I don't seem to be getting anywhere in another thread so I'll start over:

Do larger fuel injectors have poorer throttle response then smaller ones do? Is there a such thing as too big an injector in which you loose drivability in the low rpm range.

 

Injector pulse width is a function of air flow (and other several other parameters). Fuel injector capacity is a function of the maximum fuel required at redline, under full load (WOT). If larger injectors are installed and the PCM can not tailor the pulse width/fuel volume correctly, you will have driveability concerns. Going to a higher capacity fuel injectors, will not accomplish anything positive, without other mods that increase air flow.

 

Spin, I will be half talking out my butt, but I think it really depends on the tuner. I used honking injectors in my blown car and after dorking with it for a few weeks it ran just like stock and had no lag in throttle response. I had the same question you did and the tuner told me to "shut up and color". I would be interested in seeing this answered as well. Cost being a huge factor for me I have always just used the smallest injector I could get away with.

 

I almost fell out of my chair laughing....shut up and color!!!!

I didn't think it was a hard question but it is now answered. What is my application? I didn't think it mattered. If I wasn't changing injectors then I would still want to know what the driving differences are from lil' injector to big one.

If anyone is curious, I hate doing things more than once. If I get a SC later on or a mega superstroker, I don't want to have to get new injectors yet again.

I am the tuner so I will use HPtuners and install them myself. On a 100 dry shot and 95% duty cycle now would you feel safe?

If I was to actually ask that question like that, the people on this forum, most would tell me to go with a wet-shot and use smaller injectors but it never answers the question I asked. Instead of telling you what happens if you go to a bigger injector you get....ask thuinder racing, just use this injector, or what is your application.

I don't want to hear what is the better set-up. It was an injector question and thank you for answering it even if I had never changed them or planned to.....What you go through to learn.

Seems sometimes people like to answer the question they think you wanted to ask instead of the one you did ask.

If anyone is confused I posted this question an another thread and got everything except info on what I asked....Is the drivability/reponsiveness at low rpm worse with a bigger injector as opposed to a smaller one?

 

Unfortunately I know what works with particular combinations and just went with that. I learned from my tuners many hours on the dyno when to go with a bigger injector but I could never get pros and cons of the larger squirters. Seems like its still a mystery. My hands smell like gas and I need a beer.

 

It depends on how good or bad whoever does the tuning and if the injectors are just too large for idle and part throttle.

Consider GM designed the software in PCM and hardware drivers for a average injector pulse width of 3 mSecs. Now you install too large of a injector and even with tuning the average comes down to 2 mSec.
The shorter the pulse width is the less control the PCM has and it also now has to spend more time commanding then doing other PCM functions.
Add this - each injector vendor has slightly different design specs, if the larger injectors then not being what GM had spec'd will have a different injector response time of the injector's coil is different. Injector vendors do not publish that time so now if you do not change the offset times in PCM then YES larger injector will not be crisp in acting on PCM command with low engine load. If you change the offset tables values and they are wrong then injector will be firing too early or late.

Spend time in learning what your car's average pulse width time is so that when you install larger injectors you then dial in the same average pulse width time but there is no way of knowing for sure what the offset is for non stock injectors so my answer is if the tune is good and injectors are not way to big they will peform well else you will lose crisp reaction and can lose performance.
Keep in mind the longer the pulse width is the better the PCM likes it but it just cannot do a good job when short command times are needed as a average.