What size injectors are on the 318 and 325/328?

[nick_g_evans]

So, are the 6 cylinder injectors bigger than the 4 cylinder? I wouldn't think so, but I hope so. Anybody know the stock sizes?

[El Presidente]

my book shows them to be the same, but does not mention flow rate, but the FPR is set to 43.5 on both, so I imagine flow is the same.

[nick_g_evans]

Originally posted by El Presidente@Apr 1 2004, 01:37 AM
my book shows them to be the same, but does not mention flow rate, but the FPR is set to 43.5 on both, so I imagine flow is the same.

What book? The Bentely? I couldn't find it in there.

[El Presidente]

Actually the cheap Haynes manual.

[dutchbmw]

They're not the same. The 325i/328i works also with higher fuel pressure!

[Andrewsd1985]

What would be good injectors to upgrade to in a 325?

[El Presidente]

the only reason you would need larger injectors is if you biult a full race motor or went FI with a high PSI. Otherwise, you'll be wasting the money.

[Kevin325i]

Originally posted by El Presidente@Apr 1 2004, 10:37 PM
the only reason you would need larger injectors is if you biult a full race motor or went FI with a high PSI. Otherwise, you'll be wasting the money.

werd

Adding bigger injectors might give you a tiny gain. Going too big will cause your car to die when you stop on the gas. Maybe if you had a big intake so you needed more fuel to mix in otherwise you'd just run rich the whole time.

I'd say just have the injectors cleaned and put the money you'd spend on new injectors into a chip.

Just my $0.02

[El Presidente]

if this was an POS car then you would probably see a gain, but because the DME determines how much fuel is neeeded, larger injectors won't automatically flow more fuel; they have to be told to. If they did flow more you just be running rich.

[dutchbmw]

Originally posted by El Presidente@Apr 2 2004, 01:34 AM
if this was an POS car then you would probably see a gain, but because the DME determines how much fuel is neeeded, larger injectors won't automatically flow more fuel; they have to be told to. If they did flow more you just be running rich.

But why the're different injectors for 318 / 325?

BTW, it's right the DME controls the flow!

[El Presidente]

According to my book they arent any different. They operate at the same pressure.

The logic that the i6 needs bigger injectors to produce more power is flawed. The i6 produces more power because it has 2 more cylinders, but does not need more fuel flow to do so.

[Positive5]

Now when you say "controls the flow" you are talking about pulse width? I would assume because the pressure is controled by the regulator so because the DME reads the signal from the MAF, all conversions for baro.,temp. and speed are all accounted for. SO adding bigger injector wont have a power gain unless it is running lean for some other reason.

[dutchbmw]

Here a copy of my book:

[El Presidente]

interesting. I do not have my camera at home, but I shall take a pic of my manual on monday that says they are the same.

[dutchbmw]

Even I don't if M50 is different from the VANOS engines, the info in my book is from the M50 engine!! I thought the M52 is VANOS??