7MGTE 550cc injectors - max duty cycle at 11psi - WTF

[RyleyMA61]

Hi all

had the 7MGTE dynoed, very conservative timing tune, and the injectors (rc engineering 550cc) were at max duty cycle at 15 and even 10 psi. they should be good for nearly 300rwkW.

other than crook/dirty/dodgy injectors, what else could it be?

FPR?
leak?

cheers,
ryley

[BlackSupra]

What was the base fuel pressure?

Have you had the injectors flow tested to ensure they are clean?

[Celica RA45]

7mgte are low ohm injectors what are the rc engeering 1s are they the same or high ohm and as been siad what fuel pressure are you running

[RyleyMA61]

fuel pressure is standard, but i haven't measured it. i need to do this also.

about to get the injectors flow tested too to ensure they're k.

they are rc engineering low impedance ones

thanks for help guys

[TheDarkRaver]

Std turbo or something bigger?

I was running a GT35R on my 7M with 750cc injectors and std fuel pressure and the injectors were at about 45-50% duty cycle.. So unless you have a MASSIVE turbo you deffinatly should be maxing them out that early.. Though maybe at 15psi with std fuel pressure and a big turbo u could be getting closer..

550's will make 300kws but that is really pushing them!

[RyleyMA61]

it's a highflowed CT26E (ie factory turbo a highflow, that was highflowed again)...

so perhaps bang up the fuel pressure a bit?

[thechuckster]

Before changing rail pressure (which i would suggest against) ... are you sure you have good fuel pressure? it should be ~38psi at the rail with pump on and engine not running.

And the FPR is correct for this motor (is from a GTE not GE motor)?

And the vacuum line to it is from the manifold/plenum not upstream of the throttle body?

A cursory look at the MSEFI manuals suggests 550cc/min injectors will support up to ~450-500Hp (at flywheel).

Are you sure you got 550cc/min injectors?

[CrUZida]

Step 1: Check fuel pressure with engine off
Step 2: Check fuel pressure under boost
Step 3: Have injectors cleaned and flow tested
Step 4: Check wiring
Step 5: Try another tuner

[RyleyMA61]

thanks guys, definately going to get onto the fuel pressure.

had my injectors cleaned and flowed today, approx 480cc/min at 42psi

here are specs of what they should be:

http://www.rceng.com/Peak-Hold-Injec...550-P15C5.aspx

but will probably go bigger injectors due to this and make sure the pressure is good. checking the tsrm now.

[JustCallMeOrlando]

Hmm, it'd be interesting to see how close they'd have gotten at 43.5psi.

[thechuckster]

i somehow doubt another 1.5psi is going to life the flow rate (by 70cc/min) to the spec noted on their website.

My understanding is that flow rates are at 300KPa (~43psi) with a 90% duty cycle. Any idea what duty cycle they were run at to reach that flow rate?

[wilbo666]

How are you running the injectors?

Peak and hold or resistors? If resistors what is the value of your resistors - maybe not enough hold current?

Cheres
Wilbo

[CrUZida]

1.5psi will do about 5cc.
I needed about 17psi increase to go from 220cc to 250cc

[RyleyMA61]

wilbo666- yeah peak and hold
chuckster- not sure on what duty cycle but think it was at least 90%, if not 100%. certainly looked like a constant spray haha

.....

[thechuckster]

Well, you probably got ripped off with the injectors. They're flowing 10-12% below rated spec.