My turbo miata is running 220hp with 440cc injectors and the injectors suck cause i cheaped out on them (idle afr is less than 10.0 usually and the tuner couldnt do much without making it run bad) but i dont want to push more power quite yet till i rebuild the motor to handle more. My question is can I buy bigger injectors like the flowforce 640cc kit and it still be easily and reliably tuned to idle not super rich? Or should i just buy new ones around the same range. Either way i wanna getting new injectors so it can idle properly.

 

Quality of injectors go a long way. The hardest thing for them to do is spray a very small amount of fuel, so idle. If you’re referring to rx8 yellow 440ss, that’s a common issue and yes, you should switch. I can idle ID1050x injectors at 15:1 with no issues, flow force injectors are similar, with just less headroom for ethanol etc.

 

Thanks!

 

Just another anecdote, my FlowForce 640's would idle at 14.7 with no issues. I swapped over to some less reputable 1050's to support more power on E85 and now have to idle around 13 or lower on 91 and around 13.3 on E85 to keep a smooth idle.

I've heard the ID1050's are great at idle, but I don't have any first hand experience with them.