Injector Throughput
 

Hi all

I'm looking at pumping up the amount of fuel flowing into the engine. Currently, the motor is asking for 100% around 3500 r.p.m. I was looking at the 440cc injectors available, but I don't know if that's enough over the stock.

What's the rating for the stock injectors? 200? 300?

-Michael

Both P5s and MSPs have 280s, but they can flow up to 300cc when the duty cycle is maxed.

Mine were flowtested @ 320.. but not at stock fuel pressure obviously.

So the 440cc should do well for me. I have a CAI, Mazdaspeed cams, SRM cam gears, SRM header and midpipe. I'm pushing a lot of air through there without using force. =-)

-Michael

Do you have engine/fuel management?

I had a CAI, JDM intake cam, underdrive pulley, header, midpipe, catback, MP3 ECU, etc and trust me.. you aren't maxing out your injectors at all. I'm still on stock injectors, and now on top of still having most of those mods I'm turboed pushing 7psi and it's still all good.

edit: you said it's asking for 100% around 3500rpms so I'm guessing you have some management unit.. um that's really weird I gotta say

The stock ECU is reporting 100% very early. There's a LOT of air going through there. The motor runs lean. I actually had to rebuild because of a piston going bad from a too lean mixture.

My engine builder says we just need more fuel in there and the injectors are maxed out. I can even feel the starvation around 5k where the power dips.

I've ordered the 440cc injectors. Hopefully they'll feed the beast. If not, I'll get a fuel pump to go along with them.

Next, suspension...

I have a power dip in my powerband.. but my AFR is sitting at 9.2:1 so I know I'm not too lean.

With the stock ECU and your mods something is very wrong if you are running lean. Have you had your injectors flowtested? perhaps something is wrong with them.