Stock fuel injectors capacity

[dl.m3]

It seems the consensus is that the stock 340cc injectors are already reaching 80% duty cycle at 8000rpm, on stock tune.

For the guys that are full bolt-on with CSL intake plus headers, pullies, full exhaust, maybe cams, and pushing 350+ whp, is that reaching the ceiling of the stock injectors? I've been reading that over 80% duty cycle the injector becomes ineffective at responding accurately to the ECU's fueling requests.

Just wondering if anyone has logged their injectors and whether they've had fueling issues with full bolt-on mods.

Or if anybody has upgraded theirs for more headroom, any recommendations? Especially track cars that spend more time near redline, would love to hear your input.

[liam821]

The e46m3 runs at ~5 bar fuel pressure at WOT. WIth 340cc injectors, on gasoline, at 80% duty cycle it has enough fuel to support ~400hp / ~340whp. 90% duty cycle is enough for ~450hp / ~380whp. At least on gasoline, the stock injectors are probably big enough for just about any bolt-on NA build. E85 is a completely different story...

[Obioban]

Yeah, stockers are fine for pretty much level of stock internal NA build (plus cams), on pump gas. No benefit to be had unless you're going FI or e85 (which is also not worth it, IMO).