Need some advice for my E36 please. Injectors

[M3speedM50B25]

So ive finally got a fully bolt on setup on my e36 and i was wondering if it was time to upgrade the injectors a bit. Not a lot maybe from the stock 17.5lbs inectors to the 19lbs injectors. I have SS long tube race headers with free flow exhaust and cherry bombed to improve flow, dinan chip, upgraded iradium plugs, upgraded bosche ignition coils, custom cold air intake w/ massive air filter (ducts to bumper). Im not wanting to go anything higher than the 19lbs injectors mainly because it would end up hurting my performance. Any ideas? keep stock injectors or upgrade to the 19lbs?

[r33p04s]

Pretty sure they aren't maxed out and you only need to upgrade when you add boost...

Sent from my thumbs to your eyes.

[M3speedM50B25]

well i dont like the fact that there running at pretty much full duty cycle 90% or higher. if i unplug my O2 sensor the added fuel from running rich actually seems to help improve the preformance of the car giving it more pick up, I dont like running without my O2 unplugged even though it wolnt truely hurt my car but i want my car to read every bit, so considering im getting more pick up running rich my injectors seem to be running at a very high duty cycle and pretty much maxing out.

[dano670]

The stock M50 injectors are used in the S50 which makes 240 hp. So unless you are near the 240 hp, keep your stock injectors.

[M3speedM50B25]

uh.. no... the S50 in the M3 use the same inectors as the 2.8 not the 2.5

[jagerking]

The stock M50 injectors are used in the S50 which makes 240 hp. So unless you are near the 240 hp, keep your stock injectors.

This guy knows his injectors, trust me.


uh.. no... the S50 in the M3 use the same inectors as the 2.8 not the 2.5

Incorrect. S50B30 and M50B25 use the same green-top 17.5 lb injectors. S52B32 and M52B28 use the same pink-top 19 lb injectors. Like I said, Dano knows his injectors.

[flyfishvt]

well i dont like the fact that there running at pretty much full duty cycle 90% or higher. if i unplug my O2 sensor the added fuel from running rich actually seems to help improve the preformance of the car giving it more pick up, I dont like running without my O2 unplugged even though it wolnt truely hurt my car but i want my car to read every bit, so considering im getting more pick up running rich my injectors seem to be running at a very high duty cycle and pretty much maxing out.

Your logic doesn't work. You said your injectors are running at full duty cycle 90% of the time. That means there is almost zero extra capacity. According to you they are wide open for almost the entire time. THEN you say that disconnecting your o2 sensor improves your performance because it makes the car run rich.

If the injectors are maxed out then disconnecting the sensor won't add enough fuel to be noticed. The simple fact is your injectors are not maxed out. Not even close. They could probably stand to be cleaned and flow matched. Running your engine with that o2 sensor disconnected is a horrible idea. It will ruin your cats in no time. Your gas mileage just went from 28 highway to 12 highway. In other words you're dumping twice the amount of fuel into those cylinders. How do I kow this? Because I forgot to reconnect the o2 sensor on my 94 vert and I couldn't figure out why my mileage dropped so far.

Here's the logic you SHOULD be using. You unplug the o2 sensor and your engine runs so rich that your mpg drop almost in half. If that's the case then the injectors are actually capable of delivering twice the amount of fuel they normally do. They are being "metered" by the dme.

[slocar]

This guy knows his injectors, trust me.



Incorrect. S50B30 and M50B25 use the same green-top 17.5 lb injectors. S52B32 and M52B28 use the same pink-top 19 lb injectors. Like I said, Dano knows his injectors.

The pinks are 21 lb.

OP, save your money ... plug your O2 sensor back up ... let it control the AFR instead of running off some base "don't let the engine blow itself apart" map that's pre-programmed into the DME.

[dano670]

This guy knows his injectors, trust me.



.

Thankyou!

[Spyke]

OP you have ZERO reason to mess with upping injector rates. Unless you're boosted or using a custom/hybrid engine, there's no need at all. None of those are really performance upgrades, minus the header which are only a 5-15 HP increase max.

I would also listen to anything dano says about injectors.