Rb25Det Injectors

[talky]

Just a quik one ...

Wots the most power u can make .on 25det injectors.

Cheers

[KiwiRS4T]

Commonly used rule of thumb = 370hp or 277kw but as they say every car and every motor is different.

[Torques]

Is this power figure at the rear?

[GTSBoy]

No it's not. The rule of thumb for 6 cylinder engines is 1 flywheel HP per cc of injector size. 370cc injectors means ~370HP. Such a rule of thumb would be terrible (worse than useless) if it were for rear wheel power, because of all the variability in dyno readings, etc.

[The Mafia]

From a tuners perspective, most I've made was around 230rwkw.

[Simon-S14]

have personally run stockers up to 260 rwkw with upped rail pressure and 12 AFR's

generally around 230-240 is the safe limit

[joeyjoejoejuniorshabadoo]

with stock FPR ~230rwkw

[JonnoHR31]

as said it varies. usually somewhere between 190 and 240rwkw

[STATUS]

yeah be-careful nissan injectors hate high rail pressures and start to stutter misfire up near 100% duty.

[talky]

Cheers guys ..yeh and at the rear wheels

[Torques]

There is a thing called:

Brake specific fuel consumption (BSFC)

It's a figure to describe how much fuel an engine needs to produce X amounts of power.

http://www.land-and-sea.com/dyno-tech-talk/using_bsfc.htm

There is a calculator on this page ->

http://www.rceng.com/technical.aspx

My (standard) injectors are now at 85% duty cycle, I am making about 330HP at the crank. (running at AFR of 11.7)

The mixture was starting to lean out already, so I have ordered new injectors.

Edited January 26, 2012 by Torques

[fragz013]

From my personal experience the standard injectors can hold more than most think. As my 33 gtst is making 393hp@wheels on standard injectors...

For the dyno figure doubters it does 119mph down quarter..

Edited February 9, 2012 by fragz013

[Simon-S14]

almost 300 rwkw? doubtful

[Lithium]

My (standard) injectors are now at 85% duty cycle, I am making about 330HP at the crank. (running at AFR of 11.7) The mixture was starting to lean out already, so I have ordered new injectors.

Hmmm if you are finding that the fuel flow into the engine is levelling off at 85% IDC I'd consider looking at whats supplying fuel to the injectors more than the injectors themselves, personally - what pump is that with?

[Lithium]

almost 300 rwkw? doubtful

119mph isn't a bad trap speed though, to be fair... though in saying that when you are limited by small injectors you can still make a car quite a bit faster than many would expect doing sneaky wee tricks. At lower rpm you have a longer pulse period, so you can actually move more fuel with an equivalent duty cycle.

As an example - I've tuned a Silvia running a G4 Link & boost control but still on stock injectors was quite held back, hitting 85% at 7000rpm at the boost level we were setting it up for. That boost level just wasn't going to do the setup justice, so I set up a "tapering" boost curve which resulted in a boost level some 6-7psi higher at 4500rpm than at redline and progessively dropping down... but injector duty cycles still never went over 85%. The resulting change in how the car performs is VERY substantial, torque wins races and hp sells cars?