This one goes out to all the math nerds lol.

I have an ls/vtec hatch (11.5:1 pistons, stage 2 cams) that I bought a few years back. My injectors are all RC 370cc but I recently noticed that one of them is actually 1000cc. Without knowing this, I had the car tuned on an S300 by a local well-known tuner and @ 13.5:1 AFR I put down 190hp. Just for reference, I went into the S300 and verified the injectors are set to 370cc and there is no fuel trim on any of the cylinders. So, here is the hypothetical math problem: If I replace that one injector with a 370cc (to match the others) and have the car re-tuned at that same 13.5:1 AFR, how much horsepower would I gain?

I am actually going to be replacing that injector soon so I am curious to see what numbers people predict vs. the real world results. Obviously the AFR won’t be exactly the same and there are other factors involved like outside temp, how many new stickers I put on, etc etc. I just thought us math nerds could have a little fun with this one.

 

somewhere between negligible and none.

if anything, I would expect the one cylinder may run a little rich but not hurt power with the current setup. maybe you'll pick up some power down low when the properly sized injector has good atomization... but it's only 25% of the equation.

 

Over the weekend I swapped out the injectors with all new RC 750cc and updated the injector size in Hondata. I recorded my AFR before and after the injector swap.

Before: AFR @ WOT - 12.1 (average)(not sure why it's reading lower than the dyno printout)
After: AFR @ WOT - 13.2 (average)

I am surprised that one injector threw my AFR off by an entire point! I took her for a spin and second gear spun so hard I was smelling rubber (w/LSD tranny), which is not normal so I am pretty stoked so far. Next stop is the dyno!