan of bumping base fuel pressures to get some extra mileage outa injectors.

Re: Duty cycle 90+%, dsm 450's, 10psi wtf??
 

that's at least part of the problem