Upgraded Injectors on a Stage 2 M3

[ExoticM3]

Will upgrading my injectors yield me more power on a M3 with test pipes, E85, and tune? I understand that it matters more if you’re FI (Forced Induction). I was told by a reputable “Tuner” that upgrading injectors could yield me 40-50 Whp even if it’s not supercharged. I haven’t heard many M3 e9x owners talking about injectors on a vehicle that’s not FI for power gains.

[Longboarder]

A combination of going catless on a healthy S65 with new plugs and a good e85 tune could yield +50 hp gain. The injectors would be needed due to the e85, since the stock fuel system could be insufficient for this setup.

This setup would also be good for about 10mpg but would be really fun.

Common knowledge that on an equivalent basis, it takes 30% more e85 than conventional gasoline to power an internal combustion engine.

[tdott]

Full e85 tunes don't require upgrading injectors.

It wouldn't hurt to increase the injectors sizing, that way they wouldn't be overworked (higher duty cycle) with E85 like the factory ones are.

I'd say if the tuner thinks he can get more power with bigger injectors, go with his recommendation and let us know the outcome.

Keep in mind that any change in injectors need to be accounted for in the tune, you can't just throw in bigger injectors and expect them to work.

[ExoticM3]

tdott Will let you guys know the result of adding them on. I just never heard much people say “Add bigger injectors” when they talk about performance mode, usually testpipes etc.

[spammysammich]

How are the fuel lines with long term use of e85? I’ve seen it basically melt lines on older cars and I’m not 100% convinced it doesn’t contribute to stuck injectors on our cars.

[Gossypiboma]

You can run full E85 on the stock injectors so how would going with a larger injector make more power? If someone told you upgrading to larger injectors will net you a 40 to 50 hp gain you should walk away. That's called a scam.

[ExoticM3]

Gossypiboma my thoughts as well, I just never heard someone say that.

[ExoticM3]

spammysammich people run full e85 with tune with no problems. I think bigger injectors with the mods on my car won’t make a huge difference.

[ExoticM3]

spammysammich I will say… starting my car right now in Michigan with it being -2 degrees is a pain in the a** haha but worth it.

[spammysammich]

Originally Posted by ExoticM3

spammysammich I will say… starting my car right now in Michigan with it being -2 degrees is a pain in the a** haha but worth it.

Are you able to keep it on a tender? Might help a little. I haven’t even bothered trying to start up since we hit the 30s. Winter driving is what my old Subaru is for 😂

[MechEngineer408]

I doubt bigger injectors with just an E85 tune will yield much result. If it was true I'm sure many many people would have done it already with much discussion.

[ExoticM3]

spammysammich what do you mean by “tender” I had a wrx and I completely agree with ya on that lol

[spammysammich]

Battery tender/charger. Cold is hell on our battery.

[ExoticM3]

spammysammich had no clue… definitely going to have to invest in one of these. Appreciate it !