Fuel injector flow rates.

Those are Nikki injectors. Part number INP-081. They flow 210cc/min-24lbs/hr

thanks zanzer!

Get me the name and part number off the side and we can look them up.

Most NA Mazda 4 cylinders from those years are going to be running anywhere from a 14lb/hr up to a 24lb/hr depending on displacement.

When Mazda put a turbo on the car the flows jumped (sometimes substantially). A Mazda 1.6 DOHC B6T uses a 28lb/hr injector, an MX-6 turbo uses a 31lb/hr, but an [87-88] RX7 uses a 52lb/hr (low impedance) injector.

*impedance is another thing you have to be wary of when swapping injectors around. Swap a low impedance injector into a system that uses high impedance injectors (and vice versa) and you'll burn out the injector driver on the board in the ECU.


If the truck is turbo you'll want to increase the size of the injector. How much depends on the amount of boost. Also, this is where a wide band O2 sensor is your friend so you can accurately monitor AFR.

Stand alone is always the best option, but there is an old hack where you can install a raising rate FMU that will help increase fuel pressure as engine load, injector pulse width, and duty cycle increases. You have to be careful here too though since you never want to run 100% pulse (wide open injector) or more than 75% duty cycle. That will burn out a set of injectors pretty fast. That's why you increase injector size depending on the engines fuel requirements. Again, this is where a wide band is very helpful. I always say better rich than lean, especially with boost. Plugs are cheap but pistons aren't LOL. I'd rather have a slightly over sized injector running a shorter pulse width and duty cycle than one that's too small and not supplying enough fuel or that risks failing prematurely.

No problem! I loves me some injectors

I need to take a pic of the "collection" for you guys

Thanks for the help and yes, I do have experience with swapping injectors since I have been doing this for many years - just needed the flow rates.

I am currently running the FMU so if I go up in injector size I will drop the base pressure and see where it gets me.

I can see the AF on my wideband

Ok so I checked and they are the same as scotch posted (never doubted him) the red JECS.

So they are 275's?

Well, it looks like Zanzer was on the money with the flow rates. Earlier in the thread, he pegged the 2.2 injectors at 210 cc/min. Well Dan just got his back from the cleaners and they weighed in at 212-220. Here is a pic from his thread...




Seeing his post reminded me that I had a report emailed from the cleaners. So I dug it up and see that my B2600i injectors weighted in 274-280 cc/min.

Here was my report...




Notice that I had two running significantly lower flow than the other two before cleaning. All within 19%. Since the O2 sensor only reads the average of all four, the two higher flow cylinders would have been running rich to make up for the lower flow ones which would have been running lean. Bottom-line, it's important have them clean and flowing equally... within 3% ideally. If you have a plug or two that look like they've been running rich, and another one or two that look lean, think about the injectors.

Oddly enough

Thanks so much for posting this info guys, please post any more info you may have about compatible injectors, it can be a gold mine of info.

It can provide the necessary info for those who wish to swap injectors

Can someone please ID this?

It was in my B2600 with 3 stock ones...