injectors

[midnight]

does anyone know the flow rate of standard 325i injectors?

[Turbo-Brown]

They're 149cc/min.

Whyeeeee?

[Ant]

@3Bar

[Turbo-Brown]

good point!

and 100% duty cycle

[Ant]

and 100% duty cycle

maximum wrongness

mine are/were 62% @ full boost (11.7psi), plenty more left

[Turbo-Brown]

You've lost me dude

I'm talking about the standard 325i injectors flowing 149cc/min @ 3bar above manifold pressure and on 100% duty cycle.

Surely you're not still on the 715s?!

[reggid]

the 715 are not at 100% duty cycle on a stock motor. There is no proof of this anywhere

[Turbo-Brown]

Who said they were?

All I'm saying is that they will flow 149cc/min on a 100% duty cycle at 3bar effective fuel pressure.

There is evidence to suggest that they do operate at close to 100% duty cycle over on the E30tech site where someone has supposedly measured the duration.

It wouldn't be difficult for those of us who own or have the use of an oscilloscope to find out for sure either.

[Turbo-Brown]

Right, just gone over there and found the thread:

http://www.e30tech.com/forum/viewtopic. ... highlight=

From Topic: interesting fact about the m20b25 and its factory injectors.

the interesting thing i noticed while i was modding a rom file today is that that at WOT the injecotrs are at 95% pulse rate... most car companies wont run thier injectors above 80% to increase longevity, why would BMW do something so cheap... the injectors barely support the engine at 100% under high revs we all know the engine is very lean with the factory injectors... why would BMW do that?

So lets do the maths:

149cc/min x 95%=141.55cc/min

((141.55cc/min)x6cyls)/5(rule of thumb)=169.86bhp which by my reckoning is about 1bhp shy of what BMW quoted for the M20B25.

You can see why I'm sceptical about vastly higher power claims on the standard fuel system!

[Templ8e30]

Don't forget that the M20B25 runs them at 3.5 bar though

I'm running them at 3.8 bar but will be swapping them for M30 yellows if I can find a set

Cheers,

Iain T

[Turbo-Brown]

Don't forget that the M20B25 runs them at 3.5 bar though

No it doesn't.

It runs them at 3bar, like it says on the standard FPR!