civic4982

iTrader: (9)

EDIT: Max Injector Duty Cycle FOUND! Please look BELOW...

Anyone know the duty cycle their stock injectors were running on their full kit stock vortech boost (3.33 pulley for non rev and 3.12 pulley for rev) with the stock injectors and utilizing the FMU and aux inline pump setup?

I'm about to have my unichip tuned for my revup with the 3.12 on Tuesday and am considering increasing to 440cc injectors to give my tuner some room to work with.

Any input on this topic would be greatly appreciated.

civic4982

iTrader: (9)

the Vortech FAQ said this:

But for those folks who are running that 350 or less rwhp on their setup what is the max duty cycle on their setup and how long is the duty cycle past 75 or 80 % for?

It's important for me to understand how hard I'm pushing these injectors to see if I should get new ones on the stock kit.

I know the increase in fuel pressure with the FMU does not create a linear increase in fuel delivery.

Anyways, any input is appreciated.

frankie945

iTrader: (35)

not being a dick but this was just talked about. SEARCH

civic4982

iTrader: (9)

my bad, did I miss it? I'll delete this thread then but could you point me in the right direction?

GTM

iTrader: (12)

Its recommened not to run injectors past 80% DC, Anything past that I would upgrade.

civic4982

iTrader: (9)

I don't recall anyone actually stating their % of duty cycle when using the FMU and aux inline pump setup.

I know recently there was a thread about someone trying to run a utec and in tank on their stock injectors and maxing them out but the potential to make more fuel delivery with increased fuel pressure wasn't discussed in that thread.

frankie945

iTrader: (35)

Your right I read your post to fast sorry. I even tried searching. With the vortech fmu should be fine with stock injectors. The in line pump pushes more fuel at certain boost levels.I maxed out my stock injectors at 98% duty cycle at 5200 rpms when I was procharged but that was with a walbro in the tank tuned with a utec. If I were you I would get some 440's and a walbro in the tank with another EMS other than the ss box. You will want more power and this will let you achive it.

civic4982

iTrader: (9)

I wish I knew more about what a 320cc/min injector will do at a 10:1 FMU pressure with 7 PSI of boost.

With my inline pump being a 155lph pump and the 90 lph stock pump I still don't know what the LB/hr is for my fuel delivery with those injectors at that PSI.

Does anyone with more physics knowledge care to calculate this out?

The constants are all there aside from the fact that the estimated WHP will be around 320-340 rwhp.

civic4982

iTrader: (9)

well I just e-mailed vortech to see what their engineers and tuners say about the stock setup of the full vortech kit.

I know 80% is the goal as a max setting on those injectors so if they say that it runs >80% then an upgrade is a must for me to feel comfortable.

GTM

iTrader: (12)

You have to datalog your IDC, that is the only way to know where you stand.

PM sent.

civic4982

iTrader: (9)

edited. new info found.

civic4982

iTrader: (9)

edit. new info found.

civic4982

iTrader: (9)

The formula is actually as follows :

RPM * IPW / 1200 = IDC (thank you hal@IP and punkkidd from uprev for verifying)

RPM = revolutions per minute
IPW = injector pulse width in milliseconds
IDC = injector duty cycle.

So with the stock tune on the vortech unichip with a 2005 G35 6MT running the 8 psi pulley (stock pulley) and the FMU the injectors are running a maximum value of anywhere from 91-93% duty cycle as of the 4 logs that I currently have and they run them

civic4982

iTrader: (9)

So, here is it all graphed out for anyone like me who was wondering how far the Vortech full kit with the FMU actually pushes your stock injectors.

It's obvious now that this cheap way of going about it (FMU and aux inline pump) is not sufficient and does run at least a moderate risk of damage to injectors and therefore damage to the motor in the long run.

However many here have said on thread after thread that their cars have run fine for (one case was over 30K miles) many miles with the stock setup with stock injectors and even an upgraded pulley (with a proper tune of course) and that they did not max out their injectors.

This being said most tuners would not feel comfortable running over 80% of IDC at max as it increases the likelihood of the injectors going static and failing to close therefore flooding out the engine and displacing oil with finally frying your pretty little vq35.

i hope this helps out anyone out there who was going to run the full kit. many have run it with no problems and knowing this I will continue to take the risk on of running my stock injectors at a higher than recommended duty cycle knowing full well that sometime down the line these may fail.

civic4982

iTrader: (9)

btw, special thanks to uprev for the cipher cable that proved invaluable and hal@IP who were both able to correct me on my error in the IDC calculation at first.